Abstract: An apparatus for hardening cylindrical bearing faces (L) of a shaft (K), wherein at least one of the transitional radii (R1, R2) to the adjoining shaft portions (W1, W2) is constructed recessed, includes a pair of inductive heating units (1, 2), which are each formed at least by one inductor (3, 4) having two spaced-out heating conductor branches (20, 22; 21, 23); an adjusting device (11, 12) for adjusting the inductors (3, 4) simultaneously from the radial direction (R) on to the bearing face (L) to be hardened and a second adjusting device (13, 14) for moving at least the inductor (3, 4) associated with the recessed radius R1, R2) after application to the bearing face (L) by a movement directed axis-parallel with the longitudinal axis (X) of the shaft (K) in the direction of the recessed transitional radius (R1, R2) until its outer heating conductor branch (20) has moved into the particular transitional radius (R1, R2).

Abstract: A method for simultaneously hardening a group of cams on a camshaft comprises first heating the group of cams at low power for at least one heating interval, then pausing the heating for a pause interval during which no power is applied to the group of cams, and then subsequently heating the group of cams at high power for one heating interval. The pause intervals, during which no power is applied to the group of cams, are sufficient as to allow heat stored in the cams to distribute uniformly throughout the cams. Each group of cams is hardened by a linear inductor and the regions of the camshafts that are not to be hardened are shielded by a cooling device.