반연속주조된 대형 블룸에서 발생하는 거시편석 및 석출물 거동 (Behavior of Macrosegregation and Precipitation Developed in Semi-continuously Cast Large Bloom)

서지정보

· 발행기관 : 한국주조공학회
· 수록지 정보 : 한국주조공학회지 / 39권 / 1호 / 7 ~ 13페이지
· 저자명 : 김혜주, 이형록, 김경아, 이주동, 오경식, 권상흠, 김동규

초록

Few studies of large blooms over 700 mm thick among those used for the forging of raw materials have been reported. The cooling rate difference between the surface and the center of a large bloom is large, and the degradation of the mechanical properties is likely in cases involving excessively coarse precipitates resulted from the slow cooling rate of a large bloom after casting. Therefore, a schematic investigation of the growth behaviors of precipitates while varying their locations in blooms is necessary. The dissolution behaviors of precipitates were investigated by simulating a reheating process during which the bloom is heated to a high temperature. The segregation behavior of the as-cast large bloom was also investigated. Reheating specimens were obtained after an isothermal heat treatment at 1150oC with various holding times to simulate the reheating process, with the samples undergoing a subsequent water quenching step. The precipitates were extracted using an electrolytic extractor and a particle size analysis was conducted with the aid of SEM, EDS, and TEM. In the present work, Al oxide, MnS and Nb carbide were mainly observed.

영어초록

Few studies of large blooms over 700 mm thick among those used for the forging of raw materials have been reported. The cooling rate difference between the surface and the center of a large bloom is large, and the degradation of the mechanical properties is likely in cases involving excessively coarse precipitates resulted from the slow cooling rate of a large bloom after casting. Therefore, a schematic investigation of the growth behaviors of precipitates while varying their locations in blooms is necessary. The dissolution behaviors of precipitates were investigated by simulating a reheating process during which the bloom is heated to a high temperature. The segregation behavior of the as-cast large bloom was also investigated. Reheating specimens were obtained after an isothermal heat treatment at 1150oC with various holding times to simulate the reheating process, with the samples undergoing a subsequent water quenching step. The precipitates were extracted using an electrolytic extractor and a particle size analysis was conducted with the aid of SEM, EDS, and TEM. In the present work, Al oxide, MnS and Nb carbide were mainly observed.

참고자료

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