Gas metal arc welding

About: Gas metal arc welding is a research topic. Over the lifetime, 11706 publications have been published within this topic receiving 109555 citations. The topic is also known as: metal active gas welding & GMAW.

Characterization of Joint Quality in Ultrasonic Welding of Battery Tabs

Abstract: Manufacturing of lithium-ion battery packs for electric or hybrid electric vehicles requires a significant amount of joining such as welding to meet desired power and capacity needs. However, conventional fusion welding processes such as resistance spot welding and laser welding face difficulties in joining multiple sheets of highly conductive, dissimilar materials with large weld areas. Ultrasonic metal welding overcomes these difficulties by using its inherent advantages derived from its solid-state process characteristics. Although ultrasonic metal welding is well-qualified for battery manufacturing, there is a lack of scientific quality guidelines for implementing ultrasonic welding in volume production. In order to establish such quality guidelines, this paper first identifies a number of critical weld attributes that determine the quality of welds by experimentally characterizing the weld formation over time. Samples of different weld quality were cross-sectioned and characterized with optical microscopy, scanning electronic microscopy (SEM), and hardness measurements in order to identify the relationship between physical weld attributes and weld performance. A novel microstructural classification method for the weld region of an ultrasonic metal weld is introduced to complete the weld quality characterization. The methodology provided in this paper links process parameters to weld performance through physical weld attributes.Copyright © 2012 by ASME and General Motors

Mobile automated pipeline welding and quality control system

Abstract: A mobile automated pipeline welding and quality control system comprising a gas metal arc welding carriage and a weld data monitor and acquisition unit The welding carriage carries a welding torch, wire feed device for feeding consumable wire to the torch, an oscillator for oscillating the torch and a motorized drive mechanism for moving the carriage about a weldment A controller for the carriage includes digital control circuitry for dosed loop control of the drive, oscillator and wire feed devices By default, the controller operates each device at one of a plurality of pre-programmed nominal speeds selected from a mode table The controller is responsive to drive, oscillation and wire feed speed variation signals under the control of an operator, and varies the speed of each device within speed ranges which are selected to ensure compliance with welding specifications The monitor has voltage and current transducers for measuring current and voltage at the welding torch The controller supplies the monitor with speed data relating to the drive, oscillator and wire feed devices All of this information can be displayed and recorded in the monitors memory In addition, the monitor can compute and display the heat input into the weld based on the detected welding parameters This information allows the operator to make minute adjustments during the welding process to ensure that a weld falls within specifications

A dynamic model of drops detaching from a gas metal arc welding electrode

Abstract: A dynamic model of drop detachment in gas metal arc welding is presented for low and moderate welding currents in an argon-rich plasma. Simulations performed with this model are compared with extensive experimental measurements of constant-current welding images and with limited experimental measurements of pulsed-current welding images. The comparisons indicate that the experimental axial magnetic forces are much less potent than the calculated axial magnetic forces when welding-current transients are not present. To explain this finding the hypothesis that internal flows are able to develop under the relatively quiescent conditions that exist during drop development in constant-current welding is advanced.

Effect of Pulse Parameters on Weld Quality in Pulsed Gas Metal Arc Welding: A Review

Abstract: The weld quality comprises bead geometry and its microstructure, which influence the mechanical properties of the weld. The coarse-grained weld microstructure, higher heat-affected zone, and lower penetration together with higher reinforcement reduce the weld service life in continuous mode gas metal arc welding (GMAW). Pulsed GMAW (P-GMAW) is an alternative method providing a better way for overcoming these afore mentioned problems. It uses a higher peak current to allow one molten droplet per pulse, and a lower background current to maintain the arc stability. Current pulsing refines the grains in weld fusion zone with increasing depth of penetration due to arc oscillations. Optimum weld joint characteristics can be achieved by controlling the pulse parameters. The process is versatile and easily automated. This brief review illustrates the effect of pulse parameters on weld quality.