What is welded steel pipe? Just as its name implies, welded steel pipe is manufactured by steel belt or steel plate bending the barrel, and then using flux to weld, there is a weld seam on the pipe. Common types of welded steel pipe are ERW steel pipe, LSAW steel pipe, SSAW steel pipe, and so on.
General steel pipe is used to transport low-pressure fluid and easy to weld the other soft steel. Usually, the length of the delivery of 4-10m is actually different, according to the provisions of the wall thickness the pipe has two kinds of steel, the spiral seam and the straight seam.
SSAW steel pipe adopts the low carbon construction steel strip or low alloy structural steel strip to roll into a tube, and then weld together, to product large diameter SSAW steel pipe. SSAW steel pipe is mainly used for oil and natural gas pipeline, SSAW steel pipe adopts single-sided welding and double-sided welding. Welded steel pipe should ensure that water pressure test, weld tensile strength and cold bending performance can meet the requirements.
LSAW steel pipe is made by using strip steel as raw materials and doing longitudinal welded in the high-frequency welding equipment(hence the name due to the weld forms a straight line). In accordance with the use of different, there are different production process (can be divided into scaffolding tube, fluid tube, wire casing, bracket tube, fence tube, etc.).
Another commonly-used kind of welded steel pipe is ERW steel pipe. ERW steel pipe is the abbreviation Electric Resistance Welded Pipes. ERW steel pipes and tube are available in various qualities, wall thicknesses, and diameters of the finished pipes. ERW steel pipe is manufactured by rolling metal and then welding it longitudinally across its length. ERW steel pipes are welded longitudinally, manufactured from Strip / Coil and can be manufactured up to 24”OD. ERW pipe cold formed from a ribbon of steel pulled through a series of rollers and formed into a tube which is fused through a electric charge.
Welded steel pipe is the main product of Prime Steel Pipe, as the leading welded steel pipe manufacturer and exporter, we provide a large number of ERW steel pipe, LSAW steel pipe, SSAW steel pipe and other welded steel pipe for sale. More products details please click the hyperlink.
2019年4月30日星期二
Main Reasons Those Affect The Quality of Pipe Bend
When Prime Steel Pipe manufacture pipe bend, there are some factors will influence the quality of pipe bend. How to solve those problems? High-class carbon steel pipe provider - Prime Steel Pipe will share it for all of you.
1, The role of the tube in the external force M under the role of the outer layer of the lateral wall of the tensile stress & 1 role of thinning, the lateral compression stress. The role of thickening, together N1 and N2 to make the pipe cross-section changes. Based on this factor, the main reason for the decline in the quality of the elbow is the main reason for the RX and SX. Therefore, GBJ235-82, the various pressure levels in the case of the RX value and the amount of lateral thinning are made clear, the purpose is to control the RX With the value of SX, thus ensuring quality.
2, The bending accuracy of the pipe bend is also one of the factors affecting the quality. When we manufacture the bending foot, in addition to the size of the specifications required to control a certain range of tolerance, but also requires the user in accordance with the use of curved diameter selection of the corresponding bending tire.
3, The pipe itself can be curved performance and surface corrosion, may also affect the quality of the elbow. On-site construction, the operator also need to understand the processing of pipe materials, processing performance and surface corrosion to make judgments.
4, The elbow when the material outside the tensile, the medial compression of the neutral axis position and the elbow method is different from the top bending (compression bending) work when the neutral axis is about 1/3 from the outer wall, in the spin When bending (bending back), the neutral shaft is at 2/3 from the outer wall. Therefore, thin-walled pipe bending, the use of rotary method is useful.
5, According to the acceptance of pipeline processing specifications: cold-formed steel pipe, the low pressure for the 4D, high pressure for the 5D.
1, The role of the tube in the external force M under the role of the outer layer of the lateral wall of the tensile stress & 1 role of thinning, the lateral compression stress. The role of thickening, together N1 and N2 to make the pipe cross-section changes. Based on this factor, the main reason for the decline in the quality of the elbow is the main reason for the RX and SX. Therefore, GBJ235-82, the various pressure levels in the case of the RX value and the amount of lateral thinning are made clear, the purpose is to control the RX With the value of SX, thus ensuring quality.
2, The bending accuracy of the pipe bend is also one of the factors affecting the quality. When we manufacture the bending foot, in addition to the size of the specifications required to control a certain range of tolerance, but also requires the user in accordance with the use of curved diameter selection of the corresponding bending tire.
3, The pipe itself can be curved performance and surface corrosion, may also affect the quality of the elbow. On-site construction, the operator also need to understand the processing of pipe materials, processing performance and surface corrosion to make judgments.
4, The elbow when the material outside the tensile, the medial compression of the neutral axis position and the elbow method is different from the top bending (compression bending) work when the neutral axis is about 1/3 from the outer wall, in the spin When bending (bending back), the neutral shaft is at 2/3 from the outer wall. Therefore, thin-walled pipe bending, the use of rotary method is useful.
5, According to the acceptance of pipeline processing specifications: cold-formed steel pipe, the low pressure for the 4D, high pressure for the 5D.
What does the API 5L pipeline mean?
General Information of API 5L Line Pipe:
Specifications for API 5L adhere to the International Organization for Standardization ISO 3183. The API 5L specification provides standards for pipe suitable for use in conveying gas, water, and oil in the natural gas and oil industries. The API SPEC 5L covers seamless and welded steel line pipe. It includes standard-weight and extra-strong threaded line pipe; and standard-weight plain-end, regular-weight plain-end, special plain-end, extra-strong plain-end, special plain-end, extra-strong plain-end pipe; as as well as bell and spigot and through-the-flow line(TFL) pipe.
Grades covered by this specification are A25 ,A ,B (and the following "X" Grades), X42, X46, X52, X56, X60, X65, X70, X80. The two digit number following the "X" indicates the Minimum Yield Strength (in 000's psi) of pipe produced to this grade.
Pipe manufactured to ASTM106 Grade A or B are not interchangeable with API 5L. Requirements to API 5L X grades are more stringent, rolled grades are not acceptable and rework is not allowed. Moreover, particular attention is given to toughness and toughness tests for sour services and higher pressure & temperature classes.
Applications and benefits of API 5L Line Pipe:
1. API 5L line pipe is preferred in long pipelines due to its inexpensiveness, so it is widely used in gas, water and oil transportation.
2. API 5L line pipe can resist to crack propagation, so it used to pipeline steel.
3. Line Pipe and Sour Service Line Pipes.
Specifications for API 5L adhere to the International Organization for Standardization ISO 3183. The API 5L specification provides standards for pipe suitable for use in conveying gas, water, and oil in the natural gas and oil industries. The API SPEC 5L covers seamless and welded steel line pipe. It includes standard-weight and extra-strong threaded line pipe; and standard-weight plain-end, regular-weight plain-end, special plain-end, extra-strong plain-end, special plain-end, extra-strong plain-end pipe; as as well as bell and spigot and through-the-flow line(TFL) pipe.
Grades covered by this specification are A25 ,A ,B (and the following "X" Grades), X42, X46, X52, X56, X60, X65, X70, X80. The two digit number following the "X" indicates the Minimum Yield Strength (in 000's psi) of pipe produced to this grade.
Pipe manufactured to ASTM106 Grade A or B are not interchangeable with API 5L. Requirements to API 5L X grades are more stringent, rolled grades are not acceptable and rework is not allowed. Moreover, particular attention is given to toughness and toughness tests for sour services and higher pressure & temperature classes.
Applications and benefits of API 5L Line Pipe:
1. API 5L line pipe is preferred in long pipelines due to its inexpensiveness, so it is widely used in gas, water and oil transportation.
2. API 5L line pipe can resist to crack propagation, so it used to pipeline steel.
3. Line Pipe and Sour Service Line Pipes.
Manufacturing technology of steel pipe elbow
There are many kinds of steel pipe elbows, as a leading manufacturer and exporter, Prime Steel Pipe provides three kinds of steel pipe elbow for customer to choose, including carbon steel, stainless steel, and alloy steel. Among them, carbon steel elbow also includes seamless elbow and welded elbow. Next, Prime Steel Pipe will share the manufacturing process of seamless elbow and welded elbow for all of you. If you need to purchase elbow, Prime Steel Pipe must be your best choice.
Manufacturing Process of Seamless Elbow
The manufacturing process of seamless elbow usually contains heating bending and clod bending. One of the most common methods is using hot mandrel bending from straight steel pipes. Applying hot mandrel bending can manufacture a wide size range seamless elbows. After heating the steel pipe at a elevated temperature, the pipe is pushed, expanded, bended by the inner tools of mandrel step by step.
When compared to other bending method type the advantages of hot bending elbows include smaller thickness deviation and stronger bending radius. Meanwhile, using bending instead of prefabricated bends substantially reduces the number of welds needed. This reduces the amount of work required and increases the quality and usability of pipes.
