针对 2 0 Cr Mo摩擦焊接头焊缝和母材 ,采用局部法进行了解理断裂评定。通过三点弯曲 COD试验和弹塑性有限元计算 ,得出了 2 0 Cr Mo母材和焊缝的解理断裂参量——威布尔指数 m和临界解理应力σu。并对该材质焊管的摩擦焊接头抗解理断裂性能进行了可靠性评定。研究表明 ,该摩擦焊接头焊缝的抗断裂性能有待进一步提高 ,它是摩擦焊接头抗断裂的薄弱部位 For the 20 CrMo friction welded joint welds and base metal, the cleavage fracture assessment was carried out by the local method. Through the three-point bending COD test and the elasto-plastic finite element method, the cleavage fracture parameters of 20 Cr Mo base metal and weld - Weibull index m and critical cleavage stress σu were obtained. The reliability evaluation of the anti-cleavage fracture resistance of the friction welded joint of this material pipe was also carried out. The research shows that the fracture resistance of the weld of the friction welding joint needs to be further improved, which is the weak part of the friction welding joint against fracture