표제지
목차
Abstract 10
제1장 서론 13
1.1. 연구 배경 13
1.2. 연구 목적 및 범위 16
(1) TIG 자동 용접 4축 제어 시스템의 특징 16
(2) 스테인리스강의 TIG 비드용접 특성 16
(3) 스테인리스강의 TIG 맞대기 용접 특성 16
(3) 스테인리스강의 TIG 배관 용접 특성 17
제2장 이론적 배경 18
2.1. TIG 용접 프로세스 18
2.1.1. TIG 용접법의 원리 18
2.1.2. TIG 용접의 제어변수 21
2.2. 스테인리스강의 특성 및 용접성 23
2.2.1. 스테인리스강의 물성 23
2.2.2. 스테인리스강의 용접성 27
2.3. 배관 자동 용접법 40
2.3.1. 오비탈 용접 40
2.3.2. 배관 회전식 용접 43
제3장 실험방법 44
3.1. 실험재료 및 장치 44
3.1.1. 실험재료 44
3.1.2. 실험장치 45
3.2. 실험 및 분석방법 47
3.2.1. 실험 방법 47
3.2.2. 분석 방법 49
제4장 실험 결과 및 고찰 50
4.1. TIG 자동용접 4축 제어 시스템의 구성 및 특징 50
4.1.1. 기구부 및 용접부 시스템 50
4.1.2. 제어부 시스템 55
4.2. 스테인리스강의 TIG 비드 용접 특성 59
4.2.1. 용접 전류 및 속도의 영향 59
4.2.2. 용가재 송급속도의 영향 69
4.3. 스테인리스강의 TIG 맞대기 용접 평가 74
4.3.1. 갭(gap) 간격의 영향 74
4.3.2. 용접부의 경도분포 81
4.3.3. 용접부의 미세조직 83
4.4. 스테인리스강의 TIG 배관 용접 분석 85
4.4.1. 용접전류의 영향 85
4.4.2. 용접 토치의 위치 및 각도의 영향 92
4.4.3. 슬로프 제어를 통한 용접조건의 최적화 105
4.4.4. 배관 용접부의 경도 분포 및 미세조직 110
제5장 결론 114
참고문헌 116
Table 2.1. The core diameter according with the welding current... 20
Table 2.2. Physical poperties of stainless steel 25
Table 2.3. Solidification forms with the mode of stainless steel 25
Table 2.4. Cr equivalent and equivalent formula with Ni equivalent 33
Table 2.5. Physical·mechanical properties of STS304 and SS41 37
Table 3.1. Chemical composition of stainless 316L and 304L 44
Table 3.2. Specifications of TIG welding equipment 46
Table 4.1. The slide speciflcations of X and Y, Z axis 52
Table 4.2. Optimal welding parameter setting in pipe welding 107
Fig. 2.1. Tungsten Inert Gas Welding(TIG) 20
Fig. 2.2. Diagram of Peseudo-binary 26
Fig. 2.3. Examples of welding corrosion by grain boundary... 29
Fig. 2.4. Schematic illustration of grain boundary... 30
Fig. 2.5. Variation of Cr concentration by Cr carbide formation 31
Fig. 2.6. Temperature range of grain boundary sensitization... 32
Fig. 2.7. Time-temperature variation of sensitization curve with carbon concentration 33
Fig. 2.8. Schaeffler diagram 34
Fig. 2.9. Variation of crack length with Cr and Ni equivalent 34
Fig. 2.10. Shrinkage of butt weld 37
Fig. 2.11. Angle distortion with aspect ratio 37
Fig. 2.12. Welding properties of A-TIG and C-TIG 38
Fig. 2.13. Effect of oxygen content for weld characteristic in shield gas 39
Fig. 2.14. Penetration characteristic with welding parameters 39
Fig. 2.15. Orbital welding 42
Fig. 2.16. Definition of section 42
Fig. 3.1. Experiment setup 45
Fig. 3.2. Constitution of welding equipment 46
Fig. 3.3. Analysis position of pipe 48
Fig. 4.1. Photographs of X, Y and Z axis slide 52
Fig. 4.2. Semiautomatic tilting system 53
Fig. 4.3. Pipe rotate system 53
Fig. 4.4. Schematic illustration of mechanical section 54
Fig. 4.5. Composition of AVC controller 56
Fig. 4.6. Actuation mechanism of automatic welding system 57
Fig. 4.7. Flow chart of automatic welding system 58
Fig. 4.8. Bead appearance and cross-section of shape with welding... 61
Fig. 4.9. Variation bead width and penetration depth with current... 62
Fig. 4.10. Bead appearance and cross section of shape with welding current (v=40 cpm) 63
Fig. 4.11. Variation bead width and penetration depth with current... 64
Fig. 4.12. Bead appearance and cross section of shape with welding current (v=60 cpm) 65
