Carbon Steel

Iron-carbon alloy with carbon up to 2.1% by weight.

Core Principles & Analysis

• The Bessemer process, patented in 1856, first made carbon steel cheap enough for mass-produced rails and structural beams.
• Quenching from the austenite phase traps carbon in hard, brittle martensite, which is then tempered to restore toughness.
• Grades are classified by carbon content — low (below 0.30%), medium (0.30-0.60%), and high (above 0.60%) — spanning wire, axles, and cutting tools.

Specifications & Metrics

• DENSITY: 7.85 g/cm³
• YIELD STRENGTH: 350 MPa
• HARDNESS: 120 HB