Resistance spot welding of galvanized steel: Part II. Mechanisms of spot weld nugget formation

1986 ◽  
Vol 17 (4) ◽  
pp. 887-901 ◽  
Author(s):  
S. A. Gedeon ◽  
T. W. Eagar
2015 ◽  
Vol 80 (5-8) ◽  
pp. 1137-1147 ◽  
Author(s):  
J. Sagüés Tanco ◽  
C. V. Nielsen ◽  
A. Chergui ◽  
W. Zhang ◽  
N. Bay

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2336
Author(s):  
Ichwan Fatmahardi ◽  
Mazli Mustapha ◽  
Azlan Ahmad ◽  
Mohd Nazree Derman ◽  
Turnad Lenggo Ginta ◽  
...  

Resistance spot welding (RSW) is one of the most effective welding methods for titanium alloys, in particular Ti-6Al-4V. Ti-6Al-4V is one of the most used materials with its good ductility, high strength, weldability, corrosion resistance, and heat resistance. RSW and Ti-6Al-4V materials are often widely used in industrial manufacturing, particularly in automotive and aerospace industries. To understand the phenomenon of resistance spot weld quality, the physical and mechanical properties of Ti-6Al-4V spot weld are essential to be analyzed. In this study, an experiment was conducted using the Taguchi L9 method to find out the optimum level of the weld joint strength. The given optimum level sample was analyzed to study the most significant affecting RSW parameter, the failure mode, the weld nugget microstructure, and hardness values. The high heat input significantly affect the weld nugget temperature to reach and beyond the β-transus temperature. It led to an increase in the weld nugget diameter and the indentation depth. The expulsion appeared in the high heat input and decreased the weld nugget strength. It was caused by the molten material ejection in the fusion zone. The combination of high heat input and rapid air cooling at room temperature generated a martensite microstructure in the fusion zone. It increased the hardness, strength, and brittleness but decreased the ductility.


Author(s):  
YongBing Li ◽  
ZhongQin Lin ◽  
Qi Shen ◽  
XinMin Lai

Resistance spot welding (RSW) is a very complicated process involving electromagnetic, thermal, fluid flow, mechanical, and metallurgical variables. Since weld nugget area is closed and unobservable using experimental means, numerical methods are generally used to reveal the nugget formation mechanism. Traditional RSW models focus on the electrothermal behaviors in the nugget and do not have the ability to model mass transport caused by induced magnetic forces in the molten nugget. In this paper, a multiphysics model, which comprehensively considers the coupling of electric, magnetic, thermal, and flow fields during RSW, temperature-dependent physical properties, and phase transformation, is used to investigate the heat and mass transport laws in the weld nugget and to reveal the interaction of the heat and mass transports and their evolutions. Results showed that strong and complicated mass transport appears in the weld nugget and substantially changed the heat transport laws and, therefore, would be able to substantially affect the hardening, segregation, and residual stress of the weld. Compared with the traditional models which could not consider the mass transport, the multiphysics model proposed in this paper could simulate the RSW process with higher accuracy and more realities.


Author(s):  
Yong Bing Li ◽  
Zhong Qin Lin ◽  
Li Li ◽  
Guan Long Chen

Resistance Spot Welding (RSW) is a very complicated process involving electro-magnetic, thermal, fluid flow, mechanical and metallurgical variables. Since weld nugget area is close and unobservable with experimental means, numerical methods are mainly used to reveal the nugget formation mechanism. Traditional RSW models focus on the electro-thermal behaviors in the nugget, and do not have the ability to model mass transport caused by induced magnetic forces in the molten nugget. In this paper, a multi-physics model, which comprehensively considers the coupling of electric, magnetic, thermal and flow fields during RSW, temperature-dependent physical properties and phase transformation, is used to investigate the heat and mass transport laws in the weld nugget and to reveal the interaction of the heat and mass transports. Results show that the heat transport behaviors in the weld nugget, the profile of the nugget, and the thermal field evolution are significantly changed when the mass transport is considered. At the same time, a good agreement is also found between experimental and numerically calculated nugget sizes. As a result, when predicting crystal growth process, the effects of the mass transport should be considered in order to obtain a more accurate prediction results.


2021 ◽  
Vol 11 (3) ◽  
pp. 181-185
Author(s):  
Amit Hazari ◽  
Rith Saha ◽  
Bidisha Ghosh ◽  
Debraj Sengupta ◽  
Sayan Sarkar ◽  
...  

The spot welding procedure is used in a variety of industrial applications. The most critical elements influencing welding quality, productivity, and cost are the spot welding parameters. This research examines the effect of welding factors such as welding current and welding time on the strength of various welding joint designs. Resistance spot welding (RSW) is used in the automotive industry for manufacturing. This research focused on the optimization of process parameters for resistance spot welding (RSW), as well as the tensile testing and spot weld diameter. The goals of this analysis are to comprehend the physics of the process and to demonstrate the effect of electrical current, weld time, and material type on the resistance spot welding process.


Author(s):  
Zhijun Wu ◽  
Guanlin Zhang ◽  
Bingxu Wang ◽  
Kelvin Shih

Resistance Spot Welding (RSW) is one of the most common and dominant technologies utilized in the automotive industry to join the thin sheet metals together, and expulsion is a common phenomenon during the operation. How to ensure the high quality nugget formation and joining performance is essential to ensure the quality and integrity of structures. In this study, solid state resistance spot welding is introduced in order to prevent expulsion. The effect of welding current and welding time on the mechanical performance of the solid state RSW in terms of nugget size, tensile performance and nugget formation will be investigated experimentally by using steel sheet metals. Microstructure and micro-hardness of the nugget cross-section will be evaluated as well.


Author(s):  
Lin Deng ◽  
YongBing Li ◽  
Wayne Cai ◽  
Amberlee S. Haselhuhn ◽  
Blair E. Carlson

Abstract Resistance spot welding (RSW) of aluminum–aluminum (Al–Al) is known to be very challenging, with the asymmetric growth of the weld nugget often observed. In this article, a semicoupled electrical–thermal–mechanical finite element analysis (FEA) procedure was established to simulate the RSW of two layers of AA6022-T4 sheets using a specially designed Multi-Ring Domed (MRD) electrodes. Critical to the modeling procedure was the thermoelectric (including the Peltier, Thomson, and Seebeck effects) analyses to simulate the asymmetric nugget growth in the welding stage. Key input parameters such as the Seebeck coefficients and high-temperature flow stress curves were measured. Simulation results, experimentally validated, indicated that the newly developed procedure could successfully predict the asymmetric weld nugget growth. Simulation results also showed the Seebeck effect in the holding stage. The simulations represent the first quantitative investigation of the impact of the thermoelectric effects on resistance spot welding.


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