High Speed Steel Composition

High speed steel (HSS) is a type of tool steel that is commonly used in cutting tools such as drills, taps, and milling cutters. It is known for its excellent hardness, wear resistance, and ability to retain its cutting edge at high temperatures.

The composition of high speed steel typically includes several alloying elements. In the given options, option B is the correct answer, which states that high speed steel contains vanadium 1%, chromium 4%, and tungsten 18%.

Explanation

To understand why option B is the correct answer, let's take a closer look at the alloying elements commonly found in high speed steel:

1. Vanadium (1%):
- Vanadium is a strong carbide former, which means it helps in the formation of hard and wear-resistant carbides in the steel.
- It improves the hardness, toughness, and red hardness (ability to retain hardness at high temperatures) of the steel.
- Vanadium also helps in improving the heat resistance and wear resistance of the steel.

2. Chromium (4%):
- Chromium is another important alloying element in high speed steel.
- It helps in the formation of hard carbides, which contribute to the wear resistance and hot hardness of the steel.
- Chromium also improves the corrosion resistance of the steel.

3. Tungsten (18%):
- Tungsten is one of the most important alloying elements in high speed steel.
- It forms very hard and stable carbides, which greatly contribute to the hardness and wear resistance of the steel.
- Tungsten also enhances the red hardness and high-temperature strength of the steel.

Conclusion

In summary, high speed steel typically contains vanadium, chromium, and tungsten as alloying elements. The correct composition among the given options is option B, which states that high speed steel contains vanadium 1%, chromium 4%, and tungsten 18%. These alloying elements work together to provide the desired properties of high speed steel, including high hardness, wear resistance, and ability to retain cutting edge at high temperatures.