Effect of thermomechanical treatment on the susceptibility of structural steel to hydrogen embrittlement

It was established that high-temperature thermomechanical treatment (HTMT) produces a substantial reduction in the susceptibility of a medium-carbon steel 37KhN3A (tempered at a low temperature) to hydrogen embrittlement. An anisotropy of the ductility and the resistance to fracture of hydrogen-charged steel was observed after HTMT which points to a selective character of hydrogen charging and hydrogen embrittlement at the boundaries of the initial austenite grains. Torsion test results showed that hydrogen charging has practically no effect on the shear strength and affects only such structure-sensitive properties as tensile strength and ductility.