korea iron & steel associationhrd.kosa.or.kr/data/bm/스테인리스강전문가양성... ·...

2010

●●● http://hrd.kosa.or.kr

스테인리스강전문가양성 교육실무Korea l ron & Steel Associat ion

Korea lron & Steel AssociationKorea lron & Steel Association

스테인리스강전문가양성교육실무

본 과제(결과물)는 정부의 정부지원금으로 수행한 교육훈련혁신센터지원사업의 연구결과입니다.

KOREA IRON & STEEL ASSOCIATION

스테인리스강전문가양성교육실무Korea l ron & Stee l Assoc iat ion

제1절 스테인리스강의 개요

1. 스테인리스강의 정의 ······························································ 3

2. 스테인리스강의 역사 ······························································ 4

3. 스테인리스강의 종류 ······························································ 5

4. 스테인리스강의 관련 규격 ····················································· 7

제2절 스테인리스강의 분류

1. 오스테나이트계 스테인리스강 ··············································· 10

2. 페라이트계 스테인리스강 ····················································· 14

3. 2상계(duplex) 스테인리스강 ················································ 15

4. 마르텐사이트계 스테인리스강 ··············································· 16

5. 석출경화계 스테인리스강 ····················································· 17

제3절 스테인리스강의 특성

1. 스테인리스강의 물리적 특성 ················································ 17

2. 스테인리스강의 내식성 ························································· 19

3. 스테인리스강의 첨가원소 ····················································· 20

가. 탄소(C) ············································································· 20

나. 크롬(Cr) ············································································ 21

다. 니켈(Ni) ············································································ 21

라. 몰리브덴(Mo) ··································································· 21

마. 질소(N) ············································································· 21

바. 타이타늄(Ti) ····································································· 22

사. 니오븀(Nb) ······································································· 22

목 차 스테인리스강 전문가양성 교육실무

스테인리스강의 일반1장

제4절 스테인리스강의 취급

1. 스테인리스강의 활용 ···························································· 22

가. 스테인리스강이 사용되어야 하는 환경인가? ···················· 23

나. 제품에서 스테인리스강에 요구하는 성질은 무엇인가? ···· 24

다. 가공은 어떻게 할 것인가? ··············································· 24

라. 강도와 형태는 어떻게 구성할 것인가 ······························ 24

마. 유사 적용 사례는 어떠한 것이 있는가? ·························· 24

바. 소재 수급 가능 여부 ························································ 24

사. 소재비 수용 가능 여부 ····················································· 25

아. 기타 ··················································································· 25

2. 스테인리스강의 취급 요령 ···················································· 25

가. 스테인리스강 보호비닐 ····················································· 26

나. 스테인리스강 표면관리 ····················································· 26

다. 설계시 고려사항 ·······························································27

3. 스테인리스강 관련용어 정의 ················································ 28

4. 스테인리스강 Q&A ······························································ 32


제1절 용 해

1. 원 료 ····················································································· 43

2. 전기로 ··················································································· 44

가. 조업개요 ············································································ 44

나. 설비구성 ············································································ 44

다. 조업방법 ············································································ 45

제2절 정 련

1. AOD ····················································································· 52

가. 조업개요 ············································································ 52

나. AOD설비 구성 ································································· 52

다. 조업방법 ············································································ 56

2. VOD ····················································································· 63

가. 조업개요 ············································································ 63

나. 설비구성 ············································································ 64

다. 조업방법 ············································································ 70

라. 버블링 조업 ······································································ 76

제3절 주 조

1. 연속주조공정 ········································································· 84

가. 조업개요 ············································································ 84

나. 설비구성 ············································································ 86

다. 조업방법 ············································································ 90

스테인리스강

제조공정2장

2. 정정 ······················································································· 93

가. 조업개요 ············································································ 93

나. 설비구성 ············································································ 93

다. 조업방법 ············································································ 96

제4절 열간공정

1. 열간압연개요 ········································································· 98

2. 압연이론 ················································································ 99

가. 재료의 치입 ······································································ 99

나. 중립점과 선진, 후진 현상 ··············································· 100

3. 압연에 의한 조직변화 ························································· 101

4. 압연기 ················································································· 102

가. 압연기의 구조 ································································· 102

나. 압연기의 종류 ································································· 102

다. 연속압연기 ······································································ 103

5. 열간압연공정 ······································································· 105

가. 스테인리스 열간압연 ······················································· 105

나. 압연제어기술 ··································································· 112

6. 후판 및 선재압연 ································································ 116

가. 후판압연 ·········································································· 116

나. 선재압연 ·········································································· 117

제5절 냉간공정

1. 냉간압연공정 ······································································· 118

가. 산세 ················································································· 119

나. 냉간압연 ·········································································· 119

다. 소둔 ················································································· 120

라. 조질압연 ·········································································· 120

마. 정정 ················································································· 121


제1절 스테인리스 판재의 성형이론

1. 소성가공 개요 ····································································· 125

2. 기계적 특성 ········································································· 126

가. 인장특성 ·········································································· 126

나. 경도 ················································································· 128

다. 인성(Toughness) ··························································· 128

3. 성형 모드 ············································································ 129

가. 드로잉(Drawing) 모드 ··················································· 129

나. 장출(Stretching) 모드 ···················································· 130

다. 플랜지(Flange) 모드 ······················································ 131

라. 벤딩 모드 ········································································ 132

4. 성형법 분류 ········································································· 133

가. 전단 가공 ········································································ 133

나. 스테인리스 벤딩 가공 ····················································· 135

다. 스테인리스 프레스 가공 ················································· 138

제2절 스테인리스 판재의 성형성 평가법

1. 소성 이방성(Plastic anisotropy) ······································· 140

2. 에릭슨 시험(Erichsen test) ··············································· 141

3. 한계드로잉 비(Limiting Drawing Ratio: LDR) ··············· 142

4. 복합성형성(Conical Cup Test) ········································· 142

5. STS 가공시 파단 및 형상 불량 ········································ 143

스테인리스강

성형3장

제3절 프레스 공정상의 주요인자

1. 마 찰 ··················································································· 146

2. 윤 활 ··················································································· 148

가. 프레스 가공유의 첨가제 작용 및 효과 ·························· 150

제4절 성형성 예측방법

1. 항복 함수 ············································································ 152

2. 이방성 소성 이론 ································································ 152

3. 판재 성형해석 ····································································· 154

가. 전처리 과정 ···································································· 154

나. 성형해석 ·········································································· 155

다. 후처리 과정 ···································································· 156

제5절 스테인리스강 표면

1. 스테인리스강 표면마무리 ···················································· 157

2. 스테인리스강 표면조도 ······················································· 160


제1절 금속부식과 내식이론

1. 부식반응 기초이론 ······························································ 165

가. 평형전극반응 ··································································· 166

나. 구동 기전력 및 부식반응 ··············································· 166

다. 전위- pH 도표 ·······························································166

라. 부식반응 속도론 ······························································ 167

2. 부동태 이론 ········································································· 170

3. 부식의 형태 ········································································· 172

가. 균일부식 ·········································································· 172

나. Galvanic 부식 ································································ 172

다. 틈새부식 ·········································································· 174

라. 공식 ················································································· 175

마. 입계부식 ·········································································· 176

바. 선별용해부식 ··································································· 178

사. 응력부식 ·········································································· 178

아. 마모부식 ·········································································· 179

자. 대기부식 ·········································································· 179

제2절 스테인리스강의 내식성

1. 스테인리스강의 표면특성 ···················································· 180

2. 부동태 피막의 형성과 특징 ················································ 180

스테인리스강

부식4장

3. 내식성에 미치는 주요 인자 ················································ 182

가. Mn 개재물의 영향 ·························································· 182

나. Ti 개재물의 영향 ··························································· 186

다. δ-ferrite와 sigma 상의 영향 ········································· 187

라. 합금원소의 영향 ······························································ 187

4. 스테인리스강 용접부 부식 ·················································· 189

5. 스테인리스강 부식사례 ······················································· 190

가. 공식과 틈새부식 ······························································ 190

나. 응력부식 ·········································································· 191

