Characteristics of seamless steel pipes

Seamless steel pipe is actually a hollow cross section and both sides of the expansion of the resistance to air, steam, water and other weak corrosive media and acid, alkali, salt and other chemical corrosion medium corrosion of steel pipe. Also known as acid-resistant stainless steel. Stainless steel pipe suppliers are reputable to protect the environment from hygienic, cheap, and also thinner tubes as well as new, reliable, and effective ways to improve a simple and convenient connection, resulting in more irreplaceable benefits. There will be more and more engineering use, is more and more and prospects.
Seamless steel pipe for the use of engineering and construction is very widely, it is a hollow steel strip no seams, it is mainly used to transport liquids pipelines, different look and general steel,one of those heavy type steel, it has a strong resistance to corrosion, resistant to general corrosion.
Will not rust, this performance makes seamless steel tubes extend the life, the most important is that it is very clean and no toxins.
Compared with other plastic seamless steel pipe having strong mechanical resistance, impact regardless of how high a temperature is not interested in the use of seamless steel pipe, it is mounted and the other pipe is the same, can replace other piped water and other liquids.
When we place a specific order for SA 179 steel tubing, we should include below material specifications:

  • Standard and the name of material: ASTM A179 / ASME SA 179 seamless steel tubes.
  • Manufacturing types in cold drawn
  • Quantity in meters, feet, or pieces
  • Size including Diameters and minimum wall thickness
  • Length per pieces (Random or fixed length shall be specified)
  • Chemical composition (optional)                                                                                                                         

Seamless pipes by Standard

Seamless pipes by standards include: ASTM, JIS, DIN, Customers for international

usage automotive industry - Characteristics of seamless steel pipes
  • ASTM A106: Seamless Carbon Steel for High Temperature Service
  • ASTM A179– Cold-drawn Low-Carbon Steel Heat-Exchanger and Condenser Tubes
  • ASTM A192– Seamless Carbon Steel Boiler Tubes for High Pressure
  • GB 3087 – Low and medium pressure boiler seamless pipe
Most common Seamless steel pipes by Standards

ASTM seamless pipe - Characteristics of seamless steel pipes

Piping and Casing, Line Pipes by API 5L/ 5CT standard.

  • JIS seamless steel pipes
  • GB seamless steel pipes
  • ASTM seamless steel pipes
  • DIN/EN seamless steel pipes

Wall thickness tolerance of seamless steel pipe

We can makes and markets cold-drawn and hot rolled seamless steel pipes and cold-drawn special-section seamless pipes which are widely applied in the industries of petrochemical, boiler, automobile, mechanica…

Seamless steel pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. seamless steel pipes dominates 65% of market share in Chinese boiler industry.

Types Sizes allowed tolerance
Ordinary steel pipe Senior steel pipe
Hot rolled Out diameter <50 ± 0.50 mm ± 0.40 mm
≥50 ± 1 % ± 0.75 %
Wall thickness <4 ± 12.5 % ± 10 %
4-20 +15%
-12.5%
± 10 %
≥20 ± 12.5 % ± 10 %
Cold drawn Out diameter 6-10 ± 0.20 mm  ± 0.10 mm
>10-30 ± 0.40 mm ± 0.20 mm 
>30-50 ± 0.45 mm ± 0.25 mm 
>50 ± 1 % ± 0.5 %
Wall thickness ≤1 ± 0.15 mm ± 0.12 mm
1-3 + 15 %
– 10 % 
± 10 %
>3 + 12.5
– 10 %
± 10 %

Hardness of seamless steel pipes

Generally, using chemical and electrolysis ways to do pickling processing pipeline anti-corrosion chemical pickling can remove the oxide scale, rust, old coatings, and sometimes used as a sand-blasting after reprocessing.

Although chemical cleaning can reach the surface cleanliness and roughness, the bolt pattern light, and easy to pollute the environment.

Spray radio rust
Spray radio rust by high-power seamless steel pipe motor-driven jet (throw) shooting leaves high-speed rotation, making the grit, steel shot, wire, minerals and other abrasive under the centrifugal force on the steel pipe surface spray (throwing ) irradiated, not only can completely remove the rust, oxides and dirt, and the steel abrasive violent shocks and the role of friction, but also to achieve the required uniform roughness. Spray (throwing) radio rust, can not only expand the physical adsorption of the tube surface, and can enhance the mechanical adhesion of the coating with the tube surface. Therefore, spray (throwing) radio rust pipeline corrosion ideal rust ways of. Generally, shot peening (sand) blasting is mainly used for pipe surface treatment, shot blasting (sand) blasting is mainly used for pipe outer surface of the processing. Using spray (throwing) radio rust should pay attention to several issues. 
Instrument rust
Using instrument such as wire brush to polish the steel surface to remove loose or the tilt of the oxide scale, rust, welding slag. Rust can reach Sa2 grade manual tools, power tools rust can be achieved Sa3 level, if the steel surface attached to a solid oxide scale, the result is not satisfactory tools rust, amounting to less than anti-corrosion construction requirements anchor pattern depth pickling.

