For extreme demands on bond strength and wear resistance we hardface your components with one of a range of welding processes. A high-strength metallurgical bond exists between the welded overlay and the component, ensuring that the coating does not flake off, even under high mechanical loading of the component.
Tungsten Inert Gas (TIG) Welding
- Manual operation
- Can be mechanised
- Low dilution
In TIG (Tungsten Inert Gas) welding, 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. 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
- Low cost
- Ideal for repairs
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.
Plasma Transferred Arc (PTA) Welding
- Highly automated
- High powder utilisation
- Low dilution
- Very wide range of hardfacing materials
The Plasma Transferred Arc process recommends itself due to its ease of automation and thus a high degree of reproducibility of the welded overlays. In addition, because of the highly concentrated heat source, this process benefits from high powder utilisation and can achieve a very low level of iron dilution in the overlay. Because the hardfacing materials are in powder form, it is possible to produce overlays from many different materials and combinations of materials with a wide range of hardness and other properties. For this reason Kennametal Stellite offers the widest range of hardfacing materials for this process.