Cold bending is a quick and inexpensive bending method. It is a competitive option for making pipelines and machine parts. Cold bending is the process to bent the straight steel pipe at normal temperatures in a bending machine. Cold bending is suitable for pipes with an outer diameter of 17.0 to 219.1 mm, and wall thickness 2.0 to 28.0 mm. The recommended bending radius is 2.5 x Do. Normally at a bending radius of 40D. By using cold bending, we can get small radius elbows, but we need to pack the internals with sand to prevent wrinkling.
Manufacturing Process of Welded Elbow
Welded elbows are made from the steel plates, so there is a weld seam on it. Use a mould and press the steel plate to the shape of the elbow, then weld the seam to be a finish steel elbow. It is the old production method of the elbows. Recent years the small sizes elbows are almost manufactured from the steel pipes now. For the big size elbows, for example, it is very difficult to produce elbows over 36'' OD from the steel pipes . So it is commonly made from the steel plates, pressing the plate to the shape of half elbow, and welding the two halves together. Since the elbows are welded in its body , the inspection of the welding joint is necessary . Commonly we use the X-Ray inspection as the NDT.
Manufacturing Process of Seamless Elbow
The manufacturing process of seamless elbow usually contains heating bending and clod bending. One of the most common methods is using hot mandrel bending from straight steel pipes. Applying hot mandrel bending can manufacture a wide size range seamless elbows. After heating the steel pipe at a elevated temperature, the pipe is pushed, expanded, bended by the inner tools of mandrel step by step.
When compared to other bending method type the advantages of hot bending elbows include smaller thickness deviation and stronger bending radius. Meanwhile, using bending instead of prefabricated bends substantially reduces the number of welds needed. This reduces the amount of work required and increases the quality and usability of pipes.
Cold bending is a quick and inexpensive bending method. It is a competitive option for making pipelines and machine parts. Cold bending is the process to bent the straight steel pipe at normal temperatures in a bending machine. Cold bending is suitable for pipes with an outer diameter of 17.0 to 219.1 mm, and wall thickness 2.0 to 28.0 mm. The recommended bending radius is 2.5 x Do. Normally at a bending radius of 40D. By using cold bending, we can get small radius elbows, but we need to pack the internals with sand to prevent wrinkling.
Manufacturing Process of Welded Elbow
Welded elbows are made from the steel plates, so there is a weld seam on it. Use a mould and press the steel plate to the shape of the elbow, then weld the seam to be a finish steel elbow. It is the old production method of the elbows. Recent years the small sizes elbows are almost manufactured from the steel pipes now. For the big size elbows, for example, it is very difficult to produce elbows over 36'' OD from the steel pipes . So it is commonly made from the steel plates, pressing the plate to the shape of half elbow, and welding the two halves together. Since the elbows are welded in its body , the inspection of the welding joint is necessary . Commonly we use the X-Ray inspection as the NDT.
Seamless steel tube classification
Seamless steel pipe is divided into two categories, including hot-rolled and cold-rolled seamless steel pipe.
Hot-rolled seamless steel pipe contains general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, geological pipe and other steel pipe.
In addition to the general steel pipe, cold-rolled seamless steel pipe also contains low pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, other steel pipe, but also include carbon thin-walled steel pipe, alloy thin-walled steel pipe, stainless steel pipe, special-shaped steel tube.
The diameter of hot-rolled seamless pipe is generally greater than 32mm, wall thickness is 2.5-75mm, the diameter of cold-rolled seamless steel pipe can be 6mm, wall thickness can be 0.25mm, the diameter of thin tube can be 5mm, wall thickness is less than 0.25mm, Cold-rolled seamless steel pipe has higher dimensional accuracy than the hot-rolled seamless steel pipe.
The seamless steel pipe for general use: is made by 10,20,30,35,45 and other high-quality carbon steel, 16Mn, 5MnV and other low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB alloy steel by hot-rolled or cold rolled. The seamless steel pipe made by 10,20 and other low-carbon steel is mainly used for fluid transportation pipeline. The seamless steel pipe made by 45,40Cr and other carbon steel is mainly used to manufacture mechanical parts, such as cars, tractors force parts. The seamless steel pipe for general use should ensure strength and flattening test. The hot-rolled steel pipe is delivered in a hot-rolled state or a heat-treated state, cold-rolled steel is delivered in a heat-treated state.
Hot-rolled seamless steel pipe contains general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, geological pipe and other steel pipe.
In addition to the general steel pipe, cold-rolled seamless steel pipe also contains low pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, oil cracking pipe, other steel pipe, but also include carbon thin-walled steel pipe, alloy thin-walled steel pipe, stainless steel pipe, special-shaped steel tube.
The diameter of hot-rolled seamless pipe is generally greater than 32mm, wall thickness is 2.5-75mm, the diameter of cold-rolled seamless steel pipe can be 6mm, wall thickness can be 0.25mm, the diameter of thin tube can be 5mm, wall thickness is less than 0.25mm, Cold-rolled seamless steel pipe has higher dimensional accuracy than the hot-rolled seamless steel pipe.
The seamless steel pipe for general use: is made by 10,20,30,35,45 and other high-quality carbon steel, 16Mn, 5MnV and other low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2, 40MnB alloy steel by hot-rolled or cold rolled. The seamless steel pipe made by 10,20 and other low-carbon steel is mainly used for fluid transportation pipeline. The seamless steel pipe made by 45,40Cr and other carbon steel is mainly used to manufacture mechanical parts, such as cars, tractors force parts. The seamless steel pipe for general use should ensure strength and flattening test. The hot-rolled steel pipe is delivered in a hot-rolled state or a heat-treated state, cold-rolled steel is delivered in a heat-treated state.
2019年4月24日星期三
Advantages of carbon steel pipe fittings
When purchasing steel pipe fittings, it’s important to take into consideration certain factors, most importantly size and shape, to ensure that it is a perfect match for your specific purpose. However, another important aspect to consider is the material used in the making of the pipe fitters. Certain elements added to the steel, such as carbon and chrome, can dramatically affect its strength and appearance. Here are a few great reasons to invest in carbon steel pipe fittings as well as chrome plating.
Durability
Steel is one of the most popular types of pipe fittings and has been used for construction of pipes and pipe fittings for years because of its durability and strength. However, carbon steel, or plain-carbon steel, has the ability become much stronger through heat treatment. The more carbon added to the steel, the stronger it can become, which is why it is considered one of the strongest types of steel. Another way to increase the durability is to create a harder surface by adding a layer of chromium. Chrome plated pipe fittings are not only durable, but prevent corrosion and may also make the cleaning process much easier.
Multi-purpose
Carbon steel pipe fittings are typically used for industrial purposes such as commercial construction, electric-power, petroleum refinement and the building of ships, but are also often seen in the household. They are used for fire sprinkler systems and pipes carrying water, types of flammable gasses, oil or steam. Because of the addition of carbon to the steel, carbon steel pipes and pipe fittings are also much more resistant to rust. Again, chrome plated pipe fittings will also help to prevent rust and will keep steel looking newly polished. Because chrome plating has a naturally bright appearance, it is utilized more in the automobile industry.
Variety
Because steel has the ability to undergo heat treatment, it’s easy to find carbon steel pipe fittings with just the right amount of carbon for any purpose. Mild carbon steel is typically used when a project calls for a large amount of steel because of its lower price and standard usage. Medium carbon steel is mostly utilized in the automotive industry due to its erosion resistance. Due to its strength, high carbon steel is used in the making of wires and springs. However, once the carbon content reaches 1.0%, it is only used for specific, non-industrial purposes.
Durability
Steel is one of the most popular types of pipe fittings and has been used for construction of pipes and pipe fittings for years because of its durability and strength. However, carbon steel, or plain-carbon steel, has the ability become much stronger through heat treatment. The more carbon added to the steel, the stronger it can become, which is why it is considered one of the strongest types of steel. Another way to increase the durability is to create a harder surface by adding a layer of chromium. Chrome plated pipe fittings are not only durable, but prevent corrosion and may also make the cleaning process much easier.
Multi-purpose
Carbon steel pipe fittings are typically used for industrial purposes such as commercial construction, electric-power, petroleum refinement and the building of ships, but are also often seen in the household. They are used for fire sprinkler systems and pipes carrying water, types of flammable gasses, oil or steam. Because of the addition of carbon to the steel, carbon steel pipes and pipe fittings are also much more resistant to rust. Again, chrome plated pipe fittings will also help to prevent rust and will keep steel looking newly polished. Because chrome plating has a naturally bright appearance, it is utilized more in the automobile industry.
Variety
Because steel has the ability to undergo heat treatment, it’s easy to find carbon steel pipe fittings with just the right amount of carbon for any purpose. Mild carbon steel is typically used when a project calls for a large amount of steel because of its lower price and standard usage. Medium carbon steel is mostly utilized in the automotive industry due to its erosion resistance. Due to its strength, high carbon steel is used in the making of wires and springs. However, once the carbon content reaches 1.0%, it is only used for specific, non-industrial purposes.
