Plasma Arc Welding - Advantages And Uses
This type of welding is similar to gas tungsten arc welding, but is a far more superior technique which yields a better overall result. The electric arc is formed between the electrode and the metal.
This method is different from oxy fuel cutting because in the latter process, oxygen oxidizes the metal and the heat liberated from the exothermic reaction melts the metal, whereas in the new technique the high temperature arc melts the metal. The main disadvantage of oxy fuel cutting was that they could not be employed to weld stainless steel, aluminium, cast iron and other similar alloys since they form refractory oxides. The disadvantage has been eliminated with the introduction of the novel gas metal arc welding techniques.
In plasma arc welding, the shield arc is introduced between the electrode and the torch body which converts the gas into plasma. Plasma is capable of travelling at the velocity rate of sound and attains a steady temperature around 20000 degrees Celsius. Since plasma is a good conductor of electricity, the electric arc will be transferred to the work piece. The plasma arc welder is capable of intense heat which causes the metals to melt and fuse together.
In this type of welding, a tungsten electrode is placed inside a copper nozzle which has a minute opening at the tip. The arc is generated between the electrode and the nozzle tip. This intense temperate causes the formation of plasma, which it transfers the electric arc to the metal to be welded. The equipment is capable of generating a huge amount of heat to a limited area. An advantage is it can be used to weld almost all metals over a wide range of thickness with excellent results.
The equipment can be customized for different applications. This is made possible by changing the current, plasma gas flow rate and the orifice diameter. This type of welding finds wide application in welding thin metals due to the high precision of the work, producing straight and thin welds giving it preference over TIG and MIG welding.
Welding of this nature, including plasma operates at elevated temperatures, is considered to be a high risk job. Accordingly, proper safety measures should be adhered to.
Plasma arc welding is one of the most widely used welding methods today it is especially appreciated because of its efficiency and low operating cost. Even though some laser welding technology which has been introduced recently promises a much more efficient welding technique, plasma arc welding is still considered the better option because of the relatively high operating costs of laser welding equipment.
