Build Daily

Equipment And Tools

August 12, 2017 18:08

The arc - how does it work ?

welding arc: the nature of the phenomenon

it easier to get the discharge contributes to the heating of materials, closing for a short time and gradually moving apart electrodes.Qualitative methods produce a discharge can be considered a breakthrough in electric discharge gap breakdown as a result of a sharp rise in short-electrode voltage.Such stabilizer arc occurs under conditions of atmospheric pressure standards, thanks to the spark discharge.

welding or electrical arc is formed through the passage of electric current through a gas medium in the welding or cutting area.The discharge between the electrodes is the most advanced form of discharges in gases.It is characterized by low voltage and a large amount of current.The structure of the welding arc is such that in its space there is a very high ionization gas.

In the role of the cathode performs welding electrode, the anode - the processed material passes between the pole arc, surrounded by flame welding.

ionizable gas in the discharge column has a bright glow, harmful to the eyes.The axial portion of the arc column temperature develops from six to ten thousand degrees centigrade.The main factor is the ionization is such a high temperature, it is supported by the energy of the inflow powering circuits.

welding arc and its properties - why be careful?

discharge voltage - in fact, the inter-electrode voltage - depends on the distance between electrodes, that is, on which are indicators of the arc length, current, welding electrode size, physical properties and nature (composition) of the gas medium in the arc zone.

arc and its properties are controlled by adjusting interelectrode distances (0.01 to 10 mm), the current source power voltage (one-half to three thousand amperes), gas pressure (up to one kgf / cm2), the shape and size of the electrodes, the protection of inert gases of the combustion zone, compressing the arc and in many other ways.

Thermal power, which has an electric arc, is incredible, it takes a range of ten to hundreds of thousands of watts.And its concentration is from one hundred thousand to hundreds of watts per cubic centimeter.The capacity of such a wide range allow to use the discharge for welding and cutting of various metals with a thickness of a few hundredths of millimeters to tens of centimeters in one or more passes.

Forms and types of welding arcs are extremely diverse.Discharge may occur at any pressure gases can have a voltage range from a few to several thousand volts.The arc generated between the electrodes irrespective of DC or AC voltage is applied.This is understandable, since the time of occurrence of discharge is extremely small, in each positive half cycle of one of the electrodes acts as a cathode, and the second - the anode.If you change the half-periods of the electrodes "change" polarity.

arc discharge can occur at any gas pressure difference between the electrode potentials, DC or AC voltage electrode.A feature characteristic of the arc is very high cathodic current density along with low voltage.

general, dependence, which shows the voltage and current of the arc in the discharge, has an amazing feature: with increasing current voltage drops.They talk about the incident current-voltage characteristic, which means that with an increase in the discharge current falls and the resistance in the arc gap, and stress, which explains the need for ballast resistors to stabilize the discharge.

Power supplies arc - where we see them use?

And most importantly - practical application .Power supply of the arc, or machines for welding, as is clear, can work for direct and alternating current, and therefore are of the appropriate type.In this case the cathode (electrode negative polarity) becomes an electrode, but the work surface act as an anode.

When reverse polarity on the electrode is positive potential.The welding technique may be employed which melt and non-consumable (coal, tungsten) electrode.Protecting welding zone can be pairs of electrode fluxes, fed gases, dusts on the wires.

and how to: still widely used manual welding, semi-mechanized welding, full automatic.According to this acronym, respectively: MMA (manual), MIG / MAG (semi-automatic), the TIG (argon arc).But it is possible to write another couple of articles, but the welding arc, perhaps, set out everything.