Introduction
S235 and DC01 are two popular structural steel grades, differing mainly in production process and mechanical properties.
Rolling Process Comparison
S235 - Hot Rolled
- Hot rolling at temperatures above 1000°C
- Surface covered with scale (iron oxide)
- Lower dimensional accuracy (tolerances ±0.5mm)
- Lower internal stresses
- Thicknesses from 1mm and up
- Lower production cost
DC01 - Cold Rolled
- Cold rolling at room temperature
- Clean, smooth surface without scale
- High dimensional accuracy (tolerances ±0.1mm)
- Higher internal stresses (strain hardening)
- Typical thicknesses 0.5-3mm
- Higher production cost
Mechanical Properties
| Property | S235 (Hot Rolled) | DC01 (Cold Rolled) |
|---|---|---|
| Yield Strength | 235 MPa (min) | 140-280 MPa |
| Tensile Strength | 360-510 MPa | 270-410 MPa |
| Elongation | 26% (min) | 28% (min) |
| Hardness | Lower | Higher |
| Weldability | Very good | Very good |
| Bendability | Very good | Excellent |
Surface Appearance
- S235: Rough surface, dark scale, visible roll marks, requires sandblasting or cleaning before painting
- DC01: Smooth, bright metallic surface, ready for coating or painting, high aesthetic quality
When to Choose S235
- Welded constructions - frames, supports, load-bearing structures
- Thickness > 3mm (DC01 rarely available above 3mm)
- Budget projects
- Hidden elements where aesthetics are unimportant
- High load requirements
- Elements without coatings
When to Choose DC01
- Painted elements - smooth surface for coating
- Thin sheets 0.5-2mm
- Precise bending with minimal springback
- Decorative elements
- Device enclosures
- Hot-dip galvanizing - clean surface for better adhesion
Typical Thickness and Prices
- S235: 1.0, 1.2, 1.5, 2.0, 2.5, 3.0, 4.0, 5.0, 6.0, 8.0, 10.0 mm+
- DC01: 0.5, 0.6, 0.7, 0.8, 1.0, 1.2, 1.5, 2.0, 2.5, 3.0 mm (rarely above 3mm)
- Price for 2mm sheet: S235 ~140 PLN/m², DC01 ~160 PLN/m² (+14%)
Processing and Finishing
- S235: Black (with scale), sandblasted, powder-coated, hot-dip galvanized
- DC01: Raw bright surface, powder-coated, electro-galvanized, phosphated
Bending and Forming
- S235: Minimum bend radius 1× thickness, higher springback, risk of cracking on small radii
- DC01: Minimum bend radius 0.5× thickness, lower springback, better ductility for deep drawing
Dimensional Tolerances
- S235 (EN 10051): ±0.5mm thickness, ±3mm width
- DC01 (EN 10131): ±0.1mm thickness, ±1mm width
Common Selection Mistakes
- Choosing S235 for painting - requires sandblasting
- Choosing DC01 for thick welded structures (>3mm) - S235 is cheaper and more available
- Expecting smooth surface from S235 - DC01 should be chosen for smooth surfaces
Summary - Which Steel to Choose
| Criteria | Choose S235 | Choose DC01 |
|---|---|---|
| Thickness | > 3mm | < 3mm |
| Application | Load-bearing structures | Enclosures, panels |
| Finishing | No coating or hot-dip galvanizing | Painting, electro-galvanizing |
| Aesthetics | Not important | Important |
| Budget | Limited | Flexible |
Both steel grades have their place in industry – the key is to match the material to the application.