다. 미생물 부식 ···································································· 191

제3절 내식성 시험방법

1. 일반부식성 평가 ·································································· 192

2. 입계부식성 평가 ·································································· 195

3. 공식/틈새부식성 평가 ························································· 199

4. 응력부식성 평가 ·································································· 200

5. 대기부식성 평가 ·································································· 200

6. 특수목적부식성 평가 ··························································· 202


제1절 용접부의 특성

1. 용접부의 영역분류 및 영역별 특성 ···································· 205

가. 완전 혼합역 ···································································· 206

나. 미혼합역 ·········································································· 207

다. 부분 용해역 ···································································· 208

라. 용접열영향부 ··································································· 208

2. 용접부의 분류 ····································································· 209

가. 제살 용접부 ···································································· 209

나. 동종금속 용접부 ······························································ 209

다. 이종금속 용접부 ······························································ 209

제2절 페라이트계 스테인리스강의 용접

1. 페라이트계 스테인리스강의 성질 ······································· 209

가. 기본 특성 ········································································ 209

나. 기계적 성질 ···································································· 212

다. 열처리 ············································································· 215

라. 내식성 ············································································· 216

2. 용접성과 용접시공 ······························································ 220

가. 용접성 ············································································· 220

나. 용접시공 ·········································································· 221

3. 용접결함과 방지대책 ··························································· 222

가. 용접균열 ·········································································· 222

나. 용접부 인성 ···································································· 226

다. 부식성 ············································································· 229

스테인리스강의

용접5장

제3절 오스테나이트계 스테인리스강의 용접성

1. 용접부의 응고 ····································································· 231

2. 용접부의 페라이트 양 ························································· 233

가. 자기측정에 의한 방법 ····················································· 234

나. 현미경 조직에 의한 방법 ··············································· 234

다. 조직도에 의한 방법 ························································ 235

3. 용접부 응고양식/페라이트양/고온균열 감수성의 상관관계 ·· 237

4. 용접부 성능 ········································································· 241

5. 용접부의 결함 ····································································· 246

가. 용접결함의 분류 ······························································ 246

나. 결함의 발생원인 및 방지대책 ········································ 247

6. 용접시공 ·············································································· 248

가. 용접재료의 선정 ······························································ 248

나. 용접부 시공조건 및 전․후처리 ········································ 254

제4절 2상 스테인리스강의 용접기술

1. 모재의 품질특성 ·································································· 262

가. 화학조성에 의한 분류 ····················································· 262

나. 기계적 성질 ···································································· 263

다. 부식성 ············································································· 264

라. 물리적 성질 ···································································· 264

마. 가공(Forming) ································································ 265

2. 용접특성 ·············································································· 265

가. 응고조직과 오스테나이트 생성 ······································· 265

나. 페라이트와 오스테나이트 분율 ······································· 266

다. 고온 변태 ········································································ 268

라. Ageing ············································································ 269

마. 질소와 수소 ···································································· 269


3. 2상 스테인리스강의 용접부 성능 ······································· 270

가. 용접부 강도 및 굽힘특성 ··············································· 270

나. 용접부 충격특성 ······························································ 271

4. 2상 스테인리스강의 용접시공 방법 ···································· 272

가. 오스테나이트계 스테인리스강과 2상 스테인리스강과의 차이점·· 272

나. 용접부 Cleaning ····························································· 272

다. 용접이음부의 설계 ·························································· 272

라. 예 열 ··············································································· 274

마. 용접 입열량과 층간온도 ················································· 274

바. 후열처리 ·········································································· 275

사. 용접부의 상분율(페라이트/오스테나이트) 관리 ·············· 275

아. 아크 스트라이크 ······························································ 276

자. 용접 방법 ········································································ 276

차. 용접재료 ·········································································· 276

카. 보호가스와 Backing 가스 ·············································· 277

타. 용접부 후처리 ································································· 278

제5절 이종금속 용접

1. 이종금속 용접의 문제점 ····················································· 279

2. 페라이트계와 오스테나이트계의 이종금속 용접 ················· 280

3. 페라이트계의 이종금속 용접 ·············································· 282

4. 2상 스테인리스강과 이 강종 용접 ····································· 283

[표 1-1] 스테인리스강 관련 규격 ····························································· 8

[표 1-2] 표면마무리에 따른 스테인리스강 냉간압연판재 생산가능규격 · 9

[표 1-3] 규격별 표면마무리 구분 및 호환 ·············································· 9

[표 1-4] 추가공에 의한 표면마무리 구분 ················································ 9

[표 1-5] 일반적인 스테인리스강판 제조공정 ········································· 10

[표 1-6] 오스테나이트계 스테인리스강의 화학성분(KS D 3698) ········· 11

[표 1-7] 페라이트계 화학성분 ································································ 14

[표 1-8] 2상계 화학성분(KS D 3698) ··················································· 15

[표 1-9] 마르텐사이트계 화학성분(KS D 3698) ··································· 16

[표 1-10] 석출경화계 화학성분 ································································ 17

[표 1-11] 스테인리스강의 물리적 특성 ···················································· 18

[표 1-12] 주요 부식문제 사례 ·································································· 19

[표 1-13] 부식 원인 및 대책 예 ······························································ 20

[표 1-14] 스테인리스강의 무게 기준표 ···················································· 33

[표 1-15] 성분 허용치 ·············································································· 36

[표 1-16] 대기 중에서 스케일 발생 온도 요약 ······································· 39

[표 1-17] 일반적인 최고 사용 온도 ························································· 39

[표 2-1] 원료별 실수율 ·········································································· 47

[표 2-2] Loading Schedule 1 ······························································· 47

[표 2-3] Slag 조성(AISI 304) ·······························································51

[표 2-4] 취련단계별 O2 및 Inert Gas 공급량 ······································· 58

[표 2-5] 각 성분의 산화소요 산소량 및 반응열 ···································· 58

[표 2-6] 탈탄 및 Si 산화에 필요한 산소량 ··········································· 58

[표 2-7] 각 단계별 탈탄속도 ·································································· 59

[표 2-8] 강종별 온도 상승율 ·································································· 60

[표 2-9] Mn, Cr, Ni의 로내 투입시 실수율 ········································· 61

[표 2-10] AISI 316Ti 강의 이론응고온도 계산 예 ································· 62

[표 2-11] 취련작업 계산표 (예) ······························································· 62

[표 2-12] Ar Gas Bubbling에 의한 탈수소 효과의 예 ·························· 80

[표 2-13] MLAC 제어범위 ······································································ 89

[표 2-14] 연연주 작업의 구분 ·································································· 90

표 목 차 스테인리스강 전문가양성 교육실무

[표 2-15] 스테인리스강과 일반강의 압연 비교 ······································ 118

[표 2-16] 스테인리스 냉연의 표면사상 ·················································· 121

[표 3-1] 성형법 분류 ············································································ 125

[표 3-2] 스테인리스 벤딩가공 시 스프링백에 미치는 영향 ················· 137

[표 3-3] 스테인리스강의 인장특성이 성형성에 미치는 영향 ··············· 138

[표 3-4] 스테인리스 강판용 프레스 가공유 ········································· 149

[표 3-5] 표면처리 일반제품 ·································································· 159

[표 3-6] 표면처리 특수제품 ·································································· 160

[표 4-1] Galvanic series of some commercial metals and

alloys in seawater ································································ 173

[표 4-2] Effects of alloying on pitting resistance of stainless

steel alloys ············································································ 176

[표 4-3] Classification of Structure tested by Axalic Acid Etch · 196

[표 5-1] 페라이트계의 화학 성분 ························································· 212

[표 5-2] 소둔 후의 기계적 성질 ·························································· 213

