SYSTEM AND METHOD FOR ANNEALING OF AN ITEM, WHICH COMPRISES HEAT-SENSITIVE PARTS AND ANNEALED ITEM

摘要

A method and a system (11) for stress-relieving annealing one or more first parts (4) of a workpiece (1), wherein a second part (3) of the workpiece contains heat-sensitive parts. A cooling jacket (8) is placed around the part (3) of the workpiece surrounding heat-sensitive parts such that the part or parts (4) to be annealed are located outside the cooling jacket (8). The first part or parts (4) are then heated individually by induction up to the annealing temperature of the material in a first annealing zone (12) in the system under simultaneous cooling of the second part of the workpiece located in the cooling jacket (8). After annealing, the workpiece is cooled in a cooling zone (13) in the system, as annealing as well as cooling of the workpiece occurs under a protecting atmosphere. It will be possible to make a metal workpiece by shaping the workpiece and place heat-sensitive parts in a second part of the workpiece before stress-relieving annealing a first part of the workpiece without the heat-sensitive parts of the second part of the workpiece being damaged by heat during the annealing operation. The annealed workpiece is e.g. connection ends on a valve housing where the connection ends (4) are shaped by plastic deformation after mounting valve seats, valve body etc. in the central part (3) of the valve housing.