Mild Steel vs Carbon Steel
Mild steel is technically a sub-category of carbon steel — specifically low-carbon steel (≤ 0.25% C). "Carbon steel" as a term usually refers to medium and high-carbon grades that are harder, stronger, and less ductile.
Side-by-side comparison
| Attribute | Mild Steel | Carbon Steel |
|---|---|---|
| Carbon content | 0.05–0.25% | 0.30–2.0% |
| Hardness | Low | Medium to high |
| Strength | Moderate | High |
| Ductility | Excellent | Lower (decreases with C content) |
| Weldability | Excellent | Difficult above 0.45% C |
| Heat treatment | Not significantly hardenable | Hardens well with quench/temper |
| Cost | Baseline | 10–30% more |
| Common uses | Sheet metal, structural, fabrication, fasteners | Springs, tools, knives, rails, gears |
When to choose Mild Steel
Use mild steel for general fabrication, sheet metal work, structural sections, and parts that need to be welded or formed easily.
Buy Mild Steel on MetaleMartWhen to choose Carbon Steel
Use carbon steel (medium/high C) where wear resistance, hardness, and strength are critical — tools, blades, springs, axles.
Buy Carbon Steel on MetaleMartFrequently asked questions
Is mild steel a type of carbon steel?
Yes — mild steel is the low-carbon end (0.05–0.25% C) of the carbon steel family.
Can I weld high-carbon steel?
Yes, but pre-heating and post-weld heat treatment are usually required to avoid cracking. Below 0.30% C, normal welding practices work fine.
Which is harder?
Carbon steel — especially after heat treatment, it can reach 60+ HRC. Mild steel rarely exceeds 25 HRC.