Papers by Keyword: Weld Formation

Abstract: A transient mathematical model of the submerged arc welding process with the hydrostatic statement description of its basic physical phenomena has been presented. Radiative heat transfer from the arc column to the surface of the cavity arc is adopted. The heat current flowing from the electrode layer of molten flux on the arc column to the arc cavity surface is taken into account. The energy balance is considered. A comparison between the calculated and experimental data has shown their good correspondence.

Abstract: This paper presents a digital control system for swinging arc narrow gap MAG welding based on double single-chip microcomputers. The control system utilizes a single-chip microcomputer to set and display welding process parameters, and then uses another single-chip microcomputer to realize the control functions that are necessary for the swing arc process, in which the two single-chip microcomputers can exchange data through asynchronous serial communication circuit. Experimental results show that the control system works stably and reliably with strong anti-interference capabilities, and can completely satisfy the requirements of swinging arc narrow gap welding process.

Abstract: An arc-preheating wire GMAW process is proposed in this paper. The welding wire is preheated by a TIG arc to enhance the wire melting. As a result, the welding current is decrease. So the improved GMAW process is aimed at high efficiency welding with a low level heat input. In this paper, the welding system is designed. The wire temperature is measured by a pyrometer. The preheating current effect on the wire temperature is analyzed. In addition, the influence of the wire temperature on the weld current and weld formation are analyzed compared with conventional GMAW. The results show that the preheated wire can significantly enhance the wire melting. By increasing the temperature of the welding wire, the welding current decrease and the heat input of the base metal reduce accordingly. The shallow penetration and large reinforcement height are obtained at the arc-preheating wire GMAW process.

Abstract: FBTIG(Flux Bounded TIG)welding experiments for aluminum alloy were made using five species of single-component activating fluxes, including SiO₂、TiO₂、CaF₂、MgO, and NaCl, which was carried out to investigate the effects of flux gap and activating fluxes on weld formation. The mechanism of increasing welding penetration was analyzed linked with the change of arc shape in FBTIG. The experimental results indicate that five species of single-component activating fluxes can increase weld penetration obviously. Specifically, SiO₂ can increase weld penetration remarkably. When flux gap is 4mm, the D/W (depth/width) ratio of weld for FBTIG welding reaches 0.59. The significant increase of weld penetration is the result of comprehensive effect by arc contraction and reversal of the surface tension gradient in the liquid metal.

Abstract: In order to better understand heat transfer and fluid flow pattern in the weld pool of laser-metal inert gas (MIG) hybrid welding aluminum-alloy process, weld formation mechanism and weld pool dynamic behavior were analyzed by a three-dimensional mathematical model for moving laser- MIG hybrid welding. The temperature and velocity distribution of weld longitudinal section for laser-MIG moving hybrid welding at different moment were discussed to explain flow dynamic behavior in the weld pool. In addition, weld formation mechanism was illustrated by a transverse section heat history evolvement. Moreover, the effects of laser welding parameter and MIG welding parameter on important weld geometry characteristic were quantitatively studied using the mathematical model, and the simulated weld bead geometry parameters were in good agreement with experimental measurements.