How to detect the hardness of seamless steel pipe, the test methods are divided into non-blank categories, one is the tensile test, one is The hardness test.

The hardness of seamless steel testing to take into account its mechanical properties, which is related to the deformation of stainless steel as raw materials, stamping, cutting and other processing performance and quality. Therefore, all the seamless steel pipe to be tested for mechanical properties.

Tensile test is made of seamless steel pipe sample, the tensile test machine pulled the sample to fracture, and then measure one or several mechanical properties, usually only the determination of tensile strength, yield strength, elongation after fracture and rate of reduction in area. Tensile test is the most basic mechanical properties of metallic materials test methods, almost all of the metal materials, as long as the mechanical properties have required, are provided for tensile test. Especially those whose shape is not convenient for hardness testing, tensile testing becomes the only measure of mechanical properties.

Hardness test is a hard head with a hardness tester pressed into the surface of the specimen under specified conditions, and then test the indentation depth or size, in order to determine the size of the material hardness. Hardness test is the simplest, fastest and easiest to implement method in mechanical testing of materials. Hardness tests are non-destructive with approximate scaling between material hardness values and tensile strength values. Material hardness value can be converted into tensile strength value, which has great practical significance.

Since tensile testing is not convenient for testing and is easily scaled from hardness to strength, there is an increasing tendency for people to test only material hardness and less to test their strength. Especially due to the continuous improvement and innovation of the durometer manufacturing technology, some materials that could not be directly tested for hardness, such as seamless steel pipe, seamless steel plate and seamless steel strip, may now be able to directly test the hardness. Therefore, there is a tendency that the hardness test gradually replaces the tensile test.

Most of the national standards for seamless steel materials both provide tensile testing and hardness testing. For those who do not facilitate the hardness test materials, such as seamless steel pipe only provides tensile test. In the seamless steel standard, the general provisions of the cloth, Luo, Victoria three kinds of hardness test methods, determination of HB, HRB (or HRC) and HV hardness values, provides only one of the three hardness values can be measured. In particular, the latest portable rockwell hardness tester, rockwell hardness pipe, can be as thin as 0.05mm seamless steel plate, seamless steel pipe and as thin as ¢ 4.8mm seamless steel pipe for rapid and accurate hardness testing, Making the problems that were difficult to solve in the country solved in the past.

Features of Seamless steel pipe:

First, the thicker the wall thickness of the solution, it is really more cost effective and wise, the thinner the wall thickness, and its processing costs will appreciate sharply;
Second, from the process of the product determines its limitations, from the general seamless steel pipe with low accuracy: wall thickness uneven, low brightness tube appearance, fixed length of high cost, and pitting in the appearance of black spots is difficult to bring go;
Third, testing and plastic must be off-line. So it really is in the higher pressure, high strength, mechanical structure of wood reflects its superiority.
Seamless steel pipe chemical analysis: the chemical composition of the material for chemical analysis, chemical composition to meet the standard requirements.
Seamless steel pipe pressure and hydrostatic test is for pressure tube by into the hydrostatic test, which do not maintain the prescribed pressure value not less than 5 seconds, not to disclose, the regular supply hydraulic pressure test is 2.45MPa pressure The pressure test is P = 0.5MPAa. 
The corrosion test: industrial corrosion-resistant steel pipe according to standard regulations or agreement between the corrosion of steel pipe corrosion resistance test, no intergranular corrosion.
Characteristics of seamless steel pipes are as follows:

  • High precision can do small batch production.
  • Smaller diameter.
  • Weldability strong, high compression capability.
  • Steel pipe superior performance, relatively dense metal.
  • Steel Cross area is more complex.
  • High precision cold drawn products, good surface quality.

Source: China Seamless Steel Pipe Manufacturer Yaang Pipe Industry Co., Limited (www.steeljrv.com)

(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)

If you want to have more information about the article or you want to share your opinion with us, contact us at sales@steeljrv.com

Please notice that you might be interested in the other technical articles we’ve published:

  • How to get high quality stainless steel pipes

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  • Engineering Specification for Pressure Test of Piping System

  • How To Distinguish Inferior Steel Pipe

  • How to get high quality steel pipes

  • Manufacturing process of cold rolled steel pipe

  • How to get high quality boiler tubes

  • How to get high quality flanges

  • How to get high quality alloy steel pipes

  • How to get high quality pipe fittings

  • How to get high quality heat exchanger tubes

  • The difference between steel tubes and steel pipes

  • THE DIFFERENCE BETWEEN STEEL TUBES AND STEEL PIPES

  • Difference between welded steel pipe and seamless steel pipe

Reference:

  • https://www.yaang.com

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