Very pure tungsten can be cut with a hacksaw, and can be forged, spun, drawn, and extruded. The impure metal is brittle and can be worked only with difficulty. Tungsten has the highest melting point of all metals, and at temperatures over 1650C has the highest tensile strength. The metal oxidizes in air and must be protected at elevated temperatures. It has excellent corrosion resistance and is attacked only slightly by most mineral acids.
Tungsten carbide is of great importance to the metal-working, mining, and petroleum industries.
Tungsten disulfide is a dry, high-temperature lubricant, stable to 500C. Tungsten bronzes and other tungsten compounds are used in paints. Tungsten occurs in wolframite, scheelite, huebnertie, and ferberite. Twenty one other unstable isotopes are recognized. High-speed tool steels, and many other alloys contain tungsten. Tungsten carbide is of great importance to the metal-working, mining, and petroleum industries.