Seamless steel pipe wall thickness inspection
Micrometer is the main tool that is adopted. When you check, left hand holds the micrometer stand, with right hand rotation induced wheel, and the wire rod should be coincident with the diameter of the measuring point. Once found that the wall thickness is not qualified, it should be marked in time.
Outside diameter, ellipse of seamless steel pipe inspection
Calipers, vernier caliper should be taken. The caliper should be perpendicular to the axis of the steel pipe in checking, measuring the maximum and the minimum point when the pipe rotated slowly. Founding the outer diameter of large or small, you should mark it in time.
Seamless steel tube length inspection
The steel tape can be measured directly by metallic tape.
Bending inspection of seamless steel tubes
With the tools of level, feeler and line.
End profile inspection
At two ends of the steel tube should be cut into specified angle and remove burrs. The method of inspection adopts angle square and general use tube end groove clamp in the field.
2019年1月24日星期四
Different types of seamless steel tube for use
The seamless steel tube is a long strip of steel with a hollow section and no seams around it. The seamless steel pipe is formed by perforating a steel ingot or a solid tube blank, and then hot rolled, cold rolled or cold drawn. Seamless steel pipe plays an important role in China's steel pipe industry. Seamless steel pipes are widely used in water and gas pipelines, and are also used in petroleum, chemical, boiler, automobile, tractor, aviation and other fields.
According to the different production methods, seamless steel tubes are divided into hot-rolled (extruded, expanded) seamless tubes and cold drawn (tanned) seamless tubes. According to the material can be divided into: ordinary and high-quality carbon structural steel (Q215-A ~ Q275-A and 10 ~ 50 steel), low alloy steel (09MnV, 16Mn, etc.), alloy steel, stainless acid-resistant steel. According to the use, it can be divided into two types: general purpose (for water, gas pipelines and structural parts, mechanical parts) and special (for boilers, geological exploration, bearings, acid resistance, etc.).
Structural seamless steel pipe is a pipe with a hollow section and is used as a large amount of conveying fluid, such as pipes for transporting oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, the steel pipe has a lighter weight when it has the same bending and torsional strength, and is an economical section steel. Widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automotive drive shafts, bicycle frames and steel scaffolding used in construction, such as steel scaffolding, to create ring-shaped parts, which can improve material utilization, simplify manufacturing processes, save materials and processing. Working hours, it has been widely used in steel pipes.
http://www.xysteelpipe.com/info/Different-types-of-seamless-steel-tube-for-use-1321-1.htm
According to the different production methods, seamless steel tubes are divided into hot-rolled (extruded, expanded) seamless tubes and cold drawn (tanned) seamless tubes. According to the material can be divided into: ordinary and high-quality carbon structural steel (Q215-A ~ Q275-A and 10 ~ 50 steel), low alloy steel (09MnV, 16Mn, etc.), alloy steel, stainless acid-resistant steel. According to the use, it can be divided into two types: general purpose (for water, gas pipelines and structural parts, mechanical parts) and special (for boilers, geological exploration, bearings, acid resistance, etc.).
Structural seamless steel pipe is a pipe with a hollow section and is used as a large amount of conveying fluid, such as pipes for transporting oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, the steel pipe has a lighter weight when it has the same bending and torsional strength, and is an economical section steel. Widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automotive drive shafts, bicycle frames and steel scaffolding used in construction, such as steel scaffolding, to create ring-shaped parts, which can improve material utilization, simplify manufacturing processes, save materials and processing. Working hours, it has been widely used in steel pipes.
http://www.xysteelpipe.com/info/Different-types-of-seamless-steel-tube-for-use-1321-1.htm
ASTM A192 Steel Tubes for High-pressure Steel Boiler Tube
The ASTM A192 belongs to the carbon seamless tubes, which is specially designed for high, middle, low pressure purpose in seamless carbon steel boilers tube and as super heater tubes.
Description:
This specification has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for specific year of issue which has been adopted by the Department of Defense.
Size (mm): O.D.:6.0-114.0 W.T.:1-15 L:max 12000
Delivery Condition : As different requirements,It including pickling,etc.
Test:
1.Hydrostatic or Nondestructive Electric Test
2.Heat Treatment:Min temperature 650.
3.Surface Condition:Free of scale,A slight amount of oxidation will not be considered as scale.
4.Flattening Test,Flaring Test.Flange Test,Hardness Test,Hydrostatic Test
Description:
This specification has been approved for use by agencies of the Department of Defense. Consult the DoD Index of Specifications and Standards for specific year of issue which has been adopted by the Department of Defense.
Size (mm): O.D.:6.0-114.0 W.T.:1-15 L:max 12000
Delivery Condition : As different requirements,It including pickling,etc.
Test:
1.Hydrostatic or Nondestructive Electric Test
2.Heat Treatment:Min temperature 650.
3.Surface Condition:Free of scale,A slight amount of oxidation will not be considered as scale.
4.Flattening Test,Flaring Test.Flange Test,Hardness Test,Hydrostatic Test
The Usage of Seamless Steel Tubes and Welded Pipes
It is suitable for low pressure and temperature of the meson, seamless steel pipe usage in many aspects, such as high temperature and pressure for mesons, high quality requirements for fluid leak-proof, and the choice of seamless steel tubes for fear of pollution. Seamless steel pipe usage but also in terms of building structures for machining, different materials, different strengths, different thickness, different specifications, different precision, seamless pipe joints are better , according to need.
