Welding Arc

Welding Arc

 

an electric arc formed in the weld zone joint or in the area of thermal cutting when an electric current passes between electrodes through a gas. A welding arc is the most developed form of electric discharge in gases. It is characterized by a low voltage, a high current, and the presence of an ionized gas in the arc gap. The ionized gas column of the arc discharge glows brightly and has a temperature of 6,000°-10,000°C along the axis of the arc column. The principal factor responsible for ionization is the high temperature maintained by the flow of energy from a power supply.

The voltage of a welding arc, that is, the voltage between the electrode tips, depends mainly on the length of the arc, the strength of the current, the materials and dimensions of the electrodes, the gas composition, and gas pressure. The properties of a welding arc are controlled by changing the length of the arc (between 0.01 and 1 cm), the strength of the current (between 0.5 and 3,000 amperes), the pressure of the gas (between 102 and 105 newtons/m2, that is, between 0.001 and 1 kg force/cm2), or the material, shape, or dimensions of one of the electrodes. In addition, the arcing zone can be shielded by the flow of a gas, or the arc can be compressed.

The thermal power of a welding arc ranges from 10 to 105 watts at concentrations from 102 to 105 watts/cm2. The wide power range makes it possible to use welding arcs to weld and cut various materials ranging in thickness from 0.05 to 100 mm in one or more passes.

G.I. LESKOV

References in periodicals archive ?
Ultraviolet emissions from the welding arc can adversely affect human skin, which is why the demand for welding helmets are growing.
Apart from the above said attributes, major welding gases also plays vital role in defining weld penetration activity, mechanical strength of the finished weld pool and also provides the stability in the welding arc. Commercially there are numerous welding gases available in the market place named carbon dioxide, hydrogen, acetylene, helium, oxygen and argon among others.
where: Q is the effective thermal power for the welding arc; U is the welding voltage; I is the welding current; [eta] is the arc thermal efficiency--0.7 [18]; [a.sub.f], [a.sub.r], b and c are the geometric parameters of the double ellipsoid heat source model, representing the front and rear half shaft length, ellipsoid width and depth of the heat source model, respectively.
Moreover, there are adjustments for the welding arc, shield gas and amperage.
In order to strike the welding arc easily and reduce the amount of deposited metal, the gap was made as narrow as possible.
Your welding arc needs to be protected from ambient air, otherwise, it will splatter.
Born of many an electric spark, A lovely result from a welding arc. Four cows, I met along my way, Hope to see them still for many a day.
"I'm sure it started with the welding arc," he said Friday.
Three design focus areas help to deliver a precise welding arc. The Aspect 375 is available as a standalone machine or as a Ready-Pak[R], which includes a cart, cooler, torch, foot pedal, and all necessary cables and other accessories.
As the GMAW process consists of several subsystems including the power supply, the melting process of the feeding wire, the dynamics of welding arc, the drop dynamics and the material transfer process, as illustrated in Fig.
Thanks to high open circuit voltage and a very stable welding arc, users can weld all types of coated electrode.
It can control welding arc and relative timing relations of short circuit in order to reduce the mutual interference [7].