목차

Ⅰ. 서 론 ·····················································································································1
1.1 서론 ··························································································1
Ⅱ. 이론적 배경 ····························································4
2.1 자동차 차체 적용 강판의 개발 및 적용 현황··························································································4
2.2 Resistance Spot Welding (RSW)의 개요 ··························································································6
2.3 저항 점 용접 시 전극 오정렬의 영향 ··························································································10
2.4 핫 스탬핑 강 (Hot Stamping Steel)의 저항 점 용접 ····················13
Ⅲ. 실험 방법 ····························································15
3.1 표면날림 발생 거동 분석 실험 ·······························································15
3.1.1) 실험 소재 및 공정 조건 ··························································································15
3.1.2) 전극 오정렬 각도에 따른 용접 조건 ····················································································18
3.1.3) 구간 용접 시험 (Interrupted Test) 용접 조건 ··························································································20
3.1.4) 표면 날림 측정 및 발생 원인 분석 ····················································································22
3.2 표면날림 억제 기술 개발 ·······························································24
3.2.1) Up-Slope 전류 프로파일 적용 실험 ··························································································24
Ⅳ. 결과 ····························································26
4.1 표면날림 발생 거동 분석 실험 ·······························································26
4.1.1) 표면 날림의 종류 ··························································································26
4.1.2) 전극 오정렬 각도에 따른 표면날림 현상 변화 ····················································································30
4.1.3) 구간 용접 시험 (Interrupted Welding Test)을 통한 표면날림 거동 변화 ··············34
4.2 Up-Slope 전류 프로파일 적용 표면날림 억제 실험 ·······························································40
Ⅴ. 고찰 ··················································································································44
5.1 시뮬레이션 (Simufact) 적용 전극 오정렬에 기인한 표면날림 발생 메커니즘 증명············44
5.1.1) 시뮬레이션 단면 분석을 통한 표면날림 메커니즘 증명 ···································45
5.1.2) 시뮬레이션 표면 발열 및 전극 접촉 변화 분석을 통한 표면날림 발생 메커니즘 증명 ·····················48
5.2 Thermal Monitoring 적용 전극 오정렬에 기인한 표면날림 발생 메커니즘 증명 ··········53
5.3 시뮬레이션 (Simufact)을 활용한 Up-Slope 전류 프로파일 적용 표면날림 억제 메커니즘 분석 ·········56
5.3.1) 시뮬레이션 단면 분석을 통한 Up-Slope의 표면 날림 억제 메커니즘 증명 ···········57
5.3.2) 시뮬레이션 표면 발열 및 전극 접촉 변화 분석을 통한 Up-Slope의 표면날림 억제 메커니즘 증명 ······59
Ⅵ. 결 론 ··················································································································63
참고 문헌 ························································································································65
Abstract ··············································································································68
감사의 글 ···············································································································71