한국주조공학회

The HSS consists of hard carbide and matrix of martensite, and so its charateristics of wear resistance, fracture resistance, and surface roughness are good. This study was undertaken to investigate the influence of Nb and V and manufacturing conditions on microstructural behaviors and characteristics in the HSS cylindrical specimens(90 mm°'D' >< 60 mmI'D'>< 50 mm”) manufac- tured using VCC(VeItical Centrifugal Casting). In the specimen of Fe-2C-6Cr-1 .5W-3Mo-4V alloy, the amount of MC carbide was increased and MTC3 carbide was decreased with the increase of V and Nb contents. The primary VC carbide was formed and followed by the rod-type eutectic MC carbide was formed in the cell boundary in 9%V added specimen. MC carbide was increased, and M.,C3 carbide was decreased with the addition of Nb content. In the specimen containing more than 3%Nb, primary NbC carbide was formed within the cell of matrix. With increase in rpm, cell and carbides became fine, and amount of carbide M7C3 was decreased due to increase in cooling rate.