Electrodes

In arc welding, an electrode is used to conduct current through a work piece to fuse two pieces together. Depending upon the process, the electrode is either consumable or non-consumable,

Relevance of Electrodes:

The electrode is coated in a metal mixture called flux, which gives off gases as it decomposes to prevent weld contamination.

Introduces deoxidizers to purify the weld.

Causes weld-protecting slag to form

improves the arc stability,

Provides alloying elements to improve the weld quality.

Grade of electrodes:

316l – used mostly in welding molybdenum bearing austenitic alloys containing maximum carbon of 0.003%

308L – predominantly used to weld austenitic stainless steel such as 301, 302, 304, 305

Types of Electrodes.

Consumable and Non Consumable.

The choice between using a consumable and a non-consumable electrode lies between the types of metal that is set up for welding.

Consumable electrodes -… a consumable electrode can melt and mix with the weld creating a stronger bond. Here an electric arc forms between the consumable wire electrode and the work piece metal(s), which heats the work piece metal(s), causing them to melt and join. Example gas metal arc welding or shielded metal arc welding also referred to as MIG metal inert gas welding

Advantages of Consumable electrodes

High productivity leading to higher profit

More welding speed especially on metals – It is much quicker than traditional welding.

It is highly economic.

Applications

Automotive repair.

Rebuilding equipment.

Overlay of wear resistant coating.

Welding pipes.

It can even be used to reinforce the surface of a worn out railroad track.

Non Consumable electrode – are the ones that are not consumed during the process of welding. Here a constant-current welding power supply is used to produces energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma. Example Gas tungsten arc welding also referred to as TIG – Tungsten inert gas welding