用光学显微镜、透射和扫描电镜观察以及X射线应力仪分析取向硅钢热轧卷焊接接头焊态与热处理后冷弯塑性和显微组织的关系,探索了影响接头脆断的因素和裂纹的起源,并根据对断口附近大量形变孪晶的观察,分析了它对断裂过程的影响.焊态下熔合线和过热区产生的马氏体、碳化物以及过热区晶粒粗大是造成接头断裂的主要因素.形变时过热区形成的大量形变孪晶的交截和孪晶对相界的撞击也导致了裂纹的萌生,加速了焊接接头的脆性断裂. The relationship between the cold plasticity and the microstructure of the hot rolled coil welded joints of the oriented silicon steel was analyzed by optical microscopy, transmission and scanning electron microscopy, and X-ray stress analyzer. The factors affecting the brittle fracture and the origin of the cracks were explored. According to the observation of a large number of deformation twins in the vicinity of the fracture, the influence of the deformation on the fracture process is analyzed.The martensite, carbides and overheated grains produced by the weld line and overheat zone are the main factors leading to fracture During the deformation, the cross-section of a large number of deformable twins and the twin impact on the phase boundary caused the initiation of cracks and accelerated the brittle fracture of welded joints.