Hardness of carbon steel tube
The hardness of carbon steel pipe commonly used Brinell, Rockwell, Vickers hardness of three kinds of indicators to measure.
Brinell hardness
In the steel standard, it is the most widely Brinell hardness, often expressed in the indentation hardness of the material in diameter, both intuitive and convenient. However, for a hard steel or steel thin NA.
Rockwell hardness
Rockwell hardness test tube with Brinell hardness test, as are the indentation test methods. The difference is that it is a measure of the indentation depth. Steel Rockwell hardness test is a very wide application, wherein after the Brinell hardness HB HRC use in steel standard. Rockwell applicable to the determination by the extremely soft to extremely hard metal materials, which make up not Brinell method, compared with Brinell method is simple and can be read directly from the dial hardness machine hardness value. However, because of its small indentation, the Brinell hardness values better method is accurate.
Vickers hardness
The pipe is also a Vickers hardness test indentation test method for the determination of a thin metal material and a surface layer hardness. It has a Brinell, Rockwell main advantages law, and to overcome their basic shortcomings, but not as convenient method Rockwell, Vickers method is rarely used in the steel standard.
Brinell hardness
In the steel standard, it is the most widely Brinell hardness, often expressed in the indentation hardness of the material in diameter, both intuitive and convenient. However, for a hard steel or steel thin NA.
Rockwell hardness
Rockwell hardness test tube with Brinell hardness test, as are the indentation test methods. The difference is that it is a measure of the indentation depth. Steel Rockwell hardness test is a very wide application, wherein after the Brinell hardness HB HRC use in steel standard. Rockwell applicable to the determination by the extremely soft to extremely hard metal materials, which make up not Brinell method, compared with Brinell method is simple and can be read directly from the dial hardness machine hardness value. However, because of its small indentation, the Brinell hardness values better method is accurate.
Vickers hardness
The pipe is also a Vickers hardness test indentation test method for the determination of a thin metal material and a surface layer hardness. It has a Brinell, Rockwell main advantages law, and to overcome their basic shortcomings, but not as convenient method Rockwell, Vickers method is rarely used in the steel standard.
Classification of carbon steel pipes
Carbon steel pipe is a hollow steel bar, a large number of pipes for transporting fluids such as oil, natural gas, water, gas, steam, etc. In addition, engaged in bending, torsional strength, lighter, so it widely used in the manufacture of mechanical parts and engineering structures. Also used in producing a variety of conventional weapons, the barrel, shells and so on.
Carbon steel pipe classification: carbon steel pipe can be divided into seamless steel pipe and welded steel pipe points two categories. By the cross-sectional shape can be divided into the tube and shaped tubes, round steel is widely used, but there are some square, rectangular, semi-circular, hexagonal, equilateral triangle, octagon shaped steel tubing. For steel to withstand fluid pressure hydraulic test should be carried out to test its ability to withstand and quality, does not leak under pressure requirements, wet or expansion of qualified, some steel but also according to the requirements of the standard or demand side, curling trials, flaring test, flattening test.
Seamless steel pipe is ingot made of perforated or solid through the capillary tube, and then hot rolled, cold-rolled or cold call is made. Seamless steel pipe with a diameter* thickness specifications expressed in millimeters. Seamless steel pipe is divide into hot and cold seamless steel categories. Hot-rolled seamless steel pipes of general, low, medium pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe, steel pipes and other steel and other geological. Cold-rolled subject to sub- general seamless steel pipe, low pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe, the other steel, but also thin-walled carbon steel, alloy steel thin-walled, walled stainless steel, special steel pipe.
Welded steel pipe with plate or strip is bent after forming, then made by welding. Press the seam into the form of Longitudinal and spiral welded pipe. Divided into general -use pipe, galvanized pipe, blowing pipe, wire casing, metric pipe, roller pipe, deep well pump tube, automotive tube, transformer tube, welded tube, welding shaped tube and spiral welded pipe.
Carbon steel pipe classification: carbon steel pipe can be divided into seamless steel pipe and welded steel pipe points two categories. By the cross-sectional shape can be divided into the tube and shaped tubes, round steel is widely used, but there are some square, rectangular, semi-circular, hexagonal, equilateral triangle, octagon shaped steel tubing. For steel to withstand fluid pressure hydraulic test should be carried out to test its ability to withstand and quality, does not leak under pressure requirements, wet or expansion of qualified, some steel but also according to the requirements of the standard or demand side, curling trials, flaring test, flattening test.
Seamless steel pipe is ingot made of perforated or solid through the capillary tube, and then hot rolled, cold-rolled or cold call is made. Seamless steel pipe with a diameter* thickness specifications expressed in millimeters. Seamless steel pipe is divide into hot and cold seamless steel categories. Hot-rolled seamless steel pipes of general, low, medium pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe, steel pipes and other steel and other geological. Cold-rolled subject to sub- general seamless steel pipe, low pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe, the other steel, but also thin-walled carbon steel, alloy steel thin-walled, walled stainless steel, special steel pipe.
Welded steel pipe with plate or strip is bent after forming, then made by welding. Press the seam into the form of Longitudinal and spiral welded pipe. Divided into general -use pipe, galvanized pipe, blowing pipe, wire casing, metric pipe, roller pipe, deep well pump tube, automotive tube, transformer tube, welded tube, welding shaped tube and spiral welded pipe.
3PE Spiral Steel Pipe use in Oil and Gas Pipelines
3PE anti-corrosion steel pipe for buried pipeline life is critical, the same material pipes buried in the ground for decades and some non-corrosive, and some years it leaks occur. Because they use different outer coating.
In which ordinary steel for use in harsh environmental conditions, there will be severe corrosion, which will reduce the life of the steel pipe, steel pipe anti-corrosion insulation life is relatively long, generally, it can be used under normal circumstances for 30-50 years, and the proper installation and use is also possible to make the pipe network maintenance costs low, anti-corrosion pipe insulation can also set an alarm system, automatic leak detection pipe network failures, accurate knowledge of fault location and will automatically alarm.
3PE anti-corrosion steel pipe insulation performance is good, heat loss is only 25 per cent of the traditional pipe, long run can save relatively large resources, significantly reduce energy costs, and still has a relatively strong waterproof and corrosion resistance, and has no need trench directly on the ground or water can be purchased, but also easily and quickly on the construction, relatively low cost integrated, also at low temperatures and has good corrosion resistance, impact resistance, and in certain circumstances You can also directly embedded in permafrost.
In which ordinary steel for use in harsh environmental conditions, there will be severe corrosion, which will reduce the life of the steel pipe, steel pipe anti-corrosion insulation life is relatively long, generally, it can be used under normal circumstances for 30-50 years, and the proper installation and use is also possible to make the pipe network maintenance costs low, anti-corrosion pipe insulation can also set an alarm system, automatic leak detection pipe network failures, accurate knowledge of fault location and will automatically alarm.
3PE anti-corrosion steel pipe insulation performance is good, heat loss is only 25 per cent of the traditional pipe, long run can save relatively large resources, significantly reduce energy costs, and still has a relatively strong waterproof and corrosion resistance, and has no need trench directly on the ground or water can be purchased, but also easily and quickly on the construction, relatively low cost integrated, also at low temperatures and has good corrosion resistance, impact resistance, and in certain circumstances You can also directly embedded in permafrost.
Types and applications of seamless stainless steel tubes
Seamless steel pipe is widely used, and in order to cope with many use scenarios, the stainless steel material used in manufacturing seamless steel pipe is also very many. Now let's introduce it.
Seamless steel tube for structure
It is mainly used for manufacturing general structure and mechanical structure. Its representative material: #20 steel , #45 steel, Q345, 20Cr, 40Cr, 20CrMo, 30-35CrMo, 42CrMo, etc.
Seamless Steel Pipe for Fluid Conveying
Mainly used for conveying water, oil, gas and other fluids of the general seamless pipe. The representative materials are #20, Q345, etc.
Seamless Tube for Low and Medium Pressure Boiler
It is used to manufacture superheated steam pipes, boiling pipes and superheated steam pipes, large smoke pipes, small smoke pipes and arch brick pipes for various structures of low and medium pressure boilers, hot-rolled and cold-drawn seamless pipes. The representative material is steel No. 10 and No. 20.
Seamless stainless steel tube for structure
It is a hot-rolled (extruded, expanded) and cold-drawn (rolled) seamless pipe made of stainless steel widely used in chemical, petroleum, textile, medical, food, machinery and other industries. Its representative materials are 0-3Cr13, 0Cr18Ni9, 1Cr18Ni9Ti, 0Cr18Ni12Mo2Ti, etc.
