Euroguss and TAV
TAV was not personally present at Euroguss. After all, it was not even a trade fair for the presentation of heat treatment equipment. Even so, I was surprised when a banner with a tempering and annealing furnace from TAV Vacuum Furnaces was placed at the Voestalpine stand with Bohler and Eifeler.
Not only does it look nice, but in my opinion it is also a quality furnace for tempering, annealing and other thermal operations up to 750 C, with the possibility of processing in nitrogen or argon. The furnace is also extremely suitable for use in additive technologies, including the processing of parts from MIM technology, which will be subsequently hardened and tempered, because it is not sensitive to possible contamination of parts from previous operations.
The reason is the construction of the heating elements, where all the electrical connection is made from the outside of the furnace. This prevents a possible electrical short circuit at the joints of the heating elements or the insulating ceramics inside the heating chamber, and the furnace is therefore highly reliable even for processes where we cannot ensure 100% cleanliness of the parts.
This can be critical, for example, for cold drawn or hot formed parts that use graphite grease to reduce tool-to-part friction. It is not always possible to wash the parts completely before the heat treatment, and this graphite in the form of graphite dust then enters the entire furnace space. It settles as an electrically conductive layer on insulating ceramics and sooner or later a short circuit occurs on the heating elements.
From personal experience, I have verified that in some applications, the vacuum tempering and annealing furnace can be degraded in one week, resulting in the need to replace all ceramic parts in the furnace, including fused resistors.
June 14, 2022
Jiří Stanislav
