Abstract: For the partial heat treatment of tools which have a work surface and a clamping in region, there is disclosed a furnace, the useful space of which is subdivided into two separate heating spaces by a plate made of heat insulating material whereby the temperature in these heating spaces is lowered by disconnection of the connecting members between the individual heating elements of the all-around heating and the clamping in region of the work tools may be maintained below the conversion temperature of the metal.

Abstract: There is obtained a continuous rapidly responding and controllable measurement of the quenching intensity of quenching baths. A test body is inserted into the bath and a controlled heating is applied to a portion of the surface of the test body raising the temperature of that portion of the test body surface to a constant temperature of 50.degree. to 700.degree. C., especially 150.degree. to 400.degree. C. higher than the temperature of the bath. The heat energy required to maintain this temperature constant is used as a measure of the quenching intensity of the bath.

Abstract: There is provided a vacuum furnace with graphite heating consisting essentially of the furnace body and heating elements wherein the heating elements are made of flexible thin graphite sheets having a thickness of 0.5-3 mm.

Abstract: There is provided a furnace for tempering and hardening workpieces comprising an annealing chamber and a quenching chamber constructed as a fluidized bed, the quenching chamber is arranged below the annealing chamber, the fluidized bed which is stationary during the annealing treatment serves as bottom temperature insulation for the annealing chamber, and the lateral heat insulation of the annealing chamber is extended to below the surface of the stationary fluidized bed.