Driven to action

Over the past decade the once ‘all-steel’ automotive industry has faced challenges from other materials. Andrew Lee reports.

The automotive industry could be forgiven for feeling squeezed between the irresistible force and the immovable object — its customers on one hand and on the other a growing army of regulators dictating how its vehicles are built.

The former are demanding vehicles that are more stylish, more reliable and safer, yet want to pay less for the privilege. The latter, whether national governments or the EU, are also insisting on improved safety, not just for drivers but for pedestrians too, and introducing a raft of legislation connected with the environmental impact of cars.

Materials technology has emerged as a key factor in helping the industry meet its various challenges.

The overarching trend in automotive materials development is sometimes boiled down to a race between metals and plastics. This is far too crude a generalisation, but contains a grain of truth.

Steel, the most venerable of automotive materials, has been forced to raise its game over the past decade after it became clear that in several key application areas it was no longer the only option.

Jon King, director of Corus Automotive, a division of the Anglo-Dutch steel giant, said the steel sector had been given ‘a bit of a wake-up call’ by the sudden dramatic progress of other materials, notably plastics and aluminium, in the automotive sector.

Steel suppliers had to begin acting less like providers of a commodity over which the only debate was cost, and more as technology partners committed to meeting the rapidly evolving needs of the automotive sector.

‘As an industry, there was a recognition that we needed to put some work in to respond better,’ said King. ‘We began to recognise that we had a lot of technology, a lot of capabilities, but had to change the nature of the relationship and get more of a technology discussion going with the manufacturers.’

There is a growing feeling in the specialist steels sector that the tide may be turning in its favour, not least because of the looming End of Life Vehicle (ELV) directive.

This sets manufacturers tough standards over how much of the material used in their vehicles must be recoverable through recycling. By the end of next year 85 per cent of the mass volume of cars sold in the EU must be recycled, rising to 95 per cent a decade later.

This has presented the metals industry with a straightforward message to take the automotive sector — that its materials lend themselves better to recycling than plastics or composites, with the ability to produce high-performance engineering products from virtually 100 per cent reprocessed steel.

‘We’re looking at components which over the past 25 years or so have changed to other metals or plastics, and seeing whether there is the potential for recovering them to steel,’ said King.

‘There is no doubt that ELV presents an opportunity for steel.’

Pedals, engine covers, fluid reservoirs, and certain front-end structures are all firmly on Corus’s radar. Another prominent example is the fuel tank, the subject of a concerted R&D push by Corus Automotive that resulted in Neotec. This is a lead-free metallic-coated steel that, according to Corus, ticks important boxes regarding the ELV directive and the equally tough Californian partial zero emission vehicle (PZEV) legislation, which outlaws fuel evaporation from tanks.

Developing innovative technical solutions to the recycling issues facing OEMs is just one example of how the steel industry has learned to become deeply entrenched in the issues shaping the automotive sector, said King.

Fuel economy and impact protection are other high priorities for the sector that steel suppliers such as Corus are addressing.

‘This was something we had to do,’ he said. ‘As major suppliers to the industry, we’ve got to have an intimate understanding of cost, weight, vehicle performance and crashworthiness. If we’re better at that than the others, then our materials become more attractive.’

Naturally, the plastics industry is taking its own steps to ensure a continued strong presence in the automotive sector. In the UK, the British Plastics Federation is involved in an ongoing project called Prove (Plastics Reprocessing Validation Exercise) in a bid to show that plastics can be taken from used cars and recycled into high-quality new vehicle parts.

Working in conjunction with automotive industry research experts such as MIRA, the BPF is developing industry-wide standards for engineering quality plastics, with the ultimate aim of allowing recycled and virgin materials to compete on an equal footing. It has developed a range of demonstrator components including radiator grills, heating and ventilation units and air filter housings.

And the automotive industry’s use of polymers is unlikely to wane, given the versatility of the materials in a number of key application areas.

For example, some of the world’s biggest materials technology groups are showing a growing interest in the commercial vehicle sector.

Developers of commercial vehicles have many requirements running parallel with the car sector, but some have additional imperatives of their own. One pressing concern is the trade-off between size and weight. A commercial vehicle is judged by the volume of goods it can carry, and OEMs are eager to squeeze every last square centimetre of capacity out of their models.

That means they are asking suppliers for increasingly large component parts while avoiding additional weight. Excess weight is the great enemy of vans and trucks due to its adverse effect on diesel consumption.

Poor fuel economy is a non-starter for the users of commercial vehicles whose businesses are often founded on extremely tight margins which can be eroded by high fuel costs. Bayer Material Science, the materials division of the global chemical giant, has flagged up advances in polyurethane processing technology that allow ever larger parts weighing up to 50kg to be manufactured in a single shot.

According to Bayer there is a trend towards increasingly large bodywork parts switching to plastic, with polyurethane now being used for applications ranging from bumpers to huge exterior components of combine harvesters.