2020 Volume 60 Issue 7 Pages 1487-1494
In order to clear shrinkage behavior of sinter during softening process, the effects of load and reducing gas condition on the shrinkage rate of sinter packed bed has been investigated using an experimental apparatus for measuring high temperature properties under load. As a result, the shrinkage rate increased with increasing the load impressed to the packed bed in temperature range from 1270 to 1440 K, and decreased with increasing the reduction degree of sinter in temperature range from 1470 to 1570 K. The results indicate that the mechanism of shrinkage was different depending on temperature.
In this study, the shrinkage rate of sinter was formulated by dividing into two temperature regions. In the region I, the shrinkage rate increased in proportional to the impressed load, and increased in inversely proportional to the apparent softening viscosity. In the region II, the shrinkage rate increased in proportion to the generation rate of melt, and decreased with increasing the volume fraction of metallic iron in the packed bed. The shrinkage in region II was suppressed with increasing the reduction degree of sinter since the generation rate of melt decreased and the volume fraction of metallic iron increased. The shrinkage rate of each region was expressed as functions of initial composition of sinter, load, temperature, and reduction degree. The calculated values were in good agreement with the experimental ones.
