Prediction Control Method of Spot Welded Nugget Size Based on Finite Element Analysis of Thermo-Electricity Transient

2011 ◽  
Vol 415-417 ◽  
pp. 151-165
Author(s):  
Hu Cai ◽  
Peng Zhang ◽  
Yuan Xun Wang

Dual-phase steel is a type of sheet material newly developed to adapt to the lightweight and safety needs of vehicle. In this paper, 1.7 mm thick dual-phase steel DP600 was taken as the object of study, its resistance spot welding performance characteristics and welding mechanism was studied in detail. The thermoelectricity transient process of welding was simulated with the finite element software and the experiment under corresponding welding parameters. It’s found that, under proper current circumstances, the simulated nugget size and the experimental result is in good agreement except the large current, the simulated deformation morphology and experimental result can be consistent, which indicates the good accuracy of analysis on resistance spot welding mechanism of dual-phase steel DP600. According to the results, the specific method and theoretical basis about nugget size and welding deformation predictive control was discussed, created the mutual relations between the resistance spot welding performance characteristics and welding mechanism of dual-phase steel DP600. The study effort has practical significance in comprehensively understanding the resistances spot welding mechanism of dual-phase steel, as well as in application and quality control of duplex steel in automotive body welding.

2013 ◽  
Vol 860-863 ◽  
pp. 780-783
Author(s):  
Qiao Bo Feng ◽  
Yun Feng Zhu ◽  
He Xin Zhao

The process parameters and quality of resistance spot welding for DP980 dual phase steel were studied through the orthogonal experiment method, and the influence of welding current, welding time and electrode force on the strength of welding joint has been discussed. The results show that the welding current has the greatest influence on the quality of welding joint for DP980 dual phase steel, and it needs relatively lower welding current for the DP980 dual phase steel as it has high resistivity, and appropriate increasing of electrode force is a feasible way to avoid the defect of shrinkage and it improves the joint strength.


2021 ◽  
Vol 55 (2) ◽  
pp. 201-206
Author(s):  
Aleksija Djuric ◽  
Dragan Milčić ◽  
Damjan Klobčar ◽  
Biljana Marković

Resistance spot welding (RSW) is still the most used form of welding in the automotive industry, primarily for welding steel. One of the advanced steels used in the automotive industry is dual-phase steel, so it is important to properly select the welding parameter for these steels. Therefore, this paper presents multi-objective optimization in the RSW welding process of DP 500 steel. The paper considers three different mechanical characteristics i.e., the failure load (F), failure displacement (l) and weld nugget diameter (D), as all these welding characteristics play significant roles in evaluating the quality of spot welding. The results show that the welding current is the most influential parameter with respect to the mechanical characteristics. The effect of welding time on the weld quality is the least significant. The optimal parameters for welding DP 500 steel obtained in this paper are weld current 8 kA, electrode force 4.91 kN and weld time 400 ms.


2021 ◽  
Vol 66 (3) ◽  
pp. 125-136
Author(s):  
Li Hong ◽  
Liu Xusheng ◽  
Wang Bing ◽  
Li Zhuoxin

In order to meet the increasing requirements of the automotive industry for material strength grades and performance, the application of advanced highstrength steel automotive panels, represented by dual-phase steel, in lightweight vehicle bodies is increasing. Resistance spot welding is the main joining process for vehicle body manufacturing. How to improve the tensile strength and fatigue performance of dual-phase steel resistance spot welding joints is of great significance to the welding structure of the body. In this paper, resistance spot welding of cold rolled DP600 dual phase steel in the welding current range of 9000A-12000A was carried out. The effects of post-weld tempering treatment on microstructure, microhardness, shearing and fatigue of joints were compared. The results show that the microstructure transformation occurs in the weld nugget area after post-weld tempering, and the tempered martensite appears to reduce the microhardness of the weld nugget area; the nugget diameters, tensile-shear strength and failure energy are all higher than those without tempering treatment; tempering improves the fatigue strength of the spot joints, and regardless of whether the welded joints are tempered, cracks are all generated near the heat affected zone of the joint after fatigue test.


2011 ◽  
Vol 391-392 ◽  
pp. 666-671
Author(s):  
Yan Yu ◽  
Rong Ji Zhou ◽  
Feng Xue Wang

Dual phase steel resistance spot welding process is transient, rapid, invisible, complex, which makes the physical process of welding not yet be fully understood. Both the preprocessing contact stress field and thermo - electric transient process under alternative current(AC)load of the resistance spot welding of DP1000 dual - phase steel are analyzed by ANSYS12.0 finite-element analysis software. The fusion zone formation process and the contact situation of electrode and workpiece, between workpieces, lamination surface is investigated through numerical simulation. The project can help understand the phenomenon and essence of the DP1000 spot welding optimize the structure design and process design, quality control, for the dual-phase steel in vehicle body spot welding quality control to provide theoretical guidance.


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