オーステナイト系ステンレス鋼の疲労特性に及ぼす組織安定性の影響

概要

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The fatigue properties of austenitic stainless steels with different Cr/Ni equivalent values have been investigated in the high-cycles region using Ono-type rotating bending fatigue testing machine. The materials used in this test were three kinds of representative austenitic stainless steels, i. e. typical austenitic stainless steel, SUS304 and nitrogen-contained SUS304 (SUS304 N and YUS170). The main results obtained in this test are as follows ; (1) Though each material has the different δ-ferrite value according to Ni/Cr equivalent value, there are no relation between δ-ferrite value and fatigue limit. (2) The fatigue cracks do not necessarily initiate at the segregated portion of chemical content. (3) Considering Ni/Cr equivalent, the austenitic structure in YUS 170 is more stable than those in SUS 304 and SUS 304 N. Therefore, the increase of Micro-Vickers hardness due to deformation induced martensite transformation in YUS170 is lower than those in SUS 304 and SUS 304 N. (4) The lower fatigue strength, the larger the crack tip opening displacement (CTOD) of each material which has same fatigue life.
社団法人日本機械学会の論文
1999-02-25