scholarly journals Analysis of the Behavior of Dynamic Resistance, Electrical Energy and Force between the Electrodes in Resistance Spot Welding Using Additive Manufacturing

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 690
Author(s):  
Márcio Batista ◽  
Valdir Furlanetto ◽  
Sérgio Duarte Brandi
Keyword(s):  
Thermal Expansion ◽  
Additive Manufacturing ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Electrical Energy ◽  
Dynamic Resistance ◽  
Low Carbon ◽  
Resistance Spot ◽  
Welding Spot

This work is aimed at the analysis of the dynamic resistance, electrical energy and behavior of the force between electrodes (including thermal expansion) during welding at optimized parameters, referring to the process of spot welding using additive manufacturing (AMSW). For comparative purposes, this analysis also includes the conventional resistance spot welding process (RSW). The experiments were done on low carbon-zinc-coated sheets used in the automotive industry. The results regarding the welding process using additive manufacturing (AMSW), in comparison to the conventional resistance spot welding (RSW), showed that the dynamic resistance presented a different behavior due to the collapse of the deposition at the beginning of the welding, and that a smaller magnitude of electrical energy (approximately <3.35 times) is required to produce a welding spot approved in accordance with the norm. No force of thermal expansion was observed during the passage of the current, in contrast, there was a decrease in the force between the electrodes due to the collapse of the deposition at the beginning of the welding.

Micro Hardness in the Welded Area at Resistance Spot Welding

2016 ◽  
Vol 1138 ◽  
pp. 153-158
Author(s):  
Mihai Boca ◽  
Gheorghe Nagit ◽  
Laurenţiu Slătineanu
Keyword(s):  
Mechanical Properties ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Graphical Representation ◽  
Welding Process ◽  
Electrical Current ◽  
Micro Hardness ◽  
Current Time ◽  
Resistance Spot ◽  
Welding Spot

The resistance spot welding process represents the welding technology used to obtain assemblies trough welded spots characterized by adequate mechanical properties. This assembly process is used mainly into the automotive, petroleum and naval industries. It is applied due to the significant advantages concerning the technology and service properties of the obtained assembly. This paper purposes a study concerning the micro hardness change of an assembly made by resistance welding spot. The entire process of plastic deformations together with the solidification step developed in the presence of the heat generated during welding process determines the mechanical characteristics of the welded spot and, of course, of the assembly obtained. In such conditions, depending on the changes developed during the welding process, the micro hardness of the welded spot varies between the fusion area (FA) and heat affected zone (HAZ). In this way, the graphical representation of the micro hardness repartition gives clues about the weakness areas which don’t correspond to the requirements. As input factors, in this study, the values of current intensity, the electrical current time and the force pressure were considered. In order to solve the proposed problem and to graphically highlight the variation of the micro hardness obtained for welded points, it was used a classical welding device and a micro hardness device analyzer. The graphical representation shows that the micro-hardness and, as a consequence, some mechanical properties changes in the specified region and in the entire mass of the welded spot changes. In this way, the structure of welded spot is characterized by a variation of the hardness in the interest areas.

A new measurement method for the dynamic resistance signal during the resistance spot welding process

2016 ◽  
Vol 27 (9) ◽  
pp. 095009 ◽  
Author(s):  
Lijing Wang ◽  
Yanyan Hou ◽  
Hongjie Zhang ◽  
Jian Zhao ◽  
Tao Xi ◽  
...  
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Measurement Method ◽  
Welding Process ◽  
Dynamic Resistance ◽  
Resistance Spot

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.

scholarly journals Effect of Zinc Coating on Delay Nugget Formation in Dissimilar DP600 - AISI304 Welded Joints Obtained by the Resistance Spot Welding Process

2021 ◽  
Author(s):  
Mercedes Pérez de la Parte ◽  
Alejandro Espinel Hernández ◽  
Mario César Sánchez Orozco ◽  
Angel Sánchez Roca ◽  
Emilio Jiménez Macias ◽  
...  
Keyword(s):  
Welded Joints ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Zinc Coating ◽  
Welding Process ◽  
Dynamic Resistance ◽  
Time Duration ◽  
Resistance Spot ◽  
Nugget Formation ◽  
Resistance Curves

Abstract This paper researches the effect of zinc coating of galvanized DP600 steel on the dynamic resistance and the delayed nugget formation of dissimilar DP600 - AISI304 welded joints, obtained with resistance spot welding process (RSW). The RSW evaluations consisted of determining, from the dynamic resistance curves, the time involved in the different stages of the process, particularly the beginning of nugget formation. The experimental results showed that, from the dynamic resistance curves, it is possible to identify 8 distinct stages during the welding of galvanized DP600 steel and AISI304 stainless steel. In the case of the welding of uncoated DP600 steel with AISI304, only 6 stages are identified (except for stages 2 and 3), which are directly related to the heating, softening and melting of the galvanic coating. The energy used in stages 2 and 3, causes a delay in the beginning of nugget formation for welded joints obtained with galvanized DP600 steel compared to uncoated DP600 - AISI304 welded joints, reaching values between 37.28 ms and 52.29 ms for the welding conditions analyzed. Monitoring the time duration of stages 2 and 3, as defined from the analysis of the dynamic resistance curves, could be used as a tool to predict the beginning of nugget formation in the welding of galvanized steels, to avoid undesirable phenomena such as expulsion and to guarantee the quality of the welded joints.

