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Curved Aluminium Sheets

Steel and aluminium are the two most widely produced metals in the world. When planning a project in which metal is a primary component, it is important that you choose the one that will give you the best performance.

As a metal known for its strength, steel is widely used in construction. The galvanisation process involves it being dipped in molten zinc to protect it against corrosion or rust, producing a thin steel sheet that is ideal for use in steel-framed construction, truck manufacturing, household appliances, and electrical towers.

Rectangular metal tubes

Strength and weight

Generally speaking, the weight of a galvanised steel sheet is greater than its equivalent aluminium sheet, and it is also stronger. The strength of each product comes down to its density. For two pieces of equal volume, steel can actually be three times the weight of aluminium.

However, if you were to break down the weight-to-strength ratio, aluminium comes out on top. This makes aluminium a better choice for projects where a lightweight option is necessary, whereas steel would be a better choice in heavy-duty industrial applications.


How often do you need to cut and reform the metal to fit the product? Welding galvanised steel is a difficult and time-consuming job. Strict safety codes must be adhered to due to the release of toxic fumes. Aluminium is a much more malleable metal. It has an aluminium oxide surface coating, high thermal conductivity, and low melting temperature, and the material doesn’t change as the temperature meets its melting point.

Thermal conductivity

Aluminium is over four times more conductive for transferring heat effectively than steel. Metal particles are held together by strong metallic bonds. The free electronics within the metal can move around freely, allowing aluminium to efficiently conduct the heat. Aluminium is used widely in electrical appliances which incorporate a heatsink.

Surface finishings

The surface of a galvanised steel sheet is rough and porous, whereas aluminium is smooth and hard. This makes aluminium better for use in products where foodstuff is involved. The steel surface can encourage bacterial growth, which will ultimately contaminate food processing. The smooth surface of aluminium eliminates bacterial growth and is easy to clean down.

Common applications for galvanised steel sheets and aluminium

The strength of galvanised steel makes it suitable for a number of projects over and above its aluminium cousin, and although its cost is more than aluminium, its long life cycle and non-corrosive properties make it the preferred choice for large infrastructure projects such as bridges and roads, girders, construction supports, and frames.

Being lighter, more malleable, and a better thermal conductor, aluminium is ideal as a ‘dressing’ in architectural projects, such as window and door frames, balcony railings, roofing sheets, interior ceiling panels, panelling, and cladding.

Aluminium is also 100% recyclable without losing its original properties and can be recycled using only 5% of the energy required to produce new aluminium. This is of particular interest when taking into account the replacement cycle of construction finishings.

Automotive industry

Transportation is another area in which both aluminium and steel are widely used. The correlation between strength and weight is crucial in terms of performance and safety. The core of a vehicle is steel based but finished with reformed aluminium which, when shaped, can match the strength of steel while maintaining its lightweight properties.

When considering whether to use aluminium or galvanised steel, you need to consider the following:

  • Are strength and durability the most important characteristics of the project, over and above aesthetics.
  • Do you require a good strength-to-weight ratio, corrosion resistance, and malleability?
  • Is the thermal conductivity of the metal crucial to the performance of the product?
  • Is food preparation or storage a function of your product? Will it need to be cleaned regularly and kept sanitised?
  • What is the life cycle of the project at hand? Does it have a limited life span? Will it need replacing in a few years either because it no longer functions, is no longer in fashion, or technology has advanced and newer, more efficient models are now being introduced?
  • Does the product have a complicated shape?
  • Is the finished aesthetic appearance of the product important?
  • What are the cost implications? What is the cost vs. life span implication?
  • What are the environmental implications?

If you need to discuss the use of either galvanised steel sheets or aluminium sheets in your project, Rapid Metals can guide you to the right choice.

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