목차

목 차
Abstract...........................................................................................................................ⅳ
제1장 서론....................................................................................................................1
1.1 연구 목적 및 필요성.............................................................................................1
1.2 연구내용...................................................................................................................4
참고 문헌......................................................................................................................6
제2장 이론적 배경.....................................................................................................8
2.1 듀플렉스 스테인리스강의 개발과 전망............................................................8
2.2 듀플렉스 스테인리스강의 용접 및 기계적 특성..........................................13
2.2.1 용접공정 개요................................................................................................13
2.2.2 용접 공정상의 유의사항.............................................................................14
2.2.3 듀플렉스강 용접부의 기계적 성질...........................................................18
2.3 듀플렉스 스테인리스강에서 σ상의 석출기구................................................25
2.3.1 듀플렉스 스테인리스강에서 σ상의 석출.................................................25
2.3.2 듀플렉스 스테인리스강에서 σ상의 석출기구.........................................29
2.4 듀플렉스 스테인리스강의 용접금속과 질소..................................................31
2.4.1 개요...................................................................................................................31
2.4.2 용접금속에서 N의 손실과 기공 발생......................................................31
2.5 GTA 용접 시 아크전압과 전류 특성...................................................35
2.5.1 GTA 용접 시 아크전압과 전류 특성............................................35
2.5.2 GTA 용접 시 아크압력의 발생......................................................35
2.6 듀플렉스 스테인리스강 용접부의 부식 특성............................................40
2.6.1 입계부식................................................................................................41
2.6.2 균일부식..................................................................................................42
2.6.3 공식..........................................................................................................43
참고 문헌............................................................................................................48
제3장 슈퍼듀플렉스강 용접재료의 성능평가와 용접공정
개발.....................................................................................................................54
3.1 서언............................................................................................................................54
3.2 실험 방법.................................................................................................................56
3.2.1 TIG 용접 시험.................................................................................................56
3.2.2 SMAW 용접 시험..........................................................................................59
3.2.3 FCAW 용접 시험...........................................................................................61
3.2.4 현장 작업성 시험............................................................................................65
3.3 실험결과 및 고찰...................................................................................................67
3.3.1 TIG 용접...........................................................................................................67
3.3.2 SMAW 용접.....................................................................................................73
3.3.3 FCAW 용접......................................................................................................80
3.3.4 현장 작업성.......................................................................................................89
3.4 결언.............................................................................................................................95
참고 문헌........................................................................................................................98
제4장 슈퍼듀플렉스강 TIG 용접에서의 질소 침투 특성..................100
4.1 서언...........................................................................................................................100
4.2 기존의 질소 침투 모델................................................................................102
4.2.1 가스-금속계에서 용접금속 내로의 질소 침투........................................102
4.2.2 가스-플라즈마계에서 용접금속 내로의 질소 침투................................104
4.2.3 용접금속 내의 질소 침투 개선 모델.........................................................107
4.3 용접금속 내의 질소 침투에 관한 기초 실험................................................111
4.3.1 서언...................................................................................................................111
4.3.2 실험재료 및 방법..........................................................................................111
4.3.3 실험결과 및 고찰..........................................................................................113
4.4 플라즈마 스트림 모델의 타당성 검증 실험..................................................116
4.4.1 서언..................................................................................................................116
4.4.2 실험재료 및 방법..........................................................................................117
4.4.3 실험결과 및 고찰..........................................................................................118
4.5 결언..........................................................................................................................124
참고 문헌.....................................................................................................................125
제5장 슈퍼듀플렉스강 용접재료의 부식특성...........................................127
5.1 서언.................................................................................................................127
5.2 사용재료 및 실험방법.........................................................................................132
5.2.1 사용 용접재료................................................................................................131
5.2.2 열처리 및 조직관찰......................................................................................133
5.2.3 전기화학적 분극시험....................................................................................134
5.3 실험결과 및 고찰.................................................................................................138
5.3.1 미세조직 및 경도..........................................................................................138
5.3.2 경도...................................................................................................................147
5.3.3 시효온도 및 시간에 따른 σ상 및 α상의 체적분율...............................149
5.3.4 전기화학적 부식 특성...................................................................................153
5.4 결언...........................................................................................................................190
참고 문헌.....................................................................................................................191
제6장 결론....................................................................................................................196