摘要
采用单激光+激光-电弧复合焊接对10 mm厚S700MC高强钢进行焊接,对比分析了接头不同道次焊缝的组织和力学性能;通过升降法测定出S700MC母材疲劳极限为350 MPa,焊缝疲劳极限为172 MPa;采用Weibull分布模型和三参数幂函数S-N模型结合的方法拟合出S700MC焊缝的P-S-N曲线。结果表明:疲劳裂纹主要从焊缝热影响区的粗晶区萌生,该区域过热生成魏氏体,晶粒粗大,塑性差、韧性低、硬度高,使热影响区存在较大的硬度梯度,易产生应力集中,降低了接头疲劳性能。
S700MC high-strength steel with 10 mm thickness was welded by single laser+laser arc hybrid welding.The microstructure and mechanical properties of the welded joints with different weld passes were compared and analyzed.The fatigue limit of S700MC base metal was determined to be 350 MPa by the up-and-down method,the fatigue limit of the weld is 172 MPa.The P-S-N curve of the S700MC weld was accurately fitted by the Weibull distribution model and the three-parameter power function S-N model.The results show that the fatigue cracks mainly initiate from the coarse grain zone in the heat affected zone of the weld,which is overheated to form Widmanstatten structure with coarse grains,poor plasticity,low toughness and high hardness.Larger hardness gradient exists in the heat affected zone,which is easy to cause stress concentration and reduce the fatigue performance of the joint.
作者
顾思远
李子骏
刘洋
刘静静
耿韶宁
蒋平
GU Siyuan;LI Zijun;LIU Yang;LIU Jingjing;GENG Shaoning;JIANG Ping(College of Mechanical Science and Engineering,Huazhong University of Science&Technology,Wuhan 430074,China;China Railway Science&Industry Group Co.,Wuhan 430074,China)
出处
《热加工工艺》
北大核心
2025年第14期142-150,157,共10页
Hot Working Technology
基金
国家自然科学基金基础科学中心项目(52188102)
国家重点研发计划项目(2022YFB3404802)。
