Wear of components used in mining and in fragmentation processes increases time needed for maintenance and cost of elements reposition. In this research, swing hammers were exposed to impact wear inside a hammer mill which processed metallic pieces, in order to study their performance in impact wear conditions. Two Hadfield steels with different carbon and manganese contents, with and without previous shot peening treatments were tested. During the tests the mass loss and the strain hardening were measured. Specimens with higher carbon content showed lower mass loss than specimens with lower carbon content. Nevertheless, specimens with lower carbon content presented a decrease in mass loss when they were previously exposed to shot peening, while high carbon specimens showed the opposite behaviour Adhesion was identified by scanning electron microscopy, as an important wear mechanism during impact wear.