Stellite Alloy (Stellite) is a kind of hard alloy can resist various wear and corrosion and high temperature oxidation. That is to say the cobalt chromium tungsten (molybdenum) alloy or cobalt base alloy Stellite Alloy by Americans Elwood Hayness invented in 1907. Stellite alloy is based on cobalt as main ingredient, contains considerable amounts of nickel, chromium, molybdenum, tungsten and a small amount of niobium, tantalum, titanium and lanthanum alloy elements, a kind of alloy occasionally also contains iron. According to the alloy composition is different, they can be made of wire for hardfacing powder, thermal spraying, spray welding process, can also be made of casting and forging and powder metallurgy.
According to the use of classification, can be divided into Stellite stellite alloy wear resistant alloy, corrosion resistance and high temperature alloy stellite alloy in aqueous solution. The general condition is both wear resistant or wear resistant and corrosion resistant performance, some conditions may also require high temperature wear resistance and corrosion resistance, and more in this complex condition, the more it can reflect the advantage of Stellite alloy.
Typical grades of stellite alloy are: Stellite1, Stellite4, Stellite6, Stellite8, Stellite12, Stellite20, Stellite31, Stellite100 etc.. Unlike other high temperature alloy, high temperature alloy with Stellite and matrix by solid phase precipitation in order to strengthen, but the solution has been composed of a few carbide distribution strengthening austenite matrix and FCC matrix. Casting high temperature alloy Stellite is largely rely on carbide strengthening. Pure cobalt crystals are six square (HCP) crystal structures under 417 degrees centigrade, and are converted to FCC at higher temperatures. In order to avoid the occurrence of this change in the stellite alloy when used by virtually all stellite alloy nickel alloy at room temperature to the melting point, so that the temperature range of the tissue stabilization. Stellite alloy has a flat fracture stress temperature relation, but in more than 1000 DEG C is shown to have excellent resistance to hot corrosion under high temperature than the other, it may be because of the high chromium alloy, which is a feature of this kind of alloy.