High speed SBQ casting at Chaparral Steel

Chaparral Steel is a 1.8 million ton per year "market mill" located just So uth of Dallas, Texas. Our current product mix consists of 75% structural, 2 0% special bar quality (SBQ) and 5% rebar. This production is achieved with two ultra high powered EAFs, three casters, two structural mills and one b ar mill. In the summer of 1995, Chaparral Steel converted the SBQ, four strand 5 x 6 34" easter to high speed casting. Prior to that conversion "A" easter would run at approximately 85 tons per hour, which caused a bottleneck: in the s hop because the furnace could out-pace the casting machine. Consequently Fu rnace delays were very frequent. With the advent of high speed casting, the casting speed increased from 80 to 120" per minute. "A" easter can now run at more than 140 tons per hour, easily outpacing "A" furnace. This allows us to run most of the time with t hree strands operating, essentially leaving one strand as an in-line spare. This in-lint spare gives us the flexibility to either terminate cast on a strand with quality problems, or run on four strands when extra short term casting capacity is required. (C) 2000 Published by Elsevier Science Ltd on behalf of the Canadian Institute of Mining and Metallurgy. All rights rese rved.