为了改善1Cr5Mo耐热钢焊接接头拉伸力学性能，利用CO2激光对其进行了表面改性处理，通过拉伸试验考察了激光热处理对拉伸性能的影响。利用扫描电镜观察了焊接接头的断裂形式和断口形貌，并用能谱仪分析了激光热处理前后试样表面化学元素的组成，讨论了残余应力和残余奥氏体对拉伸性能的影响。结果表明，激光热处理前后试样的拉伸断口均为韧性断裂，激光热处理后断裂性能有所提高；激光热处理试样表面产生晶粒细化和残余压应力的强化层，其屈服强度和抗拉强度分别提高了3.4%和13.7%，拉伸性能得到进一步提高；激光热处理试样的残余奥氏体含量有所降低，导致焊接接头的断面收缩率下降了18.61%，而延伸率基本不变，其均匀变形能力有所增强。

In order to improve mechanical properties of 1Cr5Mo heat-resistant steel welded joints, the surface was modified with CO2 laser, and the tensile tests were conducted to research the effect of LHT(laser heat treatment) on tensile properties of welded joints. The rupture modes and the fracture morphologies were analyzed with SEM(scanning electron microscopy), the changes of chemical elements in the sample surface before and after LHT were analyzed with EDS(energy disperse spectroscopy), and the effects of residual stress and retained austenite on tensile properties were discussed. The results show that the fracture of the samples before and after LHT are ductile rupture, the rupture properties have been improved. After LHT, the strengthened layer of compressive residual stress and refined grains are generated in the sufrace, which cause yield strength and tensile strength to increase by 3.4% and 13.7%, and the tensile properties increased. The content of retained austenite decreases in the sample surface after LHT, which causes the section reduction rate to decrease by 18.61%, the elongation rate nearly doesn′t change, and the ability of uniform deformation has improved.