拡散焼なましした炭素鋼圧延丸棒平滑材の回転曲げとねじり疲労における疲労限度の比較

概要

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Rotating bending and torsional fatigue tests were carried out on plain specimens and specimens with a hole of rolled carbon steel which were diffusion annealed. The present specimens are regarded as isotropic materials although the original materials have a banded structure. The fatigue limit ratio between rotating bending and torsional fatigue (τ_w/σ_w) of the specimens is different from that of a fully annealed rolled carbon steel, and is approximately the same as that of isotropic cast carbon steel. We should use isotropic materials in discussing the effects of combined stresses on fatigue. In the torsional fatigue tests, crack propagation on plain specimens was of the shear type in the initial stage and of the tension type in the later stage. Cracks of the shear type were generated in both the circumferential and axial directions, and their length was shorter than that of fully annealed rolled carbon steel. There was no great difference between the nonpropagating crack length in torsion and that in rotating bending. The crack growth law in rotating bendig and that in torsion are expressed by dl/dN∝ σ^n_al or dl/dN∝ τ^n_al, respectively.
社団法人日本機械学会の論文
1994-10-25