Cr12高碳高铬冷作模具钢的热处理工艺研究

Study on Heat Treatment Process of Cr12 High Carbon and High Chromium Cold Working Die Steel

对Cr12冷作模具钢分别进行了不同温度的淬火及回火,研究了淬火及回火温度对模具钢组织及力学性能的影响。结果表明:在淬火态,钢的基体为片状马氏体与残留奥氏体混合组织。淬火后回火,片状马氏体消失,随着回火温度的升高,基体由粗大的片状马氏体逐渐转变为细小的板条状回火马氏体,力学性能提高,断口中的断裂韧窝增多。当淬火为1000℃,回火为550℃时,基体由细小的板条状回火马氏体与粒状回火索氏体混合组织组成,屈服强度为750 MPa,抗拉强度为1050 MPa,断后伸长率为13.6%,冲击功为63 J,此时模具钢的综合力学性能最优。

The quenching and tempering at different temperatures of Crl2 cold working die steel were carried out. The effects of quenching and tempering temperature on the microstructure and mechanical properties of the die steel were studied. The results show that under quenched state, the matrix of steel is a mixed microstructure of lamellar martensite and retained austenite. After quenching and tempering, the lamellar martensite disappeares, and with the increase of tempering temperature, the matrix is gradually transformed from coarse lameUar martensite into a small plate tempered martensite, mechanical properties improve, and fracture toughness in the fracture increases. When the quenching temperature is 1000 ℃ and tempering temperature is 550 ℃, the microstructure of the matrix is composed of a small strip tempered martensite and a granular tempered martensite, the yield strength is 750 MPa, the tensile strength is 1050 MPa, the elongation is 13.6%, and the impact absorption energy is 63 J. The comprehensive mechanical properties of the cold working die steel are optimal under this condition.