CONTROL PROCESS OF THE HEAT TREATMENT OF ALUMINIUM ALLOY STRIP

摘要

In the heat treatment of aluminium alloy strip, in which hardening of the material is effected by heat treatment to dissolve pre-existing precipitates in the metal matrix followed by quenching and ageing, the electrical conductance of the strip after qenching is measured using a conductivity probe scanned across the width of the strip, the heating being controlled in accordance with the measured conductance so as to obtain uniform electrical conductance across the width of the strip. This measured electrical conductance has a close correlation with the required mechanical properties. The conductance is measured by a transmitter (33) producing an electromagnetic field, which transmitter is movable on a C-shaped frame (35) across the strip. A receiver (36) picks up signals due to the eddy currents in the strip and provides an output processed in a computer system (57) to control the movement of flux modifiers of a transverse flux induction heater to control thereby the strip heating.