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Vol.46, No.8, 477 ~ 482, 2008
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| Title |
| Effect of Austenitizing Temperature on Secondary Hardening and Impact Toughness in P/M High Speed Vanadium Steel |
| 문희권 H. K. Moon , 양형렬 H. R. Yang , 조기섭 K. S. Cho , 이건배 K. B. Lee , 권훈 H. Kwon |
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| Abstract |
| 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. |
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| Key Words |
| high speed steel, vanadium, secondary hardening |
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