Oxidation takes place when oxygen in the air reached the hot tungsten.
Experiment conducted by University of Utah's Department of Metallurgical Engineering, under JP Bauer, DW Bridges and WM Fassell, Jr., found that tungsten rod oxidize linearly in oxygen from 600°C to 850°C at oxygen pressures ranging from 20 to 50 psia. Oxidation rate increase with increased oxygen pressure at 750°C to 850°C.
You can find tungsten at work whenever the heat's on. Because no other metal can compare with tungsten when it comes to heat resistance. Tungsten has the highest melting point of all metals and is therefore also suitable for very high-temperature applications. It is also characterized by a uniquely low coefficient of thermal expansion and a very high level of dimensional stability.
Learn more about the properties of tungsten at Plansee.com.
Of interest, light bulbs give off light by pumping electric current through a thin tungsten filament. The filament heats and gives off light. Find out why do light bulbs burn out just as they’re turned on at io9.com.