【摘要】 研究了 3 Cr- 3 Mo二次硬化钢淬火回火后的组织和力学性能。结果表明 :随回火温度的升高 ,试验钢中先后析出 M3C、M2 C和 M7C3等碳化物 ,在 5 75℃回火时硬度达到峰值 ;40 0～ 5 75℃回火后试验钢的抗拉强度约为 160 0 MPa,冲击韧性为 3 0 J/ cm2 ;回火温度高于 60 0℃时 ,强度和硬度迅速下降 ,冲击韧性增加 ;64 0℃回火时 ,以 M2 C型碳化物为主 ,抗拉强度为 110 0 MPa,冲击韧性增加至 5 5 J/ cm2 。更多还原

【Abstract】 The microstructure and mechanical properties of a secondary hardening steel containing 3 % Cr and 3 % Mo in quenched and tempered condition were investigated. It is found that increasing the tempering temperature gives rise to successive precipitation of M 3C, M 2C and M 7C 3 type carbides, resulting in a peak secondary hardening intensity at 575 ℃. When tempered at 400~575 ℃, the steel has high tensile strength of about 1600 MPa and low impact toughness of 30 J/cm 2. Drastic declines in hardness and strength as well as an increase in impact toughness are observed when the tempering temperature is increased to above 600 ℃. Tempering at 640 ℃ results in a microstructure with fine M 2C carbides in the α-matrix, which ensures a combination of high strength of 1100 MPa and good impact toughness of 55 J/cm 2.更多还原