ショットピーニングによるアルミニウム合金鋳物の疲労強度向上と要因解析(<小特集>X線材料強度小特集)

概要

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The employment of aluminum alloy castings for automotive parts is every year,and recently some of them require relatively high fatigue strength. Under these circumstances, the improvement of their fatigue strength is an important problem to be solved. One of the authors has found that it is very hard to improve the strength,especially the fatigue limit of aluminum alloy castings,either by T6 treatment or by changing their chemical compositions. Although numerous literatures show that shot peening increases the fatigue strength of aluminum alloy castings was examined first. Secondly,the improving factor of the fatigue strength of the shot peened castings was identified through the other experiment with the upset specimens of the casting,and finally an evaluation method for the fatigue limit of shot peened aluminum alloy castings was proposed. The following conclusions were derived from the present study: (1) The fatigue strength of aluminum alloy castings was able to be improved with shot peening. (2) The improving factor is a compressive residual stress at the surface layer resulting from shot peening, and the fatigue limit is evaluated by dealing with the residual stress as the mean stress during cyclic loading. (3) Hardening at the surface layer resulting from shot peening does not contribute to the im-provement of fatigue strength in aluminum alloy castings.
社団法人日本材料学会の論文
1986-07-15