汽轮机螺栓应力松弛行为预测的研究

Study on stress relaxation performance prediction for steam turbine bolts

根据高温下金属应力松弛的基本特征,建立了预测应力松弛行为的动力学方程式,该表达式可根据某初应力下的松弛试验结果预测不同初应力时的应力松弛行为。多种材料试验数据的验证结果表明,本文采用的预测方法合理,提出的动力学方程式具有广泛的适应性以及良好的拟合和预测精度,便于工程应用。利用该方程式,还分析讨论了不同初应力下的材料松弛塑性应变速率随时间的变化及其趋势比较,其规律与现有的研究结果保持一致。

The basic characteristics of metal stress relaxation at high temperature are analyzed. And the dynamic formula to predict stress relaxation performance is established. By means of relaxation data of some initial stress values, this mathematical expression can predict stress relaxation performance under various initial conditions. The validity and precision of the formula are justified by the relaxation experimental data of several bolt steels. Finally, based on the for- mula, the changes between relaxation strain rate and time as well as its trend are investigated. Test results show that the results of study are coincide with the researches.