Stainless steel seamless steel pipe for fluid conveying
Hot rolled (extruded, expanded) and cold drawn (rolled) seamless tubes made of stainless steel for conveying fluids. The representative materials are 0Cr13, 0Cr18Ni9, 1Cr18Ni9Ti, 0Cr17Ni12Mo2, 0Cr18Ni12Mo2Ti, etc.
Special-shaped seamless steel tube
It is a general term for seamless tubes of other cross-section shapes except round seamless tubes. According to the shape and size of steel tube section, it can be divided into three types: special-shaped seamless pipe with equal wall thickness (code D), special-shaped seamless pipe with unequal wall thickness (code BD) and special-shaped seamless pipe with variable diameter (code BJ). Special-shaped seamless tubes are widely used in various structural parts, tools and mechanical parts. Compared with circular pipe, special-shaped pipe generally has larger inertia moment and section modulus, has greater flexural and torsional resistance, can greatly reduce the weight of the structure and save steel.
http://www.xysteelpipe.com/info/Types-and-applications-of-seamless-stainless-steel-tubes-1381-1.htm
Seamless steel tube for structure
It is mainly used for manufacturing general structure and mechanical structure. Its representative material: #20 steel , #45 steel, Q345, 20Cr, 40Cr, 20CrMo, 30-35CrMo, 42CrMo, etc.
Seamless Steel Pipe for Fluid Conveying
Mainly used for conveying water, oil, gas and other fluids of the general seamless pipe. The representative materials are #20, Q345, etc.
Seamless Tube for Low and Medium Pressure Boiler
It is used to manufacture superheated steam pipes, boiling pipes and superheated steam pipes, large smoke pipes, small smoke pipes and arch brick pipes for various structures of low and medium pressure boilers, hot-rolled and cold-drawn seamless pipes. The representative material is steel No. 10 and No. 20.
Seamless stainless steel tube for structure
It is a hot-rolled (extruded, expanded) and cold-drawn (rolled) seamless pipe made of stainless steel widely used in chemical, petroleum, textile, medical, food, machinery and other industries. Its representative materials are 0-3Cr13, 0Cr18Ni9, 1Cr18Ni9Ti, 0Cr18Ni12Mo2Ti, etc.
Stainless steel seamless steel pipe for fluid conveying
Hot rolled (extruded, expanded) and cold drawn (rolled) seamless tubes made of stainless steel for conveying fluids. The representative materials are 0Cr13, 0Cr18Ni9, 1Cr18Ni9Ti, 0Cr17Ni12Mo2, 0Cr18Ni12Mo2Ti, etc.
Special-shaped seamless steel tube
It is a general term for seamless tubes of other cross-section shapes except round seamless tubes. According to the shape and size of steel tube section, it can be divided into three types: special-shaped seamless pipe with equal wall thickness (code D), special-shaped seamless pipe with unequal wall thickness (code BD) and special-shaped seamless pipe with variable diameter (code BJ). Special-shaped seamless tubes are widely used in various structural parts, tools and mechanical parts. Compared with circular pipe, special-shaped pipe generally has larger inertia moment and section modulus, has greater flexural and torsional resistance, can greatly reduce the weight of the structure and save steel.
http://www.xysteelpipe.com/info/Types-and-applications-of-seamless-stainless-steel-tubes-1381-1.htm
2019年4月16日星期二
Types and USES of reducing flanges
Reducing flanges are designed for when there is a change in the pipe size. The predominate flange (dimensions) matching the larger pipe size (NPT) but having a smaller bore matching the smaller pipe size (NPT). These flanges normally come in blind, slip-on, threaded and weld neck flanges.
Reducing flanges are normally provided as one of three types:
Welding neck flange, slip-on flange, threaded flange
Uses of Reducing Flanges:
1. Reducing flanges are used in pipe-to-pipe connections.
2. Reducing flanges are a little easier to bolt up than non-reducing flanges.
3. Reducing flanges provide the most perfect solution when you need to connect different size flanges.
3. These flanges are available in all types and pressures.
4. Reducing flanges are fixed by welding, gluing or clamping flanges of equal dimensions provided with different connecting pieces.
5. Reducing Flanges offer the simplest and least expensive method of mating two different sized flanges.
Reducing flanges are normally provided as one of three types:
Welding neck flange, slip-on flange, threaded flange
Uses of Reducing Flanges:
1. Reducing flanges are used in pipe-to-pipe connections.
2. Reducing flanges are a little easier to bolt up than non-reducing flanges.
3. Reducing flanges provide the most perfect solution when you need to connect different size flanges.
3. These flanges are available in all types and pressures.
4. Reducing flanges are fixed by welding, gluing or clamping flanges of equal dimensions provided with different connecting pieces.
5. Reducing Flanges offer the simplest and least expensive method of mating two different sized flanges.
Method of heat treatment for boiler pipes
Heat treatment is a method of changing the physical properties of high pressure boiler pipe by heating and cooling. Heat treatment can improve the microstructure of high pressure boiler pipe, so as to meet the required physical requirements. Toughness, hardness and wear resistance are obtained by heat treatment. In order to obtain these characteristics, it is necessary to adopt quenching, annealing, tempering and surface hardening.
a. Quenching
Hardening, also called quenching, is that high pressure boiler pipe is heated evenly to the appropriate temperature, then quickly immerse in water or oil for rapid cooling, and cooling in the air or in the freezing zone. So that the high pressure boiler pipe can obtain the required hardness.
b. Tempering
High pressure boiler pipe will become brittle after hardening. And the stress caused by quenching can make the high pressure boiler pipe tapped and broken. The tempering method can be used to eliminate brittleness. Although the hardness of high pressure boiler pipe is lighter reduced, its the toughness can be increased to reduce the brittleness.
c. Annealing
Annealing is the method to eliminate the internal stress of high pressure boiler pipe. The annealing method is that the steel parts need to be heated to the critical temperature, then put in dry ash, lime, asbestos or closed in the furnace, then let it cooling slowly.
a. Quenching
Hardening, also called quenching, is that high pressure boiler pipe is heated evenly to the appropriate temperature, then quickly immerse in water or oil for rapid cooling, and cooling in the air or in the freezing zone. So that the high pressure boiler pipe can obtain the required hardness.
b. Tempering
High pressure boiler pipe will become brittle after hardening. And the stress caused by quenching can make the high pressure boiler pipe tapped and broken. The tempering method can be used to eliminate brittleness. Although the hardness of high pressure boiler pipe is lighter reduced, its the toughness can be increased to reduce the brittleness.
c. Annealing
Annealing is the method to eliminate the internal stress of high pressure boiler pipe. The annealing method is that the steel parts need to be heated to the critical temperature, then put in dry ash, lime, asbestos or closed in the furnace, then let it cooling slowly.
Inspection method for quality of spiral steel tube
The spiral steel pipe shall be subjected to mechanical performance test, flattening test and flare test before leaving the factory, and shall meet the requirements specified in the standard. The quality inspection methods of it are as follows:
1. Judging from the surface, that is in appearance inspection. The appearance inspection of welded joints is a simple and widely used inspection method, which is an important part of the inspection of finished products, mainly to find defects and dimensional deviations on the surface of the weld. It is generally inspected by the naked eye and by means of tools such as standard templates, gauges and magnifiers. If there is a defect on the surface of the weld, there is a possibility of defects inside the weld.
2. Physical method inspection: The physical inspection method is a method of measuring or testing using some physical phenomena. Inspection of the internal defects of materials or workpieces is generally carried out by means of non-destructive testing, which includes ultrasonic flaw detection, radiographic inspection, penetrant inspection, and magnetic flaw detection.
3. Strength test of pressure vessel: In addition to the sealing test, the pressure vessel shall be subjected to a strength test. There are two types of hydraulic pressure test and air pressure test. They both verify the weld density of containers and pipes that work under pressure. The air pressure test is more sensitive and speedy than the water pressure test, and the tested product does not need to be drained, which is especially suitable for products with difficult drainage. However, the risk of the test is greater than the hydraulic test. When conducting tests, the corresponding safety technical measures must be observed to prevent accidents during the test.
4. Density test: For welding containers that store liquid or gas, the welds are not dense, such as penetrating cracks, pores, slag inclusions, incomplete penetration and loose structures, which can be found by compactness test. The methods of compactness test include: kerosene test, water carrying test, water flushing test, etc.
5. Hydrostatic test: Each steel pipe should be subjected to hydrostatic test without leakage. The test pressure is calculated according to the test. The test stress Mpa of the S-hydrostatic test in the formula P=2ST/D, and the test stress of the hydrostatic test. The corresponding steel strip standard specifies 60% of the minimum yield (Q235 is 235Mpa). Regulating time: D<50 test pressure holding time is not less than 5 seconds; D≥508 test pressure holding time is not less than 10 seconds 4, non-destructive testing steel pipe repair welding seam, steel belt butt weld and hoop seam Perform X-ray or ultrasonic inspection. For the spiral weld of the steel direction for the transportation of combustible ordinary fluids, 100% SX ray or ultrasonic inspection shall be carried out. X-rays shall be applied to the spiral welds of steel pipes used for the transportation of common fluids such as water, sewage, air and heating steam. Ultrasonic inspection spot check (20%).
