放電加工面の機械的性質に及ぼす影響
炭素鋼の疲れ強さについて
1985 年 18 巻 36 号 p. 30-41
詳細
1985 年 18 巻 36 号 p. 30-41
The electro-discharge machining technique (EDM) is now widely used in various diemaking.
However, the surface which yields to thermally induced micro-cracks and white layer damage may have a detrimental effect on the die life. In this study, the fatigue behaviour of electrosparked materials has been examined experimentally under various conditions in order to evaluate the effect of the spark-eroded surface on material strength. The results are as follows:
(1) A reduction in the fatigue limit by EDM occurs both in normalized and hardened materials, which is particularly remarkable in the latter.
(2) It is clarified that the rupture of the spark-eroded material depends on the discharge cracks, white layer and deep micro-crater.
(3) For improving the fatigue strength of the spark-eroded surface, a satisfactory improvement can be attained by removing the thickness of the heat-affected zone. Moreover, the jet machining is successful for its purpose.
