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.

A review on friction-based joining of dissimilar aluminum–steel joints

Abstract: This article showcases details on enumerative information of dissimilar aluminum (Al) to steel welds manufactured using different friction-based welding processes with an emphasis on the description of the manufacturing process, influence of parameters, microstructural variations, formation of intermetallic compounds (IMCs), and variations in mechanical properties. Friction-based welding processes such as friction welding, friction stir welding, hybrid friction stir welding, friction stir spot welding, friction stir spot fusion welding, friction stir scribe welding, friction stir brazing, friction melt bonding, friction stir dovetailing, friction bit joining, friction stir extrusion, and friction stir assisted diffusion welding are analyzed for the formation of dissimilar Al–steel joints. It can be summarized that friction-based joining processes have great potential to obtain sound Al–steel joints. The amount of frictional heat applied decides the type and volume fraction of IMCs that subsequently affects mechanical joint properties. Process variations and novel process parameters can enhance joint properties.

Deformation behaviour of spot-welded high strength steels for automotive applications

Abstract: Numerical simulation of component and assembly behaviour under different loading conditions is a main tool for safety design in automobile body shell mass production. Knowledge of local material behaviour is fundamental to such simulation tests. As a contribution to the verification of simulation results, the local deformation properties of spot-welded similar and dissimilar material joints in shear tension tests were investigated in this study for a TRIP steel (HCT690T) and a micro-alloyed steel (HX340LAD). For this reason, the local strain distribution was calculated by the digital image correlation technique (DIC). On the basis of the hardness values and microstructure of the spot welds, the differences in local strain between the selected material combinations are discussed. Additionally, the retained austenite content in the TRIP steel was analysed to explain the local strain values. Results obtained in this study regarding similar material welds suggest significant lower local strain values of the TRIP steel HCT690T compared to HX340LAD. One reason could be the decrease of retained austenite in the welded area. Furthermore, it has been ascertained that the local strain in dissimilar material welds decreases for each component compared with the corresponding similar material weld.

Expulsion detection system for resistance spot welding based on a neural network

Abstract: Resistance spot welding is one of the most important welding procedures. Therefore, a strong emphasis is placed on the quality of the welds. One of the phenomena that causes the deterioration in quality is the eruption of molten material, the so-called expulsion. Expulsion can be avoided with appropriate parameter selection. The problem, however, lies in the fact that the best quality welds are made with parameters just below the expulsion area. Therefore, for any successful control scheme an efficient and dependable expulsion detection is needed. A linear vector quantization (LVQ) neural network system is proposed to achieve this goal. The network is analysed with different sensor combinations and different materials. The results show that the LVQ neural network is able to detect the expulsion in different materials. The experiment also points to the welding force signal as the most important indicator of the expulsion occurrence.

Friction Processing Technologies

Abstract: The utilisation of friction as an efficient thermo-mechanical source to both weld and process materials in the solid phase has come a long way since the first patent filing by Bevington in the late 19th Century. It is fair to say that up until the early Eighties, rotation was the primary motion used to practice friction welding for most applications on a commercial basis, certainly for metals. Work by Searle in the Seventies with orbital motion gathered momentum to permit the welding of non-round parts. This was followed by the development of a dedicated machine to use linear reciprocating motion for joining. From the late Eighties onwards an ‘explosion’ of friction based technologies were conceived and promoted. Such processes include friction taper stud and stitch welding, friction hydro pillar processing, friction extrusion, friction plunge welding, third-body friction welding and not least friction stir welding, which must be regarded as the major step change for the welding of aluminium and its alloys. Sandwiched between motion and process developments came more detailed studies of friction surfacing and friction seam welding, which were both the subject of a patent filing in 1941. The aforementioned processes are reviewed and selected processes discussed more fully. Attention is drawn to the applications, industrial sectors, etc., to which they can be aligned.

Controller for spot welding

Abstract: A controller for a spot-welding machine compares the temperature evolution at a site at which a spot weld is being made to a standard thermal history stored in a digital read/write memory in controlling the welding current for the weld. Standard thermal histories can be generated and written into the memory as needed by an operator of the welding machine to take into account changes in operating conditions. The temperature evolution of the spot-welding operation is monitored by detecting radiant energy whose intensity provides a measure of a temperature of the weld. Phosphorescent radiation from a thermographic phosphor located in a welding tip of the welding machine and thermal infrared radiation are preferred for monitoring the temperature evolution of the spot-welding operation.