Mild steel, stainless, aluminum: choosing the material is the first decision in any sheet metal part. Get it wrong and you overpay, or the part corrodes. Here is how to decide.
The three main families
- Mild steel (S235, S275): cheap, strong, easy to weld. Corrodes if not protected.
- Stainless steel (304, 316): corrosion-resistant, clean look, more expensive.
- Aluminum (5754, 5052, 6082): light, naturally corrosion-resistant, mid-priced.
The comparison that matters
| Criterion | Mild steel | Stainless 304 | Aluminum 5754 |
|---|---|---|---|
| Relative cost | 1x | 3 to 4x | 2 to 3x |
| Density | 7.85 | 7.9 | 2.7 |
| Corrosion resistance | Poor (needs coating) | Excellent | Very good |
| Weldability | Excellent | Good | Moderate |
| Bendability | Excellent | Good | Good |
When to choose mild steel
Mild steel is the default choice when cost matters and the part will be protected (painted, galvanized) or used in a dry environment. Structures, frames, brackets, enclosures for indoor use: mild steel does the job for the lowest price. Its strength is excellent and it welds beautifully.
When to choose stainless
Stainless is the choice for corrosive environments, food and medical applications, and parts that stay visible without paint. The 304 grade covers most cases; the 316 grade, with added molybdenum, resists chlorides and is used in marine or chemical environments.
Stainless costs 3 to 4 times more than mild steel. Use it where corrosion resistance is genuinely needed — not by default.
When to choose aluminum
Aluminum wins whenever weight matters: transport, mobile equipment, portable structures. At one third the density of steel, it cuts the weight of a part dramatically. It naturally resists corrosion. The 5754 and 5052 grades bend well; the 6082 grade is stronger but harder to bend.
The decision in one line
- Cost is the priority, part is protected → mild steel
- Corrosion, hygiene, visible finish → stainless
- Weight is the priority → aluminum
DRAWLESS knows the materials
DRAWLESS integrates the properties of every common material: density, bendability, K-factor. When you describe a part, the engine adapts the geometry and the estimate to the chosen material. Change "steel S235" to "stainless 304" in your description and the flat pattern, weight and cost estimate update automatically.