利用激光冲击波对X80管线钢焊接接头表面进行了强化处理，通过拉伸实验对激光冲击处理前后焊接接头试样拉伸力学性能进行了分析，用扫描电镜和能谱分析仪观察了其断口形貌与化学成分组成，并对其断裂机理进行了探讨。实验结果表明，原始状态的X80管线钢焊接接头具有连续屈服特征，无明显的屈服平台，延伸率比较高，拉伸断口出现明显的分层开裂；激光冲击处理后X80管线钢焊接接头的强度并未得到加强，韧窝尺寸与深度变大，其断裂拉伸性能得到改善。

The surface of X80 pipeline steel welded joints is processed with laser shock wave, the tensile mechanical properties of the welded joints before and after laser shock processing (LSP) are analyzed with tensile tests. The fracture morphologies and the distributions of chemical components are observed with scanning electric microscope (SEM) and energy dispersive spectrometer (EDS) respectively, and the fracture mechanism of X80 pipeline steel welded joints is discussed. The results show that the X80 pipeline steel welded joints in primitive state have the continuous yield feature, without obvious yield flat, the elongation rate is higher, and the tensile fracture appears the clear delaminated cracking; the strength of X80 pipeline steel welded joints by LSP has not increased, the dimple size and depth become bigger, that improves the tensile properties of the fractures.