Spot welding

About: Spot welding is a research topic. Over the lifetime, 12491 publications have been published within this topic receiving 89845 citations. The topic is also known as: Spot_welding.

Nugget growth characteristic for AZ31B magnesium alloy during resistance spot welding

Abstract: An axisymmetrical finite element model for studying the distribution of temperature for resistance spot welding (RSW) to predict weld nugget growth of AZ31B Mg alloy was developed by employing a co...

Ultrasonic spot welding of rare-earth containing ZEK100 magnesium alloy to 5754 aluminum alloy

Abstract: The aim of this study was to examine the feasibility of joining a low rare-earth containing ZEK100 Mg alloy to 5754 Al alloy via solid-state ultrasonic spot welding (USW), and evaluate the interface microstructure, tensile lap shear strength, and fatigue life. A diffusion layer consisting of eutectic structure of α-Mg and Al12Mg17 intermetallic compound was observed to form at the interface during USW, and its thickness increased with increasing welding energy. The tensile lap shear strength first increased, reached a peak value and then decreased with increasing welding energy. The optimal average strength of ZEK100-Al5754 dissimilar joints arrived at ~78% of ZEK100-ZEK100 similar joints and ~55% of Al5754-Al5754 similar joints. The tensile lap shear test samples failed in an interfacial mode with partial cohesive failure through the interface diffusion layer and partial failure through Mg alloy, with Mg alloy sticking on the Al side. Fatigue life of samples welded at a welding energy of 500 J was longer than that at 1000 J at higher cyclic loading levels, and it became equivalent at lower cyclic loading levels. The bi-linear behavior of S-N curves corresponded well to the change in the failure characteristics. At higher cyclic loading levels interfacial failure prevailed, while the formation of transverse-through-thickness (TTT) crack at the nugget edge occurred at lower cyclic loading levels.

Investigation of monitoring systems for resistance spot welding

Abstract: Although many different sensors have been developed for monitoring the resistance spot welding (RSW) process, no single sensor has been found to be capable of reliably detecting all defects associated with the process. A number of sensor systems are considered to hold promise of providing information about the process. In this paper, an investigation of various sensor systems for RSW is presented and the signals are analyzed and correlated with nugget formation and growth. These include a fiber-optic displacement sensor, an acoustic emission sensor, a force transducer, and the current and voltage measurements, which are set up to simultaneously monitor the welding process. Of these sensor systems, force signals are found to provide the most information on nugget formation.

Model development for quality features of resistance spot welding using multi-objective Taguchi method and response surface methodology

Abstract: In this research, the effect of parameters in Resistance Spot Welding (RSW) on the weld zone development was first investigated using Taguchi Method. Further, the RSW parameters were to be optimized based on multiple quality features, focusing on weld nugget and Heat Affected Zone using multi-objective Taguchi Method (MTM). The optimum welding parameter for MTM was obtained using Multi Signal to Noise Ratio and the significant level was further analyzed using Analysis of Variance. Lastly, Response Surface Methodology was employed to develop the mathematical model for predicting the weld zone development. The experimental study was conducted under varied welding current, weld time and hold time. To validate the predicted model, experimental confirmation test was conducted for plate thickness of 1 and 1.5 mm. Based on the results, the developed model can be effectively used to predict the size of weld zone which can improve the welding quality and performance in RSW.

Effect of plunge speeds on hook geometries and mechanical properties in friction stir spot welding of A6061-T6 sheets

Abstract: The plunge speed of the tool was divided into two plunge speeds, including pin- and shoulder-plunging speeds, for a detailed study of the plunging process in friction stir spot welding of A6061-T6 sheets. The effect of the pin- and shoulder-plunging speeds on hook geometries and mechanical properties was investigated. The results showed that the shoulder-plunging speed had an obvious effect on the hook geometry and tensile shear load, but the pin-plunging speed had almost no effect. The effective bond width (W eff) and effective sheet thickness (T eff) used to describe the hook geometry were important factors for determining the tensile shear load and fracture mode. Two fracture modes were observed: tensile/shear mixed fracture and shear fracture. The largest tensile shear load was obtained when the joint failed in the tensile/shear mixed fracture.