레이저 스티치 용접을 적용한 자동차 펜더 용접부의 기계적 특성

Abstract

Recently from the automatic industry is caused by with continued ratio improvement and, CO environmental regulation and demand of crash safety reinforcement etc. from the world wide automobile advanced various nations leads a continued these rules and celebration of the environmental characteristic automobile development which hits the high performance and the research and development for a body lightweight and is in parallel and productivity improvement technical etc. is research and development continuously. weight lightening of car contribute to reduce emitting harmful gas. Nonferrous metal is applied in various industry. But many problems occure aspect of cost, weldability and strength. Laser welding complement drawback of spot welding and has lots of advantages like high bond strength, few deformation. technical development that is applied by laser welding is progressing favorably to retain the safety of car. Spot welding make indentations after welding and Flange depend on electrode diameter. Also it's hard to apply complicated parts. Laser welding produce good quality products and productivity is high than spot welding but first cost of installation is high. Therefore laser stitch welding is applied to complement fault of spot welding and laser stitch welding. it already applied in Europe of car and applications will be increased in the world gradually. In this study, 3types Galvanized sheet iron(Type1: 1.4t SGARC 440/2.0t SGARC 440, Type2: 1.4t SGAFC 590/2.0t SGARC 440, Type3: 1.4t SGARC 440/1.4t SGAFC 590) Nd: YAG Laser Welded Lap Joint by Laser Stitch Welding Weldability study results, the following conclusions could be drawn. The optimum conditions for laser stitch welded joints of SGARC440 and SGAFC590 is laser power of 2kW, welding speed of 4m/min shieding gas of 15/min, focal length of +1mm. The shear stength of laser stitch welded joints about 19.91KN, 20.84KN, 16.55KN, and the welding defect standard(EN ISO13191-1) for quality levels is Stringent(B). Looking at the distribution of hardness with excellence and laser welding of Galvanized sheet iron effect of hardness of the substrate during the process of the heterogenous characteristics make of them showing a width of the weld metal hardness values. it is that almost seems to have similar characteristics.