Step 1: Understanding the Concept:
Steel is primarily an alloy of iron and carbon. "Plain carbon steel" refers to steel where carbon is the primary alloying constituent and no minimum content is specified for other elements like chromium, nickel, or molybdenum.
Step 2: Key Formula or Approach:
Classify plain carbon steels by their carbon weight percentage:
Low Carbon Steel (Mild Steel):<0.3% C
Medium Carbon Steel: 0.3% – 0.6% C
High Carbon Steel:>0.6% C
Step 3: Detailed Explanation:
The properties of plain carbon steel—such as hardness, tensile strength, and ductility—are almost entirely determined by the amount of carbon present. Increasing the carbon content increases the hardness and strength but decreases the ductility and weldability. Because they do not contain significant amounts of other alloying elements, the carbon percentage is their primary distinguishing feature.
Step 4: Final Answer:
Plain carbon steels mainly differ from each other in terms of carbon content.