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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.


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Patent
18 May 2011
TL;DR: In this article, it was discovered that suitable coating compositions including an adhesive placed at the interface of assembled workpieces can alter the composition of the friction stir weld material and strengthen the resulting bond.
Abstract: When a friction stir weld tool penetrates the interface of two workpieces of dissimilar metal alloy materials, the resultant weld of the different alloy materials may produce a weak weld joint. Such weak joints are often experienced, for example, when attempting to form spot welds or other friction stir welds between a magnesium alloy sheet or strip and an aluminum alloy sheet or strip. It is discovered that suitable coating compositions including an adhesive placed at the interface of assembled workpieces can alter the composition of the friction stir weld material and strengthen the resulting bond. In the example of friction stir welds between magnesium alloy and aluminum alloy workpieces, it is found that combinations of an adhesive with copper, tin, zinc, and/or other powders can strengthen the magnesium-containing and aluminum-containing friction stir weld material.

68 citations

Journal ArticleDOI
P. Wung1
TL;DR: In this paper, a force-based formula that combines four failure modes into one dimensionless equation to govern spot weld failure under general static loading conditions was proposed, and the failure modes are shear, rotation, normal and peel.
Abstract: This paper suggests a very simple, force-based formula that combines four failure modes into one dimensionless equation to govern spot weld failure under general static loading conditions. The four failure modes are shear, rotation, normal and peel. The normal separation mode and the peel mode are corresponding to mode I (opening mode). The tensile/shear mode is mode II (sliding mode), and the in-plane rotation mode is mode III (tearing mode). Test coupons and test fixtures are designed and tested to establish and verify this equation. To further verify this equation, a long difficult to understand automotive spot weld failure problem was studied. Applying finite element-calculated resultant loads to the proposed formula resulted in analytical values that correlated very well with the long time field observed spot weld failures. This analytical prediction reasonably explained the spot weld failure mechanism and provided good design directions to improve the durability of the auto structure.

68 citations

Journal ArticleDOI
TL;DR: In this paper, the authors quantitatively modeled and analyzed the dynamic electrical resistance during resistance spot welding, which is obtained by taking the sum of temperature-dependent bulk resistance of the workpieces and contact resistances at the faying surface and electrode-workpiece interface within an effective area corresponding to the electrode tip.
Abstract: Dynamic electrical resistance during resistance spot welding has been quantitatively modeled and analyzed in this work. A determination of dynamic resistance is necessary for predicting the transport processes and monitoring the weld quality during resistance spot welding. In this study, dynamic resistance is obtained by taking the sum of temperature-dependent bulk resistance of the workpieces and contact resistances at the faying surface and electrode-workpiece interface within an effective area corresponding to the electrode tip where welding current primarily flows. A contact resistance is composed of constriction and film resistances, which are functions of hardness, temperature, electrode force, and surface conditions. The temperature is determined from the previous study in predicting unsteady, axisymmetric mass, momentum, heat, species transport, and magnetic field intensity with a mushy-zone phase change in workpieces, and temperature and magnetic fields in the electrodes of different geometries. The predicted nugget thickness and dynamic resistance versus time show quite good agreement with available experimental data. Excluding expulsion, the dynamic resistance curve can be divided into four stages. A rapid decrease of dynamic resistance in stage I is attributed to decreases in contact resistances at the faying surface and electrode-workpiece interface. In stage 2, the increase in dynamic resistance results from the primary increase of bulk resistance in the workpieces and an increase of the sum of contact resistances at the faying surface and electrode-workpiece interface. Dynamic resistance in stage 3 decreases, because increasing rate of bulk resistance in the workpieces and contact resistances decrease. In stage 4 the decrease of dynamic resistance is mainly due to the formation of the molten nugget at the faying surface. The molten nugget is found to occur in stage 4 rather than stage 2 or 3 as qualitatively proposed in the literature. The effects of different parameters on the dynamic resistance curve are also presented.

67 citations

Journal ArticleDOI
TL;DR: In this paper, the resistance spot welding of steel and aluminium sheets using aluminium clad steel sheets as insert metals was reported and the strength of these joints was of the same order as that of the aluminium joints.
Abstract: The present paper reports the resistance spot welding of steel and aluminium sheets using aluminium clad steel sheets as insert metals. Intermetallic compound layers were formed in the weld zones in direct spot welding of steel sheets to aluminium sheets. Thus, the strength of these joints was lower than that of aluminium to aluminium joints. Intermetallic compound layers were also formed at the steel/aluminium interfaces of the insert metal in welding of steel to aluminium using an insert metal sheet. However, the strength of these joints was of the same order as that of the aluminium joints. The fracture mode of these joints varied with the welding current. The suitable welding current for steel to aluminium joints varied between the values suitable for steel to steel and aluminium to aluminium joints. The fatigue strength of joints using insert metals was somewhat lower than that of the aluminium joints.

67 citations

Journal ArticleDOI
TL;DR: In this article, a model of fatigue crack initiation and early crack growth in resistance spot welds was developed by examining the stress state around a resistence spot weld and a general expression for the structural stress around the weld was formulated that is dependent only on the loading immediately surrounding the weld.
Abstract: — The main objective of this research is to develop a model of fatigue crack initiation and early crack growth in resistance spot welds that is specimen independent. This objective is achieved by examining the stress state around a resistance spot weld. A general expression for the structural stress around the weld is formulated that is dependent only on the loading immediately surrounding the weld. As such, it is specimen independent. An additional objective is to explore the feasibility of applying this fatigue crack initiation model of life estimation using structural response data from finite element analysis (FEA). This numerical technique is often used for evaluating structural integrity of assemblies. Limited verification examples show that the structural stress range as calculated from FEA reaction load data is capable of describing fatigue crack initiation and early crack growth in cyclically loaded resistance spot welds.

67 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023208
2022415
2021355
2020620
2019739
2018744