Improvement in Cold Shear Yield of Bar Mill by Computer Control System

Abstract

The rate of crop loss in bar production is greater than those of other products.
The reason is that bars devided in rolling line are sheared again simultaneously to specific lengths.Furthermore, this loss depends on the quality demanded and facilities of shearing as well as billet weight and bar size. Therefore improvement of equipment such as shear mechanism or measuring instrument is as important as sophistication of software to increase the yield.
As a result of computer simulation for Nippon Steel's new bar mill, in 1973, Dynamic Programming was found effective for minimizing crop loss and improving productivity. These results were used for modification of equipment plan under construction. In actual bar mill erected in 1974, the highly functional shearing machine and basic "Shearing schedule" were installed as a part of the total computer control system. After integral improvement of software and instruments in two stages, the yield has reached above 97.6%.
Additional approaches would become necessary in the next step such as systematization including decision of optimum billet length and introduction of Dynamic Programming to online system.