Application: Liquid Hydrogen Turbopump Vulcain space launcher
The cryogenic engines of the Vulcain space launchers has been subjected to increasingly severe operating conditions so that entirely new bearings were developed for the liquid hydrogen turbopumps.
The principal axes of development, except the optimization of the bearing geometry, were related to the improvement of the mechanical properties of the X105CrMo17 steel (AISI 440C) commonly used for this type of application and to the development of new materials able to carry out even more better performances.
A research and development program co-financed by the CNES and carried out in co-operation by SNECMA division SEP, AUBERT et DUVAL and SNR Roulements made it possible to develop the XD15NW™ nitrogen martensitic stainless steel whose properties show the possibility to operate under severe conditions of temperature, speed, loading and environment.
The XD15NW™ nitrogen martensitic stainless steel, whose advantage is to be manufactured by a classical melting process, shows interesting potentialities to replace the X105CrMo17 steel (AISI
440C) for cryogenic bearing applications with improved corrosion resistance, better metallurgical and mechanical properties, improved tribological behavior and fatigue life.