Spot Welding Technology And Quality Control Of Aluminum Alloy Body In White

With global energy crisis,automobile lightweight has become an important way to save energy and reduce emissions.Automobile lightweight is mainly divided into material lightweight and structure lightweight.Aluminum alloy has become one of the main materials in automobile lightweight because of its low density,high specific strength,good corrosion resistance,good thermal conductivity,low cost,easy processing and easy regeneration.A large number of aluminum parts are used in automobile body,and their joining technology has become a research hotspot in the whole industry.However,at present,there is no reference welding parameter system for aluminum alloy welding in China,and the fixture of aluminum parts in welding process needs to be optimized urgently.Therefore,the research on resistance spot welding process and quality control of aluminum alloy body-in-white has become an urgent research task.This paper comes from Dalian Otto Co.,Ltd.in-production project "General Motors 011 Project" as the subject source,the process parameters suitable for spot welding of aluminum alloy body in white are obtained through the systematic process research.Advanced management methods,such as improving on-site operation,eliminating seven wastes,on-time production,TQM,process error prevention,and so on,are introduced.Standardization of process and production management can effectively improve production quality,production efficiency,reduce production costs,and form the best solution for welding production line of aluminum alloy body in white.Introduce advanced concepts to form standardized production management mode on site.The test results show that the spot welding of 3mm thick 6XXX series aluminum alloy sheet and 3mm thick SF-36 alloy castings has a current of 44 kA,a time of 170 ms and a pressure of 4.9kN.The obtained spot-welding joint has the largest nugget diameter,no virtual welding,no spatter,and the hardness distribution in nugget zone and the bonding strength of spot-welding joint reach the optimum.In a certain range,with the increase of welding current and welding time,the nugget diameter of joints increases as a whole;with the increase of electrode pressure,the nugget diameter increases first and then decreases.Choosing suitable aluminum state,welding process,spot welding equipment and material,shape and size of electrode,and matching them equally,can significantly improve the service life of electrode and reduce production costs.Combining with the welding production line of General Motors 011 Project,this paper systematically expounds the general process flow and equipment composition of the welding assembly of the white body of aluminum alloy.The basic composition,design layout principle and attention Rules of the welding production line are described in detail.The product characteristics of the project are separated,and the layout of the workshop and welding fixture are designed and optimized.In order to provide reference for actual production.Based on the comprehensive consideration of welding materials,welding methods,equipment used and maintenance,the quality control system of spot welding for aluminum alloy body-in-white has been established,and the balanced production of welding production line has been realized.The production efficiency has been significantly improved.1.The mirror test of white body aluminum welding joints in 011 project is 100% qualified,and the strength of welding joints meets the requirement of welding design;the consumption of welding auxiliary materials is reduced;and the crash tests of finished cars meet the requirements of national sales.2.The production line rhythm meets the design requirements,the equipment start-up rate is balanced,and the operation is standardized;the body size meets the tolerance range of the finished car size,and the batch production size is stable.