力学性能不均匀焊接接头的强度预测

提出一种评价力学性能不均匀焊接接头强度的方法。从管线钢的低匹配焊接接头截取试样,进行硬度测量和拉伸试验。根据已有的材料硬度值和强度的关系,确定其屈服应力、最大载荷处的真应力和加工硬化指数。从而利用焊接接头的硬度分布,得到其对应各区域的局部材料性能。建立焊接接头的有限元模型,将焊缝和热影响区分割成小区,输入对应的材料性能参数,这样使有限元模型中能较准确反映焊接接头的力学不均匀性;进行有限元计算,得到相应焊接接头的试样的屈服强度和抗拉强度。与对应拉伸试验结果比较表明,这种预测焊接接头强度方法的精确度为±40 MPa。

Prediction of tensile properties of welded joint with mechanical heterogeneity

An approach to evaluate the strength of welded joints with mechanical heterogeneity was proposed.The hardness measurement and tensile testing were performed on the specimens,which were cut from the undermatching joints of pipeline steel.According to the relation between hardness and strength for metals,methods were developed to determine the yield stress,true stress at maximum load and work hardening component from the hardness measurement.Thereby the local material properties across welded joints could be obtained from the hardness distribution on them.Finite element model of welded joints was constructed to calculate their yield strengths and tensile strengths.In this model weld and heat affected zone were divided into small partitions to be given the special material properties.Comparison between the results from finite element analysis and tensile test showed that,with this model,the strength of welded joints with mechanical heterogeneity could be predicted with an accuracy of ±40 MPa.