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Vol.35, No.12, 1635 ~ 1643, 1997
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| Title |
| Microstructure and Fracture Property of High Speed Rolls Manufactured by Centrifugal Casting Method ( 2 . Fracture Property ) |
| 황근철 , 이성학 , 이희춘 Keun Chul Hwang , Sung Hak Lee , Hui Choon Lee |
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| Abstract |
| The effects of the microstructural factors such as hard carbides located along solidification cell boundary and the type of the martensite matrix on fracture property of nine high speed steel(HSS) rolls manufactured by centrifugal casting method were investigated in the present study. In situ fracture observation, fracture toughness measurement and fractographic observation were conducted on the rolls to clarify the microfracture process. From in situ observation, hard carbides located along cell boundary provided easily intercellular fracture sites under low stress intensity factor levels. In the rolls containing a small amount of intercellular carbides and lath-type tempered martensite matrix, fracture occurred along a tortuous transcellular path since carbides were well spaced, thereby leading to the enhancement of fracture toughness. For better microstucture, hardness and fracture property of the HSS rolls, it is suggested that the optimization of alloying elements is required to achieve the more homogeneous distribution of hard intercellular carbides. |
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