Effects of the microstructure and reversed austenite on the hydrogen embrittlement susceptibility of Ni-Cr-Mo-V/Nb high-strength steel

The effects of the microstructure and reversed austenite (RA) on the hydrogen embrittlement (HE) behavior were investigated in NiCrMoV/Nb high-strength steel prepared using three different heat treatments. The quenching and tempering (QT) steel showed a noble HE resistance for the lowest hydrogen diffusion and maximum apparent hydrogen concentration compared to quenching (Q) steel and quenching, lamellarizing, and tempering (QLT) steel. Thermal desorption spectroscopy (TDS) analysis confirmed that RA had an activation energy of 32.5 kJ/mol which indicates a stable trapping site. The QLT steel containing more RA exhibited a higher HE sus-ceptibility, suggesting that RA degrades the HE resistance.

Automated summary

The effects of microstructure and reversed austenite on the hydrogen embrittlement behavior of NiCrMoV/Nb high-strength steel were investigated. The quenching and tempering steel showed the highest resistance to hydrogen embrittlement due to its lower hydrogen diffusion and higher apparent hydrogen concentration. The presence of reversed austenite in the quenching, lamellarizing, and tempering steel increased its susceptibility to hydrogen embrittlement.