scispace - formally typeset
Search or ask a question
Topic

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.


Papers
More filters
Proceedings ArticleDOI
14 Aug 2001
TL;DR: In this article, the use of dynamic weld resistance for real-time monitoring and control of resistance spot welds is proposed, and a reliable technique for estimating the dynamic resistance profiles is presented.
Abstract: The real time monitoring and control of resistance spot welds is a problem of critical importance in automotive and many other manufacturing industries. One of the major problems faced by the process control engineers today is the lack of a reliable, low-cost, nondestructive technique for identifying bad welds and predicting weld strengths in real time. This paper proposes the usage of dynamic weld resistance for the above tasks. A reliable technique for estimating the dynamic resistance profiles is presented, and its usefulness in detecting and identifying a variety of bad welds is demonstrated. Both theoretical and experimental results related to estimation, analysis, and classification of resistance signatures are presented. Furthermore, an outline of the overall monitoring and control scheme is included.

28 citations

Journal ArticleDOI
TL;DR: In this paper, the authors evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium-aluminum garnet (Nd) laser beam of a 150"µm spot diameter.
Abstract: A gap is one of the most important issues to be solved in laser welding of a micro butt joint, because the gap results in welding defects such as underfilling or a non-bonded joint. In-process monitoring and adaptive control has been expected as one of the useful procedures for the stable production of sound laser welds without defects. The objective of this research is to evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium : yttrium aluminium garnet (Nd : YAG) laser beam of a 150 µm spot diameter. It was revealed that a 45 µm narrow gap was detected by the remarkable jump in a reflected light intensity due to the formation of the molten pool which could bridge the gap. Heat radiation signal levels increased in proportion to the sizes of molten pools or penetration depths for the respective laser powers. As for adaptive control, the laser peak power was controlled on the basis of the reflected light or the heat radiation signals to stably produce a sound deeply penetrated weld reduced underfilling. In the case of a 100 µm gap, the underfilling was greatly reduced by half smaller than those made with a conventional rectangular pulse shape in seam welding as well as spot welding with a pulsed Nd : YAG laser beam. Consequently, the adaptive control of the laser peak power on the basis of in-process monitoring could reduce the harmful effects due to a gap in micro butt laser welding with a pulsed laser beam.

28 citations

Journal ArticleDOI
TL;DR: In this article, the effect of welding parameters on the tensile strength and fracture mode of joints subjected to tensile/pure shear loading was investigated and defects such as voids, hooks, onion rings and bonding ligament were observed.
Abstract: The goal of investigations included in this paper is to determine the effect of welding parameters on the load capacity of joints and an analysis of the defects in welded single-lap joints obtained by the refill friction stir spot welding method. Furthermore, a study is made of the effect of welding parameters on the tensile strength and fracture mode of joints subjected to tensile/pure shear loading. The overlapping friction stir spot welded joints are made of two 7075-T6 aluminium alloy sheets with different thicknesses (1.6 and 0.8 mm). The evaluation of joint quality was done using optical microscopy and scanning electron microscopy. The load capacity of joints is determined in tensile/pure shear loading tests. Microstructural analysis showed that the important parameters affecting the quality of the joints are the duration of welding and tool plunge depth. Depending on the tool plunge depth, three types of joint damage were observed. The test results indicate that incorrect selection of welding process parameters results in defects such as voids, hooks, onion rings and bonding ligament.

28 citations

Journal ArticleDOI
TL;DR: A pneumatically driven 75kVA spot welder was used to accomplish the entire welding processes, and the welded samples were later subjected to tensile, hardness, and metallurgical tests to relate the diameter growth, loading force during tensile test, failure crack initiation, post-failure crack propagation direction, macro and microstructural changes, and also the hardness changes due to solidification process.
Abstract: Resistance spot welding is an essential welding mechanism for joining two or more metal sheets together in automotive industries. The mechanical assemblies are easily joined at discrete spots using high current flow through the area of concentration. It is easily achieved by compressing the base metals together to a certain pressure using copper electrode caps and allow the high current to flow through the concerned areas. The heat generation due to the current flow causes the metal sheets to be fused and consequently form bonds between base metals. The molten areas of base metals undergo solidification process by itself when the current flow is utterly stopped. Basically, the weld growth in any joint is determined by its process-controlling parameters, particularly the welding current, weld time, electrode force, and electrode tip. In these experiments, the welding current and weld time variations were carried out to characterize the weld growth for three types of joints mainly for stainless steel, mild steel, and both steel mixed joint. A pneumatically driven 75-kVA spot welder was used to accomplish the entire welding processes, and the welded samples were later subjected to tensile, hardness, and metallurgical tests to relate the diameter growth, loading force during tensile test, failure crack initiation, post-failure crack propagation direction, macro and microstructural changes, and also the hardness changes due to solidification process. Assessing the experimental results of 2-mm thickness of materials revealed that the welded areas’ characteristics have been varied from its original states to enriched states, in terms of shearing strength and hardness distribution as well as the microstructural orientation.

28 citations


Network Information
Related Topics (5)
Welding
206.5K papers, 1.1M citations
91% related
Alloy
171.8K papers, 1.7M citations
84% related
Microstructure
148.6K papers, 2.2M citations
83% related
Deformation (engineering)
41.5K papers, 899.7K citations
82% related
Machining
121.3K papers, 1M citations
81% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023208
2022415
2021355
2020620
2019739
2018744