高炭素クロム軸受鋼の焼割れに関する研究 : 第4報,焼入れの繰返しによる焼割れ感受性の判定について

概要

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The preceding paper has reported on the numerical evaluation of quench crack susceptibility. The disadvantage of the experimental method has been the assumption of a great number of samples i.e., high cost. This paper deals with a modified method for evaluating quench crack susceptibility. Quenching was repeated n-th times until a crack was generated, using 4~5 test pieces. The results obtained are discussed and compared with the data presented in the preceding paper. In quench cracking of a high carbon and chromium steel bar, vertical crack value in 1/n crack generation is closely related to the crack percentage, while fin crack value slightly deviates. The residual stresses caused by repeated quench were measured by the X-ray diffraction method. The residual stresses caused by repeated quench were measured by the X-ray diffraction method. The residual stress (tensile stress) on the surface increased with repeat time. It was clarified on the basis of observations using a metallurgical microscope that the repeat of quenching should be less than 3~4 times.
1988-06-25