20MnNiMo钢焊接热影响区的组织和韧性及其氢致裂纹特征

HAZ Structure, Toughness and Characteristics to Hydrogen-Induced Cracking(HIC) of Steel 20MnNiMo

摘要: 研究了焊接冷却速度对20MnNiMo钢焊接热影响区组织、韧性及氢致裂纹敏感性的影响。试验结果表明,t_8/3对焊接热影响区的组织、韧性及氢致裂纹敏感性均有显著的影响。当t_8/3小于55s时,焊接热影响区获得M或M+少量B组织,具有良好的低温韧性,但此时焊接热影响区对氢致裂纹敏感。为防止氢致裂纹的产生,同时确保焊接热影响区具有良好的韧性,20MnNiMo钢焊接时应采用适当的预热温度和焊接线能量以及及时的焊后消氢处理。

Abstract: In this paper the effect of the cooling condition during welding on HAZ structure,toughness and susceptibility to Hydrogen-Induced Cracking(HIC) of steel 20MnNiMo was studied.The experimental results showed that the cooling rate t_8/3 considerably affected both the HAZ toughness and the susceptibility to HIC.The M or M with a little B structure in HAZ and better low temperature toughness were obtained,when t_8/3 was less than 55s.However this structure was sensitive to HIC.In order to avoid HIC and get better toughness in HAZ,the lower heat input,lower temperature preheating and hydrogen removal promptly after welding were recommended.