1. What is the difference between carbon steel seamless pipe and welded carbon steel pipe?
Answer: Carbon steel seamless pipe has no welding seam, high pressure resistance and good integrity, but high production cost; welded carbon steel pipe is made by welding steel plates, with low cost, but the welding seam is a weak link, which is not suitable for high-pressure occasions.
2. What is the weight calculation formula of carbon steel seamless pipe?
Answer: The theoretical weight formula is: Weight (kg/m) = 0.02466 × (Outer Diameter - Wall Thickness) × Wall Thickness. For example, the weight of Φ57×3.5mm 20# seamless pipe is 0.02466×(57-3.5)×3.5≈4.62 kg/m.
3. What is the purpose of heat treatment of carbon steel seamless pipes?
Answer: Heat treatment is to improve the mechanical properties of the pipe. Common heat treatments include annealing (reducing hardness, improving plasticity), quenching and tempering (improving strength and toughness). For example, 45# seamless pipe is often quenched and tempered to meet the requirements of high-strength parts.
4. What are the inspection items of carbon steel seamless pipes?
Answer: The main inspection items include: chemical composition analysis, mechanical property test (tensile, yield, impact), dimensional tolerance inspection, surface quality inspection (no cracks, scars, corrosion), and pressure test (water pressure or air pressure test) to check the tightness.
5. Can 16Mn carbon steel seamless pipe be used in boiler and pressure vessel fields?
Answer: Yes. 16Mn (Q345B) seamless pipe that meets the standard GB/T 3087 can be used in low and medium pressure boilers and general pressure vessels, because it has good high-temperature resistance and pressure-bearing capacity.
