Manufacturer of steel pipe like seamless steel pipe, ERW steel pipe, LSAW steel pipe, would make each kind of product as artwork. And we all know it is uneasy if the work don’t brilliant for engineering project. So even for steel pipe’s strength, we would like to have patience for researching it.
First of all, the strength of the steel pipe relies on alloy composition. We should follow the high quality principle to add the alloy composition instead of violating it. All composition would include seamless and seamed steel pipe for substantially uniform strength alloy and its heat treatment. We can make it according to relative standard of the steel pipe.
What’s more, tensile test and three-dimensional vibration test would be necessary before selling. We all know that tearing of steel pipe joint would happen almost in away from the welding spot or the heating place. Thus we have equipment test such as Chemical Component Analysis, Mechanical Properties (Ultimate tensile strength, Yield strength, Elongation), Technical Properties (Flattening Test, Bending Test, Blow Test, Impact Test), Exterior Size Inspection, Hydrostatic Test, X-ray Test and so on.
http://www.xysteelpipe.com/info/Factors-affecting-strength-of-steel-pipe-963-1.htm
2018年3月27日星期二
How to choose the high quality 304 stainless steel tube
Firstly, before the selection of 304 stainless steel pipe, you should consider its usage and environment. We often use weld pipe for decoration, seamless steel pipes for fluid delivery, sanitary stainless steel pipes for medical or kitchen, thick-walled steel pipes for pressure. 200 series material can be used for indoors and 304 can be used for outdoors. In the alkaline or coastal areas, level over 316 materials are generally used.
Secondly, the selection of 304 stainless steel pipes must be standard. From the price analysis, if the 304 stainless steel pipe is lower than 301, then you should carefully identify. It is likely replaced by other materials. Recognize whether the surface has the material words "304", and check the quality certificate from manufacturer. Using acid reagent for test, 304 stainless steel pipes will not change color after 30 seconds but 201 will getting black. If you need to purchase in bulk, you'd better take some samples to the national authority for component testing.
Thirdly, observe the outer surface and inner wall color if it is bright and smooth, the thickness is uniform or rough. Generally, welded pipe need not to check. However, seamless steel pipe is manufactured by cold drawn or hot rolling, the surface is to crack with improper operation in the production process. If the surface is rough, it generally means seamless steel pipes have not been polished.
http://www.xysteelpipe.com/info/How-to-choose-the-high-quality-304-stainless-steel-tube-964-1.htm
Secondly, the selection of 304 stainless steel pipes must be standard. From the price analysis, if the 304 stainless steel pipe is lower than 301, then you should carefully identify. It is likely replaced by other materials. Recognize whether the surface has the material words "304", and check the quality certificate from manufacturer. Using acid reagent for test, 304 stainless steel pipes will not change color after 30 seconds but 201 will getting black. If you need to purchase in bulk, you'd better take some samples to the national authority for component testing.
Thirdly, observe the outer surface and inner wall color if it is bright and smooth, the thickness is uniform or rough. Generally, welded pipe need not to check. However, seamless steel pipe is manufactured by cold drawn or hot rolling, the surface is to crack with improper operation in the production process. If the surface is rough, it generally means seamless steel pipes have not been polished.
http://www.xysteelpipe.com/info/How-to-choose-the-high-quality-304-stainless-steel-tube-964-1.htm
2018年3月26日星期一
The Two Benefits of Seamless Steel Commercial Pipe
Steel pipes are ubiquitous and can be found underground and within residential walls, laboratories, and commercial and industrial structures. The pipes transport fluids including water, natural gas, waste and air. Three manufacturing methods exist to produce steel pipes. Seamless steel pipes are produced using an extrusion mold. Welded steel pipes are produced by rolling a sheet of steel into a tube and welding the seam.
The seamless steel pipe manufacturing process starts with a solid, round steel billet. This billet is then heated to great temperatures and stretched and pulled over a form until it takes the shape of a hollow tube. As other steel pipe suppliers will tell you, there are three great advantages to making a pipe in this way.
