Study on the Hydrogen Effect on the Temper Embrittlement of 2.25Cr-1Mo Steel

The relationship between hydrogen embrittlement and temper embrittlement of 2.25Cr-1Mo steel was investigated by Auger electron spectrometer testing and electrochemical hydrogen charging. The results indicate that atomic hydrogen increases the grain boundary concentration of impurity element P and temper embrittlement. The increscent temper embrittlement degree by hydrogen will rise with further embrittlement and the relationship between increscent temper embrittlement degree and temper embrittlement degree is ΔC_p = log[4.9351×(C_p)^1.31687]. The grain boundary segregation theory was used and results of theory calculation and testing show that the relationship between hydrogen embrittlement and temper embrittlement can be explained by theory of grain boundary segregation. The embrittlement degree of 2.25Cr-1Mo steel which is induced by hydrogen and temper embrittlement is C_p^′ = log[4.9351×(C_p)^1.31687]+C_p.