Manufacturing Engineering Multiple Choice Questions on “Metal Casting Processes and Equipment”.
1. Which of the following are typically made of sand, plaster, ceramics and similar materials and generally are mixed with various binders?
a) Permanent molds
b) Expendable molds
c) Composite molds
d) Ceramic molds
Answer: b
Clarification: Expendable molds, which typically are made of sand, plaster, ceramics, and similar materials and generally are mixed with various binders (bonding agents) for improved properties whereas permanent molds, which are made of metals that maintain their strength at high temperatures.
2. Which of the following are made of metals that maintain their strength at high temperatures?
a) Permanent molds
b) Expendable molds
c) Composite molds
d) Ceramic molds
Answer: a
Clarification: Expendable molds, which typically are made of sand, plaster, ceramics, and similar materials and generally are mixed with various binders (bonding agents) for improved properties whereas permanent molds, which are made of metals that maintain their strength at high temperatures.
3. Which of the following expandable molds are less heat conductors than metallic molds?
a) metallic
b) nonmetallic
c) composite
d) ceramic
Answer: b
Clarification: Metal molds are better heat conductors than expendable non-metallic molds, hence, the solidifying casting is subjected to a higher rate of cooling, which in turn affects the microstructure and grain size Within the casting.
4. Which of the following are made of two or more different materials (combining the advantages of each material)?
a) Permanent molds
b) Expendable molds
c) Composite molds
d) Ceramic molds
Answer: c
Clarification: Composite molds, which are made of two or more different materials (such as sand, graphite, and metal) combining the advantages of each material.
5. The directional solidification in casting can be improved by using __________
a) chaplets and riser
b) chills and padding
c) chaplets and padding
d) chills and riser
Answer: d
Clarification: Directional solidification is solidification that occurs from farthest end of the casting and works its way towards the sprue. Chills and riser are used in improving directional solidification.
6. In permanent mold casting method __________
a) molten metal is poured in a metallic mold, retained in the mold long enough for the outer skin to solidify and finally mold is turned over to remove molten metal still in molten condition
b) molten metal is poured and allowed to solidify while the mold is revolving
c) Molten metal is forced into mold under high pressure
d) none of the mentioned
Answer: d
Clarification: Permanent mold castings are used repeatedly and are designed in such a way that the casting can be removed easily and the mold used for the next casting. Metal molds are better heat conductors than expendable non-metallic molds hence, the solidifying casting is subjected to a higher rate of cooling, which in turn affects the microstructure and grain size Within the casting.
7. In which of the following casting method, the molten metal is poured and allowed to solidify while the mold is revolving?
a) die casting method
b) slush casting method
c) centrifugal casting method
d) investment casting method
Answer: c
Clarification: A casting process in which the molten metal is poured and allowed to solidify while the mold is revolving, is called centrifugal process. The casting produced under this centrifugal force is called centrifugal casting. This process is especially designed for a casting of symmetrical shape.
8. In a hot chamber die casting machine __________
a) melting pot is separate from the machine
b) melting pot is an integral part of the machine
c) melting pot may have any location
d) there is no melting pot in die casting machine
Answer: b
Clarification: In a hot chamber die casting machine, the melting pot is an integral part of the machine. The molten metal is forced in the die cavity at a pressure from 7 to 14 MPa.
9. Cast iron and steel pipes are produced by __________
a) slush casting
b) investment casting
c) true centrifugal casting
d) die casting
Answer: c
Clarification: The method of Cast Iron pipe production used universally today is to form pipes by spinning or centrifugal action. Compared with vertical casting in sand molds, the spun process results in faster production, longer pipes with vastly improved metal qualities, a smoother inner surface and reduced thickness and consequent light weight.
10. Which of the following statement is wrong?
a) The hot chamber die casting machine is used for casting zinc, tin, lead and other low melting alloys
b) The cold chamber die casting machine is used for casting aluminum, magnesium, copper base alloys and other high melting alloys
c) The castings produced by centrifugal casting method have open and coarse grained structure
d) The castings produced by centrifugal casting method have fine grained structure
Answer: c
Clarification: The casting produced by centrifugal casting process have dense and fine grained structure.
11. The melting temperature of non-ferrous alloys, to be casted in a cold chamber die casting machine are of?
a) low melting temperature
b) high melting temperature
c) two eutectic points
d) three eutectic points
Answer: b
Clarification: In a cold chamber die casting machine, the melting pot is usually separate from the machine and the molten metal is not transferred to injection mechanism by ladle. The pressure on the casting metal may vary from 21 to 210 MPa and in some cases may reach 700 MPa.
12. The centrifugal casting method, is used for casting articles of __________
a) symmetrical shape about horizontal axis
b) symmetrical shape about vertical axis
c) irregular shape
d) sphere shape
Answer: a
Clarification: In centrifugal casting, because gravity force is applied in same in horizontal direction axis, so the material is distributed equally in all directions.