Experimental Study And Application Of Dual-Phase Steel Resistance Spot Welding Procedure Parameters

With the development of automotive lightweight technology, advanced high strength steel (AHSS) is widely used in vehicle engineering because of its excellent properties. Dual-phase steel is one of the most widely used advanced high strength steel due to its low cost. Resistance spot welding is the main connection technology in the automotive industry, however, its cooling rate and thick martensite in joint organization easily produced by high proportion alloy elements of AHSS, it seriously affect the strong toughness of the joint. And it can still cause to unsoldering and half spot welding, defects such as burrs, spatter and bad appearance because of welding process selection. Welding problems become increasingly prominent and urgent. Therefore, through the study of the influence law of process parameters on the weld defects, and optimize the process parameters in order to reduce or eliminate weld defects, and it is of great significance to improve the quality of car assembly.In this paper, take the spot welding technology of new-vehicle model’s I-beam as an example to carry out spot welding experiment and process parameter analysis. Mainly complete the following three aspects of work:1. Experimental study. Welding the standard spot welding tensile shear specimen and taking the nugget metallographic analysis and mechanical test after the completion of welding sampling and the corresponding treatment of samples, and then study the influence of welding parameters on the welding quality.2. Process parameter analysis. According to different plate combination, using the rule of the experiment, the welding process was tested, and the suitable range of welding parameters was analyzed. By analyzing the experimental results, the range of process parameters for the quality of the welded joint is obtained.3. Test result application. Reference parameters analysis results and spot welding process parameters testing and metallographic test based on DP steel to guide the new-vehicle models I-beam welding and optimize the process parameters.The paper systematically studied the influence of the main process parameters of DP steel welding on welding joint microstructure and mechanical properties, its purpose is to provide the necessary theoretical basis for improving the technical level of DP steel welding, has a good application prospect.