In industrial fabrication, mild steel is the foundational material for countless applications. However, choosing the right grade is about more than just “picking metal.” At our laser and waterjet cutting facility, we primarily work with two Australian standards: Grade 250 and Grade 350.
While they might look identical on the cutting bed, their mechanical properties dictate how they will perform in the field. Here is everything you need to know to make an informed decision for your next project.
Decoding the Numbers
The grade numbers refer to the nominal yield strength of the steel, measured in Megapascals ($MPa$). This is the point at which the steel will begin to deform permanently.
Grade 250: 250 MPa yield strength.
Grade 350: 350 MPa yield strength.
By opting for Grade 350, you are gaining roughly 40% more strength. This allows for “light-weighting”—using thinner materials to achieve the same structural integrity as a thicker, heavier Grade 250 counterpart.
Grade 250: The Fabrication Workhorse
Formability: It is highly ductile, making it the superior choice if your parts require intricate folding or tight-radius bending after they leave our cutting machines..
Weldability: It is exceptionally easy to weld using standard shop equipment, with low risk of cracking or brittleness.By opting for Grade 350, you are gaining roughly 40% more strength. This allows for “light-weighting”—using thinner materials to achieve the same structural integrity as a thicker, heavier Grade 250 counterpart.
Best For: General brackets, base plates, enclosure components, and non-critical structural framing.
Grade 350: High Strength for Demanding Loads
When a project faces significant structural stress or weight constraints, Grade 350 is the professional’s choice.
Strength-to-Weight Ratio: Because it is significantly stronger, you can reduce the overall weight of a finished assembly without sacrificing safety or durability.
Durability: It offers better resistance to impact and high-stress loads, making it ideal for environments where the metal is under constant tension.Best For: General brackets, base plates, enclosure components, and non-critical structural framing.
Best For: Heavy structural members, load-bearing plates, machinery components, and civil engineering projects.
Precision Cutting Matters
Laser Cutting: Ideal for high-speed, high-precision cuts on gauges typically up to 20mm–25mm. Our laser process ensures minimal heat distortion, keeping the edges of your Grade 250 or 350 steel clean and ready for the next stage of production.Best For: Heavy structural members, load-bearing plates, machinery components, and civil engineering projects.
Waterjet Cutting: For much thicker plates or when “Heat Affected Zones” must be completely avoided to maintain the steel’s metallurgical properties, our waterjet provides a cold-cutting solution with unmatched versatility.
Technical Comparison
| Feature | Grade 250 | Grade 350 |
|---|---|---|
| Yield Strength | 250 MPa | 350 MPa |
| Bending/Folding | Excellent | Good (Requires larger radii) |
| Weight Saving | Minimal | High Potential |
| Common Applications | General Fabrication | Structural Engineering |
Expert Guidance for Your Next Build
Do you have a DXF or CAD file ready for a quote?
Our specialist cutting division is equipped to handle everything from one-off prototypes to high-volume industrial runs with the precision your project deserves.