1981 Volume 67 Issue 8 Pages 1190-1199
Simulation experiments using Mould Simulator developed by the authors and plant trials have been carried out to investigate the formation mechanism of oscillation marks and the factors affecting powder consumption rate in continuous casting.
Following results were obtained through the experiments.
1) Oscillation marks are formed as a result of interaction between solidified shell and very viscous layer of mould powder at the circumference of molten steel surface in a mould.
2) Depth of oscillation marks increases as the negative strip time of the mould oscillation cycle increases.
3) Consumption rate of mould powder, q is proportional to the positive strip time.
Low frequency mould oscillation mode with decreased amplitude has been proposed to obtain shallow oscillation marks and high consumption rate of powder for a fixed powder property.
Besides the above stated proposal, several measures which were not well documented have been studied in order to produce slabs without surface defects such as slag spots, transverse corner cracks and longitudinal facial cracks.
The results obtained are listed below.
1) Proposed mould oscillation mode is effective for reducing both slag spots and transverse corner cracks.
2) Stable molten steel level in a mould during casting is very important for decreasing both slag spots and longitudinal facial cracks.
3) A suitable viscosity range of the powder exists for minimizing the frequency of longitudinal facial cracks.