According to the quality inspection results of spiral steel pipes, spiral steel pipes are generally divided into three categories: qualified products, repaired products and waste products. Qualified products refer to spiral steel pipes whose appearance quality and intrinsic quality meet the relevant standard or delivery acceptance technical conditions; the repaired products refer to the appearance quality and internal quality which are not completely in compliance with the standard and acceptance strips, but are allowed to be repaired, and the standard and acceptance conditions can be met after rework. Spiral steel pipe; scrap refers to spiral steel pipe that is unqualified in appearance quality and internal quality, and does not require standard or acceptance conditions after repair or repair.
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1. Judging from the surface, that is in appearance inspection. The appearance inspection of welded joints is a simple and widely used inspection method, which is an important part of the inspection of finished products, mainly to find defects and dimensional deviations on the surface of the weld. It is generally inspected by the naked eye and by means of tools such as standard templates, gauges and magnifiers. If there is a defect on the surface of the weld, there is a possibility of defects inside the weld.
2. Physical method inspection: The physical inspection method is a method of measuring or testing using some physical phenomena. Inspection of the internal defects of materials or workpieces is generally carried out by means of non-destructive testing, which includes ultrasonic flaw detection, radiographic inspection, penetrant inspection, and magnetic flaw detection.
3. Strength test of pressure vessel: In addition to the sealing test, the pressure vessel shall be subjected to a strength test. There are two types of hydraulic pressure test and air pressure test. They both verify the weld density of containers and pipes that work under pressure. The air pressure test is more sensitive and speedy than the water pressure test, and the tested product does not need to be drained, which is especially suitable for products with difficult drainage. However, the risk of the test is greater than the hydraulic test. When conducting tests, the corresponding safety technical measures must be observed to prevent accidents during the test.
4. Density test: For welding containers that store liquid or gas, the welds are not dense, such as penetrating cracks, pores, slag inclusions, incomplete penetration and loose structures, which can be found by compactness test. The methods of compactness test include: kerosene test, water carrying test, water flushing test, etc.
5. Hydrostatic test: Each steel pipe should be subjected to hydrostatic test without leakage. The test pressure is calculated according to the test. The test stress Mpa of the S-hydrostatic test in the formula P=2ST/D, and the test stress of the hydrostatic test. The corresponding steel strip standard specifies 60% of the minimum yield (Q235 is 235Mpa). Regulating time: D<50 test pressure holding time is not less than 5 seconds; D≥508 test pressure holding time is not less than 10 seconds 4, non-destructive testing steel pipe repair welding seam, steel belt butt weld and hoop seam Perform X-ray or ultrasonic inspection. For the spiral weld of the steel direction for the transportation of combustible ordinary fluids, 100% SX ray or ultrasonic inspection shall be carried out. X-rays shall be applied to the spiral welds of steel pipes used for the transportation of common fluids such as water, sewage, air and heating steam. Ultrasonic inspection spot check (20%).
According to the quality inspection results of spiral steel pipes, spiral steel pipes are generally divided into three categories: qualified products, repaired products and waste products. Qualified products refer to spiral steel pipes whose appearance quality and intrinsic quality meet the relevant standard or delivery acceptance technical conditions; the repaired products refer to the appearance quality and internal quality which are not completely in compliance with the standard and acceptance strips, but are allowed to be repaired, and the standard and acceptance conditions can be met after rework. Spiral steel pipe; scrap refers to spiral steel pipe that is unqualified in appearance quality and internal quality, and does not require standard or acceptance conditions after repair or repair.
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Key technology of precision steel tube manufacturing
Precision pipe is the carbon, alloy or stainless steel pipe with high precision sizes. Usually it has been made through hot rolling or cold drawn (cold rolling) processes. So precision pipe is a kind of seamless pipe.
Key processes in manufacturing the precision steel pipe
During manufacturing processes, the key point is to do the annealing for raw materials.
Precision steel pipe manufacturing flow chart:
Raw Material Inspection – Remove Oxide Layer – Visual Inspection – Heating – Hot Rolling – Pickling and Passivation (Phosphating) – Grinding – Lubrication and Drying – Cold Rolling (Internal and external extraction) – Remove Oil – Ends Cutting – Inspection – Marking – Packing and Storage
As we know, most of precision steel pipe has cold drawn and hot rolled process. On the contrast, cold rolling will be more complicated. Not only the pipe need to be continuous rolled by three roller, but also the test have to be done after extrusion, so to guarantee the quality of the precision pipe materials.
Manufacturing methods of seamless precision pipe includes hot rolling and cold drawn. More over it could be manufactured in welding processes.
Key processes in manufacturing the precision steel pipe
During manufacturing processes, the key point is to do the annealing for raw materials.
Precision steel pipe manufacturing flow chart:
Raw Material Inspection – Remove Oxide Layer – Visual Inspection – Heating – Hot Rolling – Pickling and Passivation (Phosphating) – Grinding – Lubrication and Drying – Cold Rolling (Internal and external extraction) – Remove Oil – Ends Cutting – Inspection – Marking – Packing and Storage
As we know, most of precision steel pipe has cold drawn and hot rolled process. On the contrast, cold rolling will be more complicated. Not only the pipe need to be continuous rolled by three roller, but also the test have to be done after extrusion, so to guarantee the quality of the precision pipe materials.
Manufacturing methods of seamless precision pipe includes hot rolling and cold drawn. More over it could be manufactured in welding processes.
LSAW steel pipe manufacturing process
LSAW (Longitudinal double submerge arc welding) carbon steel pipe is a type of SAW pipe made of steel plates that were hot rolled by JCOE or UOE forming technology. JCOE technology represents the shaping and forming processes involved during manufacturing as well as the inner and outer welding and cold expansion carried out after welding.
The LSAW large diameter steel pipe manufacturing process is explained in the steps below:
1. Plate Probe: This is used for manufacturing the large diameter LSAW joints right after it enters the production line which is the initial full-board ultrasonic testing.
2. Milling: The machine used for milling does this operation through two-edged milling plate to meet the requirements of the plate width and the sides parallel to the shape and degree.
3. Pre-curved side: This side is achieved by using a pre-bending machine on the pre-bending plate edge. The plate edge needs to meet curvature requirement.
4. Forming: After the pre-bending step, in the first half of the JCO molding machine, after stamped steel, it is pressed into a “J” shape while the on the other half of the same steel plate it is bent and pressed into a “C” shape, then the final opening forms an “O” shape.
5. Pre-welding: This is to make a welded pipe steel a straight seam after it has been formed and then use gas welding seam (MAG) for continuous welding.
6. Inside weld: This is done with a tandem multi-wire submerged arc welding (about four wire) on the inner part of the straight seam welded steel pipe.
7. Outside Weld: Outside weld is the tandem multi-wire submerged arc welding on the outer part of the LSAW steel pipe welding.
8. Ultrasonic Testing: Outside and inside of the straight seam welded steel pipe and both sides of the base material are welded with 100% inspection.
9. X-ray inspection: X-ray industrial TV inspection is carried out on the inside and outside using image processing system to make sure there is detection sensitivity.
10. Expansion: This is for accomplishing submerged arc welding and straight seam steel pipe length hole diameter so as to improve the steel tube’s size precision and improve the distribution of stress in the steel tube.
11. Hydraulic test: This is carried out on the hydraulic test machine for steel after expanding by-root test for ensuring the steel pipe meets the standard requirements with the machine having an automatic recording and storage capabilities.
12. Chamfering: This involves the inspection carried out on the steel pipe at the end of the whole process.
The LSAW large diameter steel pipe manufacturing process is explained in the steps below:
1. Plate Probe: This is used for manufacturing the large diameter LSAW joints right after it enters the production line which is the initial full-board ultrasonic testing.
2. Milling: The machine used for milling does this operation through two-edged milling plate to meet the requirements of the plate width and the sides parallel to the shape and degree.
3. Pre-curved side: This side is achieved by using a pre-bending machine on the pre-bending plate edge. The plate edge needs to meet curvature requirement.
4. Forming: After the pre-bending step, in the first half of the JCO molding machine, after stamped steel, it is pressed into a “J” shape while the on the other half of the same steel plate it is bent and pressed into a “C” shape, then the final opening forms an “O” shape.
5. Pre-welding: This is to make a welded pipe steel a straight seam after it has been formed and then use gas welding seam (MAG) for continuous welding.
6. Inside weld: This is done with a tandem multi-wire submerged arc welding (about four wire) on the inner part of the straight seam welded steel pipe.
7. Outside Weld: Outside weld is the tandem multi-wire submerged arc welding on the outer part of the LSAW steel pipe welding.
8. Ultrasonic Testing: Outside and inside of the straight seam welded steel pipe and both sides of the base material are welded with 100% inspection.
