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.
Improved production technology in steel pipe
Formed on hot rolling or cold rolling, steel pipe, no matter seamless steel pipe, ERW steel pipe or galvanized steel pipe has encounter the whole improvement with the advanced technology coming.
Improved quality of raw materials for steel pipe: with the precise calculation of the components of raw material, such as steel design of low carbon, low P, S, Ni, and micro-alloying, we can make more exact quality for steel pipe which will make sure of the high quality of the steel pipe.
What’s more, technical production skill would be improved. With the improvement of advanced skill to produce steel pipe, there is no doubt that we would provide high quality steel pipe for clients. For example, we can take computer automatic compensation system to automatic control high frequency, heat input and so on. Under this situation, the data would be precious than ever.
http://www.xysteelpipe.com/info/Improved-production-technology-in-steel-pipe-956-1.htm
Improved quality of raw materials for steel pipe: with the precise calculation of the components of raw material, such as steel design of low carbon, low P, S, Ni, and micro-alloying, we can make more exact quality for steel pipe which will make sure of the high quality of the steel pipe.
What’s more, technical production skill would be improved. With the improvement of advanced skill to produce steel pipe, there is no doubt that we would provide high quality steel pipe for clients. For example, we can take computer automatic compensation system to automatic control high frequency, heat input and so on. Under this situation, the data would be precious than ever.
http://www.xysteelpipe.com/info/Improved-production-technology-in-steel-pipe-956-1.htm
Stainless steel seamless pipe processing technology
Stainless steel seamless pipes treatment technology refers to the processing of achieving uniform silver, and has a metallic luster. This is generally referred to the production of large stainless steel seamless pipes. Because large stainless steel seamless pipe is manufactured through stamping, folding and welding process, the surface of workpiece has oil, rust, macular, which is neither beautiful, and easy to rust, reducing its stainless steel quality and value.
To make stainless steel seamless pipes achieve the standard, the surface must be finished. After forming matte treatment, that can achieve beautiful appearance, but also improve its anti-corrosion and anti-discoloration performance. After the above method, the corrosion resistance of stainless steel seamless pipes can be increased by 2 to 3 times.
Stainless steel seamless pipes does not rust due to the existence of chromium, nickel components, and then through the matt treatment, not only can eliminate the matrix impurities and iron-rich layer, but also can make chromium on the surface, forming a complete purification film, play a better anti-corrosion effect. According to the complexity of stainless steel seamless pipes and user requirements, we can choose different processing technology, such as mechanical polishing, chemical polishing, electro chemical polishing and other methods to achieve specular gloss.
http://www.xysteelpipe.com/info/Stainless-steel-seamless-pipe-processing-technology-957-1.htm
To make stainless steel seamless pipes achieve the standard, the surface must be finished. After forming matte treatment, that can achieve beautiful appearance, but also improve its anti-corrosion and anti-discoloration performance. After the above method, the corrosion resistance of stainless steel seamless pipes can be increased by 2 to 3 times.
Stainless steel seamless pipes does not rust due to the existence of chromium, nickel components, and then through the matt treatment, not only can eliminate the matrix impurities and iron-rich layer, but also can make chromium on the surface, forming a complete purification film, play a better anti-corrosion effect. According to the complexity of stainless steel seamless pipes and user requirements, we can choose different processing technology, such as mechanical polishing, chemical polishing, electro chemical polishing and other methods to achieve specular gloss.
http://www.xysteelpipe.com/info/Stainless-steel-seamless-pipe-processing-technology-957-1.htm
Operation method for surface treatment of steel pipe
We know that steel pipe surface treatment is one of the key factors determine the service life of the pipeline corrosion, it is a precondition for whether the anti-corrosion layer and steel tube can be combined. It is verified by the research institutions that the life of the coating depends on the quality of coating types, coating quality and environmental factors such as construction. The steel tube surface treatment effects on coating life accounted for about 50%, therefore, we should be strictly accordance with the specification on the coating on the surface of steel pipe requirements, continuously explore and summary, continuously improve steel pipe surface treatment.
