熱間加工用金型鋼のヒートクラック形成に及ぼす焼入れ冷却速度の影響 Effects of Cooling Rate from Austenitizing Temperature on Heat Crack Formation of Die Steel for Hot Working
Thermal fatigue behaviors of die steel for hot working were investigated, in which cylindrical test bars with U-notch were directly immersed in Al-alloy melt maintained at 923 K, and then cooled quickly to water. The relation between thermal heat cracking and the cooling rate from the austenitizing temperature was mainly discussed in this study. The number of heat cracks initiated at the notch root increased and the elongation and Charpy impact value decreased as the cooling rate of the quenching decreased. While the maximum crack length was the same for all specimens due to the same tensile strength, the total length of each crack increased as the cooling rate decreased. It has therefore been concluded that raising the toughness and elongation by quenching at a fast cooling rate is effective for improving the die life.
- 鋳造工学 = Journal of Japan Foundry Engineering Society
鋳造工学 = Journal of Japan Foundry Engineering Society 70(3), 180-185, 1998-03