[표 5-3] 각종 오스테나이트 스테인리스강 용접부의 델타페라이트양 ·· 236

[표 5-4] 델타 페라이트 함량에 미치는 냉각속도의 영향 ···················· 237

[표 5-5] 오스테나이트계 스테인리스강의 기계적 특성(상온) ·············· 241

[표 5-6] 오스테나이트계 스테인리스강용 피복용접봉 ·························· 253

[표 5-7] 오스테나이트계 스테인리스강 GTAW, GMAW용 와이어 ··· 254

[표 5-8] 각종 용접전류에 대한 아르곤 가스 유량 ······························ 256

[표 5-9] 스테인리스강의 산세 ······························································ 260

[표 5-10] 2상 스테인리스강의 화학조성 ················································ 263

[표 5-11] 2상 스테인리스강의 기계적 성질 ··········································· 263

[표 5-12] 2상 스테인리스강의 부식 Data ············································· 264

[표 5-13] 2상 스테인리스강의 물리적 성질 ··········································· 265

[표 5-14] 22%Cr계 2상 스테인리스강의 용접부 인장 및 굽힘시험 결과·· 270

[표 5-15] 전용착 시험에 의한 22Cr계 2상 스테인리스강용 용접재료의

화학조성(wt.%)과 기계적 성질 ············································· 277

[표 5-16] 용접방법별 보호가스 종류 ····················································· 277

[표 5-17] 2상 스테인리스강과 이종 스테인리스강의 용접재료 종류 ···· 284

[그림 1-1] 냉간가공에 따른 오스테나이트상과

가공유기마르텐사이트상의 관계 ··········································· 13

[그림 1-2] 표면마무리별 스테인리스강 사용 예 ···································· 23

[그림 1-3] 보호비닐 옥외 방치에 따른 부식 사례 ································ 26

[그림 1-4] 스테인리스강의 표면 세척 ···················································· 27

[그림 2-1] 노체 개략도 ·········································································· 44

[그림 2-2] 전기로 장입 크레인(CRAIN) ··············································· 48

[그림 2-3] AOD 공정 Flow ·································································· 53

[그림 2-4] 노체 개략도 ·········································································· 53

[그림 2-5] 워터링 펌프 ·········································································· 66

[그림 2-6] 연주공정 Flow ······································································ 84

[그림 2-7] 종래의 연속주조법과 조괴법의 비교 ···································· 85

[그림 2-8] 연속주조기 측면 모식도 ······················································· 85

[그림 2-9] Mould 측면도 ······································································· 87

[그림 2-10] Mould 평면도 ······································································· 87

[그림 2-11] MLAC 제어 모식도 ····························································· 88

[그림 2-12] ROLL E.M.S의 구조 ··························································· 89

[그림 2-13] 주편표면결함 ········································································· 92

[그림 2-14] 작업중인 그라인딩머신 ························································· 95

[그림 2-15] 소성가공방법 ········································································· 99

[그림 2-16] 소성가공방법 ······································································· 100

[그림 2-17] 중립점과 선진, 후진 현상 ··················································· 101

[그림 2-18] 압연후 재결정 과정 ···························································· 102

[그림 2-19] 압연기의 구조 ····································································· 102

[그림 2-20] 압연기 종류 ········································································· 103

[그림 2-21] 연속압연기 ·········································································· 103

[그림 2-22] 압연롤 ················································································· 104

[그림 2-23] 표면형상에 따른 압연롤 분류 ············································· 104

[그림 2-24] 스테인리스 열간압연 및 소둔산세 ······································ 105

[그림 2-25] 열간압연공정 ······································································· 106

[그림 2-26] 가열로 ················································································· 107

[그림 2-27] Walking Beam 가열로에서 Slab의 이송 ·························· 107

그림목차 스테인리스강 전문가양성 교육실무

[그림 2-28] Edger ·················································································· 108

[그림 2-29] 조압연 ················································································· 108

[그림 2-30] 사상압연 ·············································································· 109

[그림 2-31] 사상압연기 본체 및 부대설비 ············································· 109

[그림 2-32] Crop Shear ·········································································110

[그림 2-33] 냉각(Laminar Flow) ··························································110

[그림 2-34] 권취기 ················································································· 111

[그림 2-35] 스킨패스라인 ······································································· 112

[그림 2-36] Roll Banding 현상 ····························································· 113

[그림 2-37] 압하력이 강판에 미치는 영향 ············································· 113

[그림 2-38] 강판표면 형상 결함 ···························································· 113

[그림 2-39] Roll Crown ········································································ 114

[그림 2-40] Roll Bender ········································································ 114

[그림 2-41] Pair Cross Mill ································································· 115

[그림 2-42] AGC 작동원리 ···································································· 115

[그림 2-43] 후판공정 ·············································································· 116

[그림 2-44] 스테인리스 냉간압연공정 ···················································· 117

[그림 2-45] 냉간압연 ·············································································· 118

[그림 2-46] 20단 압연기 ········································································ 118

[그림 2-47] 산세압연공정 ······································································· 119

[그림 2-48] TCM ··················································································· 119

[그림 2-49] 상자소둔공정 ······································································· 120

[그림 2-50] 조질압연 ·············································································· 120

[그림 3-1] 인장시험을 통한 응력‐변형률 곡선 예 ······························· 127

[그림 3-2] 판재 가공의 주요 성형모드 ················································ 129

[그림 3-3] 드로잉 가공 ········································································· 129

[그림 3-4] 장출(Stretching) 가공 ························································ 130

[그림 3-5] 플랜지 가공 ········································································· 131

[그림 3-6] 벤딩(Bending) 가공 ···························································· 133

[그림 3-7] 절단면 상세 ········································································· 134

[그림 3-8] 인장특성과 탄성회복 ··························································· 137

[그림 3-9] 스테인리스강의 벤딩 특성 비교 예 ···································· 137

[그림 3-10] 성형법 예(1) ······································································· 139

[그림 3-11] 성형법 예(2) ······································································· 139

[그림 3-12] r값의 측정 방법 및 방향별 시편 채취 ······························· 140

[그림 3-13] 에릭슨(Erichsen) 시험법 기구도 ········································ 141

[그림 3-14] 한계 드로잉비 (LDR) 시험 기구도 ···································· 142

[그림 3-15] 복합성형성 (Conical Cup Test)시험기 기구도 ················· 143

[그림 3-16] 스테인리스강을 이용 제작한 싱크와 자동차 배기계 시스템·· 144

[그림 3-17] 스테인리스강을 이용한 싱크 성형해석 후 부위별 변형 양상·· 144

[그림 3-18] 성형한계곡선(FLC)를 구하기 위한 금형 형상도 ··············· 145

[그림 3-19] 성형한계곡선(Forming Limit Curve) 측정 예 ················· 145

[그림 3-20] 성형한계곡선을 이용한 실물 성형품의 파단 평가 ············· 146

[그림 3-21] 마찰계수의 정의 ·································································· 146

[그림 3-22] 다양한 마찰계수 측정 방법 ················································ 147

[그림 3-23] Flat die 마찰계수 측정 방법 ············································· 147

[그림 3-24] Draw bead 마찰계수 측정 방법 ········································ 148

[그림 3-25] 마찰계수와 드로잉 응력 ····················································· 149

[그림 3-26] 파단한계 및 주름발생 한계에 미치는 윤활효과 ················· 149

[그림 3-27] 가공성에 미치는 기유의 영향 ············································· 150

[그림 3-28] 윤활영역에 따른 마찰계수 거동 ········································· 150

[그림 3-29] LDR에 미치는 유성향상제의 영향 ····································· 151

[그림 3-30] 온도변화에 따른 윤활제의 마찰거동 ·································· 151

[그림 3-31] 가공법에 미치는 극압 첨가제의 영향 ································ 151

[그림 3-32] Hill(1948) 항복함수를 이용한 400계 스테인리스강 항복곡면·· 153

[그림 3-33] 머플러쉘 CAD 데이터 ························································ 154

[그림 3-34] 성형해석용 금형과 블랭크 모델링 ······································ 154

[그림 3-35] 성형한계도상에서 성형해석 결과를 도시하여 파단부위 예측·· 156

[그림 3-36] 성형 중 주름발생 예측 ······················································· 157

[그림 3-37] 표면조도 측정길이 ······························································ 161

[그림 3-38] 표면조도 Definition 예 ······················································· 161

