【摘要】 为研究最新研制的大热输入焊接所用低合金高强实心焊丝G55,对大热输入用钢E40进行热输入分别为60、122、158 kJ/cm的双丝埋弧焊焊接.经过拉伸、冲击试验及光学显微镜、扫描电镜和透射电镜分析,对焊接接头焊缝组织性能进行研究,并对接头强韧性进行分析.结果表明:不同热输入焊缝组织均以针状铁素体组织为主;随着热输入的增加,焊缝冲击韧性增加,这是因为焊接热输入增加时,柱状晶比例减小、宽度增加,针状铁素体含量增加;焊缝中含氧量减少,夹杂物数量减少;焊接道次减少导致块状铁素体含量减少等三方面因素.随着热输入的增加,焊缝金属强度提高,主要是因焊缝针状铁素体组织含量增加.更多还原

【Abstract】 A newly developed high strength low alloy welding wire G55 for High Heat Input Welding was studied.E40 steel was welded with heat input of 60、122、158 kJ/cm by Dual Wire Arc Welding using welding wire G55.Mechanical properties were analyzed and microstructures were observed by OM(Optical Microscopy),SEM(Scanning Electron Microscopy) and TEM(Transmission Electron Microscopy).The results indicated that the microstructures of welds at different heat inputs welding were main AF(Acicular Ferrite).With heat inputs increasing,the impact toughness of welds increased due to the increasing of width of columnar grains and percentage of acicular ferrite;the reducing of oxygen content of welds and number of inclusions;and the reducing of thermal cycling and weak zone of welds with massive ferrite.The strength of welds increased mainly because of the increasing of acicular ferrite.更多还原