1. Cleaning
Using solvent and emulsion to clean the steel surface, to remove oil, grease, dirt, lubricants, and similar organic matters, but it cannot remove rust, scale, such as welding flux on the surface of the steel, so only as auxiliary in the anti-corrosion production.
2. Rust cleaning by tools
Mainly by using the steel wire brush tool to clean the steel surfaces, and it can remove the loose or cock scale, rust, slag, etc. Hand tools can achieve de-rusting Sa2 level, power tool cleaning can reach grade Sa3. If solid iron oxide adhered on the surface of the steel, tool cleaning effect is not ideal, and it cannot reach the requirements of anti-corrosion construction requirements.
3. Acid pickling
Commonly used chemical and electrolytic pickling process, and pipeline anti-corrosion only chooses chemical pickling, it can remove scale, rust, old coating, sometimes can be used as sandblasting de-rusting after reprocessing. Chemical cleaning while can make the surface reaches a certain cleanness and roughness, but the anchor lines are shallow, and easy to damage the environment.
4. Spray shot derusting
Spray shot derusting is to have spray processing of steel pipe surface under the action of centrifugal which is driven by high-power motor (cast) shoot high-speed rotating blades. It can not only thoroughly remove rust, oxides and dirt, but also can achieve the required uniform roughness.
After shot derusting spray, not only the physical adsorption on the surface of the pipe can be enlarged, but also the anti-corrosion layer and mechanical adhesion on the surface of the pipe can enhanced. Therefore, shot derusting spray (cast) is an ideal cleaning pipeline corrosion protection method. In general, shot peening (sand) cleaning is mainly used for the pipe inner surface treatment and shot (sand) is mainly used for pipe derusting outside surface treatment.
http://www.xysteelpipe.com/info/Operation-method-for-surface-treatment-of-steel-pipe-958-1.htm
1. Cleaning
Using solvent and emulsion to clean the steel surface, to remove oil, grease, dirt, lubricants, and similar organic matters, but it cannot remove rust, scale, such as welding flux on the surface of the steel, so only as auxiliary in the anti-corrosion production.
2. Rust cleaning by tools
Mainly by using the steel wire brush tool to clean the steel surfaces, and it can remove the loose or cock scale, rust, slag, etc. Hand tools can achieve de-rusting Sa2 level, power tool cleaning can reach grade Sa3. If solid iron oxide adhered on the surface of the steel, tool cleaning effect is not ideal, and it cannot reach the requirements of anti-corrosion construction requirements.
3. Acid pickling
Commonly used chemical and electrolytic pickling process, and pipeline anti-corrosion only chooses chemical pickling, it can remove scale, rust, old coating, sometimes can be used as sandblasting de-rusting after reprocessing. Chemical cleaning while can make the surface reaches a certain cleanness and roughness, but the anchor lines are shallow, and easy to damage the environment.
4. Spray shot derusting
Spray shot derusting is to have spray processing of steel pipe surface under the action of centrifugal which is driven by high-power motor (cast) shoot high-speed rotating blades. It can not only thoroughly remove rust, oxides and dirt, but also can achieve the required uniform roughness.
After shot derusting spray, not only the physical adsorption on the surface of the pipe can be enlarged, but also the anti-corrosion layer and mechanical adhesion on the surface of the pipe can enhanced. Therefore, shot derusting spray (cast) is an ideal cleaning pipeline corrosion protection method. In general, shot peening (sand) cleaning is mainly used for the pipe inner surface treatment and shot (sand) is mainly used for pipe derusting outside surface treatment.
http://www.xysteelpipe.com/info/Operation-method-for-surface-treatment-of-steel-pipe-958-1.htm
2018年3月13日星期二
Pressure Grade of Welded Steel Pipe
The pressure welded steel pipe consists of pipe, pipe fittings which include elbow, tee joint, taper pipe and other fittings, valve, flanged joint (flange, spacer as well as bolts), and these composition pieces are generally standard components, which can be fully decided by several factors such as their nominal pressure, texture of material, nominal diameter as well as wall thickness of the Welded steel pipe. And the nominal pressure of all the piping components in the same pipeline pressure grade. Thus, the nominal pressure grade of the piping components are called pipeline pressure grade in engineering.
