Screw with a partially hardened functional tip and process for the production thereof
AssigneeEJOT GmbH & Co. KG
InventorsHeinrich Friederich, Christof Homrighausen
Life of this patent
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Abstract
In a process for the production of a screw comprising a low-alloy carbon steel, having a head, an adjoining holding portion and a functional tip which, in the outer region of limited radial depth, is of a greater hardness than the holding portion, in which the screw body is shaped by pressing and rolling and then the functional tip is subjected to a hardening operation, hardening is effected by momentary heating with a high level of energy transfer and subsequent quenching and is limited to portions of the periphery of the functional tip.
Claims15
A process for the production of a screw comprising a low-alloy carbon steel, having a head, an adjoining holding portion and a functional tip, said tip having an outer region of limited radial depth, being of a greater hardness than the holding portion,
- wherein the screw body is shaped by pressing and rolling and then the functional tip is subjected to a hardening operation,
- wherein hardening is effected by momentary heating with a high level of energy transfer and subsequent quenching and is limited to portions of the periphery of the functional tip,
- and wherein the radial depth of the momentary heating which causes the increased hardness, is reduced in the axial direction from the beginning of the functional tip towards the head.
A process for the production of a screw body comprising a low-alloy carbon steel having a head, an adjoining holding portion;
- and a functional tip, said tip having an outer peripheral region of limited radial depth, formed by the process of:
- shaping the screw body by pressing and rolling subjecting the functional tip to a hardening operation comprising momentarily heating with a high level of energy transfer and subsequent quenching limited only to the portions of the outer periphery of the functional tip and further including the step of reducing the momentary heating along the periphery from in an axial direction from the beginning of the functional tip towards the head, so that the hardness is likewise reduced in said axial direction.
Dependencies are inferred from the claim text.