Experimental Study on Mold Flux Lubrication for Continuous Casting

Abstract

A new experimental apparatus for simulating mold oscillation of continuous casting was developed to clarify the flux lubrication mechanism in mold channel. Mixed oil which was simulated mold flux was poured and infiltrated down into the channel, and the consumption, liquid level and pressure of mixed oil were detected in the process of oscillation as well as the mechanism of flux process. The results show that the channel of flux with a profile becomes wider along the casting direction, and the lag time of periodical shifting pressure to the oscillating motion is strongly dependent on the flux viscosity and oscillation frequency. The liquid film thickness of flux has a significant influence on the infiltration behavior compared with the oscillating motion of the mold. The liquid flux infiltrates down from the end of positive strip time to the beginning of next positive strip time, and the infiltration is largely dependent on the negative strip time in between. The increase of viscosity of flux, casting speed and oscillation frequency enhances the liquid friction due to the reduction of the mold flux consumption. On the contrary, the higher non-sinusoidal oscillation factor improves the infiltration and decreases the frictional force. The oscillation amplitude increases the consumption and liquid friction slightly.

Mold Nonsinusoidal Oscillation Mode and Its Effect on Slag Infiltration for Lubrication and Initial Shell Growth during Steel Continuous Casting

“…Yang et al 2014 [17,18] Mathematical model Increasing α to 0.24 slightly increased slag consumption by 2.4% and the predicted slag consumption enhanced as the increases of α.…”

“…The required level of the compressive force imposed on the solidified shell increases with increased relative speed during tn and, due to the elongation of tp, the decreased relative speed in tp between the mold and strand can reduce the tensile force exerted on the solidified shell, which may be critical to solder surface cracking and strand demolding [4]. Several industrial trials and laboratory experiments [6,7,9,10,[14][15][16][17][18][19] have been conducted to investigate the influence of nonsinusoidal oscillation mode on the continuous casting process, as summarized in Table 1. Table 1.…”

Initial Solidification and Its Related Heat Transfer Phenomena in the Continuous Casting Mold

“…The temperature of molten slag on the top of liquid pool is relatively lower than the molten steel. The cooler molten slag will be pumped into the shell/mold gap with the help of natural gravity and mold oscillation . According to Ramirez‐Lopez, the combination of quick slag flow into the gap and the widening of liquid layer thickness during the negative strip time ( t n ) produces a convective cooling effect, which would enhance the initial solidification and increase the heat flux during the t n .…”

Formation of Initial Defects at Meniscus in Oscillating Mold

“…Fundamentally, the force acting on the initial solidifying shell is the direct reason of cracks formation. Aiming at the stress state in meniscus, many action mechanisms were proposed for the defects formation in solidified shell, including the flux channel pressure and the friction acting on the shell …”