Air bubbles formed on the surface of casting is probably due to________________?

Related Mcqs:

1. The porosity formed due to simultaneous nucleation of solid grains and gas bubbles at the first moment that metal freezes at the mold walls is called__________?

   A. Pinhole porosity B. Gas inclusion porosity C. Micro porosity D. Subsurface porosity...

2. 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...

3. 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...

4. Resistance to corrosion in a cobalt-chrome casting is due to presence of_______________?

   A. High quality iron B. Chrome C. Cobalt D. Nickel...

5. Glossy smooth margins of a casting are due to_____________?

   A. Shrinkage of alloy on cooling B. Investment breakdown C. Incomplete wax elimination D. Incomplete gas elimination...

6. 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...

7. The wetting of an adherent surface by an adhesive is related to________________?

   A. Surface energy of the adherent B. Surface texture of the adherent C. Surface tension of the adherent D. Nature of the adherent that is crystalline or amorphous...

8. Casting flux is used to_______________?

   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...

9. Modern dental noble metal casting alloys generally have equiaxed fine grain structures because of the incorporation of small amounts of______________?

   A. Chromium B. Indium C. Irridium D. Palladium...

10. Which zone is the hottest and efficient burning zone of the flame used for casting ?

    A. Oxidizing zone B. Reducing zone C. Combustion zone D. None of the above...