Increased Pressure Ratings
The greatest advantage of seamless steel pipes is their increased ability to withstand pressure. The weakest point in a welded steel pipe is the welded seam. But because a seamless steel pipe has not been welded, it doesn’t have that seam, making it equally strong around the entire circumference of the pipe.
It is also much easier to determine pressure calculations without being required to take weld quality into consideration.
Although seamless pipe can sometimes be more expensive than welded pipe, this increased ability to withstand pressure allows you to use pipes that are thinner and lighter, which can help cut down on expenses.
Uniformity of Shape
Because welded seam pipe is wrapped around another form before it is welded, and because welding adds heat, stress and other extraneous variables to the forming process, it can never be as round as seamless steel pipe.
Seamless steel pipe is a continuous extrusion of the alloy, meaning that it will have a round cross section that you can count on, which is helpful when you’re installing pipes or adding fittings.
http://www.xysteelpipe.com/info/The-Two-Benefits-of-Seamless-Steel-Commercial-Pipe-959-1.htm
The seamless steel pipe manufacturing process starts with a solid, round steel billet. This billet is then heated to great temperatures and stretched and pulled over a form until it takes the shape of a hollow tube. As other steel pipe suppliers will tell you, there are three great advantages to making a pipe in this way.
Increased Pressure Ratings
The greatest advantage of seamless steel pipes is their increased ability to withstand pressure. The weakest point in a welded steel pipe is the welded seam. But because a seamless steel pipe has not been welded, it doesn’t have that seam, making it equally strong around the entire circumference of the pipe.
It is also much easier to determine pressure calculations without being required to take weld quality into consideration.
Although seamless pipe can sometimes be more expensive than welded pipe, this increased ability to withstand pressure allows you to use pipes that are thinner and lighter, which can help cut down on expenses.
Uniformity of Shape
Because welded seam pipe is wrapped around another form before it is welded, and because welding adds heat, stress and other extraneous variables to the forming process, it can never be as round as seamless steel pipe.
Seamless steel pipe is a continuous extrusion of the alloy, meaning that it will have a round cross section that you can count on, which is helpful when you’re installing pipes or adding fittings.
http://www.xysteelpipe.com/info/The-Two-Benefits-of-Seamless-Steel-Commercial-Pipe-959-1.htm
Advantages of Disadvantages of Spirally Welded Pipes
The advantages of spirally welded pipes production are:
(l) Using steel strips of the same width can produce steel pipes of different diameters.
(2) Spirally welds are less stressful than straight seams, being only 75-90% of straight seam welded pipes, and are therefore able to carry larger pressures. Compared with the straight welded pipe of the same diameter, the wall thickness can be reduced by 10-25%. From the material mechanics point of view, a thin-walled circular tube (such as the oil pipeline), when it is subjected to internal pressure radial stress & c is the axis Twice the stress &l (see Equation 15-4.5.). Therefore, the radial stress is the decisive factor in determining the wall thickness. The tangent of the spiral weld seam forms an angle α with the longitudinal straight line on the surface of the tube body (ie, the parallel line on the surface of the cylinder axis). It is called forming angle.
(3) The size is correct, generally, the diameter tolerance is not more than 0.12%, the deflection is less than 1/2000, and the ellipticity is less than 1%. Generally, the sizing and the straightening process can be omitted.
(4) Continuous production: Theoretically, it is possible to produce steel pipes without infinite length. The loss of cutting and cutting tails is small, and the utilization factor of metals can be increased by 6 to 8%.
(5) Flexible operation, easy to change the type of the product (compared with the straight seam welded pipe).
(6) The equipment is light in weight and the initial investment is small. Some units make a flow and can be produced directly on the pipeline construction site.
(7) It is easy to realize urbanization and automatic production.
