40CrNiMoA合结钢喷丸强化残余应力分析

Residual Stress Analysis in Shot-peened 40CrNiMoA Alloy Structural Steel

针对表面喷丸强化处理后的40CrNiMoA合结钢圆棒试件,采用X射线无损残余应力测试手段检验其喷丸处理的效果,并通过旋转弯曲疲劳试验分析其残余应力松弛现象,评估各喷丸工艺改善疲劳寿命的程度与稳定性。结果表明,喷丸可显著提高试件的疲劳寿命,应力松弛与外应力幅、循环周期及初始应力场分布有关,表面残余应力水平并非喷丸效果评估的最关键因素,疲劳寿命的增益程度受多种因素共同作用。

Aiming at the shot-peened round bar specimens made of 40CrNiMoA alloy structural steel, the shot-peening effects were tested by XRD stress measurement. The stress relaxation was also analyzed by rotating bending fatigue tests to estimate degree and stabilization of shot-peening enhancing the fatigue life. The results show that shot-peening can enhance remarkable fatigue life, and stress relaxation is determined by external stress amplitude, loading cycle and initial residual stress field distribution. The surface residual stress level is not the key factor influencing shot-peening effects since the enhancement of fatigue life is simultaneously controlled by several factors.