WDB620钢焊接接头显微组织与力学性能分析

Analysis on Microstructure and Mechanical Properties of WDB620 Steel Welded Joints

采用手工电弧焊分别对三种厚度WDB620钢板对接接头进行焊接,并对焊接接头的金相组织和力学性能进行了试验研究。结果表明,三种板厚下WDB620钢的焊接接头都具有较高的抗拉强度和低温冲击韧性,焊接接头的塑性、抗裂性都较好,在所选用焊接工艺参数下焊接接头具有优良的综合力学性能。不管是常温或是-20℃条件下,热影响区的冲击韧性都优于焊缝区。热影响区和焊缝区的金相组织基本为粒状贝氏体+少量铁素体,且热影响区晶粒较细,焊缝区晶粒较粗,导致晶粒细小的热影响区冲击韧性优于晶粒粗大的焊缝区。

WDB620 steel plate butt joints of three kinds of thickness were welded with manual electrode arc welding respectively. The research on the metallographic and mechanical properties of the welded joints were carried out. The results show that the plate welded joints have higher tensile strength, low temperature impact toughness, plasticity and crack resistance under three kinds of thickness, which means excellent comprehensive mechanical properties when appropriate welding process parameters are selected. Whether under the normal temperature or -20~C, the impact toughness of heat affected zone is superior to the weld zone. The microstructure of the heat affected zone where has thinner crystal grains and the weld zone where has thicker crystal grains are mainly granular bainite and a small amount of ferrite, which can lead to the impact toughness of small crystal grains heat affected zone ,which are superior to the coarse crystal grains weld zone.