Since the 1930s, the development of high-quality steel rolling production and testing technology very quickly and gradually improve the quality of welding, welded steel varieties and specifications are constantly increasing, and more and more areas to be applied. Seamless steel pipe usage is lower than cost, high production efficiency. The steel pipe diameter and wall thickness ratio of less than 20 is called thick-walled steel pipe. The seamless steel pipe usage is suitable for the petroleum geology, petroleum and petrochemical cracking tubes, boiler tubes, pipes and automotive bearings, tractors, aviation structures with high precision tubes.
Cold drawn seamless steel and hot-rolled seamless steel tubes have a clear division there are several aspects of seamless steel pipe, the material and performance standard for comparison, its material, including ordinary tube and alloy tube, land transfer fluid seam steel pipe, high pressure boiler seamless pipe, fertilizer equipment, high pressure seamless steel pipe, seamless steel pipe for geological drilling, oil drilling seamless steel pipe, petroleum cracking seamless OCTG seamless drill collars, automobile axle seamless steel pipes, Ships with seamless steel tubes, cold drawn cold rolled precision seamless steel tubes. The steel ingot, as well as billet or bar which is made of seamless steel pipe perforation, makes of seamless steel pipe; welded steel pipe is hot-rolled or cold-rolled steel sheet and strip made of welded, straight seam welded longitudinally, can spiral welding. These are very good representatives and the seamless steel pipe usage is extensive.
Since the 1930s, the development of high-quality steel rolling production and testing technology very quickly and gradually improve the quality of welding, welded steel varieties and specifications are constantly increasing, and more and more areas to be applied. Seamless steel pipe usage is lower than cost, high production efficiency. The steel pipe diameter and wall thickness ratio of less than 20 is called thick-walled steel pipe. The seamless steel pipe usage is suitable for the petroleum geology, petroleum and petrochemical cracking tubes, boiler tubes, pipes and automotive bearings, tractors, aviation structures with high precision tubes.
Cold drawn seamless steel and hot-rolled seamless steel tubes have a clear division there are several aspects of seamless steel pipe, the material and performance standard for comparison, its material, including ordinary tube and alloy tube, land transfer fluid seam steel pipe, high pressure boiler seamless pipe, fertilizer equipment, high pressure seamless steel pipe, seamless steel pipe for geological drilling, oil drilling seamless steel pipe, petroleum cracking seamless OCTG seamless drill collars, automobile axle seamless steel pipes, Ships with seamless steel tubes, cold drawn cold rolled precision seamless steel tubes. The steel ingot, as well as billet or bar which is made of seamless steel pipe perforation, makes of seamless steel pipe; welded steel pipe is hot-rolled or cold-rolled steel sheet and strip made of welded, straight seam welded longitudinally, can spiral welding. These are very good representatives and the seamless steel pipe usage is extensive.
The Common Types of Welded Steel Pipes
Welded steel pipe is bent with steel or steel plate is round, square and other shapes and then welded into the surface of the seam with the steel pipe. Common types of welded steel pipe are the following:
General pipe, used to transport low-pressure fluid, easy to weld the other soft steel manufacturing. Steel pipe to pipe and thick steel pipe specifications with the nominal mouth of the water pressure, bending, flattening and other experiments, the surface quality has certain requirements, usually the length of the delivery of 4-10m is actually different, the pipe according to the provisions of the wall thickness Two kinds of steel, according to the thread and no thread two.
Roller, for belt conveyor roller welding steel pipe, the general water pressure and flattening test.
Metric welded pipe, specifications with a seamless tube form, with ordinary carbon steel, high quality carbon steel or Cape can be low-alloy steel tropical, cold belt welding, or with a tropical welding and then made by cold dial method.
Spiral welded pipe, is the low carbon carbon steel strip according to a structural steel or low alloy structure of the helix angle (called forming angle) rolled into a tube, and then welded together made of pipe, strip production of large diameter Of the steel pipe. Spiral welded pipe is mainly used for oil and natural gas pipeline, spiral welded pipe with single-sided welding and double-sided welding, welded pipe should ensure that water pressure test, weld tensile strength and cold bending performance to meet the requirements.
Metric pipe is divided into ordinary and thin wall, commonly used as structural parts, such as transmission shaft, or conveying fluid, thin wall used to produce furniture, lamps, etc., to ensure the strength of steel and bending test.
General pipe, used to transport low-pressure fluid, easy to weld the other soft steel manufacturing. Steel pipe to pipe and thick steel pipe specifications with the nominal mouth of the water pressure, bending, flattening and other experiments, the surface quality has certain requirements, usually the length of the delivery of 4-10m is actually different, the pipe according to the provisions of the wall thickness Two kinds of steel, according to the thread and no thread two.
Roller, for belt conveyor roller welding steel pipe, the general water pressure and flattening test.
Metric welded pipe, specifications with a seamless tube form, with ordinary carbon steel, high quality carbon steel or Cape can be low-alloy steel tropical, cold belt welding, or with a tropical welding and then made by cold dial method.
