Mechanical Engineering - Engineering Materials - Discussion

The correct answer is iron, carbon, and chromium.

The alloy steel you are describing is likely a chromium-molybdenum steel, which is a type of work-hardening steel that contains:

- Iron (base metal)
- Carbon (0.2-0.5%): provides strength and hardness
- Chromium (0.5-2%): provides corrosion resistance and hardenability
- Molybdenum (0.2-1%): provides additional strength and hardenability

This type of steel is often used to make heavy equipment, such as:

- Bulldozer blades
- Bucket wheel excavators
- Earthmoving equipment
- Construction machinery

The other options are not correct because:

- Silicon and manganese are common alloying elements in steel, but they are not the primary elements responsible for work hardening and high-strength applications.
- Magnesium is not typically used as an alloying element in steel.

=> Note that the exact composition of the alloy steel may vary depending on the specific application and manufacturer.

@Shubham, @Pankaj.

By addition of Mn in steel, it reacts with C and form very hard Mn3C or Mn6C at grain boundaries.

This steel is hadfield steel. By annealing, it changes to fully austenite and this increase work hardening property.

So it used in bulldozers, earth moving machinery etc.

Answer is manganese why I am supporting this manganese act as antioxidant element it may resist crack and reacts with sulphur and form magnesium sulphide to avoid crack.

Manganese is a chemical element; it has symbol Mn and atomic number 25.

It is a hard, brittle, silvery metal, often found in minerals in the combination with iron.

The purpose of using manganese is that Mn improves the work hardening of steel which is required to prevent the deformation under large force.

By addition of Mn to the steel is called hadfield manganese steels. When mechanical working done on the material it hardens more and more.

I agree with @Shubham, cr is a wear resistant and generally cr is used along with other alloys to improve wear resistance.

But why not chromium?

Cr also increases strength and resist corrosion answer fatigue.

Best explanation. Thank you all.

It is called hadfield steel.