抄録
The purpose of this report is to evaluate thermal fatigue characteristics of EDMed surface, which attribute to prolonging the life of die steels and stability of the quality of the product.
EDMed surface treated with shot-peening, gas-nitriding and laser irradiation were evaluated for thermal fatigue by use of microphotographic observation and a X-ray residual stress measurement.
As a result of these tests, it was found that tensile stress on the EDMed surface can be changed to compression stress by applying the various surface treatments, thus improving the thermal fatigue characteristics. Furthermore, the maximum crack length in the cross sectional area after the fatigue test was remarkably shorter, increasing the ability to withstand heat checking and thus proved to be an effective method for improving the EDMed surface.
