异种钢闪光对焊接头蠕变断裂力学行为

Creep Fracture Mechanical Behavior of Dissimilar Steel Joints Fabricated by Flash Butt Welding

分别对闪光对焊制备的高强匹配 (BM-WH-BL)、低强匹配 (BH-WL-BM)和中强匹配 (BL-WM-BH)的宏观力学不均匀异种钢接头进行了蠕变及蠕变断裂试验 ,并用有限元方法分析了不同匹配接头蠕变断裂的力学因素。结果表明 ,高强匹配和低强匹配接头均沿着邻近焊缝界面的低强度母材或焊缝侧发生断裂 ,并呈脆断特征 ;中强匹配接头蠕变断裂位置在远离焊缝界面的低强度母材区 ,呈延性断裂性质。应力三轴性是控制高强匹配和低强匹配接头脆性断裂的主要力学因素 ,而应变集中控制着中强匹配接头的延性蠕变断裂。

Creep and creep fracture tests for the macro mechanical heterogeneous dissimilar steel welded joints fabricated by flash butt welding with high strength match (B M W H B L),low strength match (B H W L B M) and medium strength match (B L W M B H) were carried out respectively.The mechanical factor of creep fracture for different strength match joints was analyzed by finite element method.The results indicated that the fracture occured along the low strength base metal or weld metal adjacent to the weld interface for high strength match and low strength match joints,and showed a brittle character.However,the creep fracture of medium strength match joint,located in the low strength base metal remote from the weld interface,showed a ductile fracture character.The stress triaxiality was a major mechanical factor which induced brittle fracture,and the strain concentration controlled the ductile fracture procedure.