应力状态对 16Mn 钢焊接接头断裂行为的影响

Influence of Stress State on Fracture Behaviour of Welded Joint of 16Mn Steel

利用光滑、缺口试件拉伸试验及电子显微技术研究了１６Ｍｎ钢焊接接头在不同应力状态下的强度、塑性特征，裂纹起始、扩展特性及各特征区的断裂韧性ＶＧＣ，讨论了应力状态对接头断裂行为的影响．结果表明：随着应力三轴度的增加，接头由韧性向脆性断裂方式转变，断口形貌则由韧窝向准解理、解理转化，断裂应变急剧下降．母材的ＶＧＣ值最高，熔合区、焊缝次之，过热区的ＶＧＣ值最低．

This paper studies the characteristics of strength, plasticity, crack initiation, propagation of welding joints of 16Mn steels under different stess states by use of tensile experiments of smooth and notched specimens and electronic microscopic technology,fracture toughness V GC of characteristic zones, discusses the influence of stress states on fracture behaviour of welded joints. The results show that the fracture forms are changed from ductile to brittle form, the fracture appearances are changed from void to quasi cleavage, cleavage, and the fracture strain is sharply reduced with the increase of stress triaxiality. The fracture toughness V GC of base metal is maximum, the fracture toughness V GC of fusion zone and weld metal is less than that of the base metal, the fracture toughness V GC of overheat zone is minimum.