Definition - What does Hardfacing mean?
Hardfacing is a metalworking technique involving the application of a cladding or coating of material designed to resist wear. The welded surface is much more resistant to wear and abrasion. This process improves maintenance costs by providing a longer lifetime for wear parts.
Because hardfacing is a deposition of hard and wear-resistant material on a metal surface by welding, it may be applied to a new part during production to increase its wear resistance, or it may be used to restore a worn-down surface.
Hardfacing is also known as hardsurfacing.
Corrosionpedia explains Hardfacing
Hardfacing is the deposition of thick coatings of hard, wear-resistant materials on a component surface that is subject to wear. The processes generally used to apply the hardfacing layer are:
- Thermal spraying - Preferred for applications requiring minimal thermal distortion of the component and good process control. Typical hardfacing materials deposited by thermal spraying include cermets. These coatings are applied to a thickness of about 0.3mm.
- Spray-fuse coatings - Referred to as self-fluxing overlay coatings. The Ni-Cr-B-Si-C alloy system uses a fuse process.
- Weld hardfacing - Used to deposit very thick (1 to 10mm), dense layers of wear-resistant material with high bond strength.
Commonly applied materials include:
- Cobalt-based alloys
- Nickel-based alloys
- Chromium carbide alloys
Carbon and low-alloy steels with carbon contents of less than 1 percent can be hardfaced. High-carbon alloys may require a special buffer layer. There are several techniques for hardfacing welding:
- Arc welding of electrodes
- Filler rod
- TIG welding
- Laser welding with powders
After deposition by any of the above welding processes, it is often necessary to finish the component surface.
Hardfacing by arc welding is a surfacing operation to extend the service life of industrial components, pre-emptively on new components, or as part of a maintenance program. Significant savings in machine downtime and production costs has meant that this process has been adopted across many industries such as steel, cement, mining, petrochemical and power.
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