論文
SUS304金属ベローズの結晶粒径と疲労強度の関係
2003 年 2003 巻 48 号 p. 1-6
詳細
2003 年 2003 巻 48 号 p. 1-6
It can be said that austenitic stainless steel SUS304 has the relationship of Hall-Petch in which proof stress increases with the decrease of a grain diameter. Fine grain improves both strength and toughness. In order to increase the fatigue strength of automobile parts, the author proposed the new improvement method on fatigue strength, through the clarification of the process of fatigue fracture and defensive factors. By decreasing grain diameter, it can be expected (1)proof stress (HV) increase (2)greater compressive residual stress (3)shorter amount of fatigue crack of stage I (4)surface roughness become smooth. In this study, in order to investigate relationship between grain diameter and fatigue strength in SUS304 steel, the experiment was carried out by using the metal bellows of SUS304 steel where grain diameter was adjusted by changing BA temperature after cold working. It could be realized that fatigue strength increases in proportion with decreasing grain diameter. The main reason why the fatigue strength is improved is attributed to the experimental result that the surface roughness becomes smooth by decreasing grain diameter in metal bellows.
