Arc welding

About: Arc welding is a research topic. Over the lifetime, 25393 publications have been published within this topic receiving 168182 citations.

Effects of Nd:YAG laser + pulsed MAG arc hybrid welding parameters on its weld shape

Abstract: Weld penetration depth, width, reinforcement and reinforcement to width ratio were defined as the factors to evaluate the weld shape. The effects of Nd:YAG laser + pulsed metal active gas (MAG) arc hybrid welding parameters on the weld shape were investigated with bead on plate tests. The results indicated that the laser energy mainly decides the weld penetration and the weld width depends on the arc for a given welding speed. The Nd:YAG laser has some effects on the hybrid weld appearance in varying of laser–arc distance and location of laser focus. The addition of laser energy in pulsed MAG arc welding can greatly increase its welding speed and the arc can improve the absorption of laser energy by workpiece. The test results also show that there is a matching relationship between the optimal laser–arc distance and the welding current for a given laser energy.

Power supply for electric arc welding

Abstract: A power supply connectable to a source of AC line voltage for AC electric arc welding by an AC arc current across a welding gap between an electrode and a workpiece, the power supply comprises a high capacity transformer that converts said line voltage to an AC output voltage, and a rectifier that converts the AC output voltage to a DC voltage between a positive terminal and a common terminal at generally zero volts and a negative terminal and the common terminal. The power supply has a first switch that connects the positive terminal to the common terminal across the gap when a gate signal is applied to the first switch, a second switch for connecting the negative terminal to the common terminal across the gap when a gate signal is applied to the second switch and a pulse width modulator operated for generating pulses at a frequency of at least about 18 kHz. A logic network has a first circuit for directing the pulses to the first switch for a first time, a second circuit for directing the pulses to the second switch for a second time and a controller to alternately operate first and second circuits to create AC arc welding current.

Metal vapour behaviour in thermal plasma of gas tungsten arcs during welding

Abstract: A gas tungsten arc in helium and argon was modelled taking into account the contamination of the plasma by metal vapour from the weld pool. The whole region of gas tungsten arc atmosphere including the tungsten cathode, arc plasma and weld pool was treated using a unified numerical model. A viscosity approximation was used to express the diffusion coefficient in terms of viscosity of shielding gas and metal vapour. The transient two-dimensional distributions of the temperature, velocity of plasma flow and iron vapour concentration were predicted, together with the weld penetration as a function of time for a 150 A arc current at the atmospheric pressure, both for helium and argon welding gases.It was shown that the thermal plasma in gas tungsten arcs is influenced by iron vapour from the weld pool surface and that the concentration of iron vapour in plasma is dependent on the temperature of the weld pool.