Spiral welded pipe, is the low carbon carbon steel strip according to a structural steel or low alloy structure of the helix angle (called forming angle) rolled into a tube, and then welded together made of pipe, strip production of large diameter Of the steel pipe. Spiral welded pipe is mainly used for oil and natural gas pipeline, spiral welded pipe with single-sided welding and double-sided welding, welded pipe should ensure that water pressure test, weld tensile strength and cold bending performance to meet the requirements.
Metric pipe is divided into ordinary and thin wall, commonly used as structural parts, such as transmission shaft, or conveying fluid, thin wall used to produce furniture, lamps, etc., to ensure the strength of steel and bending test.
2019年1月17日星期四
How to Weld for Large-diameter Welded Steel Pipe at Low Temperatures
Under cold conditions a low-carbon steel welding, the cooling rate of the welded joint, which has made cracking tendency to increase, especially in the first weld Heavy structures susceptible to cracking, it is necessary to take the following process steps:
1) Do not possible under conditions of low temperature bending, correction and assembly weldments.
2) Preheat, 16Mn seamless steel pipe welding process strictly maintained interlayer temperature should not fall below the preheating temperature.
3) Hydrogen or ultra-low hydrogen welding.
4) The whole seam continuous welding should be completed to avoid interruption.
5) When positioning welding to increase the welding current, welding speed slows down, due to increase tack welds cross-sectional area and length, preheated if necessary.
6) Not be performed on a base material arc groove surface other than the need to fill the crater when extinction.
1) Do not possible under conditions of low temperature bending, correction and assembly weldments.
2) Preheat, 16Mn seamless steel pipe welding process strictly maintained interlayer temperature should not fall below the preheating temperature.
3) Hydrogen or ultra-low hydrogen welding.
4) The whole seam continuous welding should be completed to avoid interruption.
5) When positioning welding to increase the welding current, welding speed slows down, due to increase tack welds cross-sectional area and length, preheated if necessary.
6) Not be performed on a base material arc groove surface other than the need to fill the crater when extinction.
What is carbon steel tube and its making process
Classification
Carbon steel pipe can be divided into two categories: hot and cold rolled (pull) steel.
Hot-rolled carbon steel tube is divided into general, low, medium pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe, geological steel pipes and other steel pipe.
Cold-rolled (allocated) not only comprises general carbon steel pipe steel pipe, low pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe and other steel pipes, but also includes carbon thin-walled steel, alloy thin-walled steel, stainless thin-walled stainless steel pipe, special- shaped steel. The diameter of hot-rolled seamless pipe is generally greater than 32mm, wall thickness 2.5-75mm. The diameter of cold-rolled seamless steel pipe can go to 6mm, wall thickness can be 0.25mm, outer diameter thin-walled tube to 5mm, wall thickness less than 0.25mm. The dimensional accuracy of cold-rolled is higher than that of hot-rolled.
General steel pipe: is hot-rolled or cold-rolled steel with 10,20,30,35,45 and other high quality carbon steel, 16Mn, 5MnV low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2,40MnB other alloy. 10, 20 and other low-carbon steel seamless pipes are mainly used for fluid pipes. The seamless tube made of medium carbon steel of 45,40Cr etc., used to fabricate mechanical parts, such as the force components of as cars, tractors. Usually carbon steel pipe is ought to ensure the strength and flattening test. Hot-rolled steel is in hot-rolled state or with heat treatment to deliver; Cold-rolled steel with heat treatment to deliver.
Preparation
The raw material of carbon steel pipe is round pipe billet. Round billet be?processed?into a length of about 1 meter blank by a cutting machine. And it should be delivered to the furnace by conveyor belt to heat. The billet is fed into the furnace to be heated with a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. Furnace temperature control is the key issue. After a round tube came out, then, go through the pressure punching machine to perforate. Generally, more common puncher is tapered roller punching machine. This kind of punching machine has high production efficiency, product quality, perforated expanding capacity, can perforate a variety of steels. After perforation, round tube billet has been skew?rolled, continuous rolled or extruded. After extrusion, to conduct detached sizing. Sizing machine through high-speed rotary by cone drills bit after the perforated steel billet to form steel. Pipe inner diameter is determined by the drill length of outer diameter sizing mill. After sizing, steel pipe should be taken into the cooling tower through spray cooling pipe. After cooling, steel pipe will be straightened. After straightening the steel pipe, it will go to conveyor belt to the metal detection machine (or pressure test) for internal testing. If cracks, bubbles and other issues exist in the internal pipe, they will be detected. After quality control, it should pass the strict manual selection. If the steel pipe pass the quality inspection, using spray paint label number, size, production batch number. And send it into the warehouse by a crane.
Technical Parameters
According to incomplete statistics, China's current steel pipe production enterprises are about 240, carbon steel pipe mills are about 250 sets, with an annual capacity of about 450 million tons. From the perspective of caliber, <φ76, accounting for 35%, <φ159-650, accounting for 25%. From the perspective of species, the general purpose pipe is 1.9 million tons, accounting for 54%; oil pipe is 760,000 tons, accounting for 5.7%; hydraulic prop and precision pipe are both 15 million tons, accounting for 4.3% of stainless steel tube bearing tube, pipe applied in automobile has a total of 50,000 tons, accounting for 1.4%.