[그림 4-1] Simplified potential-pH diagram for Fe-H2O system ··· 167

[그림 4-2] Electrode kinetic behavior of pure Zinc in acid solution,

shown schematically ·························································· 169


[그림 4-3] Relationship between corrosion rate and the electrode

potential of a metal capable of being passivated ········· 170

[그림 4-4] Effect of an oxidizing agent on the corrosion rate of a

metal capable of being passivated ··································· 171

[그림 4-5] Crevice corrosion–later stage ··········································· 175[그림 4-6] Autocatalytic process occurring in a corrosion pit ······ 175

[그림 4-7] Diagrammatic representation of a grain boundary in a

sensitized type 304 stainless steel ·································· 177

[그림 4-8] TTT diagrams of five 18Cr-9Ni stainless steels with

different carbon contents ················································· 178

[그림 4-9] Actual composition profiles for 18-12. Preparation of

21 to 72 h air exposure and in solution for 44h. Fashed

line represents zero point of the passive film. ··············· 181

[그림 4-10] Schematic of metallurgical variables affecting the

localized corrosion behavior of stainless steels ·············· 182

[그림 4-11] Pit nucleation and development at manganese sulfide

inclusion in stainless steel ·············································· 182

[그림 4-12] Potential-pH diagram for MnS-H2O-Cl- system calculated

on basis of 0.1M for the ions SO42-, Cl

- and Mn

2+······ 183

[그림 4-13] Effect of Mn content on pitting potential of various

stainless steels in oxygenerated 5% NaCl solution. ···· 184

[그림 4-14] Change of Mn and Cr content in the inclusion as a

function of S/Mn ratio in steel ······································· 185

[그림 4-15] Initiation of pit and corresponding current variation in

the anodic polarization curves. ········································· 186

[그림 4-16] Effect of element shown on resistance of austenitic

stainless steels to pitting in chloride solutions. ············· 188

[그림 4-17] Effect of nitrogen content on pitting potential of

22Cr-20Ni-4Mn-2.8Mo steel in an aerated aqueous

solution containing 0.6M NaCl and 0.1M NaHCO3 ······ 188

[그림 4-18] 스테인리스 배관 및 이음부의 공식과 틈새부식 사례 ········ 190

[그림 4-19] 온수기용 스테인리스 용접부의 응력부식 발생사례 ··········· 191

[그림 4-20] 스테인리스 매설배관의 미생물 부식발생 사례 ·················· 192

[그림 4-21] Schematic diagram anodic of a polarization cell ·········· 194

[그림 4-22] Schematic potentiostatic polarization wiring diagram ·· 194

[그림 4-23] Standard potentiodynamic polarization plot ··················· 195

[그림 4-24] Typical etching structures after oxalic test. ················· 196

[그림 4-25] Schematic diagram of a double-loop EPR test ············ 199

[그림 5-1] 용접금속의 분류 ·································································· 205

[그림 5-2] 용융역에 존재하는 3가지 결정립계 ···································· 206

[그림 5-3] 오스테나이트계 스테인리스강 용접부의 결정립계 ············· 207

[그림 5-4] 9%Ni강을 Ni기 용접재료로 용접한 이종금속 용접부에서

관찰된 미혼합역 ·································································· 208

[그림 5-5] 응고온도 범위와 부분용해역의 상관관계 ··························· 208

[그림 5-6] Fe-Cr계 상태도 ·································································· 210

[그림 5-7] Fe-Cr 합금의 α/α+γ 경계에 미치는 (C+N)의 영향 ········· 211

[그림 5-8] 분극곡선에 미치는 부동태(모식도) ····································· 216

[그림 5-9] 가열에 따른 입계 Cr량의 시간별 농도 변화 ····················· 217

[그림 5-10] 오스테나이트 및 페라이트계 스테인리스강 TTS 곡선 ····· 218

[그림 5-11] 18Cr-2Mo강 응력부식균열 감수성에 미치는 Ni, Cu의 영향·· 220

[그림 5-12] STS444 용접금속의 충격천이온도에 미치는 N 및 O의 영향·· 224

[그림 5-13] STS405 용접금속의 3점 굽힘 구속 균열시험법에 의한

균열 잠복기간과 H량의 관계 ············································· 225

[그림 5-14] 수소 취화균열 발생조건 ····················································· 225

[그림 5-15] 페라이트계 스테인리스강의 DBTT에 미치는 C+N

및 안정화 원소의 영향 ······················································· 227

[그림 5-16] 26Cr-1Mo(E-Brite 26-1, 6mm) GTA 용접금속의 충격특성·· 228

[그림 5-17] 30Cr-2Mo(STS447J1) 용접금속의 인성에 미치는 N, O의 영향·· 229

[그림 5-18] 용접 그대로의 연성과 입계 부식특성에 미치는 (C+N)과

Cr의 영향 ··········································································· 230

[그림 5-19] 5가지 형태의 응고아결정립과 아결정립 형성에 미치는

조성적 과냉의 영향 ···························································· 232

[그림 5-20] 오스테나이트계 스테인리스강 용접부 응고조직 ················· 233

[그림 5-21] 이원계 상태도 ····································································· 233


[그림 5-22] 모재에 페라이트 함량이 작은 강종에서 관찰되는

HAZ입자 조대화 ································································· 234

[그림 5-23] WRC 조직도 ······································································· 235

[그림 5-24] 드롱(DeLong) 조직도 ························································· 235

[그림 5-25] 용접부 초정응고 양식 예측도 ············································· 238

[그림 5-26] Cr-Ni-Fe 상태도(Fe : 70%) ············································· 238

[그림 5-27] Cr/Ni 함량비에 따른 델타페라이트 형상 변화 ·················· 239

[그림 5-28] 초정응고 양식에 따른 응고균열 감수성 변화 ···················· 240

[그림 5-29] 온도에 따른 오스테나이트계 스테인리스강의 고온강도 ····· 242

[그림 5-30] 오스테나이트계 스테인리스강 용접금속 및 모재의 인장특성·· 242

[그림 5-31] 오스테나이트계 스테인리스강의 크리프파단강도················ 243

[그림 5-32] 오스테나이트계 스테인리스강 용접금속의 노치

충격특성에 미치는 장시간 가열의 영향 ····························· 244

[그림 5-33] 각종 스테인리스강의 흡수에너지 ······································· 244

[그림 5-34] 오스테나이트계 스테인리스강 용접부의 충격특성 ············· 245

[그림 5-35] 저온충격특성에 미치는 페라이트양의 영향 ························ 245

[그림 5-36] 용접결함의 분류 ·································································· 246

[그림 5-37] 용접부에서 발생한 응고균열 ·············································· 248

[그림 5-38] MgCl2(154℃)용액에서의 페라이트량과 파단시간과의 관계··· 250

[그림 5-39] 용접금속의 강도에 미치는 N량의 영향 ····························· 251

[그림 5-40] 용접금속의 인성에 미치는 페라이트 양의 영향 ················· 252

[그림 5-41] 2상 스테인리스강의 Fe-Cr-Ni 3원계 상태도(단면) ·········· 266

[그림 5-42] 2상 스테인리스강의 TIG 용접부 미세조직(저배율) ·········· 267

[그림 5-43] WRC 1992 상태도 ····························································· 267

[그림 5-44] 22% Cr 2상 스테인리스강의 모재 TTT 상태도 ·············· 268

[그림 5-45] 용접금속의 TTT 상태도 ···················································· 269

[그림 5-46] 22Cr 2상 스테인리스강의 용접부 경도 분포 ····················· 271

[그림 5-47] 22Cr 2상 스테인리스강의 용접부 충격특성 ······················· 271

[그림 5-48] 2상 스테인리스강의 용접부 개선 형상의 예 ······················ 273

[그림 5-49] 희석율의 정의 ····································································· 280

[그림 5-50] 탄소강과 스테인리스강의 용접형태 ···································· 281

[그림 5-51] WRC-92 diagram ······························································ 282

스테인리스강의 일반



제3절 스테인리스강의 특성

제4절 스테인리스강의 취급

KOREA IRON & STEEL ASSOCIATION

제1장

http://hrd.kosa.or.kr

제 1 장_ 스테인리스강의 일반 3

1장_ 스테인리스강의 일반


1. 스테인리스강의 정의

1970, 80년 는 스텐 밥그릇이 혼수 1순위였고, 전통의 유기도 스텐 밥그릇에 제사상을

내어 주어야 했다. 물론 수저도 27종1) 스텐으로 바뀌었고 양은 도시락이나 유리 보온병도

스텐 재질로 만들어져 이젠 보온병에 유리가 사용되었다는 것2)을 아는 이들이 드물 정도

이다. 기존 철강재와 달리 녹이 슬지 않는다는 인식으로 주사바늘, 샤프펜슬, 휴 용기기

안테나, 자동차 배기계 등 우리 생활 곳곳에 스테인리스강이 사용되지 않는 곳이 없다.

