(p60) Tundish and SEN Development for casting long sequences of wide slabs at TATA LD3 CSP~R- India

摘要

Three years after the commissioning of the first CSP~R thin slab caster at Tata LD3 in Jamshedpur, India, the tundishsequence length was increased to improve productivity, while casting higher quality steel grades in wide slabs for (LPGcylinders, cold rolling, wheel/ Disc, tube making) applications. Increased productivity is demanding higher castingspeeds even for wide slabs despite absence of any Electro Magnetic Brake. The mold flow has been optimized toachieve these challenging casting conditions. Tundish life was increased from 10 heats maximum to more than 24heats or more than 21 hours nowadays through implementation of higher performance refractories related to bothdesign and material for the tundish furniture, the stopper and the Sub-Entry-Nozzle (SEN). Extensive numerical andphysical simulations have been conducted to determine the different measurable parameters for tundish and mold flowimprovements. Increased minimum residence time, improved inclusion floatation and turbulence reduction have beenobtained after re-designing the internal tundish geometry. A new SEN producing stable meniscus flow and optimalmold temperature distribution allowed longer sequence of wide slabs to be cast in a thin slab caster. In addition tothese refractory enhancements, TATA has significantly improved their casting parameters and stabilized the processesinvolved. The steel cleanliness levels have improved over time with tighter control on calcium levels in steel (averageof 23 ppm in tundish) and lower Aluminum levels in steel (0.037% average). Due to better co-ordination between thesteelmaking & casting shop the speed fluctuations have been reduced and higher speeds of over 5 m/min have beenrealized on a consistent basis. Stable casting conditions have resulted in better refractory performance.