A Comparative Study of AC and MFDC Resistance Spot Welding

2004 ◽  
Author(s):  
Wei Li ◽  
Daniel Cerjanec
Keyword(s):  
Comparative Study ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Median Frequency ◽  
Resistance Spot ◽  
Secondary Voltage ◽  
Nugget Growth ◽  
Welding Processes

This paper presents a comparative study of the AC and MFDC resistance spot welding process. Two identical welders were used; one with a single phase AC and the other with a median frequency DC weld control. Both welders were instrumented such that the primary and secondary voltage and current could be collected. A nugget growth experiment was conducted to compare the weld size and energy consumption in the AC and MFDC welding processes. It is found that the MFDC process generally produces larger welds with the same welding current. However, this difference is more prominent when the welding current is low. Overall the AC welding process consumes more energy to make a same size weld. The larger the welding current is used, the less efficient the AC process becomes.

Evaluation of the Role of Eddy Current in Resistance Spot Welding

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
M. Abu-Aesh ◽  
Moataza Hindy
Keyword(s):  
Eddy Current ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Work Piece ◽  
Resistance Spot ◽  
Precise Prediction ◽  
Welding Processes

Extensive work had been conducted on spot-welding due to its rapidly increasing industrial importance. The resistance spot-welding involves complicated phenomena, as several effects are found in the process, e.g., temperature, surface roughness, pressure, and eddy current effects. Most of the work exerted for analyzing the spot-welding process neglect the effect of the eddy current generated during the flow of the huge welding main current through the assembly of electrodes and work sheets. This work presents an analytical method to investigate the generation of eddy current and to determine the total effective welding current in spot-welding. The current distribution on the work sheet when it is fed by a conducting electrode is also investigated. The obtained current formula is based on electromagnetic principles, where a very strong magnetic field is generated in the core of the electrodes as well as in the materials of work sheets due to the flow of very high amperage. The final resultant effective current is the superposition of the electrode welding current and the induced eddy current in the electrode and work piece assembly. The results offer a viable mathematical model, which can be applied for a precise prediction of the effective value of welding current in spot-welding processes, if applied in a comprehensive model including all involved effects.

scholarly journals Short-Pulse Resistance Spot Welding of Aluminum Alloy 6016-T4 - Part 1

2021 ◽  
Vol 100 (01) ◽  
pp. 41-51
Author(s):  
ERIC SCHULZ ◽  
◽  
MATTHIAS WAGNER ◽  
HOLGER SCHUBERT ◽  
WENQI ZHANG ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Short Pulse ◽  
Welding Process ◽  
Welding Current ◽  
Welding Parameters ◽  
Resistance Spot ◽  
Pull Out ◽  
Welding Processes

Short-pulse welding parameters for resistance spot welding (RSW) of aluminum alloy AA6016-T4 using mediumfrequency direct current (MFDC) systems were developed to reduce the heat input required for nugget formation. Optimization of current and time parameters is critical during RSW of aluminum alloys for reducing energy requirements and avoiding weld imperfections, such as solidification cracking and expulsion, while maintaining weld quality, particularly given the high electrical and thermal conductivities of the materials. The welding time and the applied current level of the current pulse were varied systematically for thin sheets (1 mm or 0.04 in.) of AA6016-T4. The quality of the welds was evaluated by pull-out testing, ultrasound testing, and metallography techniques. Simulations of the same welding processes were performed with the finite element-based SORPAS® software. The results showed short-pulse MFDC RSW can reduce the energy required for sound welds in this alloy without requiring an increase in welding current. The simulations and experiments also showed the welding process had distinct weld nugget nucleation and growth phases.

scholarly journals Optimization on Spot Weld Parameters in Resistance Spot Welding Process on AISI 304

2021 ◽  
Vol 11 (3) ◽  
pp. 181-185
Author(s):  
Amit Hazari ◽  
Rith Saha ◽  
Bidisha Ghosh ◽  
Debraj Sengupta ◽  
Sayan Sarkar ◽  
...  
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Electrical Current ◽  
Industrial Applications ◽  
Spot Weld ◽  
Welding Parameters ◽  
Resistance Spot ◽  
Weld Time

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.

A Microscopic Approach to Determine Electrothermal Contact Conditions During Resistance Spot Welding Process

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
P. Rogeon ◽  
R. Raoelison ◽  
P. Carre ◽  
F. Dechalotte
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Electrical Contact ◽  
Welding Process ◽  
Contact Temperature ◽  
Macroscopic Model ◽  
Contact Conditions ◽  
Imperfect Contact ◽  
Resistance Spot ◽  
Nugget Growth

This study deals with resistance spot welding process modeling. Particular attention must be paid to the interfacial conditions, which strongly influence the nugget growth. Imperfect contact conditions are usually used in the macroscopic model to account for the electrical and thermal volume phenomena, which occur near a metallic interface crossed by an electric current. One approach consists in representing microconstriction phenomena by surface contact parameters: The share coefficient and the thermal and electrical contact resistances, which depend on the contact temperature. The aim of this work is to determine the share coefficient and the contact temperature through a numerical model on a microscopic scale. This surface approach does not make it possible to correctly represent the temperature profiles, with the peak temperature, observed in the immediate vicinity of the interface and thus to define, in practice, the contact temperature correctly. That is why another approach is proposed with the introduction of a low thickness layer (third body) at the level of the interface the electric and thermal resistances of which are equivalent to the electrical and thermal contact resistance values. In this case, the parameters of the model are reduced to the thickness of the arbitrarily fixed layer and equivalent electric and thermal conductivities in the thin layer, the partition coefficient and the contact temperature becoming implicit. The two types of thermoelectric contact models are tested within the framework of the numerical simulation of a spot welding test. The nugget growth development is found to be much different with each model.