스테인리스강이란 영어로 Stainless Steel로서 ‘녹이 슬지 않는다’ 또는 ‘녹이 없다’는 것

을 의미한다. 이름이 나타내듯 스테인리스강은 일반 탄소강과 비교할 때 아주 뛰어난 내

식성을 보유하고 있어 많은 용도에 광범위하게 사용되고 있다. 그러나 스테인리스강은 특

정한 환경, 사용 조건에서는 붉은색은 발청 등 녹이 스는 경우가 있으므로 소재의 선택과

취급에 한 올바른 인식이 중요하다.

특히, 스테인리스강 정의의 핵심인 녹이 슬지 않는다는 내식성은 강판의 표면에 형성된

치밀한 크롬산화물 피막(일반적으로 부동태피막이라 불린다)의 작용에 의하여 유지되는 것

이므로 이 피막이 정상적으로 생성되지 않거나 손상되었을 경우는 스테인리스강으로서 기

능을 할 수 없으며, 일반인과 전문가간의 스테인리스강에 한 인식차가 큰 부분이다.

1) 1970년 반까지 국내에는 일본의 JIS에서 규정하는 스테인리스강 규정을 따랐는데, STS304는 27종, STS430은 24종,

STS304L은 28종으로 강종을 구분하 고, 이러한 구분법이 국내에 도입되어 1990년 까지 식기, 주방기기의 등 표기

기본이 되었다. 물론 1970년 반 JIS가 SUS코드를 도입하면서 24종, 27종이라는 표 은 공식 으로 사라졌다.

2) 보온병은 간에 진공층을 가지는 이 구조로 과거에는 내부 용기를 열 도도가 낮은 유리로 만들었지만 작은 충격에도 쉽

게 깨졌기에 심가공이 가능한 스테인리스강이 개발되면서 스테인리스강이 유리 신에 보온병의 내피재를 체하게 되었다.

4 스테인리스강 전문가양성 교육실무

스테인리스강을 과학적으로 정의하기에는 단순하진 않지만 다음 몇 가지로 정의할 수

있다.

① 합금성분으로서 크롬을 함유하고 있으며 그 함유량이 스테인리스강의 내식성을 유지

하는 보호막 역할을 하는 ‘부동태피막’(passive film)을 만들 수 있는 11% 이상의

크롬성분을 함유할 것(실제 409L은 크롬이 10.5～11.0% 수준으로 엄격한 의미의 스

테인리스강이라고 할 수 없음)

② 그 합금을 공업재료로서 사용할 수 있기 위해서는 이것을 저해하는 범위 이상의 크

롬을 포함하지 말 것(크롬 32%의 경우는 크롬 합금강으로 분류)

③ 스테인리스강은 강으로서 철계 합금이므로 철을 제외한 합금 원소의 총량이 50% 이

하일 것(크롬을 비롯한 타 합금량이 50%를 넘는 경우는 별도의 합금으로 구분됨)

2. 스테인리스강의 역사

스테인리스강은 산업혁명과 근 화를 거치며 제철/제강기술 발전으로 철강제품이 량

생산되고 건축물과 선박 등 다양한 구조물 등에 적용되었으나 부식이 문제되었기에 탄생

할 수 있었다. 부식을 방지하기 위해 표면처리, 전기방식, 합금원소 첨가 등이 연구되었고,

이를 통해 부식을 억제하겠다는 동기가 스테인리스강 탄생기반이 되었다.

1820년경에 영국의 M. Faraday에 의해 크롬이 들어간 합금에 한 연구가 시작되었으

며 이후 강중의 탄소량 제어기술의 개발과 적정합금과 내식성과의 관계규명 작업이 지속

적으로 이루어졌다. 이후 20세기 초(1904～1909)에 프랑스의 L. Guillet, A. Portevin과 독

일의 Giesen 등이 13%, 17% 크롬첨가 스테인리스강을 만들게 되었으니 지금의 페라이트

계가 탄생된 것이라 하겠다.

이후 L. Guillet는 스테인리스강의 오스테나이트계, 페라이트계, 마르텐사이트계 3가지

유형을 발표하였고, 독일의 Maurer, Strauss 등에 의해 오스테나이트계의 부식 특성, 미

국의 Danitzen, Becket 등에 의해 페라이트계의 부식 특성이 연구되어 스테인리스강의 기

반이 정립되었다. 이후에도 꾸준한 합금원소의 조정과 불순물 제어로 여러 종류의 강종이

개발되었고, 석출경화계와 2상계 등 고내식, 고강도 등의 고기능을 만족하는 스테인리스강

이 개발되어 오늘에 이르렀다.

성분계가 ‘18Cr-8Ni’이며 가장 일반적인 304강의 경우는 1909년 독일 Krupp사에서 최

초로 개발하여 특허를 획득함으로써 세상에 나오게 되었고 페라이트계의 17Cr계(STS430)

와 더불어 상용 스테인리스강의 출발점이 되었다. 일본, 중국, 한국 등 아시아 업체의 적

극적인 연구개발과 공격적인 설비투자, 생산량 증 로 스테인리스강 역사가 아시아권으로



이동하고 있다.

국내는 1960년 삼미와 동양석도강판, 일본의 종합상사가 설립한 삼미특수강(현 비앤지

스틸) 울산에 중고 냉간압연기를 도입하여 냉간압연 판재를 생산한 것이 스테인리스강 역

사의 시작이라고 할 수 있다3). 초기에는 Nisshin, Kawasaki(현 JFE), NSSC, Sumitomo

등에서 열연재를 도입하여 냉간압연만 하였고, 1980년 초 창원에 삼미특수강(현 포스코

특수강)이 스테인리스강 선재/봉재의 제강/열연 설비를 갖추고 이어 1990년부터는 포스코

포항공장에서 제강/열연 설비에서 본격적인 생산이 시작되며 스테인리스강 산업이 완전한

모양을 가지게 되었다.

3. 스테인리스강의 종류

스테인리스강은 합금성분계, 미세조직, 상(相 phase), 용도 등에 따라 구분하나 일반적

으로는 상에 따라 구분하며, 이는 합금계나 일반화된 세 자리 숫자의 스테인리스강 강종명

으로 표된다. 또한 강도를 고려하여 일반재(annealed, 소둔재)와 고경도재 등으로 구분

하고, 형태 용도에 따라 판재, 선재, 용접재, 튜브재 등으로 구분하고, 주조재, 열간 가공재,

냉간 가공재 등으로도 구분한다.

KS, JIS 경우는 스테인리스강과 별도로 내열강을 규정하지만 ASTM에서는 스테인리스

강으로 내열강과 동일한 규격에서 규정하는 차이가 있다. 내열강과 스테인리스강을 통틀어

오스테나이트계, 페라이트계, 마르텐사이트계, 2상계 등으로 구분하기도 하고 200계, 300계,

400계 등으로 통칭되기도 한다.

스테인리스강은 각 계(상, xxx)별로 합금성분, 용도, 특성에 따라 고유의 강종명을 가지

고 있고, 각 규격별로 나름 로의 기준을 가지고 표기하며, KS, JIS는 유사하다.

