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Vol.35, No.9, 1254 ~ 1261, 1997
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| Title |
| Effect of Melt Superheat on Carbide Microstructure in High Speed Steels Fabricated by Spray Forming Process |
| 이언식 , 박우진 , 안상호 Eon Sik Lee , Woo Jin Park , Sang Ho Ahn |
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| Abstract |
| The variation of carbide morphologies in ASP30 and T15 high speed steels produced at different melt temperatures by the spray forming process has been investigated. The solidification behavior of a high speed steel during spray forming was greatly influenced by melt superheat that governed the thermal condition of deposited droplets. The M₂C or M_6C carbides were observed to form a carbide cell, whereas fine spherical MC carbides were found to be uniformly distributed. In case of the higher melt superheat, the cell carbides were plate-shaped and discontinuous with one another, which were identified as the M₂C type. In contrast, at the lower melt superheat, the cell carbides were the M_6C-type, whose shape were somewhat coarser and more continuous. It was observed that the size and distribution of MC carbide were insensitive to the melt superheat. It can be concluded that a higher melt superheat favors the formation of M₂C carbides rather than M_6C carbides in spray formed high speed steels. |
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