Berstoff Gmbh

Volker Wesling

Michael Behling

Uwe Motzkau

A process for producing a barrel for a twin-screw extruder with intermeshing screws from a steel block, wherein the barrel has a wear resistant inner surface, includes producing two partially intersecting bores passing completely through the steel block, the two intersecting bores forming a spectacle-shaped bore having narrowed regions where the two intersecting bores intersect, and hardening an inner surface of the spectacle-shaped bore with essentially constant depth of penetration by passing an inductor through the spectacle-shaped bore from one end to the other, the inductor is smaller than but having approximately the same shape as the inner contour of the spectacle-shaped bore and is configured such that less energy for heating the inner surface of the spectacle-shaped bore is delivered in the vicinity of the two narrowed regions of the spectacle-shaped bore by the longitudinal sections on the periphery of the inductor than in regions on the inner contour remote from the narrowed regions.

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Clausthal-Zellerfeld, Germany

Volker Wesling