JIS에서는 강종, 형태를 구별하기 위하여 강종기호와 그 말미에 알파벳을 붙인 형태를

가진다. 형태를 나타내는 분류의 기호는 다음과 같이 규정되어 있다.

- 스테인리스강재(봉·판· ·선재·선·관·형강·주강); SUS(Steel Special Use Stainless)

- 스테인리스강 주강품; SCS(Steel Casting Stainless)

- 스테인리스강 피복아크 용접봉; D(Denkyoku)

- 스테인리스강 용접용 봉 및 선재; Y(Yosetsu)

- 스테인리스강 아크용접 플럭스 선재; YF(Yosetsu Flux)

- 내열강 강재; SUH(Steel Use Heat Resisting) 및 SUS

- 내열강 주물; SCH(Steel Casting Heat Resisting)

3) 한국의 스테인리스강 생산을 열었던 고 압연설비는 2007년에 해체되어 동 국가로 옮겨 새로운 출발을 하 다.


강종기호는 스테인리스강재의 경우 SUS에 이어 3항 숫자가 있다. 이 숫자는 국제적으

로 널리 사용되고 있는 AISI(American Iron and Steel Institute) 타입 3항의 숫자에 준

하며, 1972년부터 사용되었다. 3항의 숫자 중 가장 앞자리 숫자는 강종의 분류를 나타내

며, 다음과 같이 분류된다.

- 200번 ; Cr‐Ni‐Mn계

- 300번 ; Cr‐Ni계 - 400번 ; Cr계

- 600번 ; 고온 고강도 합금계

내열강의 봉, 판에 하여 SUH 외에 SUS 표시로 AISI에 준하는 기호도 채용되고 있

다. 또 스테인리스강과 다른 밸브용 강 등 AISI에 없는 강종도 비교적 많기 때문에 오래

된 기호가 그 로 사용되고 있으며 다른 기호도 혼재되어 있다. 한편 주강은 다른 금속재

료와 마찬가지로 판재/선재와 다른 독자의 기호가 사용되고 있어 정확한 강종 비교를 위

해서는 성분계 확인이 필요하다. 또한 강종을 나타내는 숫자 앞뒤에 알파벳이 붙어있는

것이 있다. 표적인 것은 다음과 같다.

- L : 저탄소(Low Carbon)의 의미. 예: SUS 304L, SUS 316L

- J : 일본 독자강종의 의미. 예: SUS 316J1, SUS 329J3L

- XM : ASTM(American Society for Testing and materials)규격에 규정되어있는 강종.

예) SUS XM7, SUS XM 15J1

- N : 질소첨가의 의미. 예: SUS 304N1, SUS 316N1

- S : 용접성, 가공성의 개선을 목표로 C함유량을 낮추도록 규정.

예) SUS 309S

게다가 형태를 표시할 필요가 있는 경우는 강종기호의 말미에 다음에 나타내는 알파벳

을 붙여 구별한다(상세한 설명은 JIS 핸드북·철강의 철강기호 분류별 일람표 참조).

- 봉 : B(Bar)

- 열간압연강판 : HP(Hot Plate)

- 열간압연강 : HS(Hot Strip)

- 냉간압연강판 : CP(Cold Plate)

- 냉간압연강 : CS(Cold Strip)



4. 스테인리스강의 관련 규격

스테인리스강 관련 규격은 열간재, 냉간재, 선재, 판재, 특수용도재 등으로 구분되며 내

열강과 구분(KS, JIS)되거나 통합 규격을 따르기도 한다. 또한 각 규격별로 규정된 강종

이 다르고 강종코드와 표기도 매우 달라 실수요가에게 혼돈을 야기하므로 이에 한 명확

한 기준이 필요하다. 일반적으로는 KS, JIS는 동일한 규격을 사용하며 스테인리스강 코드

가 JIS의 SUS4)(Stainless Use Specialty), KS의 STS(Stainless Steel)로 구분된다. 그

리고 ASTM은 내열강과 스테인리스강을 동일 규격에서 규정하는 것과 달리 KS, JIS는

별도 내열강 규격과 강종코드를 가지고 있으므로 규격 적용시 주의가 요구된다.

스테인리스강 관련 규격은 KS, JIS, DIN과 같은 국가표준, ISO의 국제표준, EN의 지

역표준, ASTM과 같은 단체표준 등에 규정되어 있으며 형태, 용도, 가공 공정별로 구분되

어 있는 것이 일반적이다.

스테인리스강 제조업체는 공인규격 외에 독자 규격을 운영하는 사례가 있으니 업체의

제품 사양이 공인 규격과 호환 가능한가를 확인해야 한다. 그리고 냉간압연 판재는 표면

마무리도 사양에 포함되어 있으며 제조설비와 용도 등에 의존하므로 표면마무리 코드 규

격을 비교 확인하는 것도 필요하다. 또한 업체별 생산설비의 사양에 따라 제품 두께/폭,

표면에 따라 생산 가능한 규격차가 있으니 스테인리스강 냉연업체에서 보유하고 있는 설

비 사양을 파악하여 제조 가능한 규격을 확인해야 한다. 압연설비에 의존하는 두께와 달

리 폭은 슬리팅에 의해 폭 방향으로 분할하여 나눌 수 있으므로 최소 폭의 개념은 슬리팅

설비에 의존한다.

스테인리스강은 표면을 그 로 사용하므로 각 규격에서는 표면마무리를 규정하고 있으

며 규격별 제조업체별 다소 차이는 있으나 열처리 공정, 연마 조건 등으로 구분하고 있다.

규격에서 규정하는 표면 마무리 외 판재의 2차 표면처리를 통하여 다양한 의장 효과를 나

타내는데 이에 한 표면 마무리는 [표 1-4]와 같이 구분한다.

4) 스테인리스강 가공 장이나 도면 등에는 아직도 서스(SUS)가 스테인리스강의 약칭으로 불리는데 이는 JIS의 SUS에서

따른 것으로, STS 는 스테인리스강이라고 하는 것이 정확한 표 이다.


Standard Standard No. Title

KS

D 3705 열간 압연 스테인리스 강판 및 강대

D 3698 냉간 압연 스테인리스 강판 및 강대

D 3732 내열 강판

D 3534 스프링용 스테인리스 강대

D 3695 스테인리스 강판 및 내열 강판의 무게 산출 방법

JIS

G 4304 Hot Rolled stainless steel plates, sheets and strip

G 4305 Cold Rolled stainless steel plates, sheets and strip

G 4312 Heat‐resisting steel plates and sheetsG 4313 Cold rolled stainless steel strips for spring

G 4310Method of mass calculation for stainless steel plates and Sheet, and heat‐resisting steel plates and sheets

EN

10028-7Flat products made of steels for pressure purposes-‐ Part 7: Stainless steels

10029Hot rolled plates 3mm thick or above ;tolerance on dimensions, shape and mass

10151 Stainless steel strip for springs-Technical delivery conditions

10204 Metallic products–Types of inspection documents

10258Cold rolled stainless steel narrow strip and cut lengths- Tolerance on dimensions and shape

10259Cold‐rolled stainless steel wide strip and plate/sheet – Tolerances on dimensions and shape

(DIN) 10088-1 Stainless steels - Part 1: List of stainless steels

(DIN) 10088-2Stainless steels - Part 2: Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for general purposes

(DIN) 10088-3Stainless steels - Part 3: Technical delivery conditions for semi‐finished products, bars, rods, wire, sections and bright products of corrosion resisting steels for general purposes

ISO

6931‐1:1994 Stainless steels for springs - Part 1: Wire

6931‐2:2005 Stainless steels for springs - Part 2: Narrow strip

9445‐1:2009 Continuously cold‐rolled stainless steel ‐‐ Tolerances on dimensions and form - Part 1: Narrow strip and cut lengths

9445‐2:2009 Continuously cold‐rolled stainless steel ‐‐ Tolerances on dimensions and form - Part 2: Wide strip and plate/sheet

ASTM

A167Standard specification for stainless and heat resisting chromium‐nickel steel plate, sheet, and strip