Carbon steel pipe can be divided into two categories: hot and cold rolled (pull) steel.
Hot-rolled carbon steel tube is divided into general, low, medium pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe, geological steel pipes and other steel pipe.
Cold-rolled (allocated) not only comprises general carbon steel pipe steel pipe, low pressure boiler pipe, high pressure boiler pipe, steel pipe, stainless steel pipe, oil cracking pipe and other steel pipes, but also includes carbon thin-walled steel, alloy thin-walled steel, stainless thin-walled stainless steel pipe, special- shaped steel. The diameter of hot-rolled seamless pipe is generally greater than 32mm, wall thickness 2.5-75mm. The diameter of cold-rolled seamless steel pipe can go to 6mm, wall thickness can be 0.25mm, outer diameter thin-walled tube to 5mm, wall thickness less than 0.25mm. The dimensional accuracy of cold-rolled is higher than that of hot-rolled.
General steel pipe: is hot-rolled or cold-rolled steel with 10,20,30,35,45 and other high quality carbon steel, 16Mn, 5MnV low-alloy structural steel or 40Cr, 30CrMnSi, 45Mn2,40MnB other alloy. 10, 20 and other low-carbon steel seamless pipes are mainly used for fluid pipes. The seamless tube made of medium carbon steel of 45,40Cr etc., used to fabricate mechanical parts, such as the force components of as cars, tractors. Usually carbon steel pipe is ought to ensure the strength and flattening test. Hot-rolled steel is in hot-rolled state or with heat treatment to deliver; Cold-rolled steel with heat treatment to deliver.
Preparation
The raw material of carbon steel pipe is round pipe billet. Round billet be?processed?into a length of about 1 meter blank by a cutting machine. And it should be delivered to the furnace by conveyor belt to heat. The billet is fed into the furnace to be heated with a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. Furnace temperature control is the key issue. After a round tube came out, then, go through the pressure punching machine to perforate. Generally, more common puncher is tapered roller punching machine. This kind of punching machine has high production efficiency, product quality, perforated expanding capacity, can perforate a variety of steels. After perforation, round tube billet has been skew?rolled, continuous rolled or extruded. After extrusion, to conduct detached sizing. Sizing machine through high-speed rotary by cone drills bit after the perforated steel billet to form steel. Pipe inner diameter is determined by the drill length of outer diameter sizing mill. After sizing, steel pipe should be taken into the cooling tower through spray cooling pipe. After cooling, steel pipe will be straightened. After straightening the steel pipe, it will go to conveyor belt to the metal detection machine (or pressure test) for internal testing. If cracks, bubbles and other issues exist in the internal pipe, they will be detected. After quality control, it should pass the strict manual selection. If the steel pipe pass the quality inspection, using spray paint label number, size, production batch number. And send it into the warehouse by a crane.
Technical Parameters
According to incomplete statistics, China's current steel pipe production enterprises are about 240, carbon steel pipe mills are about 250 sets, with an annual capacity of about 450 million tons. From the perspective of caliber, <φ76, accounting for 35%, <φ159-650, accounting for 25%. From the perspective of species, the general purpose pipe is 1.9 million tons, accounting for 54%; oil pipe is 760,000 tons, accounting for 5.7%; hydraulic prop and precision pipe are both 15 million tons, accounting for 4.3% of stainless steel tube bearing tube, pipe applied in automobile has a total of 50,000 tons, accounting for 1.4%.
Seamless tubes are used to facilitate the transport of liquids
As an economic section steel, seamless steel pipe plays a major leading role in economic development and construction. Then every place in life can see its existence, then it means that its use is very wide, and because of its different uses, it is divided into many varieties, and because of different manufacturing processes, seamless steel pipes are also divided into hot rolling. Sewed steel pipe and cold drawn seamless steel pipe. However, cold-rolled steel pipes also have a circular tube and a shaped tube, and the use is also different.
Then seamless steel pipes are suitable for those places in our lives. In fact, we do not know the circular pipes that transport various fuels of water and oil. In fact, this pipe is a seamless steel pipe, so its first use. It is used to transport fluids. We also know that the steel pipes on the construction site are mainly used for stable structures and are used in general construction and mechanical structures, so they can also be applied to our lives. Some cylinders also need to use seamless steel tubes, just like various gas and hydraulic cylinders, not only liquid solids, but also vapors.
The seamless steel pipe for fluid transportation is a steel pipe having a hollow section and having no weld seam from beginning to end. Its practicability is better than that of lsaw steel pipe. The use of steel pipe to manufacture ring parts can improve the material utilization rate, simplify the manufacturing process, save materials and processing man-hours, such as rolling bearing rings, jack sleeves, etc., and have been widely used in steel pipes. Steel pipes are also indispensable materials for various conventional weapons, and barrels, barrels, etc. are all made of steel pipes. Steel pipes can be divided into round pipes and shaped pipes according to the shape of the cross-sectional area. Since the area of the circle is the largest under the condition of equal circumference, more fluid can be transported by the circular tube. In addition, the circular section of the ring is subjected to internal or external radial pressure, the force is relatively uniform, therefore, most of the steel pipe is a round pipe.
