Ald Vacuum Technologies Gmbh

Ald Vacuum Technologies Ag

Klaus Löser

Volker Heuer

Friedrich Preisser

Paul Heilmann

Gunther Schmitt

Wilfried Zenker

Gerhard Welzig

A process and apparatus for thermochemically hardening workpieces is provided incorporating the following steps, carried out in a variable sequence: one or more carburizing steps, each in a carbon-containing gas atmosphere at a pressure of less than 50 mbar, the workpieces being held at temperatures of 900 to 1050&#xb0; C.; if appropriate, one or more diffusion steps, each in a gas atmosphere at a pressure of less than 100 mbar; and one or more nitriding steps, each in a nitrogen-containing discharge plasma at a pressure of less than 50 mbar, the workpieces being held at temperatures of 800 to 1050&#xb0; C.

Process and apparatus for thermochemically hardening workpieces

The invention relates to a method and device for thermally treating workpieces, the device including a cooling chamber and two or more carburizing or heating chambers in which the workpieces are heated to a temperature of 950 to 1200&#xb0; C. by means of radiation, such as direct heat radiation from a heating device.

Method and device for hardening workpieces, and workpieces hardened according to the method

An apparatus for the heat treatment of work pieces comprising comprising a plurality of evacuable chambers connected through airlocks, a conveyor, preferably a circular chain conveyor for the transport of the workpieces along a path through the chambers, an electric resistance heating device, a cooling blower, and a heat exchanger, a plurality of workpieces of equal size and configuration, in particular hacksaw blades, are placed tightly one on top of another and form a stack which is placed into a frame made of profile cuts, whereby the frame is capable of being coupled to a conveyor by means of suspension elements.

Apparatus for the heat treatment of workpieces

Workpieces are quenched by gases in a heat-treatment system (1) and the circulated gases are recooled on cooling surfaces (12, 15) in at least one heat exchanger (11, 14), the cooling surfaces (15) of the heat exchanger (14) are cooled by a primary refrigeration unit (20) and a refrigerant to temperatures below 0.degree. C., preferably to temperatures below -20.degree. C. or even below -40.degree. C., to increase the intensity of the quenching. To reduce the size and power of the refrigeration unit (20), the quenching gas is sent in succession through at least one heat exchanger (11) cooled with water and at least one heat exchanger (14) cooled by a refrigerant. To reduce the size and power of the refrigeration unit (20) even further, this unit and a secondary refrigerant are used initially to cool down a storage volume of the primary refrigerant, such as a cooling brine, being stored under little or no pressure, to a temperature below 0.degree. C., whereupon this primary refrigerant is sent through the heat exchanger (14), at least one of which is present.

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Mainhausen, Germany

Klaus Löser