What is the role of 40cr round steel

　　40cr round steel is the standard steel number of GB in China, 40cr round steel is one of the most widely used steel in the machinery manufacturing industry. It has good comprehensive mechanical properties, good low temperature impact toughness and low notch sensitivity after tempering. Steel hardenability is good, water quenching can be quenched to 28 ~ 60mm, oil quenching can be quenched to 15 ~ 40mm. In addition to tempering treatment, this steel is also suitable for cyaniding and high-frequency quenching treatment. When the hardness is 174 ~ 229HB, the relative machinability is 60%. The steel is suitable for making medium plastic molds. The steel has the best comprehensive mechanical properties. The hardenability of the steel is higher than that of 45 steel, which is suitable for high-frequency quenching, flame quenching and other surface hardening treatment. 40cr round steel structural steel is suitable for shaft parts with medium precision and high speed. This kind of steel has better comprehensive mechanical properties after quenching and tempering.