Abstract: Abstract The microstructure and mechanical properties of the test 82B steel (0. 82%C,0.20%Cr) with 0. 02% ~ 0. 11% Mo Φ 12.5 mm rolled bar (end rolling at 950 °C , water cooling to 650 °C , air cooling) are measured by means of metallographic microscope, hardness tester, universal tensile testing machine and scanning electron microscope. The CCT curves of the test steels are simulated by JMATPRO teclinology. The results show that as the Mo content increases from 0.02% to 0. 11% ； (1) the depth of decarburization layer of 82B steel is all ≤0. 12 mm,and the HV hardness number is slightly increased from 305 to 317,(2) the proportion of sorbitic decreases slightly from 94% to 89% ,the fineness of sorbitic lamella increase significantly. The yield strength increases from 655 MPa to 771 MPa, the tensile strength increases from 1 054 MPa to 1 139 MPa, the reduction of area increases from 38% to 52% , and the elongation has no significant change are about 12% ,(3) The liigh temperature strengthening effect of micro Mo is obvious. At 600 °C ,the yield strength increases from 316 MPa to 369 MPa, and the tensile strength increases from 358 MPa to 399 MPa.

摘要： 采用金相显微镜、硬度计、万能拉伸试验机、扫描电镜等设备对含0.02%～0.11%Mo 82B钢（0.82%C,0.20%Cr）Φ12.5 mm轧材（终轧950℃,水冷至650℃,空冷）进行了显微组织和力学性能的测定,并利用JMATPRO技术对试验钢的CCT曲线模拟。结果表明:当Mo含量由0.02%提高至0.11%时,（1）82B试验钢脱碳层深度均在0.12 mm以下,HV硬度值由305小幅提高至317;（2）索氏体含量由94%降至89%,索氏体片层明显细化,屈服强度由655 MPa增至771 MPa,抗拉强度由1 054 MPa增至1 139 MPa,断面收缩率由38%增至52%,延伸率无明显变化,约为12%;（3）微量Mo的高温强化作用明显,在600℃时屈服强度由316 MPa增至369 MPa,抗拉强度由358 MPa增至399 MPa。