Arc welding is the process of using an electric arc to generate heat of about 6,500 degrees Fahrenheit, melting the base metals, and creating a pool of molten metal to join the two pieces.

The arc is formed between an electrode and the workpiece. A welding operator moves the electrode along the joint of the pieces being joined. Welding electrodes are lengths of wire or rods connected with your welding machine to create an electric arc. Current passing through this electrode produces an arc, generating enough heat to melt and fuse metal.

Types of Arc Welding Electrodes

The two primary types of electrodes are consumable and non-consumable:

Consumable Electrodes

Consumable electrodes are a crucial component in metal inert gas welding (MIG) and stick welding, officially known as shielded metal arc welding (SMAW). They are also used in a process called flux-cored welding (FCAW).

MIG employs a continuously-fed wire and a shielding gas, such as carbon dioxide, helium, or argon, to protect the metals from contamination. With stick welding, the arc is created between a flux-coated metal rod and the workpiece. As the metal melts, it forms a weld pool, while the flux melts to form a shielding gas. 

Similar to MIG welding, the gas-shielded flux-cored wires used in flux-cored welding eliminate the need for external shielding gas. This welding technique works well for outdoor welding and thicker metals.

Non-Consumable Electrodes

The most common non-consumable electrode welding method is tungsten inert gas welding (TIG). Also referred to as gas tungsten arc welding (GTAW), TIG generates an electric arc with a non-consumable tungsten electrode and protects the weld from air contamination with shielding gas. TIG is the preferred welding method when quality and precision are paramount.

Plasma arc welding (PAW) also uses an electric arc between a non-consumable electrode and a base metal. This method contrasts with TIG welding in that the electrode is placed in a torch, and the plasma-forming gas is separated from the shielding gas, producing narrow and deep welds.