高温高压载荷作用下P91材料蠕变寿命预测研究

Research on HTHP Creep Life Prediction of P91 Steel

对国产P91材料取样,在550℃温度下采用不同应力载荷进行持久试验,运用等温线外推法和L-M参数法对持久试样参数拟合求得10000h的持久强度,均大于标准推荐值。对原始试样和不同载荷下的持久试样利用金相、电镜扫描、X射线能谱、布氏硬度进行蠕变分析,得出蠕变孔洞是产生断裂的原因,进一步证实合金元素由固溶态向化合态转移,析出相在持久载荷随时间不断出现并聚集、老化,最后硬度降低,导致断裂。

For P91 materials,different stress loads were used to carry out the endurance test at 550℃,and isotherm extrapolation method and L-M parameter method were used to fit the parameters of the endurance samples to obtain the endurance strength of 10000h,which were all greater than the recommended value.The creep analysis of the original specimen and the permanent specimen under different loads was carried out by means of metallography,scanning electron microscopy,X-ray energy spectrum and Brinell hardness.It was found that the creep hole was the cause of the fracture.It was further confirmed that the alloy elements were transferred from solution state to composite state,and the precipitated phases appeared and accumulated and aged with time under the permanent load,and finally the hardness decreased,leading to the fracture.