Laser Welding Technology And Clamping Control System Design For Plate Heat Exchanger

Plate heat exchanger is the common heat exchange equipment in the industrial production. The sealing performance of plate heat exchanger can affect the quality of its life. Traditional cushion seal has the problem of poor compatibility, it cannot be used in the medium which has corrosive effect on rubber gasket. Laser welding has characteristics of small deformation and better continuous welding sealing, which can solve this problem effectively. As a common material of plate heat exchanger, austenitic stainless steel has been widely used. Therefore, the study of laser welding of austenitic stainless steel has a certain value. Austenitic stainless steel in0.7mm thick are welded by Nd: YAG laser in this paper. And the influence of laser power, welding speed, shielding gas on morphology and mechanical properties of welded joints are studied. The results show that, with the increase of laser power, welding width on upper surface decrease and welding width on lower surface increase. Shielding gas makes welding process more stable, the tensile strength of welded joints with shielding gas are higher than welded joints with no shielding gas in the same process parameters. However, in actual production, laser welding of stainless steel is usually carried out with no shielding gas, the selection of high-power and high-speed will get better mechanical properties of welded joints. On this basis of welding process study, in order to make welding process more reliable and efficient, a set of automatic fixture which takes S7-300PLC as the core is designed in this paper, which suits for laser welding of plate heat exchanger.