Abstract: Effect of 220 °C ,240 °C ,260 °C，280 °C ,300 °C and 320°C for 3 h tempering on microstructures and mechanical properties of 950 °C quenched test 20SiMnMo high strength steel (/% ：0. 22C,0. 80Si, 1.00Mn,0. 40Mo,0. 72Cr, 0. 20Ni)are studied by means of optical microscope, scanning electron microscope, Rockwell hardness tester, universal tensile testing machine and impact testing machine. The results show that with the increase of tempering temperature, the hardness and strength of the tested steel decrease, the elongation and impact energy at room temperature increase firstly and then decrease. After tempered at 260 °C , the steel with uniform fine martensite laths microstructure has a good comprehensive properties of strength, ductility and toughness with HRC hardness number 44. 8, impact absorption energy AKV275. 3 J, tensile strength 1 278 MPa, yield strength 1 210 MPa and elongation 15. 5%.

摘要： 采用光学显微镜、扫描电子显微镜、洛氏硬度计、万能力学试验机以及冲击试验机研究了950℃淬火220℃、240℃、260℃、280℃、300℃和320℃3 h回火试验对20SiMnMo高强度钢（/%:0.22C,0.80Si,1.00Mn,0.40Mo,0.72Cr,0.20Ni）微观组织和力学性能的影响。结果表明,随着回火温度的升高,试验钢的硬度、强度不断下降,伸长率、室温冲击功先升高再降低。当260℃回火时,试验钢具有均匀细长的板条马氏体组织,其强塑韧综合力学性能最佳:硬度值44.8HRC、AKV2冲击功75.3 J、抗拉强度1 278 MPa、屈服强度1 210 MPa、伸长率15.5%。