The Weight War – Steel vs Aluminium

According to a report by Reuters, four year ago, South Korean automakers, Hyundai and Kia, considered shifting from using steel to aluminium, which can weigh up to 30% less, but was deterred by the cost, which can be up to four times more. Meanwhile, European and American automakers have led the way in using the lighter metal, as government policies and market trend call for increasingly fuel-efficient vehicles. In the US, automakers are required to improve on fuel economy by 5% every year until 2025. 

It is a great feat, undoubtedly, for the engineers and designers, who have explored improving the efficiency of powertrains, aerodynamics and downsizing, but the easiest solution is for the vehicles to lose weight. 

Ford, for one, has announced that the 2015 F-150 pick-up truck will be sporting an aluminium body instead of the conventional steel, which effectively cuts away 700lbs in one fell swoop. The move, however, has garnered a fair share of criticism and cynicism. For a sports car or sedan, maybe, but for a mean, rough-tough machine like a pick-up truck? Although the material is also less prone to rust, aluminium is more well-known as the metal that soda cans are made of - and we all have crushed one in our hands (or, for some, on our heads) with relative ease. How then can an aluminium pick-up truck withstand the tough conditions?

Ford’s answer was to have a few F-150’s outfitted with aluminium beds and tested at an actual mining site doing actual ‘labour’, over dirt and rocks, up and down steep hills, with heavy equipment bouncing on the beds, and they appeared to be none the worse for wear.

Switching from steel to aluminium, however, would entail retooling of existing manufacturing lines, which is both costly and disruptive to production. For South Korean automakers, Hyundai and Kia, they had to also consider their relationship with Hyundai Steel Co, according to the same Reuters report. Hence, they and other Asian carmakers will continue to choose steel as their material of choice.

Furthermore, steel producers beg to differ that their metal is invariably heavier. According to Lakshmi Mittal, CEO of ArcelorMittal, the world’s biggest steel company, new forms of steel can compete with aluminum in terms of lightness, and that the aluminium industry uses outdated data to give steel a bad name.

'Steel can provide all the weight reduction that auto producers require to satisfy the new fuel-efficiency standards, for all types of vehicle,' he said during the US$832 million joint venture ceremony with Hunan Iron & Steel Co from China, where steel still rules over aluminium in the country's automotive industry. 

In 2011, Wall Street Journal reported that the automotive industry consumed about 87 million tons of steel compared to only 12.5 million tons of aluminium; with half of the automotive sales growth over the next seven years expected to occur in China, this gap may not narrow much. 

images: audiworld.com, autos.yahoo.com