9. X-ray inspection: X-ray industrial TV inspection is carried out on the inside and outside using image processing system to make sure there is detection sensitivity.
10. Expansion: This is for accomplishing submerged arc welding and straight seam steel pipe length hole diameter so as to improve the steel tube’s size precision and improve the distribution of stress in the steel tube.
11. Hydraulic test: This is carried out on the hydraulic test machine for steel after expanding by-root test for ensuring the steel pipe meets the standard requirements with the machine having an automatic recording and storage capabilities.
12. Chamfering: This involves the inspection carried out on the steel pipe at the end of the whole process.
2019年4月10日星期三
Advantages of Hot-dip Zinc Galvanized Pipe
Hot dip galvanizing can protect steel pipes very well. When zinc is in liquid state, plate the steel with a thick layer of pure zinc after the complicated physical and chemical interaction and thus will make the hot dip galvanizing come into being. Also a zinc and steel alloy layer will be generated during this process. With this kind of layer and corrosion resistance feature, galvanized pipes can be applied to different severe corrosion environments, such as strong acid, alkali frog, etc., which is incomparable to other electro galvanizing.
Advantages of hot dip zinc galvanized pipes：
First, in general atmosphere, a very thin and dense layer of zinc oxide will be formed on the surface of zinc coating. It is hard to dissolve in water, therefore plays a certain protective effect to steel substrate. So, if the surface of steel pipe is covered with a quite thick and dense pure zinc layer, the steel substrate will be protected from contacting with any corrosive solution and avoid erosion.
Second, galvanized connection is very strong. When dissolving zinc and iron together, a good wear resistance will come into being and it can help the steel pipe become more strong and durable.
Third, after hot dip galvanizing, the mechanical properties of steel pipes will be improved effectively. Also, it can eliminate the stress of steel pipes in molding and welding process and benefit the lathe work.
Forth, due to the excellent ductility of zinc, its alloy layer can combine strongly with steel pipe so that plating will be protected from damage even in rolling, bending, wiredrawing, cold blanking and other molding situations.
What’s more, the surface of galvanized pipe will become bright and beautiful after the hot dip galvanizing.
Advantages of hot dip zinc galvanized pipes：
First, in general atmosphere, a very thin and dense layer of zinc oxide will be formed on the surface of zinc coating. It is hard to dissolve in water, therefore plays a certain protective effect to steel substrate. So, if the surface of steel pipe is covered with a quite thick and dense pure zinc layer, the steel substrate will be protected from contacting with any corrosive solution and avoid erosion.
Second, galvanized connection is very strong. When dissolving zinc and iron together, a good wear resistance will come into being and it can help the steel pipe become more strong and durable.
Third, after hot dip galvanizing, the mechanical properties of steel pipes will be improved effectively. Also, it can eliminate the stress of steel pipes in molding and welding process and benefit the lathe work.
Forth, due to the excellent ductility of zinc, its alloy layer can combine strongly with steel pipe so that plating will be protected from damage even in rolling, bending, wiredrawing, cold blanking and other molding situations.
What’s more, the surface of galvanized pipe will become bright and beautiful after the hot dip galvanizing.
2019年4月9日星期二
Basic method of derusting boiler tube
The basic method of rust removal for boiler tube:
1. Cleaning
Using the solvent and emulsion to clean the surface of high pressure boiler pipe, so as to achieve the purpose of removing oil, grease, dust, lubricant and similar organic matter. But it cannot remove the dust, oxide skin, welding medicine and so on. So it is only as a supplementary method in the anti-corrosion production.
2. Tool
Tool rust removal mainly use wire brush and other tools to grind the surface of high pressure boiler pipe. It can remove loose or warping of the oxide skin, rust, welding slag and so on. Manual tool can reach SA2 level, power tool can reach SA3 level. If the iron oxide scale attached to the surface, it cannot reach the anchorage depth required by the anti-corrosion construction.
3. Acid cleaning
High pressure boiler pipe generally adopt chemical and electrolytic methods to do pickling treatment.
4. Spray rust removal
Spray rust removal cannot only remove rust, oxide and dirt completely, but also high pressure boiler pipe can achieve the required uniform roughness under the action of abrasive impact and friction force.
Spay rust removal cannot only expand the physical adsorption on the surface of high pressure boiler pipe, but also enhance the mechanical adhesion between the anti corrosion layer and the pipe surface. So spray rust removal is ideal method of rust removing for pipeline corrosion.
1. Cleaning
Using the solvent and emulsion to clean the surface of high pressure boiler pipe, so as to achieve the purpose of removing oil, grease, dust, lubricant and similar organic matter. But it cannot remove the dust, oxide skin, welding medicine and so on. So it is only as a supplementary method in the anti-corrosion production.
2. Tool
Tool rust removal mainly use wire brush and other tools to grind the surface of high pressure boiler pipe. It can remove loose or warping of the oxide skin, rust, welding slag and so on. Manual tool can reach SA2 level, power tool can reach SA3 level. If the iron oxide scale attached to the surface, it cannot reach the anchorage depth required by the anti-corrosion construction.
3. Acid cleaning
High pressure boiler pipe generally adopt chemical and electrolytic methods to do pickling treatment.
4. Spray rust removal
Spray rust removal cannot only remove rust, oxide and dirt completely, but also high pressure boiler pipe can achieve the required uniform roughness under the action of abrasive impact and friction force.
Spay rust removal cannot only expand the physical adsorption on the surface of high pressure boiler pipe, but also enhance the mechanical adhesion between the anti corrosion layer and the pipe surface. So spray rust removal is ideal method of rust removing for pipeline corrosion.
Hardness Standards for Seamless Steel Pipe
Generally, the hardness of seamless steel pipes has three standards: Brinell Hardness, Rockwell Hardness and Vickers Hardness.
1. Brinell Hardness
Brinell Hardness is the most common standard for seamless steel pipes, generally use diameter of indentation to represent the hardness of material, which is intuitive and simple. However, the standard is not suitable for hard and thin steel pipes.
2.Rockwell Hardness
Rockwell Hardness is also use indentation to represent the hardness, but Rockwell measures its depth rather than diameter. Rockwell Hardness is widely applied in testing hardness of seamless steel pipes, the standard HRC is the most popular testing method next to Brinell Hardness (HB). Rockwell Hardness can be used to test both extremely soft and hard material which supplements shortcomings of Brinell Hardness. The number of hardness can be read directly from the dial. However, due to slighter indentation, Rockwell Hardness is less accurate than Brinell Hardness.
3. Vickers Hardness
Vickers Hardness is also depending on testing indentation which can be applied to test thin metal material. Vickers Hardness combines advantages of Brinell and Rockwell, but the measurement is not as convenient as Rockwell, therefore is not widely used as the hardness standard.
1. Brinell Hardness
Brinell Hardness is the most common standard for seamless steel pipes, generally use diameter of indentation to represent the hardness of material, which is intuitive and simple. However, the standard is not suitable for hard and thin steel pipes.
2.Rockwell Hardness
Rockwell Hardness is also use indentation to represent the hardness, but Rockwell measures its depth rather than diameter. Rockwell Hardness is widely applied in testing hardness of seamless steel pipes, the standard HRC is the most popular testing method next to Brinell Hardness (HB). Rockwell Hardness can be used to test both extremely soft and hard material which supplements shortcomings of Brinell Hardness. The number of hardness can be read directly from the dial. However, due to slighter indentation, Rockwell Hardness is less accurate than Brinell Hardness.
3. Vickers Hardness
Vickers Hardness is also depending on testing indentation which can be applied to test thin metal material. Vickers Hardness combines advantages of Brinell and Rockwell, but the measurement is not as convenient as Rockwell, therefore is not widely used as the hardness standard.
Test method for API 5L pipelines
API 5L is the implementation standard of steel pipe for pipeline transportation system. As we know, this standard specification includes Grade B, X42, X46, X52, X56, X60, X65, X70, X80 etc. And divided in two product specification level, PSL1 and PSL2. More over, API 5L pipe is also the pipeline steel pipe, applied to the oil and gas transmission system. Meanwhile, other fluids like steam, water, slurry adopts the API 5L standard for the transmission purposes. Below we will introduce the methods for API 5L line pipe.
1). Hydrostatic test
a. Jointers need not be hydrostatically level, provided that the portions of pipe used in making the jointers were successfully hydrostatically tested prior to the joining operation.
b. Except the previous situation, the pipe shall withstand the hydrostatic test without leakage through the weld seam or the pipe body.
2). Bend test
Cracks should not occur in any part of the sample and opening of weld shall not occur as well.
Please Note: For all bend test, the weld extends to a distance of 6.4 mm (0.25 in) on each side of fusion line.
3). Flattening test
The flattening test method is used to verify the deformation performance of line pipe to the specified size, and display its defects. According to the stress and deformation characteristics of the specimen during the flattening process, the flattening test shall show the resistance to longitudinal cracking and circumferential cracking of the pipe, and display its internal defects and surface defects.