A 176Standard specification for stainless and heat‐resisting chromium steel plate, sheet, and strip

A 240 /A 240M

Standard specification for chromium and chromium‐nickel stainless steel plate, sheet, and strip for pressure vessels and for General Applications

A 264Standard specification for stainless chromium‐nickel steel‐clad plate, sheet, and strip

A 380Standard practice for cleaning, descaling, and passivation of stainless steel parts, equipment, and systems

A 480 /A 480M

Standard specification for general requirements for Flat‐rolled stainless and heat‐resisting steel plate, sheet, And strip

[표 1-1] 스테인리스강 관련 규격



표면마무리

두께(mm)

폭(mm)

특징 업체

2D, 2B0.3~5.0 ~1260

- 0.3mm 미만 생산 설비 없음- 2.0mm 초과는 형상 교정 어려움

0.7~5.0 ~1524 - 설비 보유 업체 소수 POSCO

BD, BA

0.3~2.0 ~1260- 2.0mm 초과 생산 설비 없음- 2.0mm 초과는 형상 교정 어려움

0.1~0.29 ~1020 - 0.3mm 미만은 최대 1020mm

0.03~0.09 ~610 - 0.1mm 미만은 광택 제한 있음 BNG

No. 4, HL 0.4~5.0 ~1260 - 습식 연마 설비 0.4mm 한계

고경도품0.1~5.0 ~1260 - 조질기호별 최대두께 제한

0.02~0.09 ~620 - 조질기호별 두께 제한 없음 BNG

EM 0.3~3.0 ~1219 - 강종, 무늬별 별도 제한 BNG

TCM 0.5~2.0 ~1250 - 표면 품질 2D로 제한 POSCO

[표 1-2] 표면마무리에 따른 스테인리스강 냉간압연판재 생산가능규격

KS JIS ASTM ENFinishing Processes

D 3698 G 4305 A 480 10088-2

‐ No. 1 No. 1 1D 열간 압연후 열처리/산세한 제품

No. 2D No. 2D No. 2D 2D 냉간압연 후 열처리/산세한 제품

No. 2B No. 2B No. 2B 2B 냉간압연, 열처리/산세 후 조질압연한 제품

BA BABright

Annealed2R

냉간압연, 광휘열처리. 고도의 조질압연으로 고광택과 높은 반사율을 가지는 제품

No. 4 No. 4 No. 4 2J 150~180mesh의 연마belt로 연마한 제품

‐ ‐ No. 7 2P800mesh 이상의 연마제와 회전 buff로 연마하여 고광택을 부여한 제품

HL HL ‐ 2M No. 4 제품에 연속 연마무늬를 부여한 제품

‐ ‐ TR 2H 가공경화성을 이용한 냉간압연 제품

[표 1-3] 규격별 표면마무리 구분 및 호환

명 칭 표면마무리의 방법

No. 8(Mirror)

순서에 따라 점점 고운 입도의 연마제로서 연마한 후 경면용 Buff로 연마한 것(AISI)

슈퍼 미러(super mirror)

BA 마무리 또는 순서에 따라 고운 입도의 연마제로 연마한 후 거울면과 동일하게 미세 연마한 표면

브라스트(shot blast)

경면재에 스틸, 유리 조각, 모래 등을 때려 광택을 낮추고 은은한 질감을 부여

바이브레이션(vibration)

연마브러쉬 또는 스카치브라이트 등으로 바이브레이션, 슬립레스, 랜덤으로 호칭되는 무방향성 연마 표면

엠보싱(embossing)

에칭 또는 기계적으로 모양을 부여한 엠보싱 Roll로 압연 한다

화학발색 INCO법, 교반전해법에 의한 발색한 것 Gold, Bronze, Black 외

코팅(coating)

경면, HL등에 전면 또는 부분을 이온 플레이팅, 스퍼터링에 의해 여러 가지 물질로 판위에 강한 박막을 생성함.

에칭(etching)

경면, HL등에 정밀한 정밀한 피복문양을 부여하여 피복이 되어 있지 않은 부분을 에칭액 속에서 용해침식 시켜 문양 을 만듦

[표 1-4] 추가공에 의한 표면마무리 구분



스테인리스강은 부분 판재 형태로 제조되며 [표 1-5]에 나타난 공정을 거치면 최종

제품화된다. 성분과 표 상으로 오스테나이트계, 페라이트계, 마르텐사이트계, 석출경화계,

2상계 등으로 구분한다. 그리고 가공공정에 따라 열간재, 냉간재, 인발재로 구분하고, 용도

에 따라 범용, 스프링용, 용접용, 강관용 등으로 구분되어 규격에 규정되어 있다.

성분은 제강과 정련공정에서 결정되고 제품의 형태는 열간, 냉간 공정, 절단 및 후가공

등에 의해 결정되는데, 스테인리스강 냉간압연 판재의 공정은 [표 1-5]와 같다. 일반 사용

자는 부분 냉연재를 사용하여 가공하므로 냉연재의 치수 공차, 물성, 표면 등을 더욱 중

요하게 생각한다. 스테인리스강의 분류는 열간재, 냉연재, 선, 판 등을 다 포함하는 조직

(상)으로 구분하는 것이 일반적이다.

공정 설명 특성 업체

제강 쇳물 용해 화학성분결정 열간압연업체

정련 정련(고순도화)

연주 쇳물 응고 연속주조

열간압연 고온 압연

열처리/산세 소둔 열처리 표면 산세

냉간압연 상온 압연 두게 공차 냉간압연업체

열처리 소둔 열처리 고온연속열처리

교정 형상 교정 조질압연 등

표면연마 #4 표면 마무리 연마 고속 belt 방식

절단/포장 Side trimming, shearing 주문 규격 절단

전단 Slitting, shearing Coil center

[표 1-5] 일반적인 스테인리스강판 제조공정

주) 스 링 특성을 부여한 고경도품은 최종압연후 열처리를 하지 않음.

1. 오스테나이트계 스테인리스강

오스테나이트계 스테인리스강은 Fe‐Cr(페라이트)계에 니켈(니켈에 준하는 오스테나이트

형성 원소 포함 ; Mn, Cu, N, C 등)을 8% 이상 첨가하면 상온에서 안정한 면심입방격형

오스테나이트 결정구조를 가지며 이를 명명한 것이다. 면심입방형 구조에서 기인하는 용이

한 가공성과 비자성 특성 등 다른 스테인리스강과는 다른 물리적인 성질을 가지고 상업적

으로 가장 널리 사용되고 있다. 열처리에 의해 경화되지 않고 냉간 가공경화를 이용하여

스프링 특성으로 활용하기도 한다.



