Manufacturing Engineering Multiple Choice Questions on “Casting Techniques For Single Crystal Components”.
1. In which of the following casting process, the metal being poured into the mold begins to solidify at ceramic walls?
a) conventional casting
b) directional solidification
c) single crystal
d) induction melting
Answer: a
Clarification: The conventional-casting process uses a ceramic mold. The molten metal is poured into the mold and begins to solidify at the ceramic walls. The grain structure developed is poly crystalline.
2. In which of the following casting process, preheating of ceramic mold is done by radiation?
a) conventional casting
b) directional solidification
c) single crystal
d) induction melting
Answer: b
Clarification: The directional-solidification process was first developed in 1960. The ceramic mold is preheated by radiant heating, and the mold is supported by a water-cooled chill plate.
3. In which of the casting process, the mold has either corkscrew or helical shape construction?
a) conventional casting
b) directional solidification
c) single crystal
d) induction melting
Answer: c
Clarification: In crystal growing, developed in 1967, the mold has a constriction in the shape of a corkscrew or helix. The cross section is so small that it allows only one crystal to fit through.
4. Which of the following casting technique has a greater impact in semiconductor industry?
a) conventional casting
b) directional solidification
c) single crystal
d) induction melting
Answer: c
Clarification: Single-crystal growing is a major activity in the semiconductor industry in the manufacture of the silicon wafers in microelectronic devices.
5. Which of the following parameter is used to determine the nature of cast components by sealing the opening in casting?
a) Surface defects
b) Pressure tightness
c) Ductility
d) Brittleness
Answer: b
Clarification: Pressure tightness of cast components (valves, pumps, and pipes) usually is determined by sealing the openings in the casting and pressurizing it with Water, oil, or air.
6. Which of the following test allows us to remove specimens form various casting sections?
a) surface defects
b) pressure tightness
c) destructive
d) non-destructive
Answer: b
Clarification: In destructive testing, specimens are removed from various sections of a casting and tested for strength, ductility, and other mechanical properties and to determine the presence, location, and distribution of porosity and any other defects.
7. In which of the following casting method, alloy is melted by induction in a ceramic crucible?
a) conventional casting
b) melt spinning
c) pressure die casting
d) vacuum arc melting
Answer: b
Clarification: In a common method called melt spinning, the alloy is melted by induction in a ceramic crucible. It is then propelled under high gas pressure against a rotating copper disk (chill block), which chills the alloy rapidly.
8. Which of the following casting technique, a seed crystal is dipped into the molten metal and then pulled out slowly?
a) crystal pulling method
b) melt spinning
c) single crystal
d) Sankaranarayanan Ramasamy method
Answer: a
Clarification: In the crystal-pulling method, a seed crystal is dipped into the molten metal and then pulled out slowly (at a rate of about 10 /, tm/s) while being rotated.
9. The zone at which a rod of polycrystalline silicon rests on a single crystal and an induction coil heats these two pieces is called as?
a) crystal pulling method
b) melt spinning
c) floating zone
d) vacuum arc melting
Answer: c
Clarification: The second technique for crystal growing is the floating-zone method. Starting with a rod of polycrystalline silicon resting on a single crystal, an induction coil heats these two pieces while the coil moves slowly upward. The single crystal grows upward while maintaining its orientation.
10. In which of the following method, dopants are added?
a) crystal pulling method
b) melt spinning
c) floating zone
d) vacuum arc melting
Answer: a
Clarification: In the crystal-pulling method, dopants may be added to the liquid metal to impart special electrical properties. Single crystals of silicon, germanium, and various other elements are grown with this process.