| dc.description.abstract | At present, automobile lightweight is a topic of great concern to the world automobile industry, and the materials used in automobiles are the key to the greatest impact on automobile lightweight. In this study, we used lighter aluminum alloys and high-strength dual-phase steels. In addition to automobile materials, the connection method of automobile panels is also the focus of automobile lightweight, especially the application of adhesives, which are widely used because they can connect different materials. This research is divided into three parts, adhesive bonding experiment, AA5754 aluminum alloy resistance spot welding and dual-phase steel resistance spot welding.
The adhesive bonding experiment uses common room temperature glue and heat curing glue on the market. The aluminum plate to be glued is mainly AA5052, supplemented with AA1050 and AA5754. It mainly discusses the influence of various types of adhesives on the bonding properties of aluminum plates. We know that the surface condition of the adherend has a great influence on the adhesion performance, so it is necessary to carry out many treatments on the surface of the aluminum plate, such as surface cleaning, surface chemical cleaning and surface roughness. Experimental results show that for the room temperature curing adhesive used in the study, chemical cleaning of the surface of the aluminum plate not only has better shear strength, but also is a relatively simple treatment method. For heat-curing adhesives, the surface of the aluminum plate does not require any treatment. The glued samples have stable shear strength, so they can be used directly.
The basic material for aluminum alloy resistance spot welding research is AA5754, the plate thickness is 1.5-1.5, 1.5-2.5 and 2.5-2.5mm. The experiment uses welding current, welding time, electrode force and plate thickness as the experimental parameters. The preliminary results of Taguchi test indicate that the thickness of the steel plate has the greatest influence on the peeling load and energy absorption, while the welding current has the greatest influence on the nugget area. The parameters were then fine-tuned to conduct experiments and discuss the effects of surface treatment. The experimental results show that the surface condition of the weldment will affect the spot welding effect, and the surface cleaning can reduce the variation of the spot welding strength. The best spot welding parameters for plate thickness of 1.5-1.5 mm are: 45 kA, 60 mS, 8 kN; the best spot welding parameters for plate thickness of 1.5-2.5 mm are: 45 kA, 70 mS, 4 kN; plate thickness is 2.5 The best spot welding parameters for plate thickness of 2.5-2.5 mm are: 55 kA, 60 mS, 8 kN.
The research on resistance spot welding of dual phase steel is based on four grades of dual phase steel with a thickness of 1 mm, including DP590, DP780, DP980 and DP1180. With 8, 9, 10, 11 kA welding current and 9, 11, 13 cycle welding time as experimental parameters, the best spot welding parameter range of 5 kN electrode force was found and a database was established. The best spot welding parameters of DP590 are: welding current 10 kA, welding time 13 cycles; the best spot welding parameters of DP780 are: welding current 9 kA, welding time 13 cycles; the best spot welding parameters of DP980 are: welding current 11 kA, welding time 13 cycles; the best spot welding parameters of DP1180: welding current 9 kA, welding time 13 cycles. | en_US |