Mechanical characteristics in Laser-Arc hybrid welded joints for the application of automotive parts(SGACC60/60)

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Recently, safety, lightness, and environmental protection have become more and more important in automotive industry. New material and new forming methods have been adopted to reduce the weight on condition of no increasing cost. However, infrastructure construction problem, performance contrast high price is still limited. Accordingly, improving durability and lightness in automotive structure have led to the wide use of galvanized steel sheets as a corrosion resistant material. Because of high strength and toughness, better performance both in high and low temperature, high resistance to abrasion and corrosion, galvanized steel sheets have attracted great attention in many academic research and industry applications. Especially, galvanized steel sheets can replace existing steel to reduce the body weight and to improve safety in automotive industry.
Although welding methods(Spot welding, MIG, TIG) that are applied to body parts of galvanized steel have been used for a long time, disadvantage such as high electricity consumption, electrode replacement and technical limitation give rise to interest in Laser-Arc hybrid welding. The hybrid welding technology that combines the advantage of laser welding(deep penetration, high speed, small heat-affected zone) and arc welding(low cost , fit-up mitigation, high-power) can improve quality of welding and productivity. Because of many process parameters of laser, arc and hybrid is not easy to optimize process. To solve this issue, various researches that affect weldability of many process parameters have been carried out.
In this paper, high-strength galvanized steel for application of the automotive cowl parts carry out respective processes MIG, Laser, Nd:Yag Laser-Mig hybrid welding. Several process parameters such as Laser-Arc distance, shieldingas and welding currents & welding speeds were investigated. Weld quality was evaluated by EN ISO13919-1(Reinforcement, Undercut, Excess weld metal Excessive penetration). In oder to evaluate weldability, This paper can carry out mechanical characteristic and metallurgical characteristic.
Alternative Title
자동차 카울 부품(SGACC60/60) 적용을 위한 레이저-아크 하이브리드 용접부의 기계적 특성
Alternative Author(s)
Jun-Ui Han
일반대학원 선박해양공학과
Awarded Date
Table Of Contents

List of Tables
List of Figures

Chapter 1. Introduction
1 . 1 Research background and purpose
1 . 2 Recent technology for automotive lightweight
1.2.1 Material sort of body for lightweight technology
1.2.2 Application of Laser-Arc hybrid welding for
body lightweight
1 . 3 Application of Laser-Arc hybrid welding
to automotive cowl

Chapter 2. Theoretical Background
2 . 1 Respective welding method
2.1.1 Principles of Nd:YAG Laser welding
2.1.1 Principles of MIG Welding
2 . 2 Laser-Arc hybrid welding technology
2.2.1 Principles of Laser-Arc hybrid welding
2.2.1 Advantage of Laser-Arc hybrid welding
2.2.3 Development of hybrid welding technology
2.2.4 Welding parameters of Laser-Arc hybrid
2 . 3 Characteristics of galvanized steel
2.3.1 Galvanized steel
2.3.2 Type of galvanized steel

Chapter 3. Experiment method of MIG, Nd:YAG Laser and Nd:YAG Laser-MIG hybrid welding process
3 . 1 Respective welding system
3.1.1 MIG welding equipment
3.1.2 Nd:YAG Laser welding equipment
3.1.3 Nd:YAG Laser-MIG hybrid welding equipment
3 . 2 Objective material
3 . 3 Experimental procedure
3.3.1 Respective B.O.P test
3.3.2 Respective butt welding
3.3.3 Effect of welding parameters on weldability
3 . 4 Evaluation of mechanical and metallurgical characteristics
3.4.1 Tensile test
3.4.2 Hardness test
3.4.3 Microstructure analysis

Chapter 4. Experimental result & Discussion
4 . 1 Respective B.O.P result
4.1.1 Experiment by MIG welding
4.1.2 Experiment by Laser welding
4.1.3 Experiment by Laser-Arc hybrid welding
4 . 2 Respective butt welding result
4.2.1 Experiment by MIG welding
4.2.2 Experiment by Laser welding
4.2.3 Experiment by Laser-Arc hybrid welding
4.2.4 Comparison result of respective welding
4 . 3 Effect of hybrid welding parameters on
4.3.1 Effect of Laser-Arc distance parameters
4.3.2 Effect of shielding gas parameters
4.3.3 Effect of Various currents & various speeds
4 . 4 Tensile test result
4.4.1 Comparison of tensile test of MIG & Laser
Laser-Arc hybrid welded joints
4.4.2 Tensile test of hybrid welded joints for
various currents & welding speeds
4 . 5 Hardness test result
4.5.1 Comparison of hardness test of MIG & Laser
Laser-Arc hybrid welded joints
4.5.2 Tensile test of hybrid welded joints for
current & welding speed
4 . 6 Microstructure analysis
4.6.1 Microstructure of respective welded joints
4.6.2 Microstructure of hybrid welded joints for
current & welding speed

Chapter 5. Conclusion
조선대학교 대학원
한준의. (2014). Mechanical characteristics in Laser-Arc hybrid welded joints for the application of automotive parts(SGACC60/60).
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General Graduate School > 3. Theses(Master)
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