Fig. 4.13. Variation bead width and penetration depth with current... 66
Fig. 4.14. Bead appearance and cross section of shape with welding current (v=80 cpm) 67
Fig. 4.15. Variation bead width and penetration depth with current... 68
Fig. 4.16. Bead appearance and cross-section of shape with filler metal feed rate... 70
Fig. 4.17. Variation bead width and penetration depth with filler... 71
Fig. 4.18. Bead appearance and cross-section of shape with filler metal feed rate... 72
Fig. 4.19. Variation bead width and penetration depth with filler... 73
Fig. 4.20. Bead appearance and cross-section of shape... 75
Fig. 4.21. Variation bead width and penetration depth with gap clearance... 76
Fig. 4.22. Bead appearance and cross-section of shape... 77
Fig. 4.23. Variation bead width and penetration depth with gap clearance... 78
Fig. 4.24. Bead appearance and cross-section of shape... 79
Fig. 4.25. Variation bead width and penetration depth with gap clearance... 80
Fig. 4.26. Hardness distribution (Rf=1 m/min, GB=1.5 mm)[이미지참조] 82
Fig. 4.27. Hardness distribution (Rf=2 m/min, GB=1.5 mm)[이미지참조] 82
Fig. 4.28. Microstructure photo of weld zone and HAZ in butt welding 84
Fig. 4.29. Bead appearance and cross-section of shape with welding current in pipe welding (I=200 A) 87
Fig. 4.30. Bead appearance and cross-section of shape with welding current in pipe welding (I=210 A) 88
Fig. 4.31. Bead appearance and cross-section of shape with welding current in pipe welding (I=220 A) 89
Fig. 4.32. Bead appearance and cross-section of shape with welding current in pipe welding (I=230 A) 90
Fig. 4.33. Bead appearance and cross-section of shape with welding current in pipe welding (I=240 A) 91
Fig. 4.34. Variation of welding torch position and angle in pipe welding 93
Fig. 4.35. Bead appearance with position of welding rod in pipe welding (Pt=11 o'clock)[이미지참조] 94
Fig. 4.36. Bead appearance with position of welding rod in pipe welding (Pt=1 o'clock)[이미지참조] 95
Fig. 4.37. Bead appearance with position of welding rod in pipe welding (Pt=2 o'clock)[이미지참조] 96
Fig. 4.38. Bead appearance with angle of welding rod in pipe welding (α=F.H 10˚) 97
Fig. 4.39. Bead appearance with angle of welding rod in pipe welding (α=B.H 10˚) 98
Fig. 4.40. Bead appearance with welding current in pipe welding (α=F.H 10˚, I=180 A) 100
Fig. 4.41. Bead appearance with welding current in pipe welding (α=F.H 10˚, I=200 A) 101
Fig. 4.42. Bead appearance with welding current in pipe welding (α=F.H 10˚, I=205 A, Rf=0.5 m/min)[이미지참조] 102
Fig. 4.43. Bead appearance with welding current in pipe welding (α=F.H 10˚, I=205 A, Rf=0.8 m/min)[이미지참조] 103
Fig. 4.44. Bead appearance with welding current in pipe welding (α=F.H 10˚, I=210 A)[이미지참조] 104
Fig. 4.45. Parameter setting method of TIG welding equipment 106
Fig. 4.46. Welding pictures in TIG Welding optimal conditions 108
Fig. 4.47. Pipe welding specimens of welding optimal conditions 108
Fig. 4.48. Bead appearance and cross section of optimal condition in pipe welding 109
Fig. 4.49. Hardness distribution of pipe welds 111
Fig. 4.50. Microstructure of longitudinal section in overlap part 112
Fig. 4.51. Microstructure of longitudinal section in middle weld of pipe 113