What grade is structural pipe?

What grade is structural pipe?

What grade is structural pipe?
Structural pipes are categorized in various ways based on material, standards, and performance grades, depending on their application scenarios and performance requirements. For example, they can be classified by standards such as GB/T 8162 and ASTM A53; by manufacturing process, they can be divided into hot-rolled, cold-drawn, and cold-rolled structural pipes; and by material and performance, they can be further subdivided into different grades of carbon structural steel and alloy structural steel.
1. Classification by Standard
The grade of structural pipe is largely determined by the standards it complies with. For example:
GB/T 8162 is a Chinese national standard applicable to seamless steel pipes for general structural use.
ASTM A53 is an American Society for Testing and Materials standard covering steel pipes for pipelines, conduction, engineering, and other applications.
API 2B is a welded structural steel pipe specifically for offshore structures such as platforms and pipelines.
2. Classification by Manufacturing Process
Hot-rolled structural pipes:
Produced from continuous casting slabs through rough rolling and finish rolling, suitable for pipe manufacturing, etc.
Cold-drawn/cold-rolled structural pipes:
Used from hot-rolled steel coils, pickled, and cold-rolled, they offer high dimensional accuracy and surface quality.
3. Classification by Material and Performance
Carbon structural pipes:
Used from carbon structural steel (e.g., GB/T 700 standard), grades include Q195, Q235, and Q275. Suitable for general building structures.
Alloy structural pipes:
Used from alloy structural steels such as Q345, 20Cr, 40Cr, and 35CrMo, they offer higher strength and wear resistance and are suitable for more complex machining or petrochemical applications.
4. Classification by Application
General Structural and Machining Pipes: Suitable for a variety of general structural components.
Chemical and Petroleum Pipes: Used in the transportation of oil, natural gas, and chemicals, requiring corrosion resistance or high-temperature and high-pressure resistance.
Metro Steel Support Pipes: Structural pipes used in rail transit applications.