Technical requirements for stainless steel seamless pipes

Posted by zora li on May 9th, 2023

Technical requirements for stainless steel seamless pipes

With the development of social economy, the application of stainless steel pipes in daily life such as construction and decoration has developed rapidly. Stainless steel pipes can be seen everywhere in life. Because of its environmental protection, safety, durability, and practicality, it has great potential in architectural decoration, and is often processed into stair railings, guardrails, and furniture. Stainless steel pipes are divided into ordinary carbon steel pipes, high carbon steel pipes, high-quality carbon structural steel pipes, alloy structural steel pipes, alloy steel pipes, bearing steel pipes, stainless steel pipes, bimetal composite pipes, precious metal-saving and coating and coating pipes that meet special requirements. . There are many types of stainless steel pipes, with different uses, different technical requirements, and different production methods.

Technical requirements for stainless steel pipes:

1) Surface quality

The outer surface of the stainless steel pipe should be clean and free from wrinkles, scratches, cracks, delamination, scale and obvious weld edge defects. For example, when the outer diameter of the steel pipe is less than 63.5mm, the surface roughness is not less than 400#; when the outer diameter of the steel pipe is larger than 63.5mm, the surface roughness is not less than 320#; the surface roughness of the square rectangular pipe is not less than 320#.

2) Mechanical properties

The mechanical properties of stainless steel pipes refer to the mechanical properties exhibited by various external loads (compression, tension, bending, impact, torsion, alternating stress, etc.) under different environments (such as temperature, humidity, medium). The required properties of the mechanical properties need to be met.

3) Corrosion resistance

One of the quality requirements of stainless steel pipes is whether the quality is good or not, and whether it is easy to rust. Experiments have proved that 304 stainless steel pipes have excellent corrosion resistance and good resistance to intergranular corrosion. For oxidizing acids, experiments have found that 304 stainless steel pipes have strong corrosion resistance in nitric acid with a concentration ≤ 65% below the boiling point; it also has good corrosion resistance to alkaline solutions and most organic and inorganic acids.

4) Process performance

The process performance of stainless steel pipes includes flattening test, flaring test and bending test. In the flaring test, when the top center taper is 60°, when the outer diameter of the steel pipe sample expands to 6% of the pipe diameter, there should be no cracks and cracks, and the nozzle should not have wrinkles. Inner side of the bending position; during the bending test, the bending angle is 90°, and the radius of the bending center is 3 times the outer diameter of the steel pipe; when the flattening test is to flatten the outer diameter of the sample to 1/3 of the pipe diameter, there should be no cracks and crack.

Stainless steel pipes are mainly used in the automobile industry, petrochemical industry, including the fertilizer industry, fluid transportation such as water and gas, equipment manufacturing and maintenance.