Numerical simulation of temperature field in solidification process of large Zn based bearing bush was carried out to predict potential shrinkage porosities （holes） and its potential position in the parts and to understand effects of flow velocity of cooling water in permanent mold and cooling time on liquid phase solidification

temperature gradient distribution and shrinkage porosities （holes）.Based on simulated result

origination of shrinkage porosities （holes） occurred in the practical products was described.And the processing optimization was conducted.The practical production verifies that shrinkage porosities （holes） can be eliminated by setting chill at the bottom of water cooling permanent mold casting bearing bush to cool hot spot from the bottom and inner surface simultaneously.