Impact of the Winding Arrangement on Efficiency of the Resistance Spot Welding Transformer

In this paper, the impact of the winding arrangement on the efficiency of the resistance spot welding (RSW) transformer is presented. First, the design and operation of the transformer inside a high power RSW system are analyzed. Based on the presented analysis, the generation of imbalanced excitation of the magnetic core is presented, which leads to unfavorable leakage magnetic fluxes inside the transformer. Such fluxes are linked to the dynamic power loss components that significantly decrease the efficiency of the transformer. Based on the presented analysis, design guidelines to reduce the unwanted leakage fluxes are pointed out. The presented theoretical analysis is confirmed by measurements using a laboratory experimental system. The presented experimental results confirm that the proposed improved winding arrangement increased the efficiency of the transformer in average for 6.27%.

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One-Sided Resistance Spot Welding of Plastic-Metal Hybrid Joints - Characterization of the Joining Zone

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.809.183 ◽

2019 ◽

Vol 809 ◽

pp. 183-189

Author(s):

Konstantin Szallies ◽

Michael Friedmann ◽

Martin Bielenin ◽

Jean Pierre Bergmann

Keyword(s):

Resistance Spot Welding ◽

Spot Welding ◽

Welding Parameters ◽

Zone Formation ◽

Resistance Spot ◽

Plastic Metal ◽

Coaxial Electrode ◽

Polymer Metal ◽

Set Up ◽

The Impact

Polymer-metal-hybrid components show a high potential regarding to lightweight applications. In particular, due to their fundamental differences in chemical and physical properties, new approaches must be developed for common industrial joining processes. In this study a new approach in order to characterize the joining zone formation for thermal direct joining based on resistance spot welding is reported. The feasibility of joining in half-section set-up using a coaxial electrode arrangement was investigated. The impact of the welding parameters on the joining zone formation was investigated. The parameters influencing the melting layer formation were pointed out.

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Simulating Thermoelectric Effect and Its Impact on Asymmetric Weld Nugget Growth in Aluminum Resistance Spot Welding

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4047243 ◽

2020 ◽

Vol 142 (9) ◽

Cited By ~ 3

Author(s):

Lin Deng ◽

YongBing Li ◽

Wayne Cai ◽

Amberlee S. Haselhuhn ◽

Blair E. Carlson

Keyword(s):

Resistance Spot Welding ◽

Spot Welding ◽

Weld Nugget ◽

Thermoelectric Effects ◽

Element Analysis ◽

Resistance Spot ◽

Seebeck Coefficients ◽

Nugget Growth ◽

Simulation Results ◽

The Impact

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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Effect of Multiple Pulse Resistance Spot Welding Schedules on Liquid Metal Embrittlement Severity

Journal of Manufacturing Science and Engineering ◽

10.1115/1.4044099 ◽

2019 ◽

Vol 141 (10) ◽

Cited By ~ 7

Author(s):

E. Wintjes ◽

C. DiGiovanni ◽

L. He ◽

S. Bag ◽

F. Goodwin ◽

...

Keyword(s):

Liquid Metal ◽

Resistance Spot Welding ◽

Spot Welding ◽

Welding Current ◽

Liquid Metal Embrittlement ◽

Additional Heat ◽

Multiple Pulse ◽

Resistance Spot ◽

Pulse Welding ◽

The Impact

Zinc-coated advanced high strength steels (AHSS) used in automotive applications are susceptible to liquid metal embrittlement (LME) during resistance spot welding (RSW). This study examines the impact of multiple pulse welding schedules on LME severity in welds of TRIP1100. Two different types of pulsing methodologies have been proposed to reduce LME severity: applying a pre-pulse before the welding current to remove the zinc coating and pulsing during the welding current to manage heat generation. However, the mechanisms by which these methods affect LME severity have not been fully explored. This work showed that a welding schedule consisting of two equal length pulses resulted in the least severe LME because it reduced the amount of free zinc available for LME without creating too much tensile stress. The majority of pre-pulse welding schedules caused an increase in LME cracking due to the additional heat introduced into the weld. However, a 4 kA (low current) pre-pulse applied for 3 cy (low time) reduced LME cracking by almost 30%. The pre-pulse allowed zinc to diffuse into the coating and stabilize the zinc, without introducing too much additional heat into the weld. These results indicate that multiple pulse welding schedules may be successfully used to reduce LME cracking, although the mechanisms by which they impact LME are more complicated than previously thought.

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