Hydrogen Embrittlement Sensitivity of a Bainite Railway Wheel Steel

The influence of diffusible hydrogen concentration (C0) on the plasticity and hydrogen induced delayed cracking of a bainite railway wheel steel was investigated by means of the slow strain rate test (SSRT) specimens and wedge open loading (WOL) specimens charged in a solution respectively. The results showed that the plasticity loss of the bainite wheel steel was larger than that of the pearlite-ferrite CL60 wheel steel. The threshold stress intensity factor of hydrogen induced delayed cracking KIH of the bainitie wheel steel decreased with the increase of diffusible hydrogen concentration. The KIH of the bainite wheel steel was much lower than that of the CL60 wheel steel when C0≥1.6×10-6, though the fracture toughness KIC of the bainite wheel steel was much higher than that of the CL60 wheel steel.