Choosing The Right Steel For The Job
Grade codes and material choices explained in plain language — enough detail to have an informed conversation with your fabricator or engineer, without needing a metallurgy degree.
Mild Steel (Carbon Steel)
The workhorse of structural fabrication — strong, weldable, and cost-effective across almost every section profile.
- Good weldability across all common processes
- High strength-to-cost ratio
- Requires protective coating in exposed environments
- Widely available in standard structural sections
- Structural frames
- Trusses & purlins
- Brackets & plate components
- Base plates & gussets
| Grade | Spec | Typical Use |
|---|---|---|
| S355JR | EN 10025-2 | Primary structural members, portal frames |
| A36 | ASTM A36 | General fabrication, brackets, plate |
| Grade 300W | SANS 1431 | Structural sections, columns, beams |
Stainless Steel
Corrosion-resistant alloy for food-grade, hygienic, coastal, and architectural applications where mild steel would corrode.
- High corrosion resistance (grade dependent)
- Hygienic, easy-clean surface finish
- Requires dedicated tooling to avoid carbon contamination
- Higher material cost than mild steel
- Food & beverage processing equipment
- Coastal architectural fittings
- Balustrades & handrails
- Hygienic wash-down areas
| Grade | Spec | Typical Use |
|---|---|---|
| 304 | ASTM A240 | General food-grade, architectural fittings |
| 316 | ASTM A240 | Coastal, marine, chemical exposure |
| 3CR12 | SANS 1431 | Mild corrosion resistance, cost-sensitive projects |
Aluminium
Lightweight, corrosion-resistant metal for applications where weight reduction matters as much as strength.
- Approximately one-third the weight of steel
- Naturally corrosion-resistant (oxide layer)
- Requires TIG welding for best results
- Lower load capacity than equivalent steel section
- Transport & trailer bodies
- Lightweight access platforms
- Marine fittings
- Architectural cladding
| Grade | Spec | Typical Use |
|---|---|---|
| 5052 | ASTM B209 | Sheet fabrication, enclosures |
| 6061-T6 | ASTM B221 | Structural aluminium components |
Hot-Dip Galvanized Steel
Mild steel finished with a zinc coating for long-term corrosion protection in exposed or agricultural environments.
- Long-term corrosion protection without a paint programme
- Self-sacrificing zinc layer protects exposed steel at cut edges
- Requires venting/drain holes to avoid coating defects
- Standard finish for exposed agricultural & outdoor structures
- Agricultural sheds & fencing
- Exposed roof structures
- Outdoor walkways & stairs
- Coastal & high-humidity structures
| Grade | Spec | Typical Use |
|---|---|---|
| SANS 121 (ISO 1461) | Hot-dip galvanizing standard | Structural steel, fencing, agricultural structures |
Not sure which material fits your project?
Tell us the environment and load — we'll recommend a grade and finish, or flag when you need engineer sign-off first.