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.

Laminated sheet material

Abstract: 1,094,480. Laminates. METAL CONTAINERS Ltd. March 2, 1965 [March 3, 1964], No. 8967/64. Heading B5N. To improve the tear resistance of laminates of films of polythene, crystalline polypropylene, polyamides, polyvinylidene chloride and polyethylene terephthalate undirectionally oriented films are secured together, with their directions of orientation differing in adjacent plies, by a combination of spot welding and a viscous lubricating material applied in areas not spot welded The lubricating material may comprise 60-80% lubricating oil, 5-15% polythene (M.W. 5000-15,000) and 10-20% polyisobutylene (M.W. 15,000) and may be applied in stripes, 2-20 times the widths of the welds, by printing apparatus, the strips preferably being at an angle bisecting that formed by the directions of orientation in adjacent films. Spot welding may be affected by the application of hot xylene vapour as described in Specification 1,084,721 to the areas between the stripes. The invention may be applied to three-ply laminates of high density polythene the middle layer of which is oriented longitudinally, the outer layers being oriented at 60 degrees to the right and left respectively.

Methods for ultrasonic inspection of spot and seam resistance welds in metallic sheets and a spot weld examination probe system (SWEPS)

Abstract: An external focused ultrasonic beam, non-destructive, open-air, inspection method of sheet metal spot and seam weldments using a probe in combination with motion measurement of the probe over the weldments during inspection without immersion of the material. Reflected ultrasonic waves are received and signals produced and processed or displayed as A-scan, B-scan and C-scan images that are easily recognized. An A-Scan is based on the time-of-flight difference between the outer surface, the weldment and inner and opposite surfaces of the component. B-scan and C-scan indicate the degree of weld fusion and provide data relative to fused thickness and defects sheet metal or welds. A special purpose scanner that enables ultrasonic examination welds. Scanner is pencil like ultrasonic probe with bearing face and position sensing device disposed adjacent a weld position. Scanner collects data for method to determine various characteristics of welded items.

Expulsion monitoring in spot welded advanced high strength automotive steels

Abstract: Although there have been a number of investigations on monitoring and controlling the resistance spot welding (RSW) of low carbon galvanised steels, those of advanced high strength steels (AHSS) are limited. A data acquisition system was designed for monitoring weld expulsion via the measurement of voltage, current, electrode force and displacement and the calculation of resistance. The dynamic resistance, electrode force and tip displacement were characterised and correlated with the phenomenon of expulsion during RSW of dual phase (DP) steel using an ac welder. Two control strategies for DP600 spot welding were proposed on the basis of the rate of change in the dynamic resistance and the electrode force.

Marangoni driven free surface flows in liquid weld pools

Abstract: Extending the weldability of novel materials, and improving the weld quality by tailoring weld microstructures are key factors to obtain the welding techniques demanded in the modern manufacturing industries. This can be done, for example, by feeding chemical elements from a consumable wire into the weld pool during welding. The mixing of chemical components in the weld pool and the resulting post-solidification weld microstructures are influenced by weld pool hydrodynamics. Weld pool hydrodynamics is known to be primarily driven by Marangoni forces acting at the free liquid surface, i.e by tangential gradients in surface tension along the liquid surface due to pronounced lateral gradients in temperature and surface active element concentration. In this research, we develop a Computational Fluid Dynamics model to study steel weld pool hydrodynamics during conduction mode laser spot welding. It is concluded that free surface deformations and instabilities have a strong impact on the fluid flow and heat transfer in weld pools, and should therefore be accounted for in weld pool simulations. With increasing the surface active element concentration and laser power, the weld pool flow becomes highly unstable and can no longer be accurately modeled with a flat surface assumption. More accurate predictions of weld pool physics can be made if the free surface, solidification stage, and three-dimensionality are taken into account. This reduces the need for the use of unphysical parameter fittings widely reported in literature.