Carmakers slowly substituting steel with aluminium

At last week's Paris motor show, carmakers are showing a multitude of materials that could one day challenge steel's omnipresence in the structure of vehicles.

New regulations requiring carmakers to save fuel and reduce carbon dioxide emissions have compelled the industry to experiment with lighter materials and reverse the tendency of each new model generation to be heavier than the last.

Aluminium is the leading pretender to steel's automotive crown as it is lightweight, resists corrosion, easily recycled and can be substituted into existing steel presses.

The amount of aluminium used per car produced in Europe increased from 50kg in 1990 to 140kg in 2012, according to the European Aluminium Association. A typical car weighs more than 1300kg.

Currently, most of that is cast aluminium used in transmissions, pistons and wheels but aluminium sheet bodywork is becoming more common.

As it is considerably more expensive than steel, aluminium bodies have been pioneered by premium carmakers such as Audi and Jaguar Land Rover who have years of experience in the material.

Jaguar is showing in Paris its aluminium F-Type sports car and Land Rover its new Range Rover sport utility vehicle - the first SUV to have a full aluminium body. Meanwhile Audi, is displaying a variety of aluminium vehicles from the compact A3 with an aluminium bonnet and front wings to the A8 saloon with an all aluminium body.

The Range Rover's body is 180kg or 39 per cent lighter than a comparable steel body, allowing it to use a smaller engine with the same performance and thus save further weight.

Although commonplace in tennis rackets, fishing rods, aeroplanes and Formula One racing cars, carbon fibre use in production cars has been limited by its high cost, complexity and labour intensity, thereby, making it suitable only for limited-volume vehicles or small components.

McLaren Automotive, the UK-based sports car company whose engineers are steeped in carbon expertise through their activities in F1, is showing its MP4 12C and P1 concept cars in Paris that are both fashioned from the composite material.

The leading high-volume carbon pioneer is BMW whose carbon fibre i3 and i8 electric vehicles will go on sale in 2013.

Indeed, car bodies built from a variety of metals and composites are set to become more common. In Paris, Audi unveiled its crosslane coupe, a concept car with a "multimaterial space frame" shell incorporating aluminium, carbon fibre-reinforced polymer and glass fibre-reinforced polymer.

Meanwhile, Mercedes-Benz launched its SLS AMG electric drive sports car, which has an aluminium and carbon fibre structure. Mercedes said it was the world's most powerful series production electric car. At €416,500, it is also one of the most expensive.

Phil Gott, managing director at IHS Automotive consulting, said that most manufacturers and car buyers are too cost-conscious to abandon steel for the time being and will instead look to new types of steel to cut weight.

Volkswagen revealed a new version of its mass market Golf, but it used advanced steels, rather than costly aluminium, to cut 23kg in body weight.