SHOT PEENING TREATMENT OF SINTERED AND FORGED MEMBER

摘要

PURPOSE:To obtain a sintered and forged member having excellent fatigue strength, rolling fatigue strength, etc. by starting a shot peening treatment for the sintered and forged member sintered and forged to a high theoretical density ratio from a high temp. above the recrystallization temp. in the cooling process thereof. CONSTITUTION:The shot peening treatment for the sintered and forged member obtd. by heating and sintering a molding obtd. by compaction molding of metallic powder then forging the molding at a high temp. and having >=80% theoretical density ratio is started from the high temp. above the recrystallization temp. at which deformation resistance is low in the cooling process for the sintered and forged member. The surface holes of the sintered and formed member are thus surely crushed and the high plastic deformation is made possible. The press welding of the unsintered part is thus made substantially secure and the fatigue strength and rolling fatigue strength of the sintered and forged member are remarkably improved.