바나듐 분말 고속도공구강의 이차경화 및 충격인성에 미치는 오스테니타이징 온도의 영향

• Published in: 대한금속·재료학회지, 46(8) Vol. 46; no. 8; pp. 477 - 481
• Main Authors: 문희권, H. K. Moon, 양형렬, H. R. Yang, 조기섭, K. S. Cho, 이건배, K. B. Lee, 권훈, H. Kwon
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 01.09.2008; 대한금속·재료학회
• Subjects: high speed steel; secondary hardening; vanadium; 재료공학
• ISSN: 1738-8228; 2288-8241

The secondary hardening and fracture behavior in P/M high speed steels bearing V content of 9 to 10 wt% have been investigated in terms of austenitizing temperature and precipitation behavior. Austenitizing was conducted at 1,100 and 1,175℃ of relatively low and high temperatures. Coarse primary carbides retained after austenitization were mainly V-rich MC type. They give a significant influence on hardeness and toughness, as well as wear resistance. Tempering was performed in the range of 500~600℃. The peak hardness resulting from the precipitation of the fine MC secondary carbides was observed near 520, irrespective of austenitizing temperature. Aging acceleration(or deceleration) did not occur with increasing austenitizing temperature because it mainly influences contents of V and C of matrix through the dissloution of coarse primary MC containing lots of V and C. The precipitation of secondary MC carbides, which also contain V and C, did not change the aging kinetics itself. In the 10V alloy containing much higher C content, the impact toughness was lower than 9V alloy, because of the larger amount of primary carbide and high hardness.