한국주조공학회

Mechanical characteristics of Hi-Cr cast irons containing 16.8%Cr and 3.0%C were studied with various heat treatments. After as- cast Y-block ingots were annealed fully, the ingots were machined into cylinderical specimens with the size of 9mm in diameter and 2omm in length in order to investigate the effect of heat-treatments on mechanical characteristics of high Cr cast irons. All specimens were heat-treated by quenching- tempering, austempering and cyclic heat at the various temperatures(950, 1000, 1050 and 1100°C) respectively. The wear amount was measured for each heat-treated specimens against the counterpart of a hardened SKD11 steel at the following conditions ; wearing velocity : 0.7 m/s, load : 1ooN and sliding distance : 70 km. After as-cast spec- imens were annealed, fine M3C carbides were formed, which affected the hardness and the wear resistance of Hi-Cr specimens. High hardness and good wear resistance were appeared on the specimens treated at 950 and 1000°C and the austempered specimens show excellent wear resistance as well as high hardness.

High Cr cast iron, M7C3 carbides, M3C carbides, Austempering treatment, Q-T treatment