Compared with solid steel such as round steel, the fluid conveying pipe is light in weight when it has the same bending and torsional strength. It is an economical section steel and is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes and automobile transmissions. Shafts, bicycle frames, and steel scaffolding used in construction. The use of steel pipes to manufacture ring-shaped parts can improve the material utilization rate, simplify the manufacturing process, save materials and processing man-hours, such as rolling bearing rings, jack sleeves, etc., and have been widely used for fluid transportation pipes.
http://www.xysteelpipe.com/info/Seamless-tubes-are-used-to-facilitate-the-transport-of-liquids-1316-1.htm
Then seamless steel pipes are suitable for those places in our lives. In fact, we do not know the circular pipes that transport various fuels of water and oil. In fact, this pipe is a seamless steel pipe, so its first use. It is used to transport fluids. We also know that the steel pipes on the construction site are mainly used for stable structures and are used in general construction and mechanical structures, so they can also be applied to our lives. Some cylinders also need to use seamless steel tubes, just like various gas and hydraulic cylinders, not only liquid solids, but also vapors.
The seamless steel pipe for fluid transportation is a steel pipe having a hollow section and having no weld seam from beginning to end. Its practicability is better than that of lsaw steel pipe. The use of steel pipe to manufacture ring parts can improve the material utilization rate, simplify the manufacturing process, save materials and processing man-hours, such as rolling bearing rings, jack sleeves, etc., and have been widely used in steel pipes. Steel pipes are also indispensable materials for various conventional weapons, and barrels, barrels, etc. are all made of steel pipes. Steel pipes can be divided into round pipes and shaped pipes according to the shape of the cross-sectional area. Since the area of the circle is the largest under the condition of equal circumference, more fluid can be transported by the circular tube. In addition, the circular section of the ring is subjected to internal or external radial pressure, the force is relatively uniform, therefore, most of the steel pipe is a round pipe.
Compared with solid steel such as round steel, the fluid conveying pipe is light in weight when it has the same bending and torsional strength. It is an economical section steel and is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes and automobile transmissions. Shafts, bicycle frames, and steel scaffolding used in construction. The use of steel pipes to manufacture ring-shaped parts can improve the material utilization rate, simplify the manufacturing process, save materials and processing man-hours, such as rolling bearing rings, jack sleeves, etc., and have been widely used for fluid transportation pipes.
http://www.xysteelpipe.com/info/Seamless-tubes-are-used-to-facilitate-the-transport-of-liquids-1316-1.htm
2019年1月16日星期三
The influence of cold air on steel pipe plant
Carbon steel pipe manufacturer in China was informed from last week, more than in response to continuous haze weather, emergency introduction of a series of initiatives. For example, the 17th night, Shijiazhuang municipal government introduced a series of emergency measures, from November 2016 to December 31, 2016, the main city of motor vehicle odd and even number limit line, pipe and other seven major industries all stop production, the units Wrong when to get off work. At the same time, Taiyuan, Shanxi Province, November 17 night release of heavily polluted yellow weather warning, which is the city since the beginning of winter issued the first yellow warning. Pipe, coking, electricity and other key industries and enterprises to limit production limited row, the focus on polluting enterprises 24-hour factory inspection, all urban housing construction, demolition construction, municipal, roads and other sites to stop earthwork operations.
Steel production impact will be affected, according to the daily normal shipments, the inventory, the impact on the steel market, Short-term or a slight decline. While steel prices or play a certain support. However, the limited outdoor construction in these areas has also resulted in short-term purchases of steel products to reduce the situation, so the short-term forecast of steel inventories or to maintain the low level.
The strongest northern cold air strikes the South more rain
According to 21 sources said the second half of the strongest cold air will be officially angry, the Central Meteorological Observatory issued a cold-wave early warning. Affected by the cold weather, 21-24, most of the eastern part of China from north to south will generally appear 6-10 ℃ cooling and 4-6 gale weather, local cooling rate can exceed 16 ℃, the cold weather will lead to China has appeared this year more than the lowest since the winter temperature.
Steel production impact will be affected, according to the daily normal shipments, the inventory, the impact on the steel market, Short-term or a slight decline. While steel prices or play a certain support. However, the limited outdoor construction in these areas has also resulted in short-term purchases of steel products to reduce the situation, so the short-term forecast of steel inventories or to maintain the low level.
The strongest northern cold air strikes the South more rain
According to 21 sources said the second half of the strongest cold air will be officially angry, the Central Meteorological Observatory issued a cold-wave early warning. Affected by the cold weather, 21-24, most of the eastern part of China from north to south will generally appear 6-10 ℃ cooling and 4-6 gale weather, local cooling rate can exceed 16 ℃, the cold weather will lead to China has appeared this year more than the lowest since the winter temperature.
ERW straight seam resistance welded steel pipe
1、 the difference between raw material and production capacity
ERW steel pipe raw material is hot rolled steel coils, UOE pipe raw material is hot rolled steel plate. So the ERW steel tube can realize continuous assembly line work, high production efficiency, production cost is low; And UOE pipe made with steel plate processing, unable to realize continuous assembly line, the production efficiency is low, the production cost is high.
