Effects of Alloying Elements on Characteristics of Copper Containing Steel Strengthened by Cold World and Precipitation Hardening

摘要

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