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

Abstract

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.