ERW steel pipe limited by the thickness of the steel coil, general can produce the biggest thickness is 25 mm, it can produce the biggest diameter is 660 mm; And can produce the maximum thickness of UOE pipe to 40 mm, it can produce the largest diameter is only restricted by steel plate width, now can produce maximum diameter is 1422 mm.
2、 the welded steel pipe
ERW steel pipe welding does not need to add solder wire; UOE pipe is added welding wire.
3、 difference in appearance
ERW steel tube to remove both internal and external welding seam, so good for anti-corrosion; UOE pipe weld more than high, inside and outside wall against corrosion.
4、 the purchase cost and the difficulty
ERW steel pipe procurement costs low, the cost of UOE pipe is very high, generally spread of 15% to 15%. Domestic production of UOE pipe manufacturer is less, purchasing difficulty is high. When diameter < Φ 406 mm, the procurement cost difference is bigger.
ERW steel pipe manufacturer is more, low purchasing difficulty, when the diameter of < Φ 406 mm, will greatly reduce the purchasing cost.
5、 the application of distinction
ERW steel tube is mainly used in natural gas, refined oil, crude oil, such as pulp land long distance pipeline.
UOE pipe is mainly used in high voltage long distance pipeline, cold area at the bottom of the two, three, four, land area.
ERW steel pipe raw material is hot rolled steel coils, UOE pipe raw material is hot rolled steel plate. So the ERW steel tube can realize continuous assembly line work, high production efficiency, production cost is low; And UOE pipe made with steel plate processing, unable to realize continuous assembly line, the production efficiency is low, the production cost is high.
ERW steel pipe limited by the thickness of the steel coil, general can produce the biggest thickness is 25 mm, it can produce the biggest diameter is 660 mm; And can produce the maximum thickness of UOE pipe to 40 mm, it can produce the largest diameter is only restricted by steel plate width, now can produce maximum diameter is 1422 mm.
2、 the welded steel pipe
ERW steel pipe welding does not need to add solder wire; UOE pipe is added welding wire.
3、 difference in appearance
ERW steel tube to remove both internal and external welding seam, so good for anti-corrosion; UOE pipe weld more than high, inside and outside wall against corrosion.
4、 the purchase cost and the difficulty
ERW steel pipe procurement costs low, the cost of UOE pipe is very high, generally spread of 15% to 15%. Domestic production of UOE pipe manufacturer is less, purchasing difficulty is high. When diameter < Φ 406 mm, the procurement cost difference is bigger.
ERW steel pipe manufacturer is more, low purchasing difficulty, when the diameter of < Φ 406 mm, will greatly reduce the purchasing cost.
5、 the application of distinction
ERW steel tube is mainly used in natural gas, refined oil, crude oil, such as pulp land long distance pipeline.
UOE pipe is mainly used in high voltage long distance pipeline, cold area at the bottom of the two, three, four, land area.
2019年1月9日星期三
Seamless steel tube hardness test
In general, seamless steel pipe uses Brinell, Rockwell, Vickers three hardness indicators to measure the hardness.
1. Brinell hardness
In the standard of seamless steel pipe, Brinell hardness is used most, it often use indentation diameter to represent the hardness of the material, which is both intuitive and convenient. But it is not suitable for harder or thinner steel pipes.
2. Rockwell hardness
The Rockwell hardness test of seamless steel tubes is the same as the Brinell hardness test, they are both indentation test method. The difference is that Rockwell hardness measures the depth of indentation. Rockwell hardness test is a widely-used method currently, HRC is next only to after Brinell hardness HB in the steel pipe standard. Rockwell hardness can be applied to measure metal material from very soft to very hard, which makes up for the weakness of Brinell method. And it is simpler than the Brinell method, it can read out the hardness value directly from the hardness of the dial. However, its hardness value is not as good as the Brinell method because its indentation is small.
3. Vickers hardness
Vickers hardness test of seamless steel tube is also an indentation test method, it can be used to measure the thin metal materials and surface layer hardness. It has the main advantages of the Brinell and Rockwell methods, and overcomes their basic shortcomings. But it is not as easy as the Rockwell method, so Vickers method is rarely used in the steel pipe standard.
1. Brinell hardness
In the standard of seamless steel pipe, Brinell hardness is used most, it often use indentation diameter to represent the hardness of the material, which is both intuitive and convenient. But it is not suitable for harder or thinner steel pipes.
2. Rockwell hardness
The Rockwell hardness test of seamless steel tubes is the same as the Brinell hardness test, they are both indentation test method. The difference is that Rockwell hardness measures the depth of indentation. Rockwell hardness test is a widely-used method currently, HRC is next only to after Brinell hardness HB in the steel pipe standard. Rockwell hardness can be applied to measure metal material from very soft to very hard, which makes up for the weakness of Brinell method. And it is simpler than the Brinell method, it can read out the hardness value directly from the hardness of the dial. However, its hardness value is not as good as the Brinell method because its indentation is small.
3. Vickers hardness
Vickers hardness test of seamless steel tube is also an indentation test method, it can be used to measure the thin metal materials and surface layer hardness. It has the main advantages of the Brinell and Rockwell methods, and overcomes their basic shortcomings. But it is not as easy as the Rockwell method, so Vickers method is rarely used in the steel pipe standard.
