Improvement in Mill Performance through Precise positioning of the Billet Distribution Table in 4-strand Wire Rod Mill, Bhilai Steel Plant

摘要

Wire Rod Mill of BSP is a continuous mill comprising of charging area, one common reheating furnace, a four strand roughing & first intermediate group and four finishing strands followed by coil handling area. The 105 mm X105 mm cross-section billets are discharged from the furnace through Ejector Ram and fed into strands for rolling through a Billet Feeding System. The billets are then rolled through roughing group comprising of stand 1-9 and a first intermediate group comprising of stands 10-15. Billet feeding into the 4 strands is accomplished with the help of billet feeding mechanisms comprising of Distribution Table (DT), Draw Out Roller (DOR) & Pinch Rolls (PR). The existing control system of the billet feeding mechanisms and other associated operations was based on hardwired relay logic. Positioning of DT to feed billets in different strands was achieved using Rotary limit Switch and Slip ring AC motor. This system was prone to mechanical failures of the limit switch and electrical breakdowns. The accuracy of positioning and repeatability was not as desired, requiring frequent adjustment of the CAM and resulting in unwanted disruption of the production process.