Loi Thermprocess Gmbh

Walter Scheuermann

Georg Velten

Friedhelm Kuhn

Frank Maschler

A top hat furnace especially adapted for annealing steel sheet metal using a protective gas includes a protective top surrounding the batches of sheet steel metal. A cooling top is arranged above the protective top forming an intermediate space. The cooling top has a cover and a lid. The cover of the cooling top has a plurality of air nozzles so that cooling air impacts the protective top in the form of jets. At least one fan produces a flow of cooling air in the intermediate space. The distance between the air nozzles increases from the bottom of the cover towards it upper end. The distance between the nozzles is from four to twelve times greater than is the diameter of each nozzle. The cooling lid is also provided with a plurality of air nozzles. The distance between the nozzles in the cooling lid is from four to seven times greater than is the diameter of each of these nozzles.

Bell-shaped furnace

Method and device for exchanging the atmosphere in a hood-shaped

Process for annealing an annealing charge and suitable annealing furnace

The present invention relates to a method for annealing metal parts, in particular sheets, in an annealing chamber of an industrial furnace under a protective-gas atmosphere, wherein the annealing comprises a heating phase, a soaking phase and a cooling phase. The annealing chamber is purged during the heating phase with hydrogen or gas rich in hydrogen until the protective gas predominantly contains hydrogen. According to the present invention a purging with an inert gas is performed towards the end of the heating phase to reduce the percentage of hydrogen in the protective gas so that the formation of carbon-containing breakdown products is largely avoided. This prevents the formation of annealing edges during the soaking phase. Towards the end of the soaking phase, a purging with hydrogen or gas rich in hydrogen is performed until the protective gas predominantly contains hydrogen and carbon-containing deposits can be removed.

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Bonn, Germany

Walter Scheuermann