Q345B is a material for steel pipes. Q represents the yield of this material, and the back 345 refers to the yield value of this material.
The Q345B steel pipe is a 16Mn steel pipe, which is one of the seamless steel pipe products. 16Mn is a material in steel. A name for steel in the past. Now called the law: Q345B. 16Mn is a low-alloy steel series. In this series, it is the most common material, or the grade of steel plate. The Q345B steel tube represents the carbon content of this steel in the range of about 0.16%. Mn alone was proposed because the five elements (carbon C, silicon Si, manganese Mn, phosphorus P, sulfur S) have high manganese content and are proposed separately. About 1.20-1.60%. Special treatment heat treatment: controlled rolling, normalizing, etc.Z-direction performance: Z15, Z25, Z35. Main features: good overall performance, good low temperature performance, cold stamping performance, good welding performance and machinability.
Q345B steel pipe weight formula [(outer diameter - wall thickness) * wall thickness] * 0.02466 = kg / m (weight per meter)
Q345B steel pipe process:
Hot rolling (extrusion
seamless steel pipe): round tube billet → heating → perforation → three-roll cross-rolling, continuous rolling or extrusion → pipe removal → sizing (or reducing diameter) → cooling → blank tube → straightening → water pressure Test (or flaw detection) → mark → into storage.
Cold drawn (rolled) seamless steel pipe: round tube billet → heating → perforation → head → annealing → pickling → oiling (copper plating) → multi-pass cold drawing (cold rolling) → blank tube →heat treatment → straightening → hydraulic test (inspection) → marking → storage.
The difference between Q235 and Q345:
Different: the lower limit of yield strength of Q235 is 235mpa, and the lower limit of yield strength of Q345 is 345mpa.
The alloy content of the two is different: Q235 is ordinary carbon steel and Q345 is low alloy steel.
