수송차량 안전벨트용 모터축재의 마찰용접 최적화(1) - 기계적 특성 및 조직

Abstract

*Bukyong Education Center for Vehicle Safety Component Technolo gy, Pukyong National University, Busan, KoreaKEY WORDS: Friction welding 마찰용접, Post weld heat treatment (PWHT) 용접후열처리, As-welded 마찰용접재, Base metal (BM) 모재, Heat affected zone (HAZ) 열영향부, Weld interface (WI) 용접계면, Welding condition 용접조건ABSTRACT: Dissimilar friction welds were produced using 15-mm diameter so lid bars of chrome molybdenum steel (KS SCM440) and carbon steel (KS SM20C) to investigate their mechanical properties. Th e main friction welding parameters were selected to ensure good quality welds on the basis of visual examination, tensile tests, Vickers hardnes s surveys of the bond area and HAZ, and macro-structure investi gations. The specimens were tested as-welded and post-weld heat treated (PWH T). The tensile strength of the friction welded steel bars was increased to 100％of the SM20C base metal under the condition of a heating time of more than four seconds. Optimal welding conditions were n = 2,000 (rpm), HP = 60 (MPa), UP = 100 (MPa), HT = 5 (s),and UT = 5 (s), when the total upset length was 7.8 (mm). The hardness distribution peak of the friction welded joints could be eliminated using PWHT. The two different kinds of materials were strongly mixed to show a well-combined structure of macro-particles, with no molten material, particle growth, or defects.교신저자 안석환: 부산광역시 남구 용당동 산100, 051-629-7565, shahn@pknu.ac.kr