The rails are made of special alloyed steel and through-hardened to a hardness value of 60 ±2 HRC. The precision relative to the parallelism variation between the raceways and the reference surface are dependent upo the quality selected (10 micron/1600 millimeters for the “standard” quality, 5 micron/1600 millimeters for the “selected” quality).
It is important to state that all the elements are individually checked during all manufacturing phases before the final inspection. Also, a non-destructive check is performed to assure the absence of internal cracks which may have been generated during heat treating. Such micro-cracks could drastically affect both the precision and the life of the rails.
