炭素鋼焼きなまし材の寸法効果について

概要

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The X-ray back diffraction method was used for the nondestructive direct of fatigue damage in the machine parts of larger size. The size effect on fatigue of annealed carbon steel was also studied. The results obtained in this experiment are as follows. (1) Whether the applied cyclic stress is larger or smaller than the fatigue limit of the specimen can be estimated by the back diffraction pattern in the case of unnotched test specimens, irrespective of the specimen sizes. On the other hand, the fatigue limit estimated from the X-ray pattern in the case of the specimen with a shoulder fillet is a little lower than the true fatigue limit. It is considered to be due to the stress gradient in the fillet. (2) Th e changes in residual stress and half-value breadth of diffraction line width during the fatigue process in the case of unnotched specimens depend on the specimen size even under the same applied stress. This result shows also that the size effect on fatigue strength must vary according to the strength near the specimen surface, which will be emphasized by stress gradient. It can also be concluded from the results obtained that the X-ray diffraction method is available for the detection of fatigue damage in the specimens of different size.
社団法人日本材料学会の論文
1968-12-15