METHOD FOR PRODUCING A SNAIL FOR AN EXTRUDER AND SNAIL

摘要

The worm (11) is provided with a wear protection layer (13) at least in one section and is preferably provided with a sliding layer (18) in at least one other section. A bed (12) for the wear protection layer (13) is initially formed in a full bar (11 '), in which the wear protection layer (13) is then applied and finally the intermediate spaces (14) between the screw flights (15) are formed. According to the invention, the wear protection layer (13), e.g. made of tungsten carbide, by build-up welding and forms the intermediate spaces (14) with a lateral distance (16, 16 ') to the wear protection layer (13). In order to produce the sliding layer, the worm (11) is then brought in the section or sections where the sliding layer, e.g. made of molybdenum, to be applied to undersize, but it provides a lateral distance (19) for wear protection layer. Thereafter, in the area (17) with undersize, the sliding layer is applied. Finally, bring the worm (11) to the specified size.