Five star in Euro NCAP tests
Giancarlo Bertoldi has borne the main responsibility for body development for a long succession of Fiat models, the latest of which is the new Fiat Grande Punto. The launch of the car in Europe has been highly successful. One of the major factors for the success is the high rating awarded to the car in the Euro NCAP crash test. The car was awarded the maximum of five stars for occupant safety, and a high safety rating is an increasingly important argument when car buyers decide on their new car.
“We are very proud of the results in the NCAP test, which confirms what can be achieved with innovative design in which the properties of advanced high strength steels are put to full use,” continues Giancarlo Bertoldi.
“We specified a very advanced geometry for the door’s internal waistline reinforcement mounted just below the front side window.” The design brief was that the component was to have a high energy absorption capacity both in a frontal crash and in a side-on collision. The internal waistline reinforcement had to be accommodated in the very limited space available below the side window, while also being lightweight and suitable for cost-effective production. The solution was a roll-formed beam made of advanced cold-rolled high strength steel with a minimum strength of 1000 N/mm2.
Realized by Wagon Automotive
The order for producing this component was awarded to Wagon Automotive – a long-standing major supplier to Fiat. The company is one of Europe’s leading manufacturers of automotive components, and has 26 factories and around 7,600 employees in a number of countries.
“We specialize in roll forming,” reveals Roberto Boggione, Managing Director of Wagon in Italy. “This process offers major benefits compared to pressing – higher quality and lower stresses in the material during forming. In my opinion, major car manufacturers such as Fiat will soon be replacing a large proportion of the traditional pressed parts with roll-formed components.” Based on the fundamental principle drawn up by Fiat, the design was refined by Wagon engineers in Turin.
“This type of structural component is normally produced in two parts which are then welded together,” explains Roberto Boggione. “But we have produced a closed profile with an asymmetric geometry, which is bent longitudinally in two planes.” The internal waistline reinforcement designs for the 3-door and 5-door models are somewhat different. The one for the 5-door Grande Punto is shorter and is made of 0.8 mm thick material, whereas the one for the 3-door model is longer and is made of 1.2 mm thick steel.
Simplifies production
Roll forming involves much lower tool costs than other production methods. Roll forming simplifies production by enabling all the holes to be made before the forming process, without compromising precision demands. Roll forming also makes it simpler to reset production from one product to another, and to adapt the production process to suit new steel grades.
“Roll forming is flexible and enables mild steel to be replaced with high strength steels in order to reduce weight and achieve better properties,” concludes Roberto Boggione.