An Improved Numerical Modeling for Resistance Spot Welding Process and Its Experimental Verification

1998 ◽  
Vol 120 (2) ◽  
pp. 246-251 ◽  
Author(s):  
O. P. Gupta ◽  
Amitava De
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Hsla Steel ◽  
Low Carbon Steel ◽  
Welding Process ◽  
Current Density Distribution ◽  
Mechanical Analysis ◽  
Electrode System ◽  
Low Carbon ◽  
Resistance Spot

A numerical model of resistance spot welding with spherical tip electrode is developed to incorporate the electro-thermal aspect as well as thermo-elasto-plastic behaviour inherent in this process. The electro-thermal aspect includes the Joule’s resistive heating along the contact surfaces and within the sheet-electrode system due to nonuniform current density distribution in the sheet-electrode. The elasto-plastic deformation of the sheet-electrode interface at higher temperature is included in the thermo-mechanical analysis. The interdependence of those two analyses has been taken care of The model is used to simulate the spot welding in low-carbon steel sheets of 1 mm and 2 mm thickness and HSLA steel sheet of 1 mm thickness. The results are compared with experimental data obtained as a part of this work and also with literature data. The comparison has shown a good agreement in all the cases. The results are later used to draw the thermal cycle curves at different location along the faying surface.

Control-Oriented Modeling and Simulation of a Low Carbon Steel A.C. Resistance Spot Welding Process

2012 ◽  
Vol 538-541 ◽  
pp. 1456-1459
Author(s):  
Yan Xi ◽  
Liang Gong ◽  
Cheng Liang Liu
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
High Performance ◽  
Physical Phenomenon ◽  
Low Carbon Steel ◽  
Welding Process ◽  
Thermal Response ◽  
Low Carbon ◽  
Thermal Dynamics ◽  
Resistance Spot

Resistance spot welding (RSW) has been extensively used as a sheet metal joining process, and the welding process identification is the essential issue for the design of high performance control strategy and set-up of a new welding schedule. However the RSW is a nonlinear time-varying uncertain process which couples the thermal, electrical, mechanical and metallurgical dynamics. To understand this complicated physical phenomenon an M-series pseudo-random electrical pattern is adopted to excite the RSW electrical-thermal dynamics and the thermal response is recorded according to the welding power outputs. Based on the experimental information the transfer function of an RSW electrical-thermal mechanism is identified, and the optimum model order and parameters are determined. Subsequently a control-oriented RSW model is established to explore the welding power control algorithm. The simulated results from the control model show their agreement with the experimental data, which validates its feasibility for corresponding welding control.

Expulsion Intensity Monitoring and Modeling in Resistance Spot Welding Based on Electrode Displacement Signals

2020 ◽  
Author(s):  
Yu-Jun Xia ◽  
Yan Shen ◽  
Lang Zhou ◽  
Yong-Bing Li
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Low Carbon Steel ◽  
Sheet Thickness ◽  
High Strength Steels ◽  
High Strength ◽  
Material Strength ◽  
Low Carbon ◽  
Resistance Spot ◽  
Electrode Displacement

Abstract Weld expulsion is one of the most common welding defects during resistance spot welding (RSW) process especially for high strength steels (HSS). In order to control and eventually eliminate weld expulsion in production, accurate assessment of the expulsion severity should be the first step and is urgently required. Among the existing methods, real-time monitoring of RSW-related process signals has become a promising approach to actualize the online evaluation of weld expulsion. However, the inherent correlation between the process signals and the expulsion intensity is still unclear. In this work, a commonly used process signal, namely the electrode displacement and its instantaneous behavior when expulsion occurs are systematically studied. Based upon experiments with various electrodes and workpieces, a nonlinear relation between the weight of expelled metal and the sudden displacement drop accompanied by the occurrence of weld expulsion is observed, which is mainly influenced by electrode tip geometry but not by material strength or sheet thickness. The intrinsic relationship between this specific signal feature and the magnitude of expulsion is further explored through geometrical analysis, and a modified analytical model for online expulsion evaluation is finally proposed. It is shown that the improved model could be applied to domed electrodes with different tip geometries and varying workpieces ranging from low carbon steel to HSS. The error of expulsion estimation could be limited within ±20.4 mg (±2σ) at a 95% confidence level. This study may contribute to the online control of weld expulsion to the minimum level.

Resistance Spot Welding of Low Carbon Steel to Austenitic CrNi Stainless Steel

2014 ◽  
Vol 875-877 ◽  
pp. 1499-1502 ◽  
Author(s):  
Ladislav Kolařík ◽  
Miroslav Sahul ◽  
Marie Kolaříková ◽  
Martin Sahul ◽  
Milan Turňa
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Weld Joint ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds

The contribution deals with resistance spot welding of low carbon steel to austenitic CrNi stainless steel. The thickness of welded dissimilar steels was 2 mm. DeltaSpot welding gun with process tape was utilized for welding of the above-mentioned combination of steels. Resistance spot welds were produced under different welding currents. The welding currents used were 7 kA, 7.5 kA and 8 kA, respectively. Optical microscopy, microhardness measurement across the weld joint and EDX analysis across the weld joint interface were used to evaluate the quality of resistance spot welds of dissimilar steels.

Expulsion Intensity Monitoring and Modeling in Resistance Spot Welding Based on Electrode Displacement Signals

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Yu-Jun Xia ◽  
Yan Shen ◽  
Lang Zhou ◽  
Yong-Bing Li
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Low Carbon Steel ◽  
Sheet Thickness ◽  
High Strength Steels ◽  
High Strength ◽  
Material Strength ◽  
Low Carbon ◽  
Resistance Spot ◽  
Electrode Displacement

Abstract Weld expulsion is one of the most common welding defects during the resistance spot welding (RSW) process, especially for high strength steels (HSS). In order to control and eventually eliminate weld expulsion in production, accurate assessment of the expulsion severity should be the first step and is urgently required. Among the existing methods, real-time monitoring of RSW-related process signals has become a promising approach to actualize the online evaluation of weld expulsion. However, the inherent correlation between the process signals and the expulsion intensity is still unclear. In this work, a commonly used process signal, namely, the electrode displacement and its instantaneous behavior when expulsion occurs are systematically studied. Based upon experiments with various electrodes and workpieces, a nonlinear correlation between the weight of expelled metal and the sudden displacement drop accompanied by the occurrence of weld expulsion is observed, which is mainly influenced by electrode tip geometry but not by material strength or sheet thickness. The intrinsic relationship between this specific signal feature and the magnitude of expulsion is further explored through geometrical analysis, and a modified analytical model for online expulsion evaluation is finally proposed. It is shown that the improved model could be applied to domed electrodes with different tip geometries and varying workpieces ranging from low carbon steel to HSS. The error of expulsion estimation could be limited within ±20.4 mg (±2σ) at a 95% confidence level. This study may contribute to the online control of weld expulsion to the minimum level.

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