Effect of heat treatment on hydrogen-assisted fracture behavior of PH13-8Mo steel

Effect of heat treatment on hydrogen-assisted fracture behavior of PH13-8Mo steel was investigated. The results show that hydrogen embrittlement susceptibility of the specimens aged at 600 °C is the lowest compared with that of the specimens aged at 430 °C and 540 °C at the same aging time. With an increase in aging time, the susceptibility to hydrogen embrittlement increases for specimens aged at 430 °C while it decreases for specimens aged at 540 °C and 600 °C. Hydrogen-assisted cracks initiate and propagate along lath and prior austenite grain boundaries. In addition, the quantitative relationship between hydrogen embrittlement index and fracture mode is given.