Materials Guide

Raw Aluminium

Substrates

Aluminium

Physically, chemically, and mechanically, aluminium has very similar qualities to steel, copper, and lead. It can be easily shaped, formed, and fabricated. Perforated aluminium sheet is one third the weight of steel but has a comparable strength to weight ratio. It is lightweight, ductile, able to withstand low-temperature conditions, and corrosion resistance makes it ideal for perforated metal processing.

Galvanised Steel

The manufacture of galvanized steel involves hot dipping steel in a galvanizing solution that coats the metal and protects it against abrasion, corrosion, and offers long term surface protection. The process adds long life, durability, and excellent performance, making galvanised steel perfect for the production of perforated sheets. 

Hot Dipped Galvanised Sheet Metal
Stainless Steel Sheet Metal

Stainless Steel

The 3 main types of stainless steel are austenitic, ferritic, and martensitic. As a premium product, stainless steel is corrosion, rust and bacteria resistant as well as being lightweight and strong. Its applications extend into hospitality and food production.

HW350/ Corten

An oxidised finish on a Steel substrate that eliminates the need for painting. The material gets its name from its two distinguishing properties – CORrosion resistance and TENsile strength. The finished treatment gives a weathering, rusted appearance.

Perforated CORTEN (Atomic)
Product Application Surface finish Material density
Substrate Interior Exterior Powder coat Anodising
Mild Steel 7.85
Galvanised Steel 7.85
Aluminium 2.71
Stainless Steel 8.18
HW350/Corten 8.20

PE Coating

Some materials (Aluminium, Stainless Steel & pre-coated Steel ) can be ordered from the mill with different plastic films applied for surface protection. There are significant differences in purpose and performance of the plastic films.  The films are intended to protect the surface of the material from scratches and scuffing during handling and working prior to and during installation. They should be removed during service.  Please discuss any particular surface treatment request with one of our technical sales staff.

Dissimilar Metals are fine how they are

When using dissimilar metals in a fabrication project, precautions must be taken to prevent galvanic reaction. This occurs when two different metals are in contact in a corrosive or conductive environment and the current flow changes. When two dissimilar metals are involved, the reaction is called galvanic corrosion.

Why Exactly Does Galvanic Reaction Occur?

When one metal contacts another, a current flow transfers between the 2 metals. The current flow changes when dissimilar metals come in contact with each other. The corrosion rate of the active, or least corrosion-resistant metal, accelerates and the inactive, or more corrosion-resistant metal, decreases.

The further apart the metals are on the corrosive scale, the stronger the galvanic reaction between the two. Similar metals have little effect on each other.

Signs of Galvanic Reaction
Metrix Group Automated Sheet Metal Stacker

For example, aluminium is considered an active metal and stainless steel is considered inactive. In a corrosive environment, aluminium corrodes at a higher rate, but the stainless steel corrosion rate decreases. Corrosion can be caused by environmental disturbances such as weathering and atmospheric oxygen.

Moisture is a key element affecting galvanic reaction. The relative surface of dissimilar metals used in a metal fabrication project should also be taken into consideration. For example, using inactive metals as the main body of the project, joined by active connectors, could cause the joints or fasteners to corrode at a quicker rate.

In this case, it may be recommended to connect two sections of similar metals with fasteners also made of the same metal. If using similar metals isn’t possible, a compatible metal is the next best choice. Metrix Group are well versed in dissimilar metal prevention and are happy to help consult on the best combinations for your project.