표제지
목차
제1장 서론 11
1.1. 연구 배경 11
1.2. 수소에너지 세계 동향 12
1.3. 수소에너지 국내 동향 14
1.4. 수소취화 거동 시험법 16
1.5. 연구 목적 및 내용 19
제2장 시험방법 21
2.1. 시험편 21
2.2. In-situ SP 시험방법 24
2.3. 중공인장시험편 사용 in-situ SSRT 시험방법 29
2.4. 수소취화 민감도의 정량 평가 33
제3장 시험결과 및 고찰 38
3.1. In-situ SP 시험결과: 배관강의 수소취화 민감도 정성 평가 38
3.1.1. API X70강 38
3.1.2. API X52강 46
3.2. In-situ SSRT 시험결과: 배관강의 수소취화 민감도 정성 평가 54
3.2.1. API X70강 54
3.2.2. API X52강 66
3.3. 배관강의 수소취화 민감도 정량 평가 73
3.3.1. API X70강 73
3.3.2. API X52강 81
3.4. 중도정지 SSRT 중공인장시험편의 단면관찰을 통한 수소취화 거동 파악 88
제4장 결론 및 향후 계획 98
4.1. 결론 98
4.2. 향후 계획 99
참고문헌 101
Abstract 105
Table 2.1. Chemical composition of materials supplied. 21
Table 2.2. Mechanical properties of materials supplied. 22
Table 2.3. Test conditions for in-situ SP tests 22
Table 2.4. Test conditions for in-situ SSRT tests using hollow tensile specimen 22
Fig. 1.1. Global hydrogen mobility and domestic hydrogen mobility markets forecast 15
Fig. 1.2. The Korea government's Roadmap to revitalize the hydrogen economy 15
Fig. 1.3. Schematics of SSRT specimen for screening test HE 17
Fig. 1.4. Flow chart of this study. 20
Fig. 2.1. Tensile stress-strain curves obtained by in-situ SSRT using hollow tensile specimens at RT(double extensometers were used) 23
Fig. 2.2. Dimensions of specimens used for in-situ HE screening tests 23
Fig. 2.3. Schematics of in-situ SP test apparatus under high-pressure H₂ gas environment at RT 25
Fig. 2.4. High pressure gas charge system 26
Fig. 2.5. Typical load-displacement curves obtained under both 10 MPa N₂ and H₂ gas environments at RT 28
Fig. 2.6. Schematics of in-situ SP test system at low temperature 29
Fig. 2.7. Schematics of in-situ SSRT apparatus using hollow tensile specimen under high-pressure H₂ gas environment at RT 31
Fig. 2.8. Schematics of in-situ SSRT test system at low temperature 33
Fig. 2.9. Measurement of specimen thickness at fracture parts using a point micrometer and cross-sectional views of specimens tested under N₂ and H₂ gas environment 35
Fig. 2.10. (a) Measurement of inner and outer diameters of hollow specimen at fracture parts using pin gauge and vernier calipers and (b) cross-sectional views of hollow... 37
Fig. 3.1. Load-displacement curves obtained by in-situ SP tests for API X70 steel at each test temperature 40
Fig. 3.2. SEM morphologies of (a) fracture parts and (b) fracture surfaces after in-situ SP tests of API X70 steel 41
Fig. 3.3. Representative load-displacement curves obtained by in-situ SP tests for various (a) punch velocities and (b) hydrogen gas pressure test conditions for API X70... 44
Fig. 3.4. SEM morphologies after in-situ SP test of API X70 steel (a) at different punch velocities and (b) at different hydrogen gas pressure test conditions at RT 45
Fig. 3.5. Load-displacement curves obtained by in-situ SP tests of API X52 steel at each test temperature 48
Fig. 3.6. SEM morphologies of (a) fracture parts and (b) fracture surfaces after in-situ SP tests of API X52 steel 49
Fig. 3.7. Load-displacement curves obtained by in-situ SP tests (a) at different punch velocities and (b) different H₂ pressure conditions of API X52 steel at RT 52
Fig. 3.8. SEM morphologies after in-situ SP test of API X52 steel (a) at different punch velocities and (b) at different hydrogen gas pressure test conditions at RT 53
Fig. 3.9. Stress-strain curves obtained by in-situ SSRT tests using API X70 steel hollow specimen at each test temperature 57
Fig. 3.10. Comparison of stress-strain curves obtained by in-situ SSRT tests using API X70 steel hollow specimen for each gas condition 58
Fig. 3.11. SEM morphologies after in-situ SSRT tests using API X70 steel hollow specimen 61
Fig. 3.12. SEM morphologies of sectioned internal holes in the specimen fractured by SSRT test at 0.1 mm/min using API X70 steel hollow specimen 62
Fig. 3.13. SEM morphologies of sectioned internal holes in the specimen fractured by SSRT test at 1.0 mm/min using API X70 steel hollow specimen 63
Fig. 3.14. SEM morphologies of sectioned internal holes in the specimen fractured by SSRT test at 0.2 mm/min using API X70 steel hollow specimen 64
Fig. 3.15. SEM morphologies of sectioned internal holes in the specimen fractured by SSRT test at 0.1 mm/min using API X70 steel hollow specimen 65
Fig. 3.16. Stress-strain curves obtained by in-situ SSRT tests using API X52 steel hollow specimens at each temperature 68
Fig. 3.17. Comparison of stress-strain curves obtained by in-situ SSRT tests using API X52 steel hollow specimen at each gas environment 69
Fig. 3.18. SEM morphologies of fractured API X52 steel hollow specimens after in-situ SSRT tests at each test conditions 71
Fig. 3.19. Cross-sectional view and magnified SEM morphologies of the sectioned internal hole after SSRT test the API X52 steel hollow specimens 72
Fig. 3.20. Variation of SP energy, ROT (reduction of thickness) and RRT (relative reduction of thickness) obtained by in-situ SP tests for API X70 steel 78
Fig. 3.21. Variation of RRT obtained by in-situ SP tests (a) for different punch velocities and (b) for different hydrogen gas pressure conditions of API X70 steel 78
Fig. 3.22. Variation of RA (reduction of area) and RRA (relative reduction of area) obtained by in-situ SSRT tests using hollow specimen for API X70 steel 79
Fig. 3.23. Comparison of HE sensitivity parameters ROT/RA and RRT/RRA obtained by in-situ SP and SSRT for API X70 steel, respectively 80
Fig. 3.24. Variation of SP energy, ROT and RRT obtained by in-situ SP tests for API X52 steel at each test condition 85
Fig. 3.25. Variation of RRT obtained by in-situ SP tests (a) for different punch velocities and (b) for various hydrogen gas pressure conditions for API X52 steel 85
Fig. 3.26. Variation of RA and RRA obtained by in-situ SSRT tests using hollowspecimen for API X52 steel 86
Fig. 3.27. Comparison of HE sensitivity using ROT/RA and RRT/RRA obtained by in-situ SP and SSRT for API X52 steel 87
Fig. 3.28. Stress-strain curves until UTS of various steels in SSRT test using hollow tensile specimen and comparison for specimen before and after the test 91
Fig. 3.29. SEM morphologies and cross-section of internal hole of hollow specimen subjected to SSRT until UTS of various steel materials 97