Mechanical Engineering - Engineering Materials - Discussion

The correct answer is: Manganese.

Manganese (Mn) is added to low-carbon steels to:

1. Prevent porosity: Manganese combines with sulfur to form manganese sulfide, which reduces the formation of pores and improves the steel's density.
2. Improve hot-working properties: Manganese helps to reduce the steel's susceptibility to hot-shortness, making it easier to forge and shape.
3. Enhance strength and hardness: Manganese is a solid-solution strengthener, increasing the steel's strength and hardness.

The other options are not accurate:

- Sulphur (S): Sulphur can contribute to porosity and hot-shortness in steel, so it's not added to prevent porosity.
- Phosphorus (P): Phosphorus is added to steel to improve its machinability, but it can also increase the risk of porosity and embrittlement.
- Silicon (Si): Silicon is added to steel to improve its electrical properties, corrosion resistance, and high-temperature properties, but it's not typically added to prevent porosity in low-carbon steels.

The specific addition of manganese or other elements depends on the steel grade, application, and desired properties.

Silicon reacts with the oxygen present in the steel. Thus the porosity decreases.

I think, the correct option is manganese.

Porous - Tiny holes.

What is porous? Can anyone define?