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Geographe carry out various thermal processes under precisely controlled conditions to improve the physical and mechanical properties of ferrous and non-ferrous materials to give improved physical and mechanical properties.  Automated heat treatment facilities provide a level of standardised quality.  These processes include Gas Carburising, Nitro-Carburising, Induction Hardening and Quench and Tempering.

Gas Carburising
The gas carburising process at Geographe is carried out in computer controlled fluid bed heat treatment furnaces using natural gas as the source of carbon enrichment. The process is carried out by introducing natural gas into the furnace for a sufficient length of time for the carbon to diffuse into the steel component. On completion of the diffusion cycle the load is quenched in oil to harden the surface. Components, such as, gears, bushes, wear plates and pins are commonly gas carburised to a hardness of approximately 60 HRc.

Nitro-Carburising
Nitro-Carburising is used to improve the wear characteristics of steels of appropriate chemistry and physical state. Nitro-carburising utilises active nitrogen from anhydrous ammonia and small quantities of carbon from natural gas to form nitrides and carbides on the surface of the steel. Case depths are typically very thin, less than 0.10mm, and the process, when used for improving wear properties, is only suited to light load anti-scuffing applications.

Induction Hardening
The induction hardening process involves heating a suitable ferrous material by electromagnetic induction and immediately quenching the component to harden the surface.  This is achieved by passing a current through an inductor along the surface of the part that requires hardening.  The current is usually produced by a high frequency generator in the range of 1-10 kHz, although lower frequencies may be used for through hardening large sections.  By varying the rate of travel, the frequency of the current, and the quenchant flow rate, the depth and hardness of the case can be controlled very accurately. This accuracy is further increased by rotating the work-piece during the process. All induction hardened products must be tempered either by induction or in a temper furnace.  This tempering improves toughness by up to 50% and greatly reduces the risk of in-service failure.