Abstract: A process for production of tempered steel support structures for motor vehicles of multiple steel parts including the steps deforming and/or trimming at least two soft-hardened steel parts, hardening the at least two steel parts, joining the steel parts to form a support structure, wherein the support structure is subject to annealing and total stress relieving in a combined thermal treatment only after the joining step.

Abstract: A method for the production of hollow shafts from welded or seamlessly produced steel tubes having a maximum carbon content of 0.35% includes (1) carburizing a tube to a carbon content greater than 0.5%; (2) slowly cooling the carburized steel tube down from the process temperature, so that it undergoes no increase in hardness; (3) machining and/or non-cutting processing the carburized and soft steel tube to produce a workpiece blank; and (4) hardening the workpiece blank by local heating and quenching at desired points.

Abstract: In a device for inductive hardening of profiled camshafts (especially those having valve cams and zero cams) during a hardening operation, the camshaft is surrounded by an inductor and is heated by means of a magnetic field emanating from the inductor. The inductor has several axial members and radial members through which the induction current flows during the hardening operation. Dynamo sheets provided on the axial branches focus the magnetic field in the radial direction. The position and the width of the dynamo sheets is adapted to the surface profile of the camshaft, so that the focusing is aimed at areas with a small diameter.

Abstract: A built-up camshaft has cam discs which are secured to a tube under mechanical prestress, are of annular design, and are inductively hardened all the way around at a boundary layer on their outer periphery before they are secured to the tube. The hardening of the boundary layer is formed in such a manner that, due to the hardening, high residual compressive stresses (at least -450 N/mm.sup.2) are produced in an at least approximately 0.5 mm deep boundary zone near the surface in such a manner that, even after the cam discs are mounted on the tube, the superimposing residual tensile stresses in the boundary zone, induced by the joining, only partly compensate the original residual compressive stresses, i.e. there are still only residual compressive stresses (at least -150 N/mm.sup.2) in the boundary zone near the surface even after the pressing-on. Sufficiently high residual compressive stress in the boundary zone can be produced by effecting the inductive heating of the cam disc in two stages.

Abstract: A built-up camshaft has cam discs which are secured to a tube under mechanical prestress, are of annular design, and are inductively hardened all the way around at a boundary layer on their outer periphery before they are secured to the tube. The hardening of the boundary layer is formed such that, due to the hardening, high residual compressive stresses (at least -450 N/mm.sup.2) are produced in an at least approximately 0.5 mm deep boundary zone near the surface such that, even after the cam discs are mounted on the tube, the superimposing residual tensile stresses in the boundary zone, induced by the joining, only partly compensate the original residual compressive stresses, i.e. there are still only residual compressive stresses (at least -150 N/mm.sup.2) in the boundary zone near the surface. Sufficiently high residual compressive stress in the boundary zone are produced by effecting the inductive heating of the cam disc in two stages.