The invention relates to a method for the induction hardening of a workpiece, in particular a toothed and/or corrugated and/or ribbed workpiece such as a gear or saw blade, wherein a matchingly shaped induction loop is guided or set over the workpiece surface to be hardened, the induction loop being formed layer-by-layer by the additive application of material, and the induction loop being shaped to match the surface to be hardened.

The invention relates to a method for the induction hardening of a workpiece, in particular a toothed and/or corrugated and/or ribbed workpiece such as a gear or saw blade, wherein a matchingly shaped induction loop is guided or set over the workpiece surface to be hardened, the induction loop being formed layer-by-layer by the additive application of material, and the induction loop being shaped to match the surface to be hardened.

In the method according to the invention, a wire (11) provided with teeth (15) passes sequentially through a first inductor (16) and a second inductor (18). The inductors (16, 18) function at different frequencies and generate different temperatures. The first inductor (16) heats in particular the base section (17), which is not to be hardened, to a high temperature below the austenitizing temperature range. The second inductor (18) heats the teeth (15) to a still higher second temperature within the austenitizing temperature range. Defined, hardened teeth of consistently high quality result at quenching.

In the method according to the invention, a wire (11) provided with teeth (15) passes sequentially through a first inductor (16) and a second inductor (18). The inductors (16, 18) function at different frequencies and generate different temperatures. The first inductor (16) heats in particular the base section (17), which is not to be hardened, to a high temperature below the austenitizing temperature range. The second inductor (18) heats the teeth (15) to a still higher second temperature within the austenitizing temperature range. Defined, hardened teeth of consistently high quality result at quenching.

An apparatus for manufacturing a stress relieved length of steel having an oxidised surface layer includes: a heating chamber; a reaction chamber coupled to the heating chamber; and a conveying mechanism conveying the length of steel along a path through the heating chamber and reaction chamber. The heating chamber includes a heating apparatus arranged to heat the length of steel in a heating portion of the path. The apparatus further includes a control means including a sealed unit defined by the heating chamber and the reaction chamber and arranged to control both the temperature of the length of steel and the atmosphere to which the length of steel is exposed in an oxidisation portion of the path within the reaction chamber in which the oxidised surface layer is formed. A method of manufacturing a stress relieved length of steel having an oxidised surface layer is also disclosed.

An apparatus for manufacturing a stress relieved length of steel having an oxidised surface layer includes: a heating chamber; a reaction chamber coupled to the heating chamber; and a conveying mechanism conveying the length of steel along a path through the heating chamber and reaction chamber. The heating chamber includes a heating apparatus arranged to heat the length of steel in a heating portion of the path. The apparatus further includes a control means including a sealed unit defined by the heating chamber and the reaction chamber and arranged to control both the temperature of the length of steel and the atmosphere to which the length of steel is exposed in an oxidisation portion of the path within the reaction chamber in which the oxidised surface layer is formed. A method of manufacturing a stress relieved length of steel having an oxidised surface layer is also disclosed.

A cutting member for a saw chain and a method for the production thereof, the cutting member comprising a support part made of a steel alloy and a cutting part welded to the support part along a welding connection made of a high speed steel. The steel alloy of the support part is a tool steel that has the following composition (specifications in % by weight):

TABLE-US-00001 Carbon (C) 0.4 to 1.0 Silicon (Si) up to 1.8 Manganese (Mn) up to 0.6 Chromium (Cr) 4.5 to 12 Molybdenum (Mo) up to 3 Vanadium (V) up to 2
Iron (Fe) and accompany elements caused by melting and impurities as the remainder. The steel alloy of the support part in a quenched and tempered state has a hardness of more than 600 HV and a tensile strength of more than 2000 MPa as a result of curing at a suitable temperature above the austenitizing temperature of the high speed steel.

A cutting member for a saw chain and a method for the production thereof, the cutting member comprising a support part made of a steel alloy and a cutting part welded to the support part along a welding connection made of a high speed steel. The steel alloy of the support part is a tool steel that has the following composition (specifications in % by weight):

TABLE-US-00001 Carbon (C) 0.4 to 1.0 Silicon (Si) up to 1.8 Manganese (Mn) up to 0.6 Chromium (Cr) 4.5 to 12 Molybdenum (Mo) up to 3 Vanadium (V) up to 2
Iron (Fe) and accompany elements caused by melting and impurities as the remainder. The steel alloy of the support part in a quenched and tempered state has a hardness of more than 600 HV and a tensile strength of more than 2000 MPa as a result of curing at a suitable temperature above the austenitizing temperature of the high speed steel.

A steel for a sawing device (100) containing in wt. %: C: 0.7-1.2 Mn: 0.3-0.7 Cr: 0-1.05 Ni: 0-1.5 Al: 0-0.5 Si: 0-0.5 wherein the total amount of C, Mn, Cr, Ni, Al, and Si is 1.5-4.5 wt. % and the balance being Fe and incidental elements and wherein the microstructure of the steel alloy is bainitic or a mixture of bainite and martensite with dispersed Fe.sub.3C-particles.

A steel for a sawing device (100) containing in wt. %: C: 0.7-1.2 Mn: 0.3-0.7 Cr: 0-1.05 Ni: 0-1.5 Al: 0-0.5 Si: 0-0.5 wherein the total amount of C, Mn, Cr, Ni, Al, and Si is 1.5-4.5 wt. % and the balance being Fe and incidental elements and wherein the microstructure of the steel alloy is bainitic or a mixture of bainite and martensite with dispersed Fe.sub.3C-particles.