回火温度对42CrMo齿轮钢组织与力学性能的影响

Effects of Tempering Temperature on Microstructure and Mechanical Properties of 42CrMo Gear Steel

采用扫描电镜(SEM)、拉伸试验机等研究了550~650℃不同温度回火对42CrMo齿轮钢显微组织与力学性能的影响。结果表明:回火态42CrMo钢组织主要为铁素体、渗碳体及少量残余奥氏体。随着回火温度的升高,试验钢中析出碳化物数量先增加后逐渐减少,碳化物的尺寸越来越细小,铁素体也从板条状逐渐转变为块状。随着回火温度的升高,试验钢的抗拉强度逐渐降低,伸长率逐渐升高。550℃回火试验钢的抗拉强度最高,达到1152 MPa;650℃回火试验钢的伸长率最高,达到17.2%。

The effects of different temperatures at 550-650 ℃ on the microstructure and mechanical properties of 42CrMo gear steel were studied by SEM and tensile testing machine. The results show that the microstructure of tempered 42CrMo steel is mainly ferrite, cementite and a small amount of retained austenite. With the increase of tempering temperature, the amount of carbide precipitated in the test steel first increases and then decreases gradually, the size of the carbide becomes smaller and smaller, and the ferrite gradually changes from strip shape to block shape. With the increase of tempering temperature, the tensile strength of the test steel decreases gradually and the elongation increases gradually. The tensile strength of tempered steel at 550 ℃ is highest, reaching 1152 MPa, and the elongation of the tempered steel at 650 ℃is highest, reaching 17.2%.