SPULENWICKLUNGSVERFAHREN FÜR METALL IN DEN STÄBEN

Coil winding method for steel bars providing, at the outlet of the rolling mill ( 2 ), cooling stages by means of WB ( 4', 4'', 4 ''') and equallsation in air so as to perform "soft" hardening on the bar which generates a microstructure consisting, on the surface, of martensite and bainite and, in the center, of ferrite and pearlite, and winding of the bar in the form of a compact coil by means of a coil winder ( 5 ). In the position wound on the coil, the bar cools slowly with tempering of the bainite and martensite formed on the surface. This is followed by a straightening stage, jo performed during the coil unwinding phase, and a natural ageing stage, maintaining the bar at ambient temperature.