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.

Formation of molten droplets at a consumable anode in an electric welding arc

Abstract: A theoretical dynamic model has been developed to predict the formation of molten droplets on a moving wire electrode in a gas metal welding arc. Calculations have been made of the droplet shape and size as a function of the welding current by accounting for the electromagnetic pinch effect, surface tension, gravitation and momentum transfer due to motion of the solid wire electrode. Our calculations start with an artificial cylindrical liquid column which, for low currents, develops into a droplet which is close to spherical. However, for currents above about 250 A, the magnetic pinch constricts the column such that a smaller elongated droplet is formed.

Elucidation of the effect of welding speed on melt flows in high-brightness and high-power laser welding of stainless steel on basis of three-dimensional X-ray transmission in situ observation

Abstract: This research was performed with the objective of clarifying the effect of welding speed on melt flows during melt-run welding of SUS304 stainless steel plates with a 6-kW power laser beam on the basis of three-dimensional X-ray transmission in situ observation. As welding speed increased from 25 to 250 mm/s, three kinds of welds characterized by porosity formation and no defects or underfilling due to spatters were produced. The average and the maximum values of measured melt flow velocity were 3 and 10 times higher than the welding speed, respectively. Two kinds of circulation flows at the inlet or the tip of a keyhole were confirmed to control heat transfer in a molten pool. It was found that the circulation flows were so sensitive to the welding speed that bubbles resulting in porosity or spatters were often formed. According to X-ray observation of the formation of spatters with tungsten carbide (WC) tracers, as the melt flow rose along the keyhole wall, the velocity was accelerated from 0.24...

Robust Control of Pulsed Gas Metal Arc Welding

Abstract: A system is developed to control the pulsed gas metal arc welding process. To achieve controlled detachment of the droplet, the welding current is switched from a peak level to a background level to induce droplet oscillation. When the droplet moves downwards, the current is switched back to peak level. The combination of downward momentum of the oscillating droplet and increased electromagnetic force guarantees detachment of the droplet. Instead of adjusting duration of the background current, the waveform of the current is adjusted to control the melting rate of the electrode wire without having to change the transfer frequency. It is found that the dynamic model of the process depends on welding operational parameters, which vary with applications, and therefore it is unrealistic for operators to provide welding machines these parameters as inputs. Hence, welding operational parameters are considered as unfixed and their ranges are used to quantify the resultant uncertainty in the dynamic model. As a result, the process is controlled using a single algorithm at different operational parameters. Experiments verified the effectiveness of the system in overcoming two common variations in welding operational parameters, wire speed and contact tube-to-work distance.

Flux cored arc welding electrode

Abstract: A flux cored arc welding electrode of the type used with external shielding gas wherein the electrode comprises an outer ferrous sheath and a particulate fill material comprising an acidic flux system and alloying agents with the fill material including an arc stabilizer, titanium dioxide, calcium fluoride, an alloying system of 0-4.0 percent by weight of electrode selected from the class consisting of aluminum, silicon, titanium, carbon and manganese. Iron powder controls the percentage of the fill of the electrode and 0.2-1.0 percent by weight of electrode is polytetrafluoroethylene powder.