For years, the majority of car producers used welded or carbon tubes. But standards have risen. Now, the most innovative companies want more efficient and eco-friendly solutions, such as seamless stainless tubes, which is the core competence for Centravis.
The welded tubes are good as long as the working pressure doesn’t exceed 300 bars. Now engines have 350 bars, and the next generation will be 400 bars, and higher. The seamless tube offers the solution that does not include the disadvantage of the weld.
One of the first CENTRAVIS orders from car producers was in 2011. It was for cold finished bright annealed (CFA) instrumentation tubes (hydraulic tubes) with 21mm OD & 2.8mm WT. The main difficulty in the production of this first order for vehicles was the limited tolerance on the outer (± 0.1 mm) and inner (±0.08 mm) diameter, which was even more stringent than the requirements of the EN 10305.
Currently, the majority of automotive precision tubes are produced from TP304/304L steel grades. However, keeping the above trends and requirements in mind, CENTRAVIS is actively developing new products from duplex steel grades. For example, in using advanced heat treatment technology, developed by CENTRAVIS for duplex cold finished tubes, we are able to reach mechanical properties of super duplex grades (UNS S 32750/EN 1.4410 and UNS S 32760/EN 1.4501) without a loss in ductility or corrosion resistance.
