The most lightweight bus body material concept by Stalatube – 500 kg off?

The most lightweight bus body material concept by Stalatube – 500 kg off?


"There are around 300 000 buses and coaches in the world covering around 100 000 kilometers a year. If one of these vehicles became 500 kilograms lighter, it would mean a 3 990 kg cut in carbon dioxide emissions every year per bus," calculates Jori Määttänen, Stalatube's SBA Sales Director.

The calculations are, of course, theoretical, but they illustrate how little things can make a big difference.

Transport industry weight savings

Small but powerful actions have also contributed to the growth of Stalatube's transportation equipment sector. "We started from zero ten years ago. We have grown at a rate of 10 % a year, and now we hold over 60 % of the global market share," says Määttänen. Taking over the market has required rapid product development and an ear for what is happening in the field.

"The environmental and safety standards of the industry have continuously risen. We thought about how we could meet these standards, and started to develop our products and production methods according to them." 

Today Stalatube, formerly known mainly as a supplier of austenitic standard hollow sections, tailors an increasing proportion of its products to meet the needs and demands of individual customers in the bus and coach industry.

"We are currently the only manufacturer in the world who has the raw materials, the manufacturing technology and the know-how needed to deliver a finished product directly to the end user," Määttänen states.

The company's product range includes stainless specialty steel components for bus chassis and body structures, such as tubes, plates and ready-made parts made up of such smaller components. Products are manufactured from both traditional ferritic stainless steel and a material known as Lean Duplex, which is significantly stronger than regular stainless steel and carbon steel.

Stalatube has created a material concept for manufacturing extremely lightweight bus bodies with its stainless steel components. The strength classes, STALA400F for stronger ferritics and STALA630D for stronger Lean Duplex, enable the manufacturing of even lighter bus bodies, thanks to the material's yield strength of up to 630 MPa, together with its excellent elongation and energy absorption properties.

"In comparison to carbon steel or aluminium, Stalatube's Lean Duplex is superior in terms of life cycle costs, strength (and consequently lightness) and corrosion resistance as well as eco-friendliness. The lightness of the material helps reduce fuel costs, increase passenger capacity and reduce the environmental footprint," Määttänen explains.

Currently, Stalatube therefore focuses on advocating the benefits of Lean Duplex. Replacing just a few parts with lighter materials already has a significant impact on the weight and properties of the vehicle, but in the future, it is likely that the entire chassis and body structure of buses will be optimized more efficiently than today.

"This translates as hundreds of kilograms of weight savings per vehicle. Even if Lean Duplex, for instance, is slightly more expensive as a raw material, the total cost is still very moderate thanks to the reduced amounts of material, and the investment pays back in just a few months," Määttänen says.

It is therefore no wonder that many bus and coach manufacturers have woken up to the benefits of the new materials and products. This, in turn, translates as even quicker growth for Stalatube.

"Stalatube's focus has long been to keep developing according to the customers' requirements and tailor the perfect solutions for them. In the transportation sector, there is an obvious demand for special materials and solutions tailored to the customers' needs. We therefore decided to focus on that. This has proven to be the right solution for both parties."

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Transport Industry