Welding defects and welding quality of SSAW steel pipe
What is the welding qulity of SSAW steel pipe? It is the the degree to which the welding product meets the design technical requirements. Pipe manufacturer usually ensure the welding qulity of SSAW steel pipe by design quality, processing quality, quality inspection, post-weld treatment, etc., since the welding quality not only affects welding products's use performance and life, it also affects personal and property safety.
Welding quality usually appears as welding defects, that includes external defects and internal defects. External defects refer to excess height does not meet the requirements, welding tumor, undercut, crater, arc burns, surface pores, surface cracks, welding deformation and warping. Internal defects refer to cracks, not penetration, not fused, slag and porosity.
How to prevent the appearance of welding defects to ensure the welding quality?
1. Welding method should be suitable for the characteristics of components, and its economical efficiency should be good. The welding process should be able to minimize stress, deformation and stress concentration. Production labor and material consumption should be as small as possible, the convenience of flaw detection should also be taken into consideration when design the joint. The type of joint used in the welding product and its calculated strength should meet the actual carrying capacity.
2. The performance of the base metal, wire, flux or welding electrodes and other welding materials those adopted by pipe manufacturer should meet the design requirements. The performance of welder, auxiliary equipment and testing equipment should be good. Before welding, the welding material should be dried according to the provisions, the welding groove of workpiece should meet the requirements and remove the cutting residue, cracks and dirt.
3. Pipe manufacturer should carry out quality inspection through the whole production process from design to finished product, we must ensure that the test method used in the quality inspection process is rationality, the reliability of the testing instrument and inspection staff technical level. We should use various inspection methods to test the properties of the joints, physical properties, mechanical properties, microstructure, chemical composition, corrosion resistance, appearance dimensions and welding defects of products after welding.
Welding quality usually appears as welding defects, that includes external defects and internal defects. External defects refer to excess height does not meet the requirements, welding tumor, undercut, crater, arc burns, surface pores, surface cracks, welding deformation and warping. Internal defects refer to cracks, not penetration, not fused, slag and porosity.
How to prevent the appearance of welding defects to ensure the welding quality?
1. Welding method should be suitable for the characteristics of components, and its economical efficiency should be good. The welding process should be able to minimize stress, deformation and stress concentration. Production labor and material consumption should be as small as possible, the convenience of flaw detection should also be taken into consideration when design the joint. The type of joint used in the welding product and its calculated strength should meet the actual carrying capacity.
2. The performance of the base metal, wire, flux or welding electrodes and other welding materials those adopted by pipe manufacturer should meet the design requirements. The performance of welder, auxiliary equipment and testing equipment should be good. Before welding, the welding material should be dried according to the provisions, the welding groove of workpiece should meet the requirements and remove the cutting residue, cracks and dirt.
3. Pipe manufacturer should carry out quality inspection through the whole production process from design to finished product, we must ensure that the test method used in the quality inspection process is rationality, the reliability of the testing instrument and inspection staff technical level. We should use various inspection methods to test the properties of the joints, physical properties, mechanical properties, microstructure, chemical composition, corrosion resistance, appearance dimensions and welding defects of products after welding.
Difference between cold drawn and hot rolled seamless steel tube pickling
Pickling is an important step during the seamless steel pipe production. And there is difference for cold drawing and hot rolling in this step. We need to pay attention to it, thus we will provide suitable and high quality pipelines for our clients.
Generally speaking, we should take notice that if there is a large amount of foaming on the surface. As this may lead to the wrong standard for pipeline which will have influence for quality.
Appearance: Cold-rolled pipe is shorter than that of hot-rolled pipe.
Wall thickness: The wall thickness of cold-rolled pipe is generally smaller than that of hot-rolled pipe.
Surface looks: The surface looks brighter than thick-walled seamless steel pipe.
Generally speaking, we should take notice that if there is a large amount of foaming on the surface. As this may lead to the wrong standard for pipeline which will have influence for quality.
Appearance: Cold-rolled pipe is shorter than that of hot-rolled pipe.
Wall thickness: The wall thickness of cold-rolled pipe is generally smaller than that of hot-rolled pipe.
Surface looks: The surface looks brighter than thick-walled seamless steel pipe.
Method for distinguishing between seamless and straight welded steel tubes
Nowadays, all walks of life are really very competitive. No matter what industry has competition, the straight seam steel pipe industry is no exception. Many manufacturers will use straight seam steel pipe as a seamless steel pipe in order to increase profits. It is not advisable, let's take a look at it in detail.
Straight seam steel pipes are all submerged arc welding or electric resistance welding. There is only one weld seam in this steel pipe. The bad traders use the polishing machine to polish and weld the weld seam. After repeated grinding and polishing, the weld seam will be worn away. The smooth surface as a whole is a seamless steel pipe. It is not seen by professionals. This kind of falsification, the equipment has no way to detect it. Whether it is straight seam or seamless, only the insider can see it. Some projects need appearance. Brushing a layer of anti-rust paint, which makes it harder to distinguish, which makes many buyers very distressed.
So how do you distinguish between straight seam steel pipes and seamless steel pipes? Seamless steel tubes are made directly in steel mills. Straight seam steel pipe manufacturers are not produced at all. When we buy, we will try our best to provide the supplier with the guarantee and certificate of steel pipe, and even if they do it well. There are also traces. Generally, the width of a straight seam steel pipe weld is about two centimeters.