강종 C Si Mn P S Ni Cr Mo 기타

STS2010.15 1.00

5.507.50

‐0.045

‐0.030

3.505.50

16.0018.00

N0.25 이하

STS2020.15 1.00

7.5010.00

‐0.045

‐0.030

4.006.00

17.0019.00

N0.25 이하

STS301‐

0.15‐

1.00‐

2.00‐

0.045‐

0.0306.008.00

16.0018.00

‐ ‐STS301L

‐0.03

‐1.00

‐2.00

‐0.045

‐0.030

6.008.00

16.0018.00

‐ N0.20 이하

STS301J10.080.12

‐1.00

‐2.00

‐0.045

‐0.030

7.009.00

16.0018.00

‐ ‐STS302

‐0.15

‐1.00

‐2.00

‐0.045

‐0.030

8.0010.00

17.0019.00

‐ ‐STS302B

‐0.15

2.003.00

‐2.00

‐0.045

‐0.030

8.0010.00

17.0019.00

‐ ‐STS304

‐0.08

‐1.00

‐2.00

‐0.045

‐0.030

8.0010.50

18.0020.00

‐ ‐STS304J1

‐0.08

‐1.70

3.005.00

‐0.045

‐0.030

6.009.00

15.0018.00

‐ Cu 1.0~3.0

STS304J2‐

0.08‐

1.70‐

3.00‐

0.045‐

0.0306.009.00

15.0018.00

‐ Cu 1.0~3.0

STS304L‐

0.03‐

1.00‐

2.00‐

0.045‐

0.0309.0013.00

18.0020.00

‐ ‐STS304N1

‐0.08

‐1.00

‐2.50

‐0.045

‐0.030

7.0010.50

18.0020.00

‐ N 0.10~0.25

STS304N2‐

0.08‐

1.00‐

2.50‐

0.045‐

0.0307.5010.50

18.0020.00

‐ N 0.10~0.25Nb 0.15이하

STS304LN‐

0.03‐

1.00‐

2.00‐

0.045‐

0.0308.5011.50

17.0019.00

‐ N 0.12~0.22

STS305‐

0.12‐

1.00‐

2.00‐

0.045‐

0.03010.5013.00

17.0019.00

‐ ‐STS309S

‐0.08

‐1.00

‐2.00

‐0.045

‐0.030

12.0015.00

22.0024.00

‐ ‐STS310S

‐0.08

‐1.50

‐2.00

‐0.045

‐0.030

19.0022.00

24.0026.00

‐ ‐STS316

‐0.08

‐1.00

‐2.00

‐0.045

‐0.030

10.0014.00

16.0018.00

2.003.00

‐STS316L

‐0.03

‐1.00

‐2.00

‐0.045

‐0.030

12.0015.00

16.0018.00

2.003.00

‐STS316N

‐0.08

‐1.00

‐2.00

‐0.045

‐0.030

10.0014.00

16.0018.00

2.003.00

N 0.10~0.22

[표 1-6] 오스테나이트계 스테인리스강의 화학성분(KS D 3698)

대부분의 합금 원소가 설비, 조업 기술에 따라 차이가 있지만 최근 추세는 나름대로의

목표 관리를 하며 고가의 몰리브덴, 니켈, 크롬 등은 매우 엄격하게 관리한다. 구리는 아

시아권에서 주로 사용하는 합금원소로 타 지역에 비해 KS, JIS에서 구리가 첨가된 종류

가 많다. 수 십 가지 이상의 강종이 있지만 오스테나이트계 스테인리스강의 성분유형은

내식성, 가공성, 강도 등과 연관이 있으며 각각을 유형별로 다음과 같이 구분할 수 있다.


강종 C Si Mn P S Ni Cr Mo 기타

STS316LN‐

0.03‐

1.00‐

2.00‐

0.045‐

0.03010.5014.50

16.5018.50

2.003.00

N 0.12~0.22

STS316Ti‐

0.08‐

1.00‐

2.00‐

0.045‐

0.03010.0014.00

16.0018.00

2.003.00

Ti 5XC% 이상‐

STS316J1‐

0.08‐

1.00‐

2.00‐

0.045‐

0.03010.0014.00

17.0019.00

1.202.75

Cu 1.0~2.5

STS316J1L‐

0.03‐

1.00‐

2.00‐

0.045‐

0.03012.0016.00

17.0019.00

1.202.75

Cu 1.0~2.5

STS317‐

0.08‐

1.00‐

2.00‐

0.045‐

0.03011.0015.00

18.0020.00

3.004.00

‐STS317L

‐0.03

‐1.00

‐2.00

‐0.045

‐0.030

11.0015.00

18.0020.00

3.004.00

‐STS317LN

‐0.03

‐1.00

‐2.00

‐0.045

‐0.030

11.0015.00

18.0020.00

3.004.00

N 0.10~0.22

STS317J1‐

0.04‐

1.00‐

2.50‐

0.045‐

0.03015.0017.00

16.0019.00

4.006.00

‐STS317J2

‐0.06

‐1.50

‐2.00

‐0.045

‐0.030

12.0016.00

23.0026.00

0.501.20

N 0.25~0.40

STS317J3L‐

0.03‐

1.00‐

2.00‐

0.045‐

0.03011.0013.00

20.5022.50

2.003.00

N 0.18~0.30

STS836L‐

0.03‐

1.00‐

2.00‐

0.045‐

0.03024.0026.00

19.0024.00

5.007.00

N 0.25 이하

STS890L‐

0.02‐

1.00‐

2.00‐

0.045‐

0.03023.0028.00

19.0023.00

4.005.00

Cu 1.0~2.0

STS321‐

0.08‐

1.00‐

2.00‐

0.045‐

0.0309.0013.00

17.0019.00

‐ Ti 5XC%이상

STS347‐

0.08‐

1.00‐

2.00‐

0.045‐

0.0309.0013.00

17.0019.00

‐ Nb 10XC%이상

STSXM7‐

0.08‐

1.00‐

2.00‐

0.045‐

0.0308.5010.50

17.0019.00

‐ Cu3.00~4.00

STSXM15J1‐

0.083.005.00

‐2.00

‐0.045

‐0.030

11.5015.00

15.0020.00

‐ ‐STS350

‐0.03

‐1.00

‐1.50

‐0.035

‐0.020

20.0023.00

22.0024.00

6.006.80

Cu 0.40 이하N 0.21~0.32

주) XM15J1에 해서는 필요에 따라 표의 원소 이외의 합 원소를 첨가할 수 있다.

- 입계부식과 용접 열영향부의 예민화를 억제 ; 저탄소계(low‐carbon, 0.03% 이하) 또

는 타이타늄, 니오븀 등을 첨가 304L, 316L, 347, 348

- 오스테나이트계 안정화 ; 저탄소계 및 니켈 함량을 증 하여 가공경화를 최소화하고

비자성 특성을 활용 305, 304L

- 공식 및 틈새부식 저항성 증 ; 해수 분위기, 화학플랜트 등에 사용하기 위해 몰리

브덴 첨가 316계, 317계

- 고온 특성 향상 ; 고온 강도, 크립(creep) 특성, 내산화성 증 를 위해 니켈 및 크롬

함량 폭 증 309S, 310S 높은 규소 함량으로 고온의 내산화성 향상 302B



- 절삭 가공성 향상 ; 황(S)과 세륨(Se)을 함유하여 절삭가공성을 개선 303F, 303Se

- 강도 향상 ; 질소를 첨가하여 강도 및 가공경화도 증 301L, 304N

오스테나이트계는 안정, 준안정 등으로 세부 구분하는데 이는 상온에서의 오스테나이트

계 상의 안정성을 나타내는 것으로 가공경화량, 자성 등으로 인지하게 된다. 표적인

STS304는 18Cr-8Ni-Fe 스테인리스강으로 고온에서 저온까지 오스테나이트상이 안정화

되어 있으며 자성을 띠지 않는다. 그러나 냉간가공에 의하여 변형되면 일부 준안정 오스

테나이트상(meta‐stable austenite)과 가공유기 마르텐사이트5)(strain induced martensite)

로 변태하여 오스테나이트 보다 강도가 높고 자성을 띠는 마르텐사이트의 생성에 의해 약

한 자성과 높은 가공경화 특성을 띠게 된다.

실제 사용자의 입장에서는 가공 직후 발생하는 자성이 이해하기 어려운 부분이므로 예를

들어 설명하겠다. STS304의 경우 외부 응력에 의해 변형될 경우 변형량에 따라 가공유기

마르텐사이트 양이 증가한다([그림 1-1] 참조). Press 성형 가공(Stamping)하면 위치별 압

축, 인장 등으로 인해 두께 변화가 나타나고 위치별 변형량에 기인하는 가공유기 마르텐사

이트상이 생성되고 자성 정도를 결정하게 된다. 냉간가공에 의해 생성된 가공유기 마르텐사

이트는 소둔 열처리를 하면 다시 오스테나이트상으로 변하고 물성과 자성도 회복된다.

[그림 1-1] 냉간가공에 따른 오스테나이트상과

가공유기마르텐사이트상의 관계6)

5) STS304의 오스테나이트상이 냉간가공에 의해 변태 생성된 마르텐사이트상은 마르텐사이트계의 마르텐사이트상과 구분

한다.

6) Handbook of Stainless Steels, Peckner and Bernstein, McGraw‐Hill

korea iron & steel associationhrd.kosa.or.kr/data/bm/스테인리스강전문가양성... ·...

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