Choice And Optimize Of Inverter Spot Welding Technology On Hot Steel Rolling Truck Longeron

FAW Jiefang Co.Ltd.Truck Plant adopt the welding technics of acid washing and hydroforming during the welding of truck longeron, but because of the used acid cannot be called back efficiently, which will make the environment polluted. From the view of protecting environment, the company decided to weld the hot steel rolling directly, cancel the acid washing technics. But because of the soundness film of oxidation existing on the surface of the hot steel rolling,using spot welding equipment presently and adopting the actual welding technics, it will bring on a series of problems such as shortage of the nugget diameter resulting in not enough intension, a great deal of welding spatter and severe electrode abrasion and so on. Therefore, this paper is going to develop some interrelated research on the hot steel rolling spot welding technics.This paper has done some research on the hot steel rolling welding technics on the basis of a great deal of experiments, through the design and demonstration of the system of the experiment scheme, ultimately have gotten the results to utilize the uniform design experimentation to optimize the welding technical parameters to get the high quality welded joints during the process of the hot steel rolling welding. The actual spot welding experiments validate the correctness of the optimized parameter. All of these establish the foundation of the real actual welding production about the auto longeron.During the study, it has accomplished five group of experiments (twelve in each group), in order to get the welding spots which are in the various welding condition parameters through the actual operation. In the processing of analyzing the workpiece, a series of quality index of welding technologic are assessed by their mechanical properities, metallographic structure analyse and the variety of structure. The proof shows that the local overheating will cause coarsening of grains and this may patently lead to reduce the mechanical properties of welded joints of hot steel rolling especially their impact toughness. By comparision between nugget diameter, the rate of penetration and the tensile-shear load the results show that nugget diameter, the rate of penetration put an important effect on the mechanical properities of the welding spot.On the basis of experiment and analysis, Uniform Design Software is utilized to optimize the final data, and get the most optimized spot welding technological parameter of the hot steel rolling, which is supplied for the theoretic guarantee of the most idealism quality of the spot welding.Through the studying and analyzing the task, it is proved that: in the actual welding production, utilizing the final spot welding technical parameter not only from mechanical properties, nugget diameter but also from the face state of welding spot has achieved the design require.