The disadvantages of spirally welded pipe production are: due to the use of rolled steel as the material, there is a larger crescent of the crescent, and the welding point is in the region of the edge of the strip with elasticity, so it is not easy to align the welding torch, affecting the welding quality. For this purpose, complex weld seam tracking and quality inspection equipment needs to be set up.
http://www.xysteelpipe.com/info/Advantages-of-Disadvantages-of-Spirally-Welded-Pipes-960-1.htm
(l) Using steel strips of the same width can produce steel pipes of different diameters.
(2) Spirally welds are less stressful than straight seams, being only 75-90% of straight seam welded pipes, and are therefore able to carry larger pressures. Compared with the straight welded pipe of the same diameter, the wall thickness can be reduced by 10-25%. From the material mechanics point of view, a thin-walled circular tube (such as the oil pipeline), when it is subjected to internal pressure radial stress & c is the axis Twice the stress &l (see Equation 15-4.5.). Therefore, the radial stress is the decisive factor in determining the wall thickness. The tangent of the spiral weld seam forms an angle α with the longitudinal straight line on the surface of the tube body (ie, the parallel line on the surface of the cylinder axis). It is called forming angle.
(3) The size is correct, generally, the diameter tolerance is not more than 0.12%, the deflection is less than 1/2000, and the ellipticity is less than 1%. Generally, the sizing and the straightening process can be omitted.
(4) Continuous production: Theoretically, it is possible to produce steel pipes without infinite length. The loss of cutting and cutting tails is small, and the utilization factor of metals can be increased by 6 to 8%.
(5) Flexible operation, easy to change the type of the product (compared with the straight seam welded pipe).
(6) The equipment is light in weight and the initial investment is small. Some units make a flow and can be produced directly on the pipeline construction site.
(7) It is easy to realize urbanization and automatic production.
The disadvantages of spirally welded pipe production are: due to the use of rolled steel as the material, there is a larger crescent of the crescent, and the welding point is in the region of the edge of the strip with elasticity, so it is not easy to align the welding torch, affecting the welding quality. For this purpose, complex weld seam tracking and quality inspection equipment needs to be set up.
http://www.xysteelpipe.com/info/Advantages-of-Disadvantages-of-Spirally-Welded-Pipes-960-1.htm
Advantages of Prepainted Galvanized Steel Coil
Prepainted galvanized steel coil made of hot-dip galvanized sheet, hot-dip aluminum zinc plate, electro-galvanized sheet, after surface pretreatment (chemical degreasing and chemical conversion treatment). Prepainted galvanized steel coil is coated with layers of organic paint, and then baked, through the curing process. This steel plate has bright appearance, which has good performance of a variety of materials.
Prepainted galvanized steel coils not only greatly improve the chemical stability of the material, but also have more effective anti-rust and anti-corrosion properties. The extensive applications of prepainted galvanized steel coil also depends on its good performance, high quality prepainted galvanized steel coil is coated with high strength steel materials, and easy to shape.
It is worth to mention that all the raw materials used in the production of prepainted galvanized steel coils are environmentally friendly materials, whether it is the production or later use, it has a very high environmental characteristics.
Prepainted galvanized steel coil has features such as light weight, good corrosion resistance. It can be processed directly. In general, we can see color gray, navy, red brick in market. Prepainted galvanized steel coil can be widely used in the advertising industry, construction, household appliances industry, electrical industry, furniture industry and transport industry.
http://www.xysteelpipe.com/info/Advantages-of-Prepainted-Galvanized-Steel-Coil-961-1.htm
Prepainted galvanized steel coils not only greatly improve the chemical stability of the material, but also have more effective anti-rust and anti-corrosion properties. The extensive applications of prepainted galvanized steel coil also depends on its good performance, high quality prepainted galvanized steel coil is coated with high strength steel materials, and easy to shape.
It is worth to mention that all the raw materials used in the production of prepainted galvanized steel coils are environmentally friendly materials, whether it is the production or later use, it has a very high environmental characteristics.