The pipeline material grade is the piping components selecting and using regulations established by the designing institute or the engineering companies. And it is always given in the form of the excel sheet. In addition, the engineering and technical staff can make sure the detail specific provision of all kinds of dimensions and specifications of the piping components on the conditions of some certain pressure, temperature as well as fluid media which are correspond to these detail specific regulations according to the pipeline material grade sheet. When the engineering as well as technical staffs choose piping components, they base on this pipeline material grade sheet. Every letter and every number in the pipeline material grade codes represents different meanings. And it is usual that there are two grade codes that represent pressure grade in the welded steel pipe and texture of material respectively.
On the technological process map that draws the piping and instruments diagram, there are labels of pipeline pressure grade codes for every black steel pipe. Pipeline pressure grade codes usually consist of a couple of units, and every unit is represented by the letters as well as numbers. And they show the piping pressure grade in the welded steel pipe the main texture of material of the pipelines, seal or types of connection, corrosion allowance and other quality parameter separately. Except for that, every designing institute as well as engineering company has its own expressive method for piping pressure grade codes. Although different letters and different numbers are symbols of different meaning, the contexts they express are the same.
Branch pipe connection table is a sheet given by engineering companies as well as designing institute, stipulating the types of connection of the main pipes as well as the branch pipes. Technological staffs are able to find out what kind of connection methods the different main pipes and different branch pipes should adopt easily under every different piping pressure grade in the welded steel pipe according to this sheet. The main types of connection consist of connection of the welded pipes, API steel pipe, tee joint (isometric or reducing tee), direct connection of main pipes as well as branch pipes or connection of tee joint plus reducing pipe transition.
http://www.xysteelpipe.com/info/Pressure-Grade-of-Welded-Steel-Pipe-935-1.htm
The pipeline material grade is the piping components selecting and using regulations established by the designing institute or the engineering companies. And it is always given in the form of the excel sheet. In addition, the engineering and technical staff can make sure the detail specific provision of all kinds of dimensions and specifications of the piping components on the conditions of some certain pressure, temperature as well as fluid media which are correspond to these detail specific regulations according to the pipeline material grade sheet. When the engineering as well as technical staffs choose piping components, they base on this pipeline material grade sheet. Every letter and every number in the pipeline material grade codes represents different meanings. And it is usual that there are two grade codes that represent pressure grade in the welded steel pipe and texture of material respectively.
On the technological process map that draws the piping and instruments diagram, there are labels of pipeline pressure grade codes for every black steel pipe. Pipeline pressure grade codes usually consist of a couple of units, and every unit is represented by the letters as well as numbers. And they show the piping pressure grade in the welded steel pipe the main texture of material of the pipelines, seal or types of connection, corrosion allowance and other quality parameter separately. Except for that, every designing institute as well as engineering company has its own expressive method for piping pressure grade codes. Although different letters and different numbers are symbols of different meaning, the contexts they express are the same.
Branch pipe connection table is a sheet given by engineering companies as well as designing institute, stipulating the types of connection of the main pipes as well as the branch pipes. Technological staffs are able to find out what kind of connection methods the different main pipes and different branch pipes should adopt easily under every different piping pressure grade in the welded steel pipe according to this sheet. The main types of connection consist of connection of the welded pipes, API steel pipe, tee joint (isometric or reducing tee), direct connection of main pipes as well as branch pipes or connection of tee joint plus reducing pipe transition.
http://www.xysteelpipe.com/info/Pressure-Grade-of-Welded-Steel-Pipe-935-1.htm
Common defects for ERW steel pipe
ERW steel pipe from Tianjin Xinyue Steel Group, with its durable function, has devoted to various engineering projects nowadays. Of course, there are some points we should take care during the production of the ERW steel pipe.
1. Inclusions (fired black oxide) : inclusions may cause the bad performance like intensity and corrosion resistance problem.
