Reasons for Adding Tungsten to Steel

Steel is widely used in industrial production due to its high strength, corrosion resistance, high temperature resistance, impact resistance, good plasticity and easy processing. However, the performance of steel is not only related to the production process and process parameters, but also to its raw material ratio, raw material type, raw material purity and other factors. In terms of chemical composition, the composition of steel includes carbon (C), molybdenum (Mo), tungsten (W), silicon (Si), manganese (Mn), phosphorus (P), sulfur (S), chromium (Cr), nickel (Ni), vanadium (V), etc., all of which have a certain influence on the properties of steel. Among them, the main reasons for adding tungsten to steel are:

(1) Tungsten is a metal material with high melting point, high specific gravity and high hardness. Because it forms tungsten carbide (WC) with carbon, it can improve the red hardness, thermal strength and wear resistance of steel, making it more suitable for Used as cutting tools and forging dies.

(2) To refine the grains of the steel, the effect of tungsten is stronger than that of chromium, which can significantly reduce the overheating tendency of the steel, thereby improving the strength, toughness and thermal stability of the steel.

(3) The combination of tungsten and molybdenum, silicon and other elements can improve the corrosion resistance and oxidation resistance of steel, and is suitable for the manufacture of heat-resistant steel.

(4) It can improve the yield point, fatigue strength, thermal stability, coercivity and hardenability of steel.

However, it should be noted that the addition of tungsten element will increase decarburization and prevent graphitization, reduce the forge temperature range and thermal conductivity, and if the resulting tungsten carbide is unevenly distributed, it will affect the performance of the steel. Generally speaking, the content of tungsten in alloy structural steel is between 0.3-1.0%; the content of tungsten in heat-resistant non-skinned steel is between 0.3-3.2%; the content of tungsten in alloy tool steel is between 1-18% .

Extended information: Tungsten carbide is a black powder with metallic luster, similar in hardness to diamond, and twice as rigid and dense as steel. It has strong acid resistance and good electrical and thermal conductivity.