What is the range of carbon percentages that defines an iron

What is the range of carbon percentages that defines an iron-carbon alloy as steel?

Solution

Carbon steel is steel in which the main interstitial alloying constituent is carbon in the range of 0.12–2.0%.

Generally, carbon is the most important commercial steel alloy. Increasing carbon content increases hardness and strength and improves hardenability. But carbon also increases brittleness and reduces weldability because of its tendency to form martensite. This means carbon content can be both a blessing and a curse when it comes to commercial steel.

Now, any steel in the 0.35 to 1.86 percent carbon content range can be hardened using a heat-quench-temper cycle. Most commercial steels are classified into one of three groups: