Device for zone-annealing of a workpiece consisting of a high-temperature material, and zone-annealing process

摘要

In a device and process for zone-annealing a workpiece (1) of a high-temperature material, the workpiece (1) is suspended on a suspending device (2) actuated by a drive motor (4) via a roll (3) and is provided with a plate-shaped covering diaphragm (10) having an orifice. For immersing the workpiece (1), a salt bath (5) is provided underneath thereof, the salt bath being enclosed in an insulating vessel (6), being provided with a heater (7) having centrally symmetrical baffles (8) and with a floating insulating cover (9) which seals the top. Cooling of the non-immersed part of the workpiece (1) is ensured by a cooling body (11), bearing a flow of cooling air (14), with a central passage (12) and a rim (13) serving as a stop for the covering diaphragm (10) and projecting at the lower end of the passage (12). A controlled grain structure is adjustable by in each case sectional variation of the advancing speed of the workpiece (1) by means of the drive motor (4) and the rate of cooling air (14). Reduction of the lateral heat flux by shell-like insulating facings of the workpiece (1). <IMAGE>