9th ECCC European Continuous Casting Conference – ECCC 2017

Demands on high profits and low costs in steelmaking industries are increasing and increasing recently as a result of strong global competition. The continuous casting process has been a good solution until now because of a high yield, energy saving, and omission of blooming process. But there remains to be solved the problem of how to cast an extra large section size strand and high-alloy specialty steel to replace ingot casting process. Therefore a large bloom ingot continuous caster(LICC) was developed by POSCO with ultra low casting speed and more than 120 heat were cast through the LICC pilot caster of 700(T)x700(W)x3000(L)mm bloom. During casting, fluctuation of casting speeds which was 0.05m/min ±0.05mm by LICC occurred due to oscillation movement. It has been solved by optimum oscillation mode derived from various operating parameters. Initial solidification behavior such as heat transfer, fluid flow and solidifying shell thickness in the mold and surface quality of the strand were investigated for various casting conditions such as casting speeds, mold shapes, oscillation modes, mold EMS conditions, and steel grades. It was found that the initial solidification behavior in LICC strand should be much different from that in a conventional section size strand and surface quality be mainly affected by casting speeds and fluctuation of molten steel level. Key Words: extra large section size, LICC, ultra low casting speed, LICC pilot caster, initial solidification behavior