锰对C-Mn钢多层焊缝低温韧性影响的机理

本文通过热模拟、夏氏冲击及启裂源组织观察等实验,研究了锰对C-Mn钢多层焊缝韧性影响的机理。结果发现:启裂的最薄弱环节组织一般为原始柱状晶过热区(1350℃)、不完全重结晶区(860℃)及两者共同作用的再热区域;当锰含量较高时,细晶区也可成为薄弱环节,随着锰含量的升高,薄弱环节中针状铁素体的比例增大,该区的韧性升高,从而使整个焊缝的韧性升高;当锰含量为1.34％时,焊缝的韧性最佳。

The Effect of Manganese on the Low Temperature Toughness of C-Mn Multipass Weld Metals

By using the thermo-simulation and Charpy-V notch impact test along with observation of the microstructures in the cleavage crack is initiated, the effect of manganese on the toughness of various zones in C-Mn multipass weld metals is investigated. The results indicate that the weakest zone of multipass weld metals are generally the superheated zone ( 1350C) of column crystals, the incomplet recrystallization of about 860C, and their combination reheated regions. However, the weakest zone may move to the region with fine grains with a higher content of manganese. With increasing the manganese, the toughness of the weakest zone is improved as the content of acicular ferrite in the zone is increased, leading to increasing the toughness of the entire multipass weld metals. The optimum toughness of weld metals is attained at the content 1.34% of manganese.