Low permeability molds and low pouring temperature of the molten metal causes ......................... defect in castings.

For casting of turbine blades made of high temp and high strength alloys, the most suitable process is

The problem of shrinkage cavity is more likely to occur while casting ......... A ............ B.......... a chill block

(A.) metal / plastic , (B.) with / without.

Negative allowance is provided on the pattern to take care of