Prepainted galvanized steel coil has features such as light weight, good corrosion resistance. It can be processed directly. In general, we can see color gray, navy, red brick in market. Prepainted galvanized steel coil can be widely used in the advertising industry, construction, household appliances industry, electrical industry, furniture industry and transport industry.
http://www.xysteelpipe.com/info/Advantages-of-Prepainted-Galvanized-Steel-Coil-961-1.htm
Welding process of straight seam welded pipe
Longitudinal straight seam welded pipe butt weld joint cross-sectional shape, depending on the thickness of the body to be welded before welding groove and then type two sides. When welding thick steel plate, for penetration in contact at the edges out of various shapes of the groove, so that more easily into the welding rod or wire. Groove patterns are one-sided welding the welding groove and the sides of the groove. When you select groove type, in addition to outside should be considered to ensure penetration welding convenient, less filler metal Chi, small welding deformation and beveling of Longitudinal low cost factor.
Linker connecting the two is in the welding Longitudinal seam formed called weld. Both sides of the weld in the welding welding heat effect will be, but the organization and performance vary, this area is known as the heat affected zone. Welding due to the workpiece material welding materials, Longitudinal welding current so different, after welding may occur in the weld and heat affected zone of overheating, embrittlement, hardening or softening, but also the weldment performance degradation, deterioration of weldability. This need to adjust the welding conditions, before welding weldment interface preheating, post-weld heat when and weld heat treatment can improve the quality of welding weldment quality.
Longitudinal is of two or more homogeneous or heterogeneous material through a combination of diffusion and the question of the atom or molecule is integrally connected to the process, prompting the question of atoms and molecules produce binding and diffusion method is to heat or pressure, or simultaneously heated and pressurized.
In addition, a local weld foot rapid heating and cooling process, the weld zone due to the binding body and four weeks of the workpiece can not freely expand and contract in the weldment after cooling will produce welding stress and deformation. Important product after welding is required to eliminate welding stress, welding distortion correction.
Check www.tjxysteel.com for more info
Linker connecting the two is in the welding Longitudinal seam formed called weld. Both sides of the weld in the welding welding heat effect will be, but the organization and performance vary, this area is known as the heat affected zone. Welding due to the workpiece material welding materials, Longitudinal welding current so different, after welding may occur in the weld and heat affected zone of overheating, embrittlement, hardening or softening, but also the weldment performance degradation, deterioration of weldability. This need to adjust the welding conditions, before welding weldment interface preheating, post-weld heat when and weld heat treatment can improve the quality of welding weldment quality.
Longitudinal is of two or more homogeneous or heterogeneous material through a combination of diffusion and the question of the atom or molecule is integrally connected to the process, prompting the question of atoms and molecules produce binding and diffusion method is to heat or pressure, or simultaneously heated and pressurized.
In addition, a local weld foot rapid heating and cooling process, the weld zone due to the binding body and four weeks of the workpiece can not freely expand and contract in the weldment after cooling will produce welding stress and deformation. Important product after welding is required to eliminate welding stress, welding distortion correction.
Check www.tjxysteel.com for more info
Causes of Hot Rolling Cracks in N80 Oil Casing
Hot-rolled seamless steel pipe production is one of the important processes, the rational development of its process plan or not, a direct impact on the size of the steel pipe after rolling the surface of the precision and quality,
Unreasonable process plan will cause the inner surface of the steel pipe to produce the defects such as folding, crack and concave.
N80 steel casing is a standard oil casing commonly used in oil (for the seamless steel pipe), the standard provisions of the finished pipe heat treatment process for quenching and tempering.
N80 casing production process is as follows: furnace refining → continuous casting → annular furnace → perforation → continuous rolling → stepping furnace → sizing → sawing → tempering treatment → straightening → physical and chemical testing → testing → thread processing → Coupling tight → water pressure test → measuring length weighing, marking → packaging storage. The billet was heated in an annular furnace for about 2.5 hours, perforated at about 1250 °C and then subjected to continuous rolling. The sintering temperature was 950 °C and the finish rolling temperature was 900 °C. The chemical composition of the tube from the test results can know the chemical composition of the tube is not the cause of the formation of cracks. From the metallographic, The results of EDS analysis show that both the crack tip and the middle part contain iron oxide inclusions. The crack is a non-quenching crack and should be produced before the heat treatment. This is probably caused by the perforation and hot rolling of the steel tube.
