应用等效应变法的30Cr1 Mo1 V钢疲劳-蠕变交互作用的试验分析

Tests and Analysis of Fatigue-Creep Interaction of Steel 30 Cr1MoV by the Equivalent Strain Method

在540℃和565℃两种温度下进行了30Cr1Mo1V转子钢的疲劳-蠕变交互作用实验。采用Felltham公式建立了应变保持下应力与时间的关系;得到了应变循环幅保持不变、疲劳-蠕变交互作用下的循环应力-应变关系。根据等效应变概念建立了应变-寿命关系,并从分散度因子和标准偏差方面对等效应变法和线性累计损伤法的寿命预测有效性进行了比较;建立了等效应变的临界损伤公式和考虑硬度修正的等效应变寿命关系。试验结果表明,在预测寿命时等效应变法比线性累计损伤法具有更高的精度,等效应变的应力下临界损伤公式能够很好地预测实际损伤,考虑硬度修正的等效应变-寿命曲线和纯疲劳应变-寿命曲线基本一致。

Experimental tests on fatigue-creep interaction of rotor steel 30Cr1Mo1V have been carried out at temperatures 540℃and 565℃. By making use of the Felhham formula, a relationship between stress and time, with strain held constant, is obtained, and herewith the cyclic stress-strain relationship under fatigue-creep interacting conditions and the cycle＇s strain range held constant. Based on the equivalent strain （ES） concept, a relation between strain and life expectancy was set up and compared with the linear method of summing up damages （LSD）, from the point of view of scatter band factors and standard deviations; herewith a critical damage formula is established and also an equivalent strain-life relationship with hardness modification. Test results show that the equivalent strain method exhibits a higher life assessment precision as compared to that by linear damage summation. The critical damage formula for equivalent strain can quite well predict the actual damage incurred and the equivalent strain-life curve with hardness modification fundamentally conforms with the pure fatigue strain-life curve. Figs 5, tables 2 and refs 9.