不锈钢振动时效过程的循环蠕变机理

The mechanism for vibratory stress relief of stainless steel

采用疲劳试验机研究了不锈钢焊接试件在循环载荷下应力应变的变化规律。采用拉-压疲劳模拟实际焊接构件的振动时效过程。结果显示动态应变呈循环蠕变状态,蠕变的大小、速度与循环应力幅值有关。循环应力越大,最终蠕变也越大,应变达到稳定所需要的循环周次越多。应用X射线衍射法测量了不同循环载荷作用下,焊趾位置的纵向残余应力的变化。根据试验结果提出了振动时效过程的循环蠕变机理。

The cyclic strain and stress of 304L stainless steel welded specimens were investigated on material testing system.To simulate the vibratory stress relief(VSR) processing,the tensile-compress cyclic loading was applied.The experimental results showed that the dynamic strain has feature of cyclic creep.Cyclic loading affected the creep and creep speed.The bigger the loading,the bigger the creep and the creep speed,and the longer time that the strain became stable.The residual stresses at weld toe were measured using X-ray diffraction method after different cyclic stress amplitude.According to the experimental results,the cyclic creep mechanism during VSR processing was presented.