1). Hydrostatic test
a. Jointers need not be hydrostatically level, provided that the portions of pipe used in making the jointers were successfully hydrostatically tested prior to the joining operation.
b. Except the previous situation, the pipe shall withstand the hydrostatic test without leakage through the weld seam or the pipe body.
2). Bend test
Cracks should not occur in any part of the sample and opening of weld shall not occur as well.
Please Note: For all bend test, the weld extends to a distance of 6.4 mm (0.25 in) on each side of fusion line.
3). Flattening test
The flattening test method is used to verify the deformation performance of line pipe to the specified size, and display its defects. According to the stress and deformation characteristics of the specimen during the flattening process, the flattening test shall show the resistance to longitudinal cracking and circumferential cracking of the pipe, and display its internal defects and surface defects.
2019年4月2日星期二
Difficulties and control measures in steel pipe manufacturing
1. Due to the arc deviation, local distortion of longitudinal seam welding, The radian and ovality deviation of steel pipe will be difficult to ensure the deviation, and it take the following measures to guarantee.
(1) To design and produce longitudinal seam local arc calibration machine, after welding longitudinal seam, to use machine calibration to ensure its partial arc deviation.
(2) Set up the reasonable steel pipe support to ensure deformation value and ovality of steel pipe.
2. In order to ensure the straightness of the deviation when steel pipe assembling, following measures can be taken.
(1) Improving groove design, adopting asymmetric X groove, leaving no space, cleaning with carbon arc air gouging after the inseam welding, making inside and outside of the weld actual area is almost close to equal, these measures are helpful to reduce the deformation and the residual stress.
(2) Improving welding technology taking small-area welding, especially the first layer of the welding, increasing welding level, to reduce deformation and decrease steel pipe dimension deviation.
(3) Straight tube butt: on the seam welding machine, at first, to adjust clearance, wrong tooth and check dimension as a whole, the, if qualified, to weld as a whole.
(4) Bent pipe assembly: pipe bending is a special socket, the overshoot of dimension error will bring certain difficulties to installment and therefore it requires the whole assembly.
(1) To design and produce longitudinal seam local arc calibration machine, after welding longitudinal seam, to use machine calibration to ensure its partial arc deviation.
(2) Set up the reasonable steel pipe support to ensure deformation value and ovality of steel pipe.
2. In order to ensure the straightness of the deviation when steel pipe assembling, following measures can be taken.
(1) Improving groove design, adopting asymmetric X groove, leaving no space, cleaning with carbon arc air gouging after the inseam welding, making inside and outside of the weld actual area is almost close to equal, these measures are helpful to reduce the deformation and the residual stress.
(2) Improving welding technology taking small-area welding, especially the first layer of the welding, increasing welding level, to reduce deformation and decrease steel pipe dimension deviation.
(3) Straight tube butt: on the seam welding machine, at first, to adjust clearance, wrong tooth and check dimension as a whole, the, if qualified, to weld as a whole.
(4) Bent pipe assembly: pipe bending is a special socket, the overshoot of dimension error will bring certain difficulties to installment and therefore it requires the whole assembly.
2019年4月1日星期一
Common inspection methods for steel pipes
Inspection of steel pipes generally includes: inspection of geometrical dimensions and surface quality; chemical composition, mechanical properties, process performance, inspection of high and low-fold microstructures; non-destructive testing; certain special performance inspections and length measurement.
(1) Geometrical inspection of steel pipes
The outer diameter, wall thickness, bending and length of the steel pipe can be inspected on the inspection table with an outer caliper, a micrometer and a bending ruler, and a length tape measure.
For the outer diameter, wall thickness and length, automatic size detection devices (such as automatic diameter measurement, thickness measurement, length measuring device) can also be used for continuous detection. Steel pipe production plants put into operation in the late 1980s generally have online automatic diameter measuring and thickness measuring devices, and measuring length weighing equipment is provided in the finishing area. Thread parameters are also checked for OCTG steel tubes.
(2) Inspection of the inner and outer surfaces of steel pipes
The inner and outer surface inspections are generally performed by visual inspection, and the inner surface can be inspected by using a reflective prism in addition to visual inspection. Some special-purpose steel pipes also require inspection of the quality of the inner and outer surfaces of steel pipes through non-destructive testing, including eddy currents, magnetic flux leakage, ultrasonic waves, and magnetic particle inspection.
(3) Mechanical properties and process performance check
In order to verify that the mechanical properties of the steel pipe meet the requirements of the standard, it is necessary to test the mechanical properties of the steel pipe.
Mechanical properties test mainly includes tensile strength, yield strength, elongation, impact work and so on. Process performance inspection mainly includes flattening test, flare test, hydraulic test, crimp test, cold bend test, perforation test and so on. These inspection items are selected according to the differences in standards and the use of steel pipes.
(4) Nondestructive testing
Non-destructive testing refers to the direct inspection of internal and surface defects without damaging the steel pipe. At present, magnetic flux leakage testing, ultrasonic testing, eddy current and fluorescent magnetic particle testing have been widely used in steel pipe enterprises. In recent years, the non-destructive testing method has been greatly developed. Recently, new technologies such as acoustic emission holography, ultrasonic spectrum analysis and flaw detection, ultrasonic imaging inspection and ultrasonic high-temperature flaw detection have appeared.
(5) Chemical composition test
According to the standard requirements, the main components of the steel pipe are retested according to the batch number.
(6) High and low test
It includes the inspection and measurement of low-magnification of steel pipes, non-metallic inclusions, actual grain size, metallographic microstructure, decarburization layer, etc. It must be carried out according to the requirements of the standard.
(7) Weight detection
For steel pipes with a single weight requirement, it is also necessary to check whether the weight meets the contract or standard requirements by means of a weighing device.
http://www.xysteelpipe.com/info/Common-inspection-methods-for-steel-pipes-1358-1.htm
(1) Geometrical inspection of steel pipes
The outer diameter, wall thickness, bending and length of the steel pipe can be inspected on the inspection table with an outer caliper, a micrometer and a bending ruler, and a length tape measure.
For the outer diameter, wall thickness and length, automatic size detection devices (such as automatic diameter measurement, thickness measurement, length measuring device) can also be used for continuous detection. Steel pipe production plants put into operation in the late 1980s generally have online automatic diameter measuring and thickness measuring devices, and measuring length weighing equipment is provided in the finishing area. Thread parameters are also checked for OCTG steel tubes.
(2) Inspection of the inner and outer surfaces of steel pipes
The inner and outer surface inspections are generally performed by visual inspection, and the inner surface can be inspected by using a reflective prism in addition to visual inspection. Some special-purpose steel pipes also require inspection of the quality of the inner and outer surfaces of steel pipes through non-destructive testing, including eddy currents, magnetic flux leakage, ultrasonic waves, and magnetic particle inspection.
(3) Mechanical properties and process performance check
In order to verify that the mechanical properties of the steel pipe meet the requirements of the standard, it is necessary to test the mechanical properties of the steel pipe.
Mechanical properties test mainly includes tensile strength, yield strength, elongation, impact work and so on. Process performance inspection mainly includes flattening test, flare test, hydraulic test, crimp test, cold bend test, perforation test and so on. These inspection items are selected according to the differences in standards and the use of steel pipes.
(4) Nondestructive testing
Non-destructive testing refers to the direct inspection of internal and surface defects without damaging the steel pipe. At present, magnetic flux leakage testing, ultrasonic testing, eddy current and fluorescent magnetic particle testing have been widely used in steel pipe enterprises. In recent years, the non-destructive testing method has been greatly developed. Recently, new technologies such as acoustic emission holography, ultrasonic spectrum analysis and flaw detection, ultrasonic imaging inspection and ultrasonic high-temperature flaw detection have appeared.
(5) Chemical composition test
According to the standard requirements, the main components of the steel pipe are retested according to the batch number.
(6) High and low test
It includes the inspection and measurement of low-magnification of steel pipes, non-metallic inclusions, actual grain size, metallographic microstructure, decarburization layer, etc. It must be carried out according to the requirements of the standard.
(7) Weight detection
For steel pipes with a single weight requirement, it is also necessary to check whether the weight meets the contract or standard requirements by means of a weighing device.
http://www.xysteelpipe.com/info/Common-inspection-methods-for-steel-pipes-1358-1.htm
Ultrasonic testing of seamless steel tubes
The ultrasonic probe can be realized electricity harmonies which can the mutual conversion of the Q and ultrasonic wave propagation in elastic media, the physical characteristic is the basis of the seamless steel pipe principle of the ultrasonic flaw detection.
