The evolution of truck materials

The evolution of truck materials

From steel to polymer and from bakelite to polyurethane, the materials used in trucks have changed dramatically over the past 50 years, with exciting changes ahead.

The materials that go in to making a modern truck are a far cry from those used in the 1960s.

Today’s vehicles are constructed using materials that provide significantly longer life, as well as increased strength and reduced weight. And more change is on the way, with strong and light new composite materials just around the corner, making use of renewable carbon fibre.

Perhaps the area where today’s trucks most resemble their forebears is the basic structure. Ingegerd Annergren, Head of Materials Technology within Scania’s Research and Development division, explains many cylinder blocks are still cast in grey iron. Load bearing components such as frames, beams and coachwork, meanwhile, are still generally produced from steel.

Truck in the 60s

Then: Engine block Grey iron, Side mirror Chromed steel, Trim Steel, Muffler Steel, Fuel tank Steel, Steering wheel Bakelite, Gearbox Steel. Good for 400,000 km, weighed 300 kg, Sump Steel, and later aluminium, Bumper bar Steel

“But while we still make extensive use of steel, a lot has happened in terms of materials,” says  Annergren. “Today’s steels are significantly more durable and malleable, which means manufactured items don’t need to be as large as before. What’s more, the steel surface is treated in a completely different way today, with techniques that allow it to withstand a lot more stress. The steel is also galvanised and gets several layers of lacquer to protect it against corrosion.”

Lighter materials

Scania truck

Now. Side mirror Aluminium, steering wheel Polyurethane with an aluminium core. Future coachwork/cab Composite materials with carbon fibre. Future seats Composite material, moulded into a single unit. Future load-bearing frame in cab High strength steel carbon fibre. Muffler Rust resistant steel. Future cross- and side beams steel with additional integrated features, such as a built-in fuel tank Future wheels/rims Carbon fibre Fuel tank Aluminium, steel (for some demanding applications such as mining and construction) Gearbox Higher strength steel. Good for 1 million km, weighs 320 kg Engine block Grey iron/CGI Sump Glass-fibre reinforced plastic Under-run protection High strength steel (thin, minimizes weight) Bumper bar Polymer material Trim Polymer materials, moulded into one piece Future windscreen Glass with built-in functionality that allows it to act as a display screen

The trend within the passenger car segment for increasingly lighter materials – as well as new materials, such as composite materials using carbon fibre – is also being seen within heavy vehicles. But the motivation behind it is completely different.

“You have to remember that a truck is a machine that needs to be out on the roads making money,” says Annergren. “For this reason, the primary focus is on strength, fatigue, and length of life. A truck needs to be able to cope with heavy loads in a totally different way to a passenger car. But, obviously, even within the heavy vehicle segment, we’re continuing to slim down the materials to cap costs, reduce weight and to avoid using materials as ‘wastefully’ as we do today.

More high-strength steels

Scania envisions a future where an increasing range of materials will be used in vehicles. This involves diversification, which means using exactly the right material for the right application.

“We’ll see more high-strength steels in load-bearing structures in the chassis and cabin,” says  Annergren. “We’ll also see more polymers incorporating carbon fibre and other composite materials in load-bearing structures, cab elements and leaf springs, while new hybrid materials will make it possible to integrate several functions into the same element. We’re also looking at light metals such as aluminium for bus  mounts and parts, and magnesium for interior details such as table surfaces and mounts.”

Annergren continues, “Another trend is that materials will need to be functional in a different way as to today. This could mean surface treatments which divert heat away along the coachwork, windscreen glass upon which information can be projected, like a computer monitor, or load-bearing beams that contain pipes.”