Question

To inhibit corrosion, at least 11% chromium is added to steel so that a hard oxide forms on the metal surface; this is known as _________________

(a) ironless steel

(b) cast iron

(c) hard iron

(d) stainless steel

I have been asked this question by my school principal while I was bunking the class.

This interesting question is from Steel and Iron Work in section Rules and Methods of Measurement of Civil Engineering Drawing

Answer 1

Correct option is (d) stainless steel

To elaborate: Stainless steels are notable for their corrosion resistance, which increases with increasing chromium content. Molybdenum additions increase corrosion resistance in reducing acids and against pitting attack in chloride solutions. Thus, there are numerous grades of stainless steel with varying chromium and molybdenum contents to suit the environment the alloy must endure.