Directional transmission of the ultrasonic beam propagation in Seamless encounter defects, and produces both a reflection of the wave generated wave attenuation. After the flaw detector of the signal processing, such as obtained using a reflection method flaw defect echo signals, such as penetration method flaw virtue through the degree of attenuation of the wave guide to the defect signal. Both can be a quantitative defect indication is given by the instrument. The use of the piezoelectric effect or the electromagnetic induction principle different types of ultrasonic wave can be excited within the tube. Therefore, the piezoelectric ultrasonic and electromagnetic ultrasound can be used to pipe ultrasonic inspection. But the electromagnetic ultrasonic applies only to the ferromagnetic material.
Ultrasonic inspection of seamless pipes method
1. Wave (or plate waves) reflection method the (or penetration method), in the state where the relative movement of the probe and a high pressure boiler tubes automatic inspection, the only special large-diameter seamless cam manual inspection. Automatic or manual inspection should ensure the sound beam scanning the surface of all of seamless steel pipe.
2. Longitudinal defect inspection acoustic beam in the tube wall along the circumferential direction of propagation; test transverse defects propagation direction of the acoustic beam in the tube wall along the tube axis. The longitudinal and transverse defect inspection should be carried out in two opposite directions on the tube.
3. In demand-side transverse defect inspection is not made for the party inspection of longitudinal imperfections. Both parties agree that the buyer and the seller, the inspection of longitudinal and transverse defects can be only in the direction of the tube.
4. Automatic or manual inspection should be chosen coupled to good effect and without prejudice to the seamless steel pipe surface coupling medium.
Directional transmission of the ultrasonic beam propagation in Seamless encounter defects, and produces both a reflection of the wave generated wave attenuation. After the flaw detector of the signal processing, such as obtained using a reflection method flaw defect echo signals, such as penetration method flaw virtue through the degree of attenuation of the wave guide to the defect signal. Both can be a quantitative defect indication is given by the instrument. The use of the piezoelectric effect or the electromagnetic induction principle different types of ultrasonic wave can be excited within the tube. Therefore, the piezoelectric ultrasonic and electromagnetic ultrasound can be used to pipe ultrasonic inspection. But the electromagnetic ultrasonic applies only to the ferromagnetic material.
Ultrasonic inspection of seamless pipes method
1. Wave (or plate waves) reflection method the (or penetration method), in the state where the relative movement of the probe and a high pressure boiler tubes automatic inspection, the only special large-diameter seamless cam manual inspection. Automatic or manual inspection should ensure the sound beam scanning the surface of all of seamless steel pipe.
2. Longitudinal defect inspection acoustic beam in the tube wall along the circumferential direction of propagation; test transverse defects propagation direction of the acoustic beam in the tube wall along the tube axis. The longitudinal and transverse defect inspection should be carried out in two opposite directions on the tube.
3. In demand-side transverse defect inspection is not made for the party inspection of longitudinal imperfections. Both parties agree that the buyer and the seller, the inspection of longitudinal and transverse defects can be only in the direction of the tube.
4. Automatic or manual inspection should be chosen coupled to good effect and without prejudice to the seamless steel pipe surface coupling medium.
The Purpose Guidance of Welded Steel Pipe
Generally speaking, the welded steel pipes are divided into general welded pipe, galvanized welded pipe, oxygen welding tube, metric system welded tube, transformer tube, welding thin wall pipe and spiral welded pipe etc.
General welded pipe:
General welded pipe adopts Q195A, Q215A and Q235A or mild steel as raw materials. It is used to transfer the low pressure fluid. In addition, the pipes need water pressure, bending and flattening test etc. Usually, it has some certain requirements on the surface quality.
The length of delivery is often from 4 to 10mm. The specifications of welded pipe in nominal diameter are different from actual size. Depending on the wall thickness, welded pipe are also divided into common steel pipe and thicken steel pipe.
Galvanized welded pipe:
In order to enhance the corrosion resistance, the general welded pipe is galvanized zinc as protective layer. Galvanized steel pipe has two types: hot dip galvanized pipe with thicken zinc layer and electrical-galvanized pipe with low cost.
Metric system welded tube:
The metric system welded tube is made from the common carbon steel, quality carbon steel or low alloy steel with the hot and cold welding or after hot welded by the cold again. The specification adopts the seamless steel pipe form with outside diameter*wall thickness (mm). The common metric system welded tube is usually used as structural elements like axis of rotation or transporting the fluid etc. The thin-walled tube is utilized for processing furniture, lamps and lanterns. But the manufacturers need to guarantee the strength and bending of steel pipe in the processing.
Spiral welded tube:
The spiral welded tube uses low carbon structural steel or low alloy structural steel strip according to certain helix angle (forming angle) rolled into a tube billet, then welded the pipe joints to be made. The spiral welded tube can use narrow strip steel to produce large diameter steel pipe. It is broadly applied as oil or natural gas pipeline. Moreover, spiral welded pipe has one side welding and double sided welding.
General welded pipe:
General welded pipe adopts Q195A, Q215A and Q235A or mild steel as raw materials. It is used to transfer the low pressure fluid. In addition, the pipes need water pressure, bending and flattening test etc. Usually, it has some certain requirements on the surface quality.
The length of delivery is often from 4 to 10mm. The specifications of welded pipe in nominal diameter are different from actual size. Depending on the wall thickness, welded pipe are also divided into common steel pipe and thicken steel pipe.
Galvanized welded pipe:
In order to enhance the corrosion resistance, the general welded pipe is galvanized zinc as protective layer. Galvanized steel pipe has two types: hot dip galvanized pipe with thicken zinc layer and electrical-galvanized pipe with low cost.
Metric system welded tube:
The metric system welded tube is made from the common carbon steel, quality carbon steel or low alloy steel with the hot and cold welding or after hot welded by the cold again. The specification adopts the seamless steel pipe form with outside diameter*wall thickness (mm). The common metric system welded tube is usually used as structural elements like axis of rotation or transporting the fluid etc. The thin-walled tube is utilized for processing furniture, lamps and lanterns. But the manufacturers need to guarantee the strength and bending of steel pipe in the processing.
Spiral welded tube:
The spiral welded tube uses low carbon structural steel or low alloy structural steel strip according to certain helix angle (forming angle) rolled into a tube billet, then welded the pipe joints to be made. The spiral welded tube can use narrow strip steel to produce large diameter steel pipe. It is broadly applied as oil or natural gas pipeline. Moreover, spiral welded pipe has one side welding and double sided welding.
Solution treatment of seamless stainless steel tubes
The solution temperature is mainly determined by chemical composition. In general, the solution temperature should increase for those containing many kinds of alloy elements or with high alloy. Especially for those that contains high steel, like manganese, molybdenum, nickel, silicon. Only by increasing the solution temperature can we dissolve and soften them. But for stabilized steels such as 321 stainless steel pipe, when the solution temperature is high, the carbide of the stabilizing elements are fully dissolved in the austenite and precipitate in the grain boundary with the form of Cr23C6 after cooling. That can cause intergranular corrosion. We often adopt the lowest solution temperature for carbide(Tic and NbC) of the stabilizing elements which can't be dissolved or treated by solid solution.
For seamless stainless steel pipe, the three elements of the solution treatment are temperature, holding time and cooling rate. What is the role of solution treatment of seamless stainless steel pipe?
1. Keep uniformity for organization and composition of the stainless steel seamless tube are particularly important for raw materials. For the rolling temperature and cooling rate of the different sections of the hot rolling pipe are not the same, which can cause organizational structure inconformity. Under the high temperature, the atomic activity increases, σ dissolves, the chemical composition tends to be uniform, and the uniform single-phase structure is obtained after rapid cooling.
2. Eliminate the work hardening in order to facilitate the cold processing. Through the solution treatment, the crooked lattice will recover and elongate, and the broken grain recrystallize, inner stress eliminate, wire tensile strength decrease and elongation increase.
3. Restore the inherent corrosion resistance of stainless steel tube. The cold processing has caused precipitation of the carbide and lattice defect, which decreases the corrosion resistance of stainless steel pipe. After the solution treatment, the corrosion resistance of stainless steel seamless pipe is restored to the best condition.
For seamless stainless steel pipe, the three elements of the solution treatment are temperature, holding time and cooling rate. What is the role of solution treatment of seamless stainless steel pipe?
1. Keep uniformity for organization and composition of the stainless steel seamless tube are particularly important for raw materials. For the rolling temperature and cooling rate of the different sections of the hot rolling pipe are not the same, which can cause organizational structure inconformity. Under the high temperature, the atomic activity increases, σ dissolves, the chemical composition tends to be uniform, and the uniform single-phase structure is obtained after rapid cooling.
2. Eliminate the work hardening in order to facilitate the cold processing. Through the solution treatment, the crooked lattice will recover and elongate, and the broken grain recrystallize, inner stress eliminate, wire tensile strength decrease and elongation increase.
3. Restore the inherent corrosion resistance of stainless steel tube. The cold processing has caused precipitation of the carbide and lattice defect, which decreases the corrosion resistance of stainless steel pipe. After the solution treatment, the corrosion resistance of stainless steel seamless pipe is restored to the best condition.
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