热循环峰值温度对Q690钢热影响区组织与韧性的影响

Influence of Peak Temperature on Microstructure and Toughness of Heat Affected Zone of Q690 Steel

根据焊接热影响区各亚区热循环特征,采用热模拟试验机模拟了单道次焊接Q690高强贝氏体钢热影响区不同峰值温度热循环过程。采用SEM表征了试样微观组织结构和断口形貌,测试了不同峰值温度热模拟试样的冲击韧性和显微硬度。研究结果表明,各亚区显微组织特征对其冲击韧性具有重要影响。在焊接热影响区各亚区中,粗晶区是性能最为薄弱环节。

Based on thermal cycling characteristics of sub-regions of heat affected zone, the thermal cycles with different peak temperaure of heat affected zone of Q690 high strength steel under single bead welding condition were simulated by thermomechanical simulator. The microstructure and fractograph were characterized by SEM. The impact toughness and microhardness of the samples with different peak temperature were tested. The results show that the microstructure has major influence on the impact toughness of sub-regions of heat affected zone. The coarse grain region is the weakest part in the sub-regions of heat affected zone of the welded joint.