2. Pre-arc (white burn oxidation): pre-arc would have the influence for hardness of the steel pipe.
3. Lack of fusion (slotted): slotted problem has similar affects like the inclusion.
4. Lack of fusion in the center (cold welding center): Cold welding center has the influence for endurance too.
5. Edge not Fusion (wavy edge): wavy edge would have the problem of leakage if they used for some fluid or gas transportation.
6. Rod welding (welding)
7. Cast welding (weld welding)
8. Pores (pinhole)
9. Jump welding
http://www.xysteelpipe.com/info/Common-defects-for-ERW-steel-pipe-936-1.htm
1. Inclusions (fired black oxide) : inclusions may cause the bad performance like intensity and corrosion resistance problem.
2. Pre-arc (white burn oxidation): pre-arc would have the influence for hardness of the steel pipe.
3. Lack of fusion (slotted): slotted problem has similar affects like the inclusion.
4. Lack of fusion in the center (cold welding center): Cold welding center has the influence for endurance too.
5. Edge not Fusion (wavy edge): wavy edge would have the problem of leakage if they used for some fluid or gas transportation.
6. Rod welding (welding)
7. Cast welding (weld welding)
8. Pores (pinhole)
9. Jump welding
http://www.xysteelpipe.com/info/Common-defects-for-ERW-steel-pipe-936-1.htm
Raw materials on quality of steel pipe
There are demands for various steel pipes from seamless steel pipe, ERW steel pipe, galvanized steel pipe as well as SSAW steel pipe in market for transportation of low pressure products like water and high pressure products like oil and gas.
However, no matter which kind of steel pipe we choose from, we know that raw material would play an important role during the steel pipe’s production process.
1. From the point of welding, the influence of raw material on quality of ERW steel pipe is mainly reflected in welding and organization of materials.
2. The composition of the elements in raw material would lead to the impact on intensity, hardness. For example, high content of sulfur and phosphorus in the material can easily cause segregation of crystals. And so does for the impact of high carbon content, too large grain size of the metal structure.
Once we choose the relevant standards from API 5L, API 5CT, ASTM 53, EN10217, DIN 2458. IS 3589, JIS G3452, BS1387 about ERW steel pipe, it is our responsibility to know their difference before purchasing.
http://www.xysteelpipe.com/info/Raw-materials-on-quality-of-steel-pipe-937-1.htm
However, no matter which kind of steel pipe we choose from, we know that raw material would play an important role during the steel pipe’s production process.
1. From the point of welding, the influence of raw material on quality of ERW steel pipe is mainly reflected in welding and organization of materials.
2. The composition of the elements in raw material would lead to the impact on intensity, hardness. For example, high content of sulfur and phosphorus in the material can easily cause segregation of crystals. And so does for the impact of high carbon content, too large grain size of the metal structure.
Once we choose the relevant standards from API 5L, API 5CT, ASTM 53, EN10217, DIN 2458. IS 3589, JIS G3452, BS1387 about ERW steel pipe, it is our responsibility to know their difference before purchasing.
http://www.xysteelpipe.com/info/Raw-materials-on-quality-of-steel-pipe-937-1.htm
Application of spiral steel tube
What is the scope of application of the spiral steel tubes Spiral steel pipes are widely used industrial, construction and other industries of steel, is widely used in various production areas, both inside and outside, oil, gas, sewage treatment plant, water, water supply and drainage, water conservancy project construction pile driving with steel tube, the signs, overhead Bridges and other industries.
1, generally low pressure fluid conveying with seam submerged arc spiral welded pipe scale on hot rolled steel coil tube billet, often temperature spiral forming, adopting double automatic submerged arc welding or one side welding into legal system for water, gas, air and steam general low-pressure fluid conveying with submerged arc welding steel pipe.
2, low pressure fluid conveying in spiral welded pipe steel pipe is also called general welded pipe, commonly known as the clarinet. Is used to transport oil, gas, air, water and heating steam and other general low pressure fluid and other purposes of welded steel pipe.
