Flexibility and Utilization of Roll Pass Sequences in some Swedish Wire Rod Mills

Abstract

A computer program has been developed to calculate the working range for series of two-symmetrical grooves including oval, round, false round, square and diamond shapes. Eight different pass designs are compared. The geometry of rolling or entry bar height over roll radius is in the range 0.09-0.26 for squares, 0.10-0.23 for false round and 0.06-0.21 for ovals. Square-oval and round-oval have similar flexibility, but in the round-oval sequence, the flexibility can be extended by opening up the gaps and run the rounds as false rounds. In the square-oval sequence the flexibility can be improved by making the squares with larger corner radii but the reduction capability will be reduced. The false round-oval sequence has the best flexibility and the working range can be extended by making “flatter” ovals. Improvement of the roll pass design in Fagersta Stainless AB has made it possible to roll wire rod with higher flexibility and better quality.