The temperature field distribution of the guide vane of heavy-duty gas turbine was analyzed by combining with precision casting experiment and numerical calculation.In addition

the forming process of shrinkage porosities was expounded by semi-quantitative theoretical calculation.The results reveal that the shrinkage porosities are closely related to the shrinkage volume in solidification stage

and the shrinkage volume is closely related to temperature gradient

wall thickness and mushy-zone width.Through increasing the temperature gradient in all directions

the shrinkage volume can be reduced to be eliminated.Meanwhile

it can also slow down the overheating of the casting on the core and shell side.