# US 9,518,318 B2 · Method and device for hardening work pieces and workpieces hardened according to said method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,318 B2 - Document ID: US9518318B2 - Status: Granted - Kind: B2 - Application number: 13/394,795 - Filed: 2010-09-06 - Published: 2012-07-05 - Granted: 2016-12-13 - Earliest claimed: 2009-09-10 - Assignees: ALD Vacuum Technologies GmbH - Applicants: Volker Heuer; Klaus Loeser; Gunther Schmitt; Gerhard Welzig - Inventors: Volker Heuer; Klaus Loeser; Gunther Schmitt; Gerhard Welzig - Web page: https://patentgrep.com/patent/US9518318B2 ## CPC - C23C 8/02: Pretreatment of the material to be coated (C23C8/04 takes precedence) - C23C 8/06: using gases (C23C8/36 takes precedence) - C23C 8/20: Carburising - C23C 8/22: of ferrous surfaces - C23C 8/24: Nitriding - C23C 8/26: of ferrous surfaces - C23C 8/80: After-treatment - C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04) ## Abstract The invention relates to a method and device for thermally treating workpieces, the device including a cooling chamber and two or more carburizing chambers in which the work pieces are heated to a temperature of 950 to 1200° C. by means of direct heat radiation from a heating device. ## Claims ### Claim 1 A device for hardening metallic workpieces comprising a rack designed to hold workpieces arranged in one layer or row, two or more carburizing chambers, at least one cooling chamber, a lock chamber arranged between the carburizing chambers and the cooling chamber, and a transfer system for handling racks for the workpieces, wherein the cooling chamber can be connected to the lock chamber via a vacuum gate valve, each of the carburizing chambers can be connected to the lock chamber via thermal insulation gate valves, and each of the carburizing chambers has a receptacle for the rack and at least two heating elements consisting of graphite or carbon-fiber-reinforced carbon, said heating elements positioned to emit radiation directly onto the surface of each of the workpieces at an average solid angle of 0.5 π to 2 π, and said heating elements are meandering heaters having a U-shaped serpentine form disposed on a bottom side and a top side of each of the carburizing chambers, wherein the lock chamber further comprises a rack repository, and the cycle time based on one workpiece is 5 to 120 seconds. ### Claim 2 (depends on 1) The device as claimed in claim 1, wherein the thermal insulation gate valves are vacuum gate valves. ### Claim 3 (depends on 1) The device as claimed in claim 1, wherein the transfer system comprises vertically arranged chain drives with upper and lower guides and chains and also a horizontally movable telescopic fork for receiving pallets, wherein the telescopic fork is coupled to one of the chains via a gearing mechanism. ### Claim 4 (depends on 1) The device for hardening workpieces as claimed in claim 1, wherein the racks are grid-like pallets. ### Claim 5 (depends on 4) The device for hardening workpieces as claimed in claim 4, wherein the pallets have an opening ratio of greater than 60%. ### Claim 6 (depends on 5) The device for hardening workpieces as claimed in claim 5, wherein the racks consist of carbon-fiber-reinforced carbon. ### Claim 7 (depends on 1) The device for hardening workpieces as claimed in claim 1, wherein the carburizing chambers further comprise a multilayer lining of graphite plate as a heat-storing material and graphite felt as a thermally insulating material. ### Claim 8 (depends on 1) The device for hardening workpieces as claimed in claim 1, wherein said parking receptacle is arranged vertically relative to the carburizing chambers. ### Claim 9 (depends on 1) The device for hardening workpieces as claimed in claim 1, wherein said cooling chamber, said lock chamber and said carburizing chamber are evacuated independently of one another. ### Claim 10 (depends on 1) The device for hardening workpieces as claimed in claim 1, wherein said device comprises chambers consisting of said carburizing chambers, at least one cooling chamber and said lock chamber. ### Claim 11 (depends on 1) The device for hardening workpieces as claimed in claim 1, wherein said rack is selected from a grid-like pallet, frame with suspension brackets or a support plate with spikes or bores. ### Claim 12 A hardening system comprising (i) metallic workpieces arranged in a single layer on a grid-like pallet having an opening ratio of greater than 60% and (ii) a device for hardening workpieces comprising four or more carburizing chambers, at least One cooling chamber, a lock chamber arranged between the carburizing chambers and the cooling chamber, a transfer system, and a pallet repository, wherein die cooling chamber can be connected to the lock chamber via a vacuum gate valve, each of the carburizing chamber can be connected to the lock chamber via thermal insulation gate valves, and each of the carburizing chambers consists essentially of (i) lined walls; (ii) a gate valve; (iii) a receptacle for the grid-like pallet and (iv) at least two heating elements consisting of graphite or carbon-fiber-reinforced carbon and (v) connections far gas and vacuum, said heating elements positioned to emit radiation directly onto the surface of each of the workpieces at an average solid angle of 0.5 π to 2 π and said heating elements are meandering heaters having a U-shaped serpentine form disposed on a bottom side and a top side of each of the carburizing chambers, wherein the cycle time based on one workpiece is 5 to 120 seconds.