由于焊接过程中加热不均匀的结果,使焊接结构中产生相当大的内应力,甚至超过材料的屈服极限和强度极限,前者将发生结构的残余变形,后者产生裂缝。焊接接头中的裂缝是最危险的缺陷,它将改变力线方向,造成相当大的应力集中,降低了焊接结构的使用性能,是导致破坏的重要因素。国外曾发生过许多 As a result of uneven heating during the welding process, considerable internal stress is generated in the welded structure, even beyond the yield limit and strength limit of the material, the former will undergo residual deformation of the structure and the latter will produce cracks. Cracks in welded joints are the most dangerous flaws. They will change the direction of the lines of force, cause considerable stress concentration and reduce the serviceability of the welded structure, which is an important factor leading to the destruction. There have been many foreign countries