3, low pressure fluid conveying with galvanized welded steel pipe is also called galvanized welded steel pipe, commonly known as the white tube. Is used to transport oil, gas, air, water and heating steam, warm water generally low pressure fluid or other purposes such as hot dip galvanized welded butt weld or welding steel pipe. Steel tube wall thickness is divided into ordinary galvanized steel pipe and thickening of galvanized steel pipe; To take over the side form is divided into without thread galvanized steel pipe and galvanized steel pipe with screws. Specifications of steel pipe in nominal diameter and nominal diameter is inside diameter of approximation.
4, pressurized fluid conveying with submerged arc welding spiral pipe scale on hot rolled steel coil tube billet, often spiral shape, with double-sided submerged arc welding method, welding, spiral seam steel pipe used for pressurized fluid conveying. Steel tube confined ability, good welding function, through a variety of strict scientific inspection and testing, the use of safe and reliable. Steel pipe diameter is big, high transmission efficiency, and can save laying pipelines. Mainly used for conveying oil, natural gas pipeline.
1, generally low pressure fluid conveying with seam submerged arc spiral welded pipe scale on hot rolled steel coil tube billet, often temperature spiral forming, adopting double automatic submerged arc welding or one side welding into legal system for water, gas, air and steam general low-pressure fluid conveying with submerged arc welding steel pipe.
2, low pressure fluid conveying in spiral welded pipe steel pipe is also called general welded pipe, commonly known as the clarinet. Is used to transport oil, gas, air, water and heating steam and other general low pressure fluid and other purposes of welded steel pipe.
3, low pressure fluid conveying with galvanized welded steel pipe is also called galvanized welded steel pipe, commonly known as the white tube. Is used to transport oil, gas, air, water and heating steam, warm water generally low pressure fluid or other purposes such as hot dip galvanized welded butt weld or welding steel pipe. Steel tube wall thickness is divided into ordinary galvanized steel pipe and thickening of galvanized steel pipe; To take over the side form is divided into without thread galvanized steel pipe and galvanized steel pipe with screws. Specifications of steel pipe in nominal diameter and nominal diameter is inside diameter of approximation.
4, pressurized fluid conveying with submerged arc welding spiral pipe scale on hot rolled steel coil tube billet, often spiral shape, with double-sided submerged arc welding method, welding, spiral seam steel pipe used for pressurized fluid conveying. Steel tube confined ability, good welding function, through a variety of strict scientific inspection and testing, the use of safe and reliable. Steel pipe diameter is big, high transmission efficiency, and can save laying pipelines. Mainly used for conveying oil, natural gas pipeline.
16mn seamless steel tube is widely used
16 mn seamless steel tube is widely used in combustible and flammable fluid pipeline and boiler, steel structure. This is not to deceive consumers fakes, but according to the requirements of the equipment and produce steel pipe, seamless steel pipe between pure seamless and welded pipe, the quality is better than that of welded pipe, the cost is lower than the pure seamless, is an ideal substitute products. Production of the developed countries in the world has been extensively used in fluid pipe, boiler tube welded pipe seamless process, with the development of the society, the domestic situation of hot rolled welded pipe instead of seamless tube gradually has formed.
1, the principle of 16 mn seamless steel tube stacking requirements are on the premise of pallet firm, ensure safety, do according to the bottle, pallet specifications, different varieties, different materials, different specifications of the spiral welded steel pipe to pallet respectively, prevent the erosion of muddied and each other.
2.16 mn low forbidden deposit around the steel pipe piling location for steel tube erosion.
3. The bottom of the spiral welded steel pipe pile should be mat tall, strong, smooth, prevent the material to be affected with damp be affected with damp or deformation.
4. The same material of the spiral welded steel pipe needs according to the order of warehouse stacking, easy to implement the principle of improving predecessors starts.
5. Such as 16 mn seamless steel tube pile up in the open, must under the spiral steel tube to prevent the wood or stone, and buttress face should be tilted slightly, to facilitate drainage, and pay attention to whether or not steel pipe lay flat, prevent the steel tube bending deformation.
