Molybdenum
In addition to carbide, tungsten partly dissolves into iron to form solid solution. Its effect is similar to that of molybdenum, and its general effect is not as significant as that of molybdenum. The main pattern of tungsten in steel is to increase tempering stability, red hardness, thermal strength and wear resistance due to carbide formation. Therefore, it is mainly used in tool steel, such as high speed steel, hot forging die steel and so on.
Tungsten forms refractory carbides in high-quality spring steel. When tempered at higher temperature, it can alleviate the aggregation process of carbides and maintain high-temperature strength. Tungsten can also reduce the overheat sensitivity, increase hardenability and hardness of steel. After hot rolling, 65simnwa spring steel has high hardness after air cooling. The spring steel with a section of 50mm2 can be quenched in oil, and can be used as an important spring bearing heavy load, heat resistance (no more than 350 ℃) and impact. 30W4Cr2VA high strength heat resistant high quality spring steel has high hardenability. After quenching at 1050 ～ 1100 ℃ and tempering at 550 ～ 650 ℃, the tensile strength reaches 1470 ～ 1666Pa. It is mainly used for manufacturing springs used in high temperature (no more than 500 ℃).
As the addition of tungsten can significantly improve the wear resistance and machinability of steel, tungsten is the main element of alloy tool steel.
