加工硬化と析出硬化を強化機構とするCu含有鋼の特性に及ぼす合金元素の影響

抄録

Authors developed the low C(0.08%) Cu-bearing steel with ferrite-pearlite structure, which is strengthened by cold work and subsequent aging. Regardless of cold work, 0 to 50% reduction in height, the hardness of 1.5%Cu steel reaches the peak at the aging around 773K for 3.6ks. By this aging after 50% cold work, 1.5%Cu steel shows the largest increment in hardness, 150HV in all, and the highest hardness itself, 300HV, surpassing 2%Cu one. The 1.0% Ni is sufficient to prevent the surface hot cracking due to the grain boundary penetration of Cu-rich molten phase below the oxide scale in 1.5%Cu steel. The cold worked and aged steel with 1.5%Cu and 1.0%Ni possesses the tensile strength equivalent to the quenched and tempered medium C steel and the fatigue ratio superior to it.