A steel containing 16 to 18% chromium and about 0.12% carbon is called

Solution (By Examveda Team)

The correct answer is Option A: Ferritic stainless steel.
Let's break down why:

Stainless steels are a family of steels known for their corrosion resistance.
This resistance comes mainly from the presence of chromium (Cr).

There are different types of stainless steel, and they're classified based on their microstructure (the arrangement of atoms within the metal).

* Ferritic stainless steel:
* Contains 12 to 30% chromium and a low amount of carbon (typically less than 0.1%).
* They are magnetic and cannot be hardened by heat treatment.
* The given composition of 16 to 18% chromium and about 0.12% carbon fits this description.

* Austenitic stainless steel:
* Contains chromium (typically 16-26%) and nickel (typically 6-22%).
* Nickel is a key element in Austenitic stainless steel which makes them non-magnetic in nature.
* They are generally more corrosion resistant and easier to weld than ferritic stainless steels.
* The question does not include nickel so it can't be Austenitic stainless steel.

* Martensitic stainless steel:
* Contains chromium (typically 11.5-18%) and a moderate amount of carbon (typically 0.1-1.2%).
* They can be hardened by heat treatment.
* The carbon content in the question is relatively low for a typical martensitic stainless steel.

* Nickel steel:
* This is a general term for steel alloyed with nickel.
* While nickel can improve some properties of steel, it doesn't define the type of stainless steel in this case.

Therefore, a steel with 16 to 18% chromium and about 0.12% carbon is most accurately described as Ferritic stainless steel.