After buying a seamless steel pipe, if we see a trace of about two centimeters on the whole of the steel pipe, we can cut it to verify whether there is a problem. The seamless steel pipe is painted with anti-rust paint. We can verify it by simple and rough method. It is to cut the steel pipe directly in the middle part. The seamless steel pipe is not butted, and the straight seam steel pipe is a plate. After the folding, the joint is welded.
http://www.xysteelpipe.com/info/Method-for-distinguishing-between-seamless-and-straight-welded-steel-tubes-1310-1.htm
Straight seam steel pipes are all submerged arc welding or electric resistance welding. There is only one weld seam in this steel pipe. The bad traders use the polishing machine to polish and weld the weld seam. After repeated grinding and polishing, the weld seam will be worn away. The smooth surface as a whole is a seamless steel pipe. It is not seen by professionals. This kind of falsification, the equipment has no way to detect it. Whether it is straight seam or seamless, only the insider can see it. Some projects need appearance. Brushing a layer of anti-rust paint, which makes it harder to distinguish, which makes many buyers very distressed.
So how do you distinguish between straight seam steel pipes and seamless steel pipes? Seamless steel tubes are made directly in steel mills. Straight seam steel pipe manufacturers are not produced at all. When we buy, we will try our best to provide the supplier with the guarantee and certificate of steel pipe, and even if they do it well. There are also traces. Generally, the width of a straight seam steel pipe weld is about two centimeters.
After buying a seamless steel pipe, if we see a trace of about two centimeters on the whole of the steel pipe, we can cut it to verify whether there is a problem. The seamless steel pipe is painted with anti-rust paint. We can verify it by simple and rough method. It is to cut the steel pipe directly in the middle part. The seamless steel pipe is not butted, and the straight seam steel pipe is a plate. After the folding, the joint is welded.
http://www.xysteelpipe.com/info/Method-for-distinguishing-between-seamless-and-straight-welded-steel-tubes-1310-1.htm
2019年1月8日星期二
Trachoma in welded pipe and galvanized pipe
Welded pipes and galvanized pipes often bear major tasks such as structural support, fire water supply, etc., which are related to the safety of people's lives and property, and must not be lost. Problems such as trachoma and leakage welding may cause the stress structure of the pipe to change and the pressure bearing capacity to become weak, resulting in bending and fracture of the structural pipe, and accidents such as water leakage and pipe bursting of the water supply pipe. So, why are there problems with trachoma and leakage welding in pipe products? Mainly for the following reasons:
1. The strip of production pipe is deformed by collision
The welded pipe is also good, and the galvanized pipe is also welded by strip rolling. If the strip is in the process of transportation, the edge receives the collision, the bending is deformed, and the trachoma and the missing welding are easy to occur during the welding. phenomenon. To solve this problem, in addition to avoiding the collision during the transportation of the strip steel, pay attention to the protection of the strip steel, that is, mark the obvious deformation parts before the strip steel machine, and focus on the marked parts after the tube production is completed. Dispose of waste immediately if there is a quality problem.
2. Welder jump fire
The situation of welder fire jumping is mainly caused by the negligence of the staff and does not occur frequently. However, in the event of a welder flashover, it will inevitably lead to leakage welding.
3. Production line replacement production product size specifications
When the pipe production line is replaced with the size specification of the production product, the first few pipe products produced are prone to problems of trachoma and leakage welding due to the size specifications of the machine that have not been adapted at the beginning. Manufacturers with better quality control management will directly scrap the several tubes that were just started when the product size specifications were replaced. In order to improve the yield and reduce the production cost, many manufacturers sell such pipes as qualified products. Although the price is cheap, the problems caused by them are infinite.
http://www.xysteelpipe.com/info/Trachoma-in-welded-pipe-and-galvanized-pipe-1309-1.htm
1. The strip of production pipe is deformed by collision
The welded pipe is also good, and the galvanized pipe is also welded by strip rolling. If the strip is in the process of transportation, the edge receives the collision, the bending is deformed, and the trachoma and the missing welding are easy to occur during the welding. phenomenon. To solve this problem, in addition to avoiding the collision during the transportation of the strip steel, pay attention to the protection of the strip steel, that is, mark the obvious deformation parts before the strip steel machine, and focus on the marked parts after the tube production is completed. Dispose of waste immediately if there is a quality problem.
2. Welder jump fire
The situation of welder fire jumping is mainly caused by the negligence of the staff and does not occur frequently. However, in the event of a welder flashover, it will inevitably lead to leakage welding.
3. Production line replacement production product size specifications
When the pipe production line is replaced with the size specification of the production product, the first few pipe products produced are prone to problems of trachoma and leakage welding due to the size specifications of the machine that have not been adapted at the beginning. Manufacturers with better quality control management will directly scrap the several tubes that were just started when the product size specifications were replaced. In order to improve the yield and reduce the production cost, many manufacturers sell such pipes as qualified products. Although the price is cheap, the problems caused by them are infinite.
http://www.xysteelpipe.com/info/Trachoma-in-welded-pipe-and-galvanized-pipe-1309-1.htm
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