Effects of shot-peening on permeation and retention behaviors of hydrogen in alpha iron

•Hydrogen permeation through the shot-peened pure Fe was suppressed by a factor of ten at the lower temperature below 453 K.•The effects were disappeared or lost at higher temperatures than 473 K.•Hydrogen was trapped at least two trapping sites induced by the shot-peening treatment.•Amount of hydrogen in the shot-peened surface was three times larger than that in the normal surface of pure Fe. Effects of the shot-peening on hydrogen permeation and retention behaviors were examined by applying tritium tracer techniques to the gas-driven hydrogen permeation experiments. Hydrogen permeability in shot-peened iron was reduced by a factor of ten in comparison with the as-received iron at lower temperatures of 298 K and 453 K. The effects were disappeared at higher temperatures than 473 K. Hydrogen was trapped at least two trapping sites induced by the shot-peening treatment. The amount of trapped hydrogen in the shot-peened surface was three times larger than that in the normal surface of the as-received iron.