Optimum Deformation Value For Fatigue Strength Improvement By Roller Working.
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S.-I. Nishida, N. Hattori, S.- W. Wang & J.-Y. Ye
Optimum Deformation Value for Fatigue Strength Improvement by Roller-Working S.-I. Nishida N. Hattori S.-W. Wang & J.-Y. Faculty of Science & Engineering, Saga University, Japan Abstract Fatigue tests had been performed in this study to investigate the optimum value of deformation of notched specimen by roller-working using a medium plain carbon steel (US standards S25C). The deformation values are 0, 0.25, 0.5, 1.0 and 1.5 mm by keeping the final shapes and dimensions except for deformed value. The main results obtained are as follows: (1) The fatigue strength of notched specimen by roller-working increases with increasing the plastic deformation value when the deformation value is less than 0.5mm. and reaches to the maximum value at this point. In addition, when the value exceeds 0.5mrrt the result decreases. (2) The fatigue limit of D05 (roller-worked specimen by 0.5mm) is improved to 370MPa. which is about 220% of that of ND (non-roller- worked specimen). (3) There exists th