2019 Volume 105 Issue 8 Pages 785-792
In order to formulate shrinkage behavior of sinter during softening process, the effects of load and reducing gas concentration on the shrinkage rate of sinter packed bed has been investigated using a softening-melting furnace. As a result, the shrinkage rate increased with increasing the load on 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 shrinkage mechanisms vary depending on temperature.
In this study, softening process 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 softening viscosity. In the region II, the shrinkage rate increased in proportion to the generation rate of melt, and decreased with increasing the volume of metallic iron in the packed bed. The shrinkage in region II was inhibited with increasing the reduction degree of sinter since formed metallic iron served in the role of aggregate. The shrinkage rate of each region was expressed as functions of initial concentration of sinter, load, temperature, and reduction degree. The calculated values were in good agreement with the experimental ones.
