표제지
목차
I. 서론 10
1.1. 연구배경 10
1.2. 연구목적 12
II. 이론적 배경 13
2.1. 알루미늄 합금의 특성 13
2.1.1. 알루미늄 및 합금의 분류 13
2.1.2. 알루미늄 합금의 물리·화학적 성질 15
2.2. MIG용접의 특성 17
III. 실험내용 및 방법 21
3.1. 실험대상 및 재료 21
3.2. 실험장치의 구성 23
3.3. 실험방법 26
3.3.1. 용접시편 제작 26
3.3.2. 용접부 평가방법 30
IV. 실험결과 및 고찰 36
4.1. 용접시편 분석 36
4.1.1. 용접비드 외관 및 매크로 분석 36
4.1.2. 인장시험 43
4.1.3. 굽힘시험 58
4.1.4. 경도시험 63
4.2. 적정 용접 조건 68
4.3. 피로시험 검증 71
V. 결론 75
참고문헌 77
요약 81
ABSTRACT 83
Table 2.1. Characteristic of aluminium alloying groups 13
Table 2.2. Basic symbol and definition 14
Table 2.3. Classification of symbol T 16
Table 2.4. Comparison of the properties of pure aluminium and iron 16
Table 2.5. Recommended aluminum alloy filler metals for structural welding... 20
Table 2.6. Chemical composition of ER4043 and ER5356... 20
Table 3.1. Chemical composition of 6005A-T6 Aluminium profile raw material 22
Table 3.2. Acceptance criteria of tensile testing and hardness testing... 22
Table 3.3. Specification of auto MIG welding system 24
Table 3.4. Specification of TPS5000MV welding machine 25
Table 3.5. Welding test coupon item 28
Table 3.6. Fixed welding variable for welding coupons 28
Table 3.7. Dimensions of welding joint 29
Table 3.8. Dimensions of tensile test specimen 32
Table 3.9. Dimensions of bend test specimen 33
Table 3.10. Dimensions of fatigue test specimen 35
Table 4.1. Result of Macro&Appearance of welded coupon 38
Table 4.2. Acceptance criteria of tensile testing of welded 6005A-T6. alloy 45
Table 4.3. Results of tensile testing for lower side welding by ER5356 48
Table 4.4. Results of tensile testing for upper side welding by ER5356 49
Table 4.5. Results of tensile testing for lower side welding by ER4043 50
Table 4.6. Results of tensile testing for upper side welding by ER4043 51
Table 4.7. Mean value of tensile test for welded coupon by ER5356 and 2.5Hz 52
Table 4.8. Mean value of tensile test for welded coupon by ER5356 and 4.5Hz 53
Table 4.9. Mean value of tensile test for welded coupon by ER4043 and 2.5Hz 54
Table 4.10. Mean value of tensile test for welded coupon by ER4043 and 4.5Hz 55
Table 4.11. Percentage of decrease in tensile test value compared to... 56
Table 4.12. Percentage of decrease in tensile test value compared to... 56
Table 4.13. Percentage of decrease in tensile test value compared to... 57
Table 4.14. Percentage of decrease in tensile test value compared to... 57
Table 4.15. Hardness testing results of lower welding by ER5356 63
Table 4.16. Hardness testing results of upper welding by ER5356 64
Table 4.17. Hardness testing results of lower welding by ER4043 64
Table 4.18. Hardness testing results of upper welding by ER4043 65
Table 4.19. Test result for select of optimal welding condition 70
Table 4.20. Fatigue testing result of welded 6005A-T6 alloys 73
Table 4.21. Fatigue testing result of unwelded 6005A-T6 alloys 74
Fig. 1.1. Configuration of carbody structure 11
Fig. 2.1. Gas metal arc welding process 19
Fig. 2.2. Typical semiautomatic GMAW setup 19
Fig. 3.1. Cross-section view of aluminium railway vehicles 21
Fig. 3.2. Configuration of auto MIG welding system 23
Fig. 3.3. Auto MIG welding system 24
Fig. 3.4. TPS5000MV welding machine 25
Fig. 3.5. Welding bead shape comparison of general MIG welding and... 27
Fig. 3.6. Stiffener of under frame aluminium profile 27
Fig. 3.7. Shape of welding joint 29
Fig. 3.8. Welded coupon for mechanical property testing 29
Fig. 3.9. Location of test specimens for mechanical properties testing... 30
Fig. 3.10. Section of welded aluminium profile for under frame 31
Fig. 3.11. Specimen for Macro testing of aluminium profile 31
Fig. 3.12. Universal testing machine 32
Fig. 3.13. Specimen for tensile test of a butt weld 32
Fig. 3.14. Specimen for bend test of a butt weld 33
Fig. 3.15. Location of Hv testing 34
Fig. 3.16. Specimen for fatigue testing 35
Fig. 4.1. Comparison of Macro&Appearance of lower welding by ER5356 39
Fig. 4.2. Comparison of Macro&Appearance of upper welding by ER5356 40
Fig. 4.3. Comparison of Macro&Appearance of lower welding by ER4043 41
Fig. 4.4. Comparison of Macro&Appearance of upper welding by ER4043 42
Fig. 4.5. Weld metal fracture of specimen by tensile testing 45
Fig. 4.6. Heat affected zone fracture of specimen by tensile testing 45
Fig. 4.7. Each average value of tensile testing result... 46
Fig. 4.8. Each average value of tensile testing result... 46
Fig. 4.9. Each average value of tensile testing result... 47
Fig. 4.10. Each average value of tensile testing result... 47
Fig. 4.11. Example of crack by root bending test of welded specimen 58
Fig. 4.12. Bend testing results of lower welding by ER5356 59
Fig. 4.13. Bend testing results of upper welding by ER5356 60
Fig. 4.14. Bend testing results of lower welding by ER4043 61
Fig. 4.15. Bend testing results of upper welding by ER4043 62
Fig. 4.16. Hardness testing graph of lower welding by ER5356 66
Fig. 4.17. Hardness testing graph of upper welding by ER5356 66
Fig. 4.18. Hardness testing graph of lower welding by ER4043 67
Fig. 4.19. Hardness testing graph of upper welding by ER4043 67
Fig. 4.20. S-N Curves of welded 6005A-T6 alloys 71
Fig. 4.21. S-N Curves of unwelded 6005A-T6 alloys 72