In Tungsten inert gas (TIG ) welding, also known as gas tungsten arc welding (GTAW), an arc is drawn between a non-consumable tungsten electrode and the workpiece. The electrode, the arc and the weld-pool are protected from the atmosphere with an inert shielding gas. For manual welding the hardfacing material is in the form of a rod. Advantages of the TIG process include simple manual operation and good control of the welding arc. The process can also be mechanised, in which case a manipulator is used to move the workpiece in relation to the welding torch and the hardfacing rod or wire.
Advantages:
- Manual operation
- Can be mechanised
- Low dilution
Oxy-fuel welding (commonly called oxy-acetylene welding, oxy welding, or gas welding) are processes that use fuel gases (or liquid fuels such as gasoline) and oxygen to weld metals.
Rods are also used for hardfacing with the oxy-acetylene welding process. With the correct operation, a very low level of iron dilution can be achieved in the overlay.
Manual metal arc welding (MMA or MMAW), also known as shielded metal arc welding (SMAW), flux shielded arc welding or informally as stick welding, is a manual arc welding process that uses a consumable electrode covered with a flux to lay the weld. In this process an arc is drawn between a coated consumable electrode and the workpiece. The metallic core-wire is melted by the arc and is transferred to the weld-pool as molten drops. The electrode coating also melts to form a gas shield around the arc and the weld pool as well as a slag on the surface of the weld-pool, thus protecting the cooling weld-pool from the atmosphere. The slag must be removed after each layer.
Manual Metal Arc welding is still a widely-used hardfacing process. Due to the low cost of the equipment, the low operating costs of the process and the ease of transporting the equipment, this flexible process is ideally suited to repair work.
Advantages:
- Flexible
- Low cost
- Mobile
- Ideal for repairs
