Study On Laser Welding Process Of Railway Dedicated Stainless Steel

As the requirements of shrinking global resources and the rapid growth of industrial, the train of high speed and lightweight face enormous challenges. During the "twelfth five-year", considering the demand of high-speed railway train increased, stainless steel material has the characteristics of high strength, good welding performance, easy to cold, as well as the low price, which is just meet the demand. So the relevant departments recommended that manufacture of railway vehicles had better to use stainless steel. And the use of stainless steel has been further attention. In this paper, aiming at solving the weld defects of stainless steel car body, the advantages of laser welding technology is being made full use of. Laser welding which has the advantage of little deformation and high efficiency cooperates with the robot to weld rail train body of stainless steel SUS301 L. After welding, comparative study on the laser welding and arc welding is researched, which can prove the feasibility of laser welding technology in the stainless steel car body manufacturing and advantages.In this paper, orthogonal test and single factor optimization test is done for three kinds of different joint types. Mainly including:2.0 mm plate laser butt weld shows good appearance, no obvious oxidation surface color. The weld tensile strength reached 92% of parent metal, weld cross section morphology and microstructure are good. There are no obvious flaws, and the butt weld has good organization and properties.The study of laser lap weld found that weld carrying capacity mainly depends on the size of the lap joint surface area size when the penetration is a certain number. When the width of the lap is more close to the process parameters under the WMAX, the bearing capacity of the weld will be better. In order to meeting the actual application, non-penetrating lap is studied for getting a good weld which has good mechanical properties and exterior morphology.For tee joint laser welding process, something is found that its key factor on the weld quality is different from butt joints and lap joints. The important factors which impacts the tee joint is the attitude of the beam that is the laser incident angle and beam incident location. Through the reasonable adjustment of process parameters, single-sided welds on three sides forming tee joint tissue is obtained under the single laser beam and not filling the welding material. Finally, transverse tensile strength can achieve to 64% of the original metal.Finally, fiber laser welding and MIG welding is studied in this paper. The study found that fiber laser welding seam whose weld appearance and deformation degree is better than the MIG welding. Laser welding tensile fracture in the weld zone and MIG welding fracture in heat affected zone and laser welding is obviously better than the MIG welding in mechanical properties. So fiber laser welding technology on stainless steel car body manufacturing's advantage is shown.