1. What is the standard for carbon steel seamless pipes in China?
Answer: The common national standard is GB/T 8163-2018 (Seamless steel pipes for fluid transport), which is applicable to common carbon steel pipes; high-specification pipes for high-pressure boilers adopt GB/T 5310-2017, and for low-alloy steel pipes adopt GB/T 8163-2018 (for high-pressure fluid).
2. What are the international standards for carbon steel seamless pipes?
Answer: Common international standards include ASTM A106 (American standard), EN 10210 (European standard), JIS G3454 (Japanese standard). These standards specify the material, size, performance and inspection requirements of carbon steel seamless pipes.
3. How to distinguish common and high-specification carbon steel seamless pipes by appearance?
Answer: It is difficult to distinguish only by appearance. Generally, high-specification pipes have stricter dimensional tolerance (smoother surface, more accurate diameter and wall thickness), and the surface may be marked with material marks (such as "45#", "16Mn"). The final judgment needs to rely on material testing.
4. What is the weight calculation formula of carbon steel seamless pipes?
Answer: The weight per meter (kg/m) = 0.02466 × wall thickness (mm) × (outer diameter (mm) - wall thickness (mm)). This formula is applicable to both common and high-specification carbon steel seamless pipes (the density of carbon steel is 7.85g/cm³).
5. Can carbon steel seamless pipes be welded?
Answer: Yes. Common carbon steel pipes (10#, 20#) have good weldability and can be welded by arc welding, gas welding and other methods; high-specification pipes such as 45# have poor weldability (easy to crack), so preheating before welding and heat treatment after welding are required.