6. The spiral steel pipe stacking height, artificial homework no more than 1.2 m, mechanical work no more than 1.5 m, crib is not more than 2.5 m wide.
7. Between the spiral welded steel pipe pile and pile should have certain channels, check the width of the road in 0.5 m or so commonly, in and out of the channel width and transport machinery, according to the volume of material in commonly 1.5 to 2 m.
8.16 mn seamless steel tube pile bottom pad high level according to the specific situation, if the warehouse to the cement ground in xiangyang, higher height of 0.1 m; If the mud, must be 0.2 to 0.5 m high. If stored in the open, cement floor MATS should be from 0.3 to 0.3 m high, high silt ground pad should be from 0.5 to 0.5 m.
1, the principle of 16 mn seamless steel tube stacking requirements are on the premise of pallet firm, ensure safety, do according to the bottle, pallet specifications, different varieties, different materials, different specifications of the spiral welded steel pipe to pallet respectively, prevent the erosion of muddied and each other.
2.16 mn low forbidden deposit around the steel pipe piling location for steel tube erosion.
3. The bottom of the spiral welded steel pipe pile should be mat tall, strong, smooth, prevent the material to be affected with damp be affected with damp or deformation.
4. The same material of the spiral welded steel pipe needs according to the order of warehouse stacking, easy to implement the principle of improving predecessors starts.
5. Such as 16 mn seamless steel tube pile up in the open, must under the spiral steel tube to prevent the wood or stone, and buttress face should be tilted slightly, to facilitate drainage, and pay attention to whether or not steel pipe lay flat, prevent the steel tube bending deformation.
6. The spiral steel pipe stacking height, artificial homework no more than 1.2 m, mechanical work no more than 1.5 m, crib is not more than 2.5 m wide.
7. Between the spiral welded steel pipe pile and pile should have certain channels, check the width of the road in 0.5 m or so commonly, in and out of the channel width and transport machinery, according to the volume of material in commonly 1.5 to 2 m.
8.16 mn seamless steel tube pile bottom pad high level according to the specific situation, if the warehouse to the cement ground in xiangyang, higher height of 0.1 m; If the mud, must be 0.2 to 0.5 m high. If stored in the open, cement floor MATS should be from 0.3 to 0.3 m high, high silt ground pad should be from 0.5 to 0.5 m.
2018年3月2日星期五
Shape requirement of LSAW steel pipe
LSAW steel pipe weld appearance basic requirements:
Straight seam steel pipe before NDT, weld visual inspection should meet the requirements. General requirements for straight seam steel pipe weld appearance and surface quality of welded joints are as follows:
Welding should look good shape, width of each side groove edge 2mm overshadowed appropriate. Fillet weld leg height should meet the design requirements, the shape should be smooth transition.
Welded joint surface requirements:
(1) Does not allow cracks, lack of fusion, pores, slag, spatter exist.
(2) The design temperature is below -29 degrees pipes, stainless steel and hardened alloy steel pipes tend to be larger weld surface, without undercut. Other material pipe weld undercut depth should be greater than 0.5mm, continuous undercut length should not exceed 100mm, and both sides of the weld undercut always grow up to 10 percent of the entire length of the weld.
(3) Shall not be lower than the surface of the weld surface of the pipe. Weld reinforcement and no more than 3mm, (the maximum width of weld joints after groove).
(4) Welded joints the wrong side of the wall thickness should be less than 10% and not more than 2mm.
Straight seam steel pipe before NDT, weld visual inspection should meet the requirements. General requirements for straight seam steel pipe weld appearance and surface quality of welded joints are as follows:
Welding should look good shape, width of each side groove edge 2mm overshadowed appropriate. Fillet weld leg height should meet the design requirements, the shape should be smooth transition.
Welded joint surface requirements:
(1) Does not allow cracks, lack of fusion, pores, slag, spatter exist.
(2) The design temperature is below -29 degrees pipes, stainless steel and hardened alloy steel pipes tend to be larger weld surface, without undercut. Other material pipe weld undercut depth should be greater than 0.5mm, continuous undercut length should not exceed 100mm, and both sides of the weld undercut always grow up to 10 percent of the entire length of the weld.
