Production specification: Outer diameter of steel pipe 20-426 Steel pipe wall thickness of 20-426 Product introduction: The purpose of 42crmo seamless steel pipe: the special steel for bridge is "42crmo", the special steel for automobile girder is "42CRmo", the special steel for pressure vessel is "42Crmo". This kind of steel is to rely on the adjustment of carbon (C) content to improve the mechanical properties of steel, therefore, according to the carbon content of high and low, this kind of steel can be divided into: low carbon steel - carbon content is generally less than 0.25%, such as 10, 20 steel, etc.; Medium carbon steel - carbon content is generally between 0.25 ~ 0.60%, such as 35, 45 steel, etc. High carbon steel - carbon content generally greater than 0.60%. Such steel is not normally used to make steel pipes. Process specification: Hot working specification Heating temperature 1150 ~1200°C, starting temperature 1130 ~1180°C, end temperature > 850°C,φ> 50mm, slow cooling. Normalizing specification Normalizing temperature 850~900°C, out of the oven air cold. High temperature tempering specification Tempering temperature 680~700°C, out of the oven air cold. Specification for quenching and tempering Preheating temperature 680 ~700°C, quenching temperature 840~880°C, oil cooling, tempering temperature 580°C, water cooling or oil cooling, hardness ≤217HBW. Specification for hardening and toughening under - temperature quenching Quenching temperature 900°C, tempering temperature 560°C, hardness (37±1) HRC Specification for induction hardening and tempering Quenching temperature 900°C, tempering temperature 150~180°C, hardness 54 ~60HRC.