Hydrogen Embrittlement In Shot-Peened Steel

This work investigates the role of shot peening on hydrogen embrittlement resistance in quenched and tempered 1070 steel. Thermal desorption spectroscopy results revealed that shot-peened specimens contained nearly twice the hydrogen (H) content of unpeened samples when charged under the same electrochemical conditions, suggesting the introduction of additional trapping sites occur during peening. The mechanism underlying this behavior can be associated with increased dislocation density and is more consistent with the HELP mechanism. Residual stress measurements show a significant relaxation of compressive stresses in shot-peened specimen after H charging, indicating H enhanced dislocation rearrangement. Both unpeened and peened specimens exhibited reduced ductility and strength after H charging; however, the peened samples demonstrated a smaller reduction (72.6% vs 55.8%). Despite higher overall H uptake, the shot-peening reduced susceptibility to embrittlement as compared to the unpeened condition.