Abstract: The influence of 82B steel with Mo （mass fraction） of 0. 02%，0. 04%，0. 07% and 0. 11% on microstructures and properties after high temperature stretching at different temperatures and the toughness mechanism of Mo element on 82B high carbon steel were studied. The results showed that：（1） During 200-300 ℃ high temperatures tensile， four groups of experimental steels had good mechanical properties ， at 300 ℃ to reach the peak， it was optimal experiment group with Mo content 0. 11% ， tensile strength increased from 1 139 MPa to 1 192 MPa， yield strength slightly reduced to 736 MPa， elongation and section shrinkage significantly increased to 22% and 72. 9%. Compared to the experimental steels with 0. 02% Mo content， the yield strength reduced by about 5%， but the tensile strength increased by 5%， the elongation and section shrinkage increased significantly， and the plasticity increased simultaneously with the Mo content， with the temperature continued to rise， the mechanical properties tended to decrease as the materials start to soften.（2） When the Mo content was 0. 02% and 0. 04%， the microstructures except carburite gradually increased with the increasing of tensile temperature， sorbite and pearlite did not appear obvious changes， and the same as room temperature， when the Mo content increased to 0. 07% and 0. 11%， sorbite and pearlite clusters are progressively finer and more evenly distributed. At the same time， four groups of experimental steels showed blue brittleness during high temperature tensile at 300 ℃，through the fractures observation found that there was Al， Si and other elements of inclusions， and failure mode was ductile fracture， the fracture can mainly be divided into the shear lip areas and fiber areas，the shear lip areas with the increase in temperature gradually reduced.

Key words: 82B Steel, Mo Microalloying, Tensile Strength, High Temperature Tensile, Refractory Steel

摘要： 研究了添加Mo（质量分数）为0. 02%、0. 04%、0. 07%、0. 11%的82B钢对不同温度下高温拉伸后的组织和性能的影响及Mo对82B 高碳钢的强韧化机理。结果表明：（1）200～300 ℃高温拉伸时，4 组试验钢力学性能较好，300 ℃达到峰值，Mo为 0. 11%验验组最优，抗拉强度由1139 MPa增至1192 MPa，屈服强度为736 MPa，略有降低，伸长率与断面收缩率均有显著提高，分别为22%和72. 9％。相较于Mo为0. 02%试验钢，虽屈服强度下降约5%，但抗拉强度升高5%，伸长率、断面收缩率大幅增加，且塑性随Mo含量同步提高，随着温度继续升高，由于材料开始软化，各项力学性能均呈下降趋势。（2）Mo为 0.02%和 0.04%时，显微组织除渗碳体随拉伸温度的提高逐渐增多外，索氏体与珠光体未出现明显变化，与室温相同，当Mo增至0. 07%和0. 11%时，索氏体、珠光体团逐渐细化且分布均匀。同时，4组试验钢在300 ℃高温拉伸时出现蓝脆现象，通过断口观察发现，有Al、Si等元素的夹杂物存在，且失效方式为韧性断裂，断口主要可分为剪切唇区和纤维区，剪切唇区的面积随着温度的升高逐渐缩小。

关键词: 82B钢, Mo微合金化, 抗拉强度, 高温拉伸, 耐火钢