Research On Laser Welding 304 Austenitic Stainless Steel Sheet

Stainless steel 304 is a type of austenitic stainless steel with a series of excellent performance such as good corrosion resistance, no-magnetic, high toughness and plasticity, etc ., which can be applied to atmospheric vessel, biotechnology engineering, chemical engineering, aircraft industry and nuclear industry. Recently, the application of stainless steel sheet has a greatly increased in many filed, such as aerospace, electronic devices, medical equipment, nuclear industry, and mechanical instrument. Therefore, the package and welding of the ultra-thin stainless steel become more and more important today. The traditional welding methods hardly ensure the quality of welding forming. While, the laser welding that can decrease certain welding defects, possess lots of advantage more than the traditional welding. Then, research on the technology of stainless steel 304 sheet welding appear depend on the above advantages.According to the physical characteristics of 304 stainless steel, the power density that needed by the welding of stainless steel was calculated, and then the type of welding was determined. A brief analysis of the mechanism of sheet penetration welding was shown, as well as the analysis and initial choice of the laser welding parameters. Laser butt welding experiments test were conducted on stainless steel thin sheet(0.3mm) using single factor experiment method. The influence of parameters changed on the weld head were investigated and the experimental results were analyzed combined with the laser welding theory, through the analysis of welding penetration and surface morphology, the combination of welding process parameters were optimized and a expected welded joints were obtained.The microstructure, phase, grain size and mechanical properties of the thin sheet weld joints were tested by metaloscope, X-ray diffractometer, SEM(scanning electron microscope), microhardness and other analytical instruments, the results obtained during the inspection of the thin sheet weld joints was analyzed and discussed.Combined the experimental results and test data, the numerical simulation of welding temperature field were conducted with the general-purpose finite element software ANSYS thermal analysis module. The distribution of the welding temperature field was analyzed as the foundation of the further analysis of the mechanism of thin sheet welding distortion.