Axles are made by heating rods of iron embedded in charcoal powder. The process is known as : — Metallurgy and Isolation of Elements Chemistry Question

💡 Solution & Explanation

Step 1: Case hardening (or carburization) is a process used to harden the outer surface of a metal while leaving the deeper core tough and ductile. Step 2: Heating iron rods embedded in carbonaceous material like charcoal powder causes carbon to diffuse into the outer layer of the iron, converting it to high-carbon steel. Step 3: This process is known as case hardening, matching option (d).