DED 공정의 다중 비드 적층 시 비정상 열전달 특성 분석

국문 초록 (Abstract)

이 연구에서는 DED 공정을 이용하여 S45C 구조용 강 위 Inconel 625 및 Stellite 21 초합금 다중비드 적층 시 발생하는 열전달 특성을 3차원 비선형 유한요소 해석을 통해 고찰하고자 한다. 실험 결과를 이용하여 비드간 거리와 오버랩이 고려된 유한요소 해석 모델을 개발하였다. 열원은 가우시안 분포를 가지는 체적 열원 모델을 사용하였다. 열손실은 대류 및 복사 조건이 동시에 고려된 온도의존 등가열손실 모델을 활용하였다. 단일 비드 적층 해석을 통하여 재료에 따른 열원 효율을 도출하였다. 이열비드 적층 해석에서는 적층 간 시간과 적층 방향에 따른 열전달 특성 변화를 분석하였다. 최종적으로 평면 및 다층 적층 해석을 통해 적층 중 발생하는 열전달 특성 및 온도 이력 변화를 고찰하였다.

다국어 초록 (Multilingual Abstract)

The goal of this study is to investigate transient heat transfer during Inconel 625 and Stellite 21 multi-bead deposition on S45C structural steel using a directed energy deposition (DED) process. Using experimental results, a finite element (FE) model, considering the hatch distance and overlap, is developed to analyze three-dimensional transient heat transfer characteristics. A volumetric heat flux with a gaussian distribution and an equivalent heat loss model, including temperature dependent convection and irradiation, are used. The efficiencies of heat flux for different deposition materials are estimated through an FE analysis (FEA) for single line bead. The influence of the interpass time and the deposition direction on the formation of heat affected zone (HAZ) is examined through FEAs for double bead deposition. Finally, the variation of temperature distributions and thermal histories during multi-lines and multi-layers deposition is investigated.

목차 (Table of Contents)

• 초록
• Abstract
• 1. 서론
• 2. 적층 실험 및 유한요소 해석
• 3. 결과 및 고찰
• 4. 결론
• 참고문헌(References)

참고문헌 (Reference)

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