Abstract: The effects of heat treatment ( quenched at 860 〜950 °C + tempered at 200 ~ 400 ℃ ) on the microstructure and mechanical properties of a new medium carbon 40CrMnSiB low alloy ultra-high strength steel (0. 41C,0. 84Cr, 0.76Mn, 1.44Si,0. 006B) are investigated by OM,SEM and JMatPro7. 0 analysis techniques. The results show that with quenched at 920℃ . and tempered at 300 °C ,the mechanical properties of the steel reach the best toughness matching,that is,the tensile strength 1943 MPa,the yield strength 1931 MPa,the elongation 9% ,and the reduction of area 39. 5% , the impact absorption work 44 J,and the HRC hardness value 52.7.

摘要： 采用OM、SEM、JMatPro7.0分析技术,研究了热处理工艺(860～950℃淬火+200～400℃回火)对新型中碳40CrMnSiB低合金超高强度钢(0.41C,0.84Cr,0.76Mn,1.44Si,0.006B)微观组织及力学性能的影响。结果表明:920℃淬火和300℃回火钢的力学性能达到最佳强韧性匹配,即抗拉强度为1 943 MPa、屈服强度为1 931 MPa、延伸率为9%、断面收缩率为39.5%、冲击吸收功为44J、HRC硬度值为52.7。