Design of Rupture Strength Based on Confidence Level of HK40 Steel

The strength of high temperature components is designed according to creep rupture strength. A statistical processing of creep rupture data of HK40 steel was performed by Z-parameter method based on Larson-Miller method. The data has been studied to evaluate the distribution under different temperature and stress. And the distribution of Z-parameter was investigated. With the application of Z-parameter, reliability design for allowable stress of creep rupture strength was carried out according to design life. The results show that the distribution of Z-parameter is supported by normal distribution. In comparison with allowable stress designed by conventional safety factor method, reliability design based on Z-parameter is more agree with experimental data.