scholarly journals Modified Recurrence Plot for Robust Condition Monitoring of Electrode Tips in a Resistance Spot Welding System

2020 ◽  
Vol 10 (17) ◽  
pp. 5860
Author(s):  
Wonho Jung ◽  
Hyunseok Oh ◽  
Dong Ho Yun ◽  
Young Gon Kim ◽  
Jong Pil Youn ◽  
...  
Keyword(s):  
Condition Monitoring ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Process ◽  
Recurrence Plot ◽  
External Noise ◽  
Dynamic Resistance ◽  
Resistance Spot ◽  
Welding Electrode ◽  
Welding System

Degraded electrodes in a resistance spot welding system should be replaced to ensure that weld quality is maintained. Welding electrodes are subjected to different environmental and operational loading conditions during use. When they are replaced with a fixed interval, replacement may occur too early (raising maintenance costs) or too late (leading to quality issues). This motivates condition monitoring strategies for resistance spot welding electrode tips. Thus, this paper proposes a modified recurrence plot (RP) for robust condition monitoring of welding electrode tips in resistance spot welding systems. The overall procedure for the proposed condition monitoring approach consists of three steps: (1) transformation of a one-dimensional signal to a two-dimensional image, (2) unsupervised feature extraction with LeNet architecture-based convolutional neural networks, and (3) health indicator calculation. RP methods convert dynamic resistance waveforms to RPs. The original RP method provides an image with binary-colored pixels (i.e., black or white) that makes this method insensitive to the change of the waveform signal. The proposed RP method is devised to be sensitive to the change of the waveform signal, while enhancing robustness to external noise. The performance of the proposed RP method is evaluated by examining simulated aperiodic waveform signals with and without external noise. A case study is presented to examine the proposed method’s ability to monitor the condition of resistance spot welding electrodes. The results show that the proposed method outperforms handcrafted, feature-based condition monitoring methods. This study can be used to accurately determine the lifetime of welding electrodes in real time during the spot welding process.

scholarly journals Development of a Resistance Spot Welding Process Using Additive Manufacturing

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 555 ◽  
Author(s):  
Márcio Batista ◽  
Valdir Furlanetto ◽  
Sérgio Duarte Brandi
Keyword(s):  
Additive Manufacturing ◽  
Tensile Stress ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Manufacturing Industry ◽  
Low Cost ◽  
Welding Process ◽  
Chemical Compositions ◽  
Automotive Manufacturing ◽  
Resistance Spot

For several decades, the electrical resistance spot welding process has been widely used in the manufacturing of sheet metal structures, especially in automotive bodies. During this period there was no significant development for this welding process. However, in recent years, in order to meet the demand for lighter, economical, and low-cost vehicles, the automotive manufacturing industry is undergoing a revolution in the use of high strength steel sheet combinations, chemical compositions, and of different thicknesses. In this context, the present work focuses on the study and development of a new resistant spot welding technology using additive manufacturing (AMSW) in zinc-coated steel sheets, used in the automotive industry. As a comparison, spot welding was also performed by the conventional resistance spot welding process (RSW). The results showed that the spot welding process using additive manufacturing (AMSW), through the optimized parameters, compared to the conventional resistance spot welding process (RSW), was 34.47% higher in relation to the shear tensile stress, as well as 28.57% higher tensile stress with a perpendicular load to the weld spot. The indentation or thermomechanical mark on the surface of the sheet was imperceptible to the visual inspection, producing a smooth face in the spot region.

scholarly journals Adaptive Control of Resistance Spot Welding Based on a Dynamic Resistance Model

2019 ◽  
Vol 24 (4) ◽  
pp. 86 ◽  
Author(s):  
Kas ◽  
Das
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Controller Design ◽  
Welding Process ◽  
Dynamic Resistance ◽  
Resistance Spot ◽  
Control Scheme ◽  
Metal Sheets ◽  
One Step ◽  
Welding Processes

Resistance spot welding is a process commonly used for joining a stack of two or three metal sheets at desired spots. Such welds are accomplished by holding the metallic workpieces together by applying pressure through the tips of a pair of electrodes and then passing a strong electric current for a short duration. This kind of welding process often suffers from two common drawbacks, namely, inconsistent weld quality and inadequate nugget size. In order to address these problems, a new theoretical approach of controlling resistance spot welding processes is proposed in this paper. The proposed controller is based on a simplified dynamical model of the resistance spot welding process and employs the principle of adaptive one-step-ahead control. It is essentially an adaptive tracking controller that estimates the unknown process parameters and adjusts the welding voltage continuously to make sure that the nugget resistance tracks a desired reference resistance profile. The modeling and controller design methodologies are discussed in detail. Also, the results of a simulation study to evaluate the performance of the proposed controller are presented. The proposed control scheme is expected to reduce energy consumption and produce consistent welds.

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