North Star BlueScope Steel Quality Productivity Improvements After Conversion From A 90mm To A 100mm Slab Thickness

摘要

North Star BlueScope Steel's Caster was a 90mm x 960mm - 1560mm Sumitomo Heavy Industries parallel mold design, casting at 4.0 - 4.8 m/min, with throughputs from 3.27 TPM to 4.64 TPM, utilizing an EMBR brake to help control SEN/ mold flow, producing 1.8 M TPY of hot band coil product Higher cast speeds, up to 5.2m/min. were trialed with the 90mm slab to fully utilize the 15.7 meter metallurgical length which would allow productivity to be improved up to 2.0M TPY to match the EAF MORE burner system upgrade. Caster steel flow and quality problems indicated the difficulty of this route. After undergoing a thorough product quality evaluation, the 15mm gap between the SEN and the copper wall was identified as being too restrictive to be able to promote good mold powder lubrication & steel flow, in order to prevent longitudinal crack generation. A decision was made to change the caster to a 100mm mold design, to increase the gap, improve surface quality and create the opportunity to fully utilize the machine's metallurgical length in order to be able to match the EAF's 2.0 M TPY capability of quality product. This paper will review the quality measurement systems development, identification of specific problem areas, machine conversion issues and the productivity, quality & cost benefits from in converting from a 90mm to 100mm slab.