(3) Shall not be lower than the surface of the weld surface of the pipe. Weld reinforcement and no more than 3mm, (the maximum width of weld joints after groove).
(4) Welded joints the wrong side of the wall thickness should be less than 10% and not more than 2mm.
Description of production process equipment of seamless steel pipe
1. Oiled marking: steel pipe hydrostatic testing machine after passing were oiled to prevent corrosion, and according to user requirements for marking.
2. Leveling milling: the flat steel anvil machine so that the original curl, and then through the edge milling machine for two-sided steel milling, so as to meet the requirements of the plate width, plate edge parallelism and groove shape.
3. Shear molding: the steel plate production line along the outer edge of the spiral curl into a tube.
4. Butt cut: seamless steel pipe market equipment using advanced technology pre double submerged arc welding, internal welding, outside welding. The welded steel pipe using a plasma-foot cut to specification length.
5. Visual inspection: by professional and technical personnel to some of the basic parameters to be checked.
6. The ultrasonic flaw detection: scrap development of the inner and outer sides of the base metal and weld seam 100% inspection.
7. X-ray detection: internal and external welds 100% X-ray industrial TV check image processing system to ensure that the use of detection sensitivity.
8. The pressure test: the steel pipe hydrostatic testing machine shall be tested individually to ensure that the test pressure pipe meet the required standards.
9. Chamfering flat head: seamless steel pipe inspection devices will be qualified after the pipe end processing, to meet the requirements of the pipe end (spiral welded pipe mill) groove dimensions.
10. Final inspection: leveler again ultrasound and X-ray detection as well as magnetic particle inspection pipe end, check if there are problems and welding pipe ends defects.
11. Unwinding board probe: After entering the unwinding plate production line, the first full-board ultrasonic testing.
2. Leveling milling: the flat steel anvil machine so that the original curl, and then through the edge milling machine for two-sided steel milling, so as to meet the requirements of the plate width, plate edge parallelism and groove shape.
3. Shear molding: the steel plate production line along the outer edge of the spiral curl into a tube.
4. Butt cut: seamless steel pipe market equipment using advanced technology pre double submerged arc welding, internal welding, outside welding. The welded steel pipe using a plasma-foot cut to specification length.
5. Visual inspection: by professional and technical personnel to some of the basic parameters to be checked.
6. The ultrasonic flaw detection: scrap development of the inner and outer sides of the base metal and weld seam 100% inspection.
7. X-ray detection: internal and external welds 100% X-ray industrial TV check image processing system to ensure that the use of detection sensitivity.
8. The pressure test: the steel pipe hydrostatic testing machine shall be tested individually to ensure that the test pressure pipe meet the required standards.
9. Chamfering flat head: seamless steel pipe inspection devices will be qualified after the pipe end processing, to meet the requirements of the pipe end (spiral welded pipe mill) groove dimensions.
10. Final inspection: leveler again ultrasound and X-ray detection as well as magnetic particle inspection pipe end, check if there are problems and welding pipe ends defects.
11. Unwinding board probe: After entering the unwinding plate production line, the first full-board ultrasonic testing.
2018年3月1日星期四
Technical analysis of galvanized seamless steel pipe
Due to the wide range of applications of galvanized seamless steel pipe, there are lots of manufacturers have workshop for this product. Generally speaking, the production process is no difference, whether it is hot-dip seamless tube, or cold-plated seamless pipe. Today, Tianjin Xinyue steel pipe would have a detail list for process production of galvanized seamless steel pipe.
First of all, furnace roll mill:
The mill includes of a reciprocating roughing mill and a 4-roll reciprocating mill. Two hot-rolling mills were installed on the conveyor lines on both sides of the finishing mill. The output roller train normally consists of a laminar cooling system and a take-up station.
