Q690CFD高强钢焊接热影响区断裂韧性分析  

Fracture Toughness of CGHAZ of.Q690CFD High-Strength Steel

作　　者：张楠[1] 张熹[1] 李晓刚[1] 杨建炜[1] 齐建[1] 金茹[1] 

机构地区：[1]首钢技术研究院

出　　处：《首钢科技》2016年第2期13-21,共9页Shougang Science and Technology

摘　　要：采用Gleeble-1500型试验机模拟了2种成分Q690CFD高强钢的CGHAZ，测试了CGHAZ的冲击吸收功，并通过3点弯曲试样测试了CGHAZ的CTOD特征值。利用SEM对CTOD试样断口及近断口区裂纹扩展行为进行了分析。结果表明，冲击吸收止裂功及CTOD特征值占随温度降低呈明显下降趋势；将CTOD特征值占用Boltzmann函数拟合后所得脆韧转变温度与示波冲击变化规律相对应；2种成分试验钢的CTOD失稳裂纹扩展路径与近断口区组织亚结构中大角度晶界和M／A岛分布位置有关。In this paper, Q690CFD high-strength steel with two different alloys were chosen, and single thermal-cycles to simulating coarse grain heat affect zone （CGHAZ） were carried out by Gleeble-1500 to study its impact toughness and values of CTOD by a series of three point bending tests. The fracture behavior of cracking in CGHAZ were analyzed based on fractography of CTOD samples by SEM analysis. The results show that the variation trend of critical CTOD values δ and instrumented extension energy is decline as temperature decreases; the transition temperature from brittle to ductile, fitted by Bohzmann function, is accordant with variation tendency of instrumented impact. The path of cracking propagation in CGHAZ on two different Q690CFD steels is determined by the position of M/A islands and high angle boundarys （≥ 15°） on metastructure nearby the fracture zone.

关 键 词：焊接 CGHAZ CTOD 大角度晶界M/A岛 

分 类 号：TG457.11[金属学及工艺—焊接]