Influence of casting parameters on shrinkage porosity of a 19 ton steel ingot

摘要

In order to improve metal yield during manufacture of steel ingots, influences of casting parameters on the shrinkage porosity of a 19 ton steel ingot were investigated by numerical simulation. A three-dimensional numerical model of filling and solidification of a 19 ton steel ingot was developed. The model was validated by method of infrared temperature surveying. Based on this model, a series of numerical experiments was carried out and the influences of casting parameters such as height-to-diameter ratio (H/D), taper, height of insulation, pouring temperature and pouring rate on the depth of shrinkage cavity and the tightness in structure were investigated. Two dimensionless factors were proposed to help to evaluate the effect of these casting parameters on the shrinkage porosity. In which, the absolute difference of the maximum and minimum values of each parameter allowed in industrial process, the difference of the two values used in the simulation of each parameter and the difference of the depth of shrinkage cavities calculated under the smaller and larger values of each parameter were all taken into consideration. Results show that decreasing taper, pouring rate and H/D ratio, or increasing height of insulation can all reduce the depth of shrinkage cavity in the ingot effectively so as to improve the metal yield. While, pouring temperature almost has no influence on the depth of shrinkage cavity. H/D ratio and pouring rate have significant negative correlations with density ratio of the ingot. On the contrary, taper has a positive correlation with density ratio of the ingot. Pouring temperature and height of insulation have few influences on the density ratio of the ingot. Decreasing H/D ratio and pouring rate within acceptable limits can reduce the depth of shrinkage cavity and increase the density ratio significantly.