Effect of Resistance Spot Welding Parameters on the Austenitic Stainless Steel 304 Grade by Using 23 Factorial Design

2011 ◽  
Vol 216 ◽  
pp. 666-670 ◽  
Author(s):  
Prachya Peasura
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Welding Time ◽  
Tensile Shear ◽  
Resistance Spot ◽  
Electrode Force

This research was study the effect of resistance spot welding process on physical properties. The specimen was austenitic stainless steel sheet of 1 mm. The experiments with 23 factorial design. The factors used in this study are welding current at 8,000 and 12,000 Amp, welding time at 8 and 12 cycle and electrode force were set at 1.5 and 2.5 kN. The welded specimens were tested by tensile shear testing according to JIS Z 3136: 1999 and macro structure testing according to JIS Z 3139: 1978. The result showed that the welding current, welding time and electrode force had interaction on tensile shear and nugget size at 95% confidential (P value < 0.05). Factors affecting the tensile shear are the most welding current of 12,000 amp., welding time of 8 cycle and electrode force of 2.5 kN. were tensile shear of 9.83 kN. The nugget size was maximum at 7.15 mm. on welding current of 12,000 amp., welding time of 12 cycle and electrode force of 1.5 kN This research can bring information to the foundation in choosing the appropriate parameters to resistance spot welding process.

Development of advanced resistance spot welding process using control of electrode force and welding current during welding

2012 ◽  
Vol 28 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Rinsei Ikeda ◽  
Yasuaki Okita ◽  
Moriaki Ono ◽  
Koichi Yasuda ◽  
Toshio Terasaki
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Resistance Spot ◽  
Electrode Force

Modeling and On-Line Estimation of Electrode Wear in Resistance Spot Welding

2004 ◽  
Vol 127 (4) ◽  
pp. 709-717 ◽  
Author(s):  
Wei Li
Keyword(s):  
Contact Area ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Estimation Algorithm ◽  
Contact Condition ◽  
Electrode Wear ◽  
Resistance Spot ◽  
On Line

Electrode wear is inherent in the resistance spot welding process. It determines the electrical and mechanical contact condition and thus strongly affects the resistance spot weld quality. A practical approach to minimizing the electrode wear effect is to compensate the welding current as the electrodes wear. However, the existing methods for welding current compensation rely on either a predetermined stepper schedule or an expulsion detection algorithm. These methods are not reliable since the welding current is not determined based on the contact condition for each weld made in the welding process. This paper presents an on-line electrode wear estimation approach to determining the contact condition and the welding current needed to make every weld a good weld during the entire life of the electrodes. In the study, an incrementally coupled finite element simulation was first formulated to analyze the contact area behavior in the resistance spot welding process. A lumped parameter model was then developed to characterize the contact area change with the dynamic resistance measurement. A calibration and an estimation algorithm were subsequently devised for on-line applications. The proposed approach has been validated with experimental data. The results have shown that the estimation algorithm is robust under various process conditions including both welding current and electrode force.

Study on Nonlinear Multiple Regression Modeling of Nugget Morphology for Unequal-Thickness Dissimilar Steel Welding

2011 ◽  
Vol 189-193 ◽  
pp. 3300-3308
Author(s):  
Yi Luo ◽  
Chang Hua Du ◽  
Chun Tian Li ◽  
Jin He Liu
Keyword(s):  
Multiple Regression ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Welding Current ◽  
Current Electrode ◽  
Factors Affecting ◽  
Dissimilar Steel ◽  
Resistance Spot ◽  
Multiple Regression Modeling

The special thermal effect makes some alterations to nugget morphology during resistance spot welding on unequal-thickness dissimilar steel. Method of nonlinear multiple orthogonal regression assembling design was introduced to design the experiment and investigate the resistance spot welding process. The indexes studied in experiments were nugget diameter and nugget deviation, which were the primary factors affecting the nugget morphology. Furthermore, four process parameters, namely welding current, electrode force, welding current duration and heat-treatment pulse current, and interactions among them were considered as the factors impacting the indexes. The nonlinear multiple regression models about nugget morphology parameters were developed on the basis of optimization. The experimental results showed that there was an effective prediction on nugget size based on the optimized models. The optimization to welding process also can be realized by the analysis to the effects of parameters and interactions.

Single-Side Resistance Spot Welding Process for Joining Pipes and Sheets

2013 ◽  
Vol 7 (1) ◽  
pp. 114-119 ◽  
Author(s):  
Hitomi Nishibata ◽  
◽  
Shota Kikuchi ◽  
Manabu Fukumoto ◽  
Masato Uchihara
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Numerical Study ◽  
Welding Process ◽  
Welding Parameters ◽  
Resistance Spot ◽  
Welding Technology ◽  
Single Side ◽  
Side Resistance ◽  
Nugget Growth

This paper describes a Single-Side resistance Spot Welding (SSSW) process which is expected to be a productive welding technology for the joining of stamped sheet panels to hollow parts for auto bodies. To obtain guidelines for making a sound weld with the SSSW process, the effects of welding parameters and the alignment of specimens on nugget growth are investigated experimentally. In addition, a numerical study is carried out to discuss the mechanism of nugget growth in the SSSW process.

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