High-Carbon Steel is a category of carbon steel containing approximately 0.60% to 1.25% carbon, with controlled amounts of manganese, silicon, sulphur, and phosphorus. The high carbon content enables exceptional hardness, very high strength, superior wear resistance, and excellent edge retention after heat treatment.
Because of these properties, high-carbon steel is widely used in cutting tools, industrial machinery components, springs, dies, wear parts, and high-stress applications where durability and hardness are critical.
Typical Chemical Composition
| Element | Typical Range (%) |
|---|---|
| Carbon (C) | 0.60 – 1.25 |
| Manganese (Mn) | 0.30 – 0.90 |
| Silicon (Si) | ≤ 0.40 |
| Sulphur (S) | ≤ 0.050 |
| Phosphorus (P) | ≤ 0.050 |
| Iron (Fe) | Balance |
Microstructure & Metallurgical Behavior
High-carbon steel typically exhibits:
• Pearlite + cementite structure in annealed condition
• Martensite after quenching
• Tempered martensite after tempering
The increased presence of cementite (iron carbide) is responsible for the high hardness, abrasion resistance, and cutting capability of high-carbon steel.
Key Characteristics
High Hardness & Strength
• Achieves hardness up to ~65 HRC after heat treatment
• Withstands high mechanical loads and surface stresses
Excellent Wear & Abrasion Resistance
• High carbide content resists friction and surface deformation
• Ideal for repetitive contact and sliding applications
Superior Edge Retention
• Maintains sharp cutting edges for long service life
• Used in knives, blades, saws, and precision tools
Lower Ductility & Toughness
• Reduced elongation compared to low and medium carbon steels
• Requires tempering to balance hardness and toughness
Highly Heat Treatable
• Excellent response to annealing, quenching, and tempering
Typical Mechanical Properties
| Property | Typical Range |
|---|---|
| Tensile Strength | 700 – 1200 MPa |
| Yield Strength | 400 – 900 MPa |
| Hardness | 45 – 65 HRC (heat-treated) |
| Elongation | 5 – 15% |
| Impact Toughness | Low to moderate |
| Density | ~7.85 g/cm³ |
| Modulus of Elasticity | ~200 GPa |
Heat Treatment Capabilities
• Annealing – Improves machinability and reduces stresses
• Normalizing – Refines grain structure
• Quenching – Produces very high hardness and strength
• Tempering – Reduces brittleness while retaining hardness
• Surface hardening – Enhances wear resistance in selected areas
Machinability & Weldability
Machinability:
• Fair to good in annealed condition
• Poor in hardened condition
• Requires carbide or coated cutting tools
Weldability:
• Generally poor due to high carbon content
• Preheating and post-weld heat treatment required
• Welding often avoided where possible
Available Forms
✔ Sheets & plates
✔ Coils
✔ Bars (round, square, flat)
✔ Strips & precision strips
✔ Wires & wire rods
✔ Forged blocks & billets
Applications
Tools & Cutting: Knives, blades, chisels, punches, saws, drill bits
Industrial Components: Springs, gears, dies, molds, wear plates
Automotive & Construction: Suspension springs, high-strength wires, agricultural tools
Advantages
✔ Exceptional hardness and wear resistance
✔ Superior cutting and edge retention
✔ High strength under mechanical stress
✔ Cost-effective alternative to alloy steels for wear parts
Limitations
⚠ Lower ductility and impact toughness
⚠ Poor weldability
⚠ Risk of cracking if improperly heat-treated
⚠ Requires corrosion protection
Comparison: Carbon Steel Types
| Feature | Low Carbon | Medium Carbon | High Carbon |
|---|---|---|---|
| Carbon Content | ≤ 0.25% | 0.30 – 0.60% | 0.60 – 1.25% |
| Hardness | Low | Medium | Very High |
| Ductility | High | Moderate | Low |
| Wear Resistance | Low | Moderate | Excellent |
| Weldability | Excellent | Moderate | Poor |
| Typical Use | Structural | Mechanical parts | Tools & blades |
Why Choose High-Carbon Steel
High-carbon steel is chosen when maximum hardness, wear resistance, and cutting performance are required. Its ability to maintain sharp edges, resist abrasion, and perform reliably under high stress makes it indispensable in tooling, industrial machinery, automotive components, construction equipment, and mining applications.