the steel according to the invention includes the following chemical composition elements in weight percent carbon in an amount limited to 0 006 included this element can be harmful because it can provoke steel ageing and or precipitation which would deteriorate the magnetic properties the concentration should therefore be limited to below 60 ppm 0 006 wt si minimum content is 2 0 while its maximum is limited to 5 0 both limits included si plays a major role in increasing the resistivity of the steel and thus reducing the eddy current losses below 2 0 wt of si loss levels for low loss grades are hard to achieve above 5 0 wt si the steel becomes fragile and subsequent industrial processing becomes difficult consequently si content is such that 2 0 wt u2266 si u2266 5 0 wt in a preferred embodiment 2 0 wt u2266 si u2266 3 5 wt even more preferably 2 2 wt u2266 si u2266 3 3 wt aluminium content shall be between 0 1 and 3 0 both included this element acts in a similar way to that of silicon in terms of resistivity effect below 0 1 wt of al there is no real effect on resistivity or losses above 3 0 wt al the steel becomes fragile and subsequent industrial processing becomes difficult.