What's more, CSP casting and rolling:
In the CSP production line, there is process for controlling of niobium, vanadium, titanium composite micro-alloyed low-carbon manganese steel. The use of appropriate controlled rolling and cooling and coiling can ensure the mechanical properties and micro-structure of the pipe line with the modern X60 stainless steel stamping elbow The technical requirements, in line with the development of modern stainless steel pipe fittings elbow.
http://www.xysteelpipe.com/info/Technical-analysis-of-galvanized-seamless-steel-pipe-912-1.htm
First of all, furnace roll mill:
The mill includes of a reciprocating roughing mill and a 4-roll reciprocating mill. Two hot-rolling mills were installed on the conveyor lines on both sides of the finishing mill. The output roller train normally consists of a laminar cooling system and a take-up station.
What's more, CSP casting and rolling:
In the CSP production line, there is process for controlling of niobium, vanadium, titanium composite micro-alloyed low-carbon manganese steel. The use of appropriate controlled rolling and cooling and coiling can ensure the mechanical properties and micro-structure of the pipe line with the modern X60 stainless steel stamping elbow The technical requirements, in line with the development of modern stainless steel pipe fittings elbow.
http://www.xysteelpipe.com/info/Technical-analysis-of-galvanized-seamless-steel-pipe-912-1.htm
Round steel pipe or square steel pipe
It seems like lots of steel pipes used in project are round and there are rare square one. Why? What’s the difference when we choose the round one and square one, like the seamless steel pipe?
Here are some introduction for it:
Production process: Round steel pipe is generally circular in finished pipe and they would be added the base and column cap composition; While square column is generally a combination of columns, which is assembled from steel.
Fore taking difference: There is difference for pressure taking due to the different production process. Their composition determines their force's different. Round steel pipe is generally bearing axial stress or eccentric force in smaller parts. However, square steel column would take the pressure in one direction larger cross-section, this decides that it can be used for large eccentric stress places.
Thus, we can tell that lots of steel pipe has the function of transportation so that we can see them often instead of the square steel pipe.
http://www.xysteelpipe.com/info/Round-steel-pipe-or-square-steel-pipe-913-1.htm
Here are some introduction for it:
Production process: Round steel pipe is generally circular in finished pipe and they would be added the base and column cap composition; While square column is generally a combination of columns, which is assembled from steel.
Fore taking difference: There is difference for pressure taking due to the different production process. Their composition determines their force's different. Round steel pipe is generally bearing axial stress or eccentric force in smaller parts. However, square steel column would take the pressure in one direction larger cross-section, this decides that it can be used for large eccentric stress places.
Thus, we can tell that lots of steel pipe has the function of transportation so that we can see them often instead of the square steel pipe.
http://www.xysteelpipe.com/info/Round-steel-pipe-or-square-steel-pipe-913-1.htm
Additional element for steel pipe
Lots of additional elements would be added in various steel pipes like seamless steel pipe, ERW steel pipe, SSAW steel pipe and so on. According to the supplier of steel pipe, tell us that it is an art by adding additional elements in steel pipe because:
It would affect the character of corrosion resistance. We should clear that lots of steel pipe would add additional elements like Mn, Si, and so on. However, we should get the percentage for it. For example, there is a limit for the additional elements of Seamless Steel Pipe EN 10216:
What’s more, it would have influence on steel pipe’s strength and toughness. For example, large quantities of niobium, titanium or vanadium are forming fine carbides or carbonitrides in the steel pipe, which makes the steel pipe losing the strength and toughness of the coarse ferrite grains and of the progressive steel.
http://www.xysteelpipe.com/info/Additional-element-for-steel-pipe-914-1.htm
It would affect the character of corrosion resistance. We should clear that lots of steel pipe would add additional elements like Mn, Si, and so on. However, we should get the percentage for it. For example, there is a limit for the additional elements of Seamless Steel Pipe EN 10216:
What’s more, it would have influence on steel pipe’s strength and toughness. For example, large quantities of niobium, titanium or vanadium are forming fine carbides or carbonitrides in the steel pipe, which makes the steel pipe losing the strength and toughness of the coarse ferrite grains and of the progressive steel.
http://www.xysteelpipe.com/info/Additional-element-for-steel-pipe-914-1.htm
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