부산대학교 도서관

This study is aimed at developing a cobalt-free hardfacing alloy alternative to Co based alloy, whose use in a nuclear environment is not desirable. The new alloy, presently under development, consists of Cr, Mo, Nb and Ni. Effects of these alloy contents on wear resistance were investigated at room temperature. The alloys studied contain 15-35%Cr, 7-12.5%Mo and 5-14%Nb. The wear loss of Ni-Cr-Mo-Nb alloys decreased with increasing Cr content, but showed a minimum at 30%Cr content. It also decreased with increasing Mo content, but little improvement was observed above 10%Mo. The wear loss decreased with increasing Nb content. Above 10%Nb content, it seemed to increase slightly. An increase of (Cr, Ni)2(Nb, Mo) intermetallic compound and matrix strengthening with increasing Cr, Mo and Nb contents seemed to improve the wear resistance. Enlarged CraNi2 intermetallic compounds, however, decreased the wear resistance. Ni-(25-30%)Cr-(10-12%)Mo-(8-12%)Nb alloys are desirable from a viewpoint of wear resistance.The Ni-25%Cr-11%Mo-10%Nb alloy powder was manufactured for trial and welded on carbon steel using the plasma-transfer-arc process. Sound deposits were obtained and the weld deposit showed wear and corrosion resistance equivalent to that for Co based alloy Stellite 6.