In the process of perforation of steel pipe, because temperature non-uniformity and uneven deformation have a large additional stress, the blank in the perforation easy to crack; And the heating temperature is too high, will also be due to reduce the intergranular binding force cracks; if the heating temperature is too low, due to lower plasticity, deformation resistance and deterioration of the perforation conditions, will also crack. In addition, the perforation process, due to the presence of additional deformation, when the billet surface will produce longitudinal shear stress and transverse shear shear stress. Therefore, there is a large lateral and longitudinal additional stress in the outer layer of the steel tube. In the case of non-uniform heating of the tube, when the superposition of the transverse basic stress and the additional tensile stress exceeds the intergranular bonding force, Small cracks, these cracks in the subsequent rolling and sizing process, along the rolling direction is elongated and extended to form the final crack. Therefore, in the future production should pay special attention to the perforation temperature, sizing temperature and finishing temperature of the monitoring and control, as far as possible the temperature fluctuations in the control within ± 20 ℃, and should increase the light tube end of the test strength, If necessary, increase the cut length of the pipe end.
N80 casing pipe end crack is in the steel pipe perforation and rolling process; when the billet is hole, due to uneven heating temperature, at the same time in the transverse and longitudinal additional stress, resulting in crack formation and expansion.
Unreasonable process plan will cause the inner surface of the steel pipe to produce the defects such as folding, crack and concave.
N80 steel casing is a standard oil casing commonly used in oil (for the seamless steel pipe), the standard provisions of the finished pipe heat treatment process for quenching and tempering.
N80 casing production process is as follows: furnace refining → continuous casting → annular furnace → perforation → continuous rolling → stepping furnace → sizing → sawing → tempering treatment → straightening → physical and chemical testing → testing → thread processing → Coupling tight → water pressure test → measuring length weighing, marking → packaging storage. The billet was heated in an annular furnace for about 2.5 hours, perforated at about 1250 °C and then subjected to continuous rolling. The sintering temperature was 950 °C and the finish rolling temperature was 900 °C. The chemical composition of the tube from the test results can know the chemical composition of the tube is not the cause of the formation of cracks. From the metallographic, The results of EDS analysis show that both the crack tip and the middle part contain iron oxide inclusions. The crack is a non-quenching crack and should be produced before the heat treatment. This is probably caused by the perforation and hot rolling of the steel tube.
In the process of perforation of steel pipe, because temperature non-uniformity and uneven deformation have a large additional stress, the blank in the perforation easy to crack; And the heating temperature is too high, will also be due to reduce the intergranular binding force cracks; if the heating temperature is too low, due to lower plasticity, deformation resistance and deterioration of the perforation conditions, will also crack. In addition, the perforation process, due to the presence of additional deformation, when the billet surface will produce longitudinal shear stress and transverse shear shear stress. Therefore, there is a large lateral and longitudinal additional stress in the outer layer of the steel tube. In the case of non-uniform heating of the tube, when the superposition of the transverse basic stress and the additional tensile stress exceeds the intergranular bonding force, Small cracks, these cracks in the subsequent rolling and sizing process, along the rolling direction is elongated and extended to form the final crack. Therefore, in the future production should pay special attention to the perforation temperature, sizing temperature and finishing temperature of the monitoring and control, as far as possible the temperature fluctuations in the control within ± 20 ℃, and should increase the light tube end of the test strength, If necessary, increase the cut length of the pipe end.
N80 casing pipe end crack is in the steel pipe perforation and rolling process; when the billet is hole, due to uneven heating temperature, at the same time in the transverse and longitudinal additional stress, resulting in crack formation and expansion.
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