A. Prevent the oxidation of the metal during melting
B. increase the melting point of the flux
C. Flaring the point of the sprue attachment
D. None of the above
Related Mcqs:
- Flux is used during casting to________________?
A. Remove the oxides formed on the gold alloy
B. Lower the melting point
C. Replace casting wax
D. Speed the burnout process - Fins and spines on the casting is seen due to_______________?
A. Prolonged heating:
B. Rapid heating me
C. Water film contamination
D. Too high pressure during casting - Addition of large amounts of platinum to a casting gold alloy will________________?
A. Decrease its strength and ability to be hardened
B. Decrease its tarnish resistance
C. Increase its fusion temperature
D. Redden the alloy - Incomplete casting is the result of_____________?
A. More porous investment in the mould
B. Narrow sprue diameter
C. Hollow sprue pin
D. Large reservoir - Crucible indicated for casting base metal alloys is______________?
A. Carbon crucible
B. Clay crucible
C. Quartz crucible
D. High melting plastic crucible - Suck back porosity in the casting can be eliminated by________________?
A. Increasing the mould metal temperature difference
B. Increasing the flow of molten metal
C. Flaring the point of the sprue attachment
D. All of the above - Asbestos liner is used in a casting ring to________________?
A. Facilitate venting of the mold
B. Retard the heating of the investment
C. Permit expansion of the world
D. All of the above - Impurities in casting is removed by________________?
A. Annealing
B. Degassing
C. Pickling
D. Conditioning - The gold alloys used for casting contain at least…. percent of precious metal according to ADA specification number 5________________?
A. 55
B. 65
C. 75
D. 85 - Casting shrinkage is compensated by_______________?
A. Thermal expansion
B. Hygroscopic expansion
C. Wax expansion
D. All of the above
