For custom metal fabrication, the metal you choose determines how strong, lightweight, or corrosion-resistant the final project is. So selecting the best metal for fabrication matters.
No single choice is best in every scenario. Often, fabrication material selection comes down to the project’s purpose. While we cannot cover all the complexities of that choice here, consider this a primer on how to generally choose between mild steel, stainless steel, and aluminium for your project.
We’ll pit mild steel vs. stainless steel vs. aluminium against one another, as these are the three fabrication materials that come up most often in commercial and industrial applications. Read on to see how they compare in strength, weight, corrosion resistance, and fabrication.
Mild Steel
Among mild steel, stainless steel, and aluminium, mild steel earns its name for two reasons: its wide use and its carbon content.
‘Mild steel’ is the colloquial name for low-carbon steel, which usually has less than 0.3% carbon. Don’t let the name fool you, though. Mild steel is strong and readily weldable, which makes it a popular choice for structural and general metal fabrication. For applications where structural strength matters and weight isn’t a concern, mild steel is one of the best metals for fabrication.
Beyond its structural strength, this metal is highly workable. It welds cleanly using all common methods, machines well, and responds predictably to most surface treatments. Those surface treatments are necessary because, left unprotected, mild steel rusts fairly readily (especially near a coastline or when exposed to industrial solvents). Therefore, surface coating is vital for anything designed with mild steel in mind.
Stainless Steel
Next in our breakdown of mild steel vs. stainless steel vs. aluminium is stainless steel. In fabrication, stainless steel is harder to work than mild steel, but its chromium content offers more benefits.
Stainless steel contains over 10.5% chromium, creating a layer atop the base metal that oxidises when it comes into contact with air. This protects the base metal itself more than a surface treatment would, as it’s a self-repairing metallurgical property of this metal type.
As a result of this higher chromium content, stainless steel is tougher on tooling and more sensitive to heat during the metal fabrication process. This metal is also vulnerable to contamination by other metals during fabrication, which can affect its structural strength and malleability.
In short, this is arguably the best metal for fabrication projects where the metal will be visible and used every day. Applications like food processing, commercial kitchens, and marine-exposed structures warrant this material choice.
This is only true if an experienced team can handle the added complexity of working with stainless steel. There is also a higher cost, both because more consumables go into the fabrication process and because it is a more specialised material. That said, the material’s inherent corrosion resistance alone is enough to make the extra complexity worthwhile.
Aluminium
When comparing mild steel, stainless steel, and aluminium, aluminium is an excellent choice when you need something strong and lightweight. Aluminium fabrication isn’t as strong as steel, but its lightweight nature gives it a similar strength-to-weight ratio. It can actually outperform structural steel in certain applications, when fabricated by a competent crew.
The key concern with aluminium is actually heat. While it is the best metal for fabrication where weight matters, aluminium has higher thermal conductivity than steel. That means it behaves differently and has a lower melting point.
When welding, we must use TIG, MIG, or Laser welding methods with aluminium-specific wire and shielding gas to protect the metal. Without these measures, it’s more likely to distort or soften in certain areas.
Fortunately, aluminium is an excellent choice for fabrication materials. With the right crew working on metal fabrication, aluminium is a perfect selection for many applications, including:
· Lightweight structures
· Transport equipment
· Marine applications
· Architectural joinery
· Access platforms and handrails
Basically, if you need something strong and lightweight, aluminium is the best choice.
Overall, mild steel is generally the best metal for fabrication if you need something strong and low-cost; stainless steel is best for corrosion resistance; and aluminium reduces weight.
When in doubt, speak to a team experienced in fabrication materials. Discuss the purpose of your project and its constraints; this will help determine your final fabrication material selection.
Otahuhu Engineering, home of expert custom metal fabrication.
Our experienced team provides a full range of metal fabrication services. We support you at every stage, from material selection to final fabrication, to ensure your product meets your project’s needs.
We offer stainless steel and aluminium fabrication, as well as specialist welding services across all metal types. For a free, no-obligation quote on your metal fabrication, please contact us today.
