Vehicles today are expected to fulfil numerous requirements that at times seem contradictory. They are supposed to be lightweight and low-cost, and deliver outstanding fuel economy. But at the same time, occupants demand ever more comfort and safety, which calls for a stronger and stiffer body. In the fourth-generation OCTAVIA, ŠKODA is utilising an intelligent material mix, with comprehensive use of high-strength steels, to combine superior economy and efficiency with outstanding comfort and optimal occupant protection. The five-star rating that the latest generation of the brand’s best-seller has achieved in the Euro NCAP test is the result of a fruitful collaboration between various development departments in areas such as Styling, Concept, Numerical Simulations, Design and Quality Assurance.
Large proportion of high-strength steels lowers weight and enhances safety
The all-new OCTAVIA’s exceptionally strong body is above all the result of a high proportion of high-strength steels. While using only 26.3 per cent of so-called deep-drawn steel – mainly for surface components – 20.6 per cent of the body is made of ultra-high-strength hot-formed steel. This type of steel is up to seven times stronger than conventional deep-drawn steel variants. During manufacture of components, it is heated to a temperature of around 950 degrees Celsius and then pressed. Afterwards, being still part of the shape, it is cooled down to 180 degrees Celsius during a controlled process that takes 5.5 seconds. The resulting exceptional material strength allows for thinner and therefore more lightweight components to be used even in areas designed to withstand frontal and lateral impacts in a collision.
Tailor-rolled blank for variable sheet thickness
The tailor-rolled blank technology was first used by the Volkswagen Group in 2004 for the ŠKODA OCTAVIA II. The combination of the tailor-rolled blank process and hot forming was first used for the ŠKODA OCTAVIA III. Until then, it was not technically feasible to combine these production processes. The tailor-rolled blank allows for the production of parts with varying sheet thickness. Increased thickness is only used where it is needed to achieve the required strength. The all-new OCTAVIA uses this technology to produce the A-pillar and B-pillar, for example. In numerous areas that are also subject to such high stresses the Czech manufacturer relies on multi-phase steel (dual-phase steel), which shows a high mechanical strength after the forming process has been done, and as a result, it is very ductile and very strong. In the OCTAVIA the dual-phase steel is first used also in the boot lid surface. Multi-phase steel and ultra-high-strength steel account for almost 14 per cent of the body’s weight. Using innovative materials and the most advanced computation methods, such as topology optimization, enables continuous optimisation of body characteristics. To give an example, in the fourth-generation OCTAVIA ŠKODA has once again achieved an increase in dynamic torsional stiffness compared to the predecessor model. The result is that ride comfort has been taken to an even higher level than before.