Casting And Welding

Chills are used in casting moulds to

• Achieve directional solidification

• Reduce the roughness of top surface of the casting product

• Increase the solidification time

• Reverse excess molten metal

In sand casting fluidity of the molten metal increases with

• Increases in degree of super heat

• Decrease in pouring rate

• Increase in thermal conductivity of mold

• Increase in sand grain size

Which of the following casting processes uses expandable pattern and expandable mold

• Shell mold casting

• Investment casting

• Pressure die casting

• Centrifugal casting

Hot chamber die casting is NOT suited for

• Lead and its alloys

• Zinc and its alloys

• Tin and its alloys

• Aluminium and its alloys

Which one of the following is NOT a property of a sand mold?

• Permeability

• Collapsibility

• Strength

• Fluidity

The primary function of a riser is to

• Feed molten metal to casting as it solidifies

• Prevent atmospheric air from contaminating the metal in the mold

• Allow gases to easily escape from mould cavity

• Allow molten metal to raise above mould cavity

Investment casting uses (a)   as pattern material and is preferred for small parts with simple and intricate designs.

Chaplets are placed between mold in order to

• Promote directional solidification

• Help alloying the metal

• Facilitate easy removal of core from casting

• Prevent core movement due to buoyancy

Ceramic slurry is used in making the molds for

• Investment casting

• Die casting

• Shell mold casting

• Centrifugal casting

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

• Die casting

• Investment Casting

• Centrifugal casting

• Slush Casting