焊接线能量对高强钢焊接接头组织性能的影响

采用1.3、1.6、1.9 kJ/mm 3种不同线能量对960QT钢进行焊接，研究了线能量对960QT钢焊接接头组织和性能的影响。研究表明，随着线能量的增加，焊接接头强度下降，但塑性提高，焊缝冲击韧性变化不大，热影响区冲击韧性先降低后增大，热影响区冲击韧性均高于焊缝。对3种线能量下960QT高强钢的焊接接头进行金相分析，发现焊缝组织主要为针状铁素体和粒状贝氏体。随着线能量的增加，针状铁素体发生粗化，数量相对减少，粒状贝氏体数量增多。焊接接头热影响区的金相组织主要为板条M/B和粒状贝氏体。随着焊接线能量的增大，冷却速率减小，粒状贝氏体组织数量相对增加，而板条贝氏体组织的数量逐渐减少。

Influence of welding energy inputs on microstructure and performance of welding joint of high strength steel

960QT steel was welded with three different energy inputs of 1.3、1.6、1.9 kJ/mm.The influence of energy inputs on the microstructure and properties of 960QT steel's welding joint was studied.The results show that with the increase of energy inputs,the strength of welding joint decreases,but the plasticity increases,the impact toughness of welding seam does not change much,and the impact toughness of heat affected zone decreases first and then increases.The impact toughness of the heat affected zone is higher than that of the welding seam.Metallographic analysis of welding joint of 960QT high strength steel under three energy inputs show that the welding seam microstructure is mainly acicular ferrite and granular bainite.As the energy inputs increases,the acicular ferrite coarsens,the amount decreases,and the number of granular bainite increases.The metallographic structure of the heat affected zone of the welding joint is mainly lath M/B and granular bainite.As the welding energy inputs increases,the cooling rate slows down,the number of granular bainite structures increases,and the number of lath bainite structures decreases.