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.
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TL;DR: The average absorptances determined optically are compared with calorimetrically determined values, and it is found that the calorimeter severely underestimates the absorbed energy due to mass lost during the spot weld.
Abstract: High-irradiance lasers incident on metal surfaces create a complex, dynamic process through which the metal can rapidly change from highly reflective to strongly absorbing. Absolute knowledge of this process underpins important industrial laser processes such as laser welding, cutting, and metal additive manufacturing. Determining the time-dependent absorptance of the laser light by a material is important, not only for gaining a fundamental understanding of the light-matter interaction but also for improving process design in manufacturing. Measurements of the dynamic optical absorptance are notoriously difficult due to the rapidly changing nature of the absorbing medium. These data are also of vital importance to process modelers, whose complex simulations need reliable, accurate input data; yet, there are very few available. In this work, we measure the time-dependent, reflected light during a 10-ms laser spot weld using an integrating-sphere apparatus. From this, we calculate the dynamic absorptance for 1070-nm-wavelength light incident on 316L stainless steel. The time resolution of our experiment (less than 1 μs) allows the determination of the precise conditions under which several important physical phenomena occur, such as melt and keyhole formation. The average absorptances determined optically are compared with calorimetrically determined values, and it is found that the calorimeter severely underestimates the absorbed energy due to mass lost during the spot weld. Weld-nugget cross sections are also presented to verify our interpretation of the optical results, as well as to provide experimental data for weld-model validation.
44 citations
Patent•
06 Mar 2014
TL;DR: In this article, an indirect spot welding is proposed for welding members including at least two overlapping steel sheets that have a ferrite phase as the main phase by holding a welding electrode (23) against a steel sheet (21) from one side while applying pressure with the electrode, attaching a feeding point (24) to the steel sheet at the other side at a location remote from the welding electrode, and allowing current to flow between the electrode and the feeding point, regardless of the rigidity of the members.
Abstract: This indirect spot welding is for welding members including at least two overlapping steel sheets that have a ferrite phase as a main phase by holding a welding electrode (23) against a steel sheet (21) from one side while applying pressure with the electrode (23), attaching a feeding point (24) to a steel sheet (22) at the other side at a location remote from the electrode (23), and allowing current to flow between the electrode (23) and the feeding point (24). This welding includes contacting magnetic rigid bodies (26-1, 26-2) to a peripheral area of the electrode (23) from the one side against which the electrode (23) is held and securing an overlapping region in the peripheral area of the electrode (23) by a magnetic force produced by the rigid bodies (26-1, 26-2), thereby obtaining a weld having fully satisfactory strength, regardless of the rigidity of the members.
43 citations
TL;DR: In this paper, the relationship between weld fusion zone attributes and failure behavior was studied. But, it was observed that increasing fusion zone size is accompanied by an increase in load carrying capacity and energy absorption capability.
Abstract: Resistance spot welding was used to join austenitic stainless steel sheets. Mechanical properties of the spot welds were evaluated using tensile shear test. Mechanical behaviour was described by peak load, failure energy and failure mode. The relationship between weld fusion zone attributes and failure behaviour was studied. Generally, it was observed that increasing fusion zone size is accompanied by an increase in load carrying capacity and energy absorption capability. However, when expulsion occurs, despite almost constant weld fusion zone size, energy absorption capability reduces significantly due to increase in electrode indentation depth. Considering the failure location and failure mechanism in the tensile shear test, minimum required fusion zone size to ensure the pull-out failure mode was estimated using an analytical model. According to this model, in addition to sheet thickness, ratio of fusion zone hardness to failure location hardness is the key metallurgical factor governing failur...
43 citations
TL;DR: In this article, the effect of electromagnetic stirring (EMS) on the nugget formation, microstructure, and mechanical properties of magnesium alloy resistance spot weld (RSW) was investigated.
43 citations
Patent•
30 Apr 1984
TL;DR: In this paper, an integral spot resistance welding gun and transformer unit are mounted on an end of a robot arm actuator to provide a mounting for a sliding gun cylinder having a piston connected to one of the lower jaw electrodes.
Abstract: An assembly is provided for mounting on an end of a robot arm actuator as an integral spot resistance welding gun and transformer unit. A gun slide support bracket is connected to the transformer and serves to provide a mount for a sliding gun cylinder having a piston connected to one of the jaw electrodes. The lower jaw is removably connected to the cylinder. Roller shunts are used to provide electrical connection between secondary terminals on the transformer and the two electrodes. A proximity switch assembly is advantageously utilized to provide signals to the robot controller indicating a fully retracted position of the jaws.
43 citations