Simulating Study on the Shrinkage Cavity and Porosity of a Microalloyed Steel Ingot

Abstract

A 3D solidification model coupling heat transfer, solidification, and shrinkage porosity are established. The effect of melting temperature and cooling modes on the solidification time, shrinkage cavity, and porosity is investigated by the simulation. When the melting temperatures are 1510, 1530, and 1550 °C, the depth of the shrinkage cavity changes little, and they are about 44.8 mm. Maximal shrinkage porosity below the shrinkage cavity are 79.0%, 80.5%, and 82.0%, respectively. When the melting temperature is 1570 °C, the depth of the shrinkage cavity increases to 52.7 mm, and the maximal shrinkage porosity below the shrinkage cavity decreases to 75.5%. For three cooling modes, water cooling, air cooling, and furnace cooling, the cooling intensity gradually decreases, the solidification time increases, and the time of complete solidification is 72.0, 218.5, and 1382.2 s, respectively. With the decrease of cooling intensity, the shrinkage cavity shape and depth of the ingot vary obviously, and the depth of the V-shaped shrinkage cavity is 39.9, 44.6, and 0 mm. The maximal shrinkage porosity is 76.0%, 82.0%, and 90.9%, respectively. Considering solidification time, shrinkage cavity, and porosity, water cooling mode should be used to obtain the dense internal quality of the steel ingot.