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.

Resistance and friction stir spot welding of DP600: a comparative study

Abstract: Efforts to reduce vehicle weight and improve crash performance have resulted in increased application of advanced high strength steels (AHSS) and a recent focus on the weldability of these alloys. Resistance spot welding (RSW) is the primary sheet metal welding process in the manufacture of automotive assemblies. Friction stir spot welding (FSSW) was invented as a novel method to spot welding sheet metal and has proven to be a potential candidate for spot welding AHSS. A comparative study of RSW and FSSW on spot welding AHSS has been completed. The objective of this work is to compare the microstructure and mechanical properties of Zn coated DP600 AHSS (1 . 2 mm thick) spot welds conducted using both processes. This was accomplished by examining the metallurgical cross-sections and local hardnesses of various spot weld regions. High speed data acquisition was also used to monitor process parameters and attain energy outputs for each process. Results show a correlation found among microstructure, failure loads, energy requirements and bonded area for both spot welding processes.

Factors affecting the properties of friction stir welded aluminum lap joints

Abstract: Friction stir welding (FSW) is a solid-state joining process invented at The Welding Institute (TWI) in 1991. The ability to produce high-quality welds in high-strength aluminum alloys sets FSW apart from typical fusion welding techniques. The process has mainly been used for making butt joints in aluminum alloys. Development of FSW for use in lap joint production would expand the number of applications that could benefit from the technique. In this study, an extensive investigation was carried out on FSW lap joints, including interface morphology and mechanical properties. Two materials, Alclad 2024-T3 and AI7075-T6, sheet materials commonly used in the aerospace industry, were joined. Welding variables included welding speed, rotational speed and, of particular importance, tool dimensions. Examination of metallographic cross sections and failure locations showed a critical sheet interface present in all welds. Consequently, a second weld pass was added to eliminate the critical sheet interface. Results indicated FSW lap joints may, on the basis of strength, potentially replace other joining processes like resistance spot welding and riveting.

Dissimilar laser welding of AISI 316L stainless steel to Ti6–Al4–6V alloy via pure vanadium interlayer

Abstract: Successful continuous laser joining of AISI 316L stainless steel with Ti6Al4V titanium alloy through pure vanadium interlayer has been performed. Three welding configurations were tested: one-pass welding involving all three materials and two pass and double spot welding involving creation of two melted zones separated by remaining solid vanadium. For the most relevant welds, the investigation of microstructure, phase content and mechanical properties has been carried out. In case of formation of a single melted zone, the insertion of steel elements into V-based solid solution embrittles the weld. In case of creation of two separated melted zones, the mechanical resistance of the junction is determined by annealing of remaining vanadium interlayer, which can be witnessed by observing the increase of grain size and decrease of UTS. The two pass configuration allows attain highest mechanical resistance: 367 MPa or 92% of UTS of annealed vanadium. Double spot configuration produces excessive heat supply to vanadium interlayer, which results in important decrease of tensile strength down to 72% of UTS of annealed vanadium. It was found that undesirable σ phase which forms between Fe and V is not created during the laser welding process because of high cooling rates. However, the zones whose composition corresponds to σ homogeneity range are crack-susceptible, so the best choice is to reduce the V content in steel/vanadium melted zone below σ phase formation limit. In the same time, the proportion between V and Ti in Ti6Al4V/vanadium melted zones does not influence mechanical properties as these elements form ideal solid solution.