This set of Metal Casting Multiple Choice Questions & Answers (MCQs) focuses on “Squeeze Casting”.
1. The main purpose of squeeze casting is to produce castings of large volume with high segregation.
a) True
b) False
View Answer
Explanation: In squeeze casting, the objective is to make the castings of compact size with good strength. In this technique, product quality is greatly improved by solidifying the casting under heavy pressure to prevent the formation of shrinkage defects and retain dissolved gases in solution until freezing is complete.
2. In the squeeze casting method, extreme care is taken while pouring of molten metal into the die cavity.
a) True
b) False
View Answer
Explanation: Very carefully metered charge of molten metal is poured into the die cavity as to maintain the exact amount required for the casting. Excess of molten metal can lead to an increase in work time and the overall working efficiency is also decreases. So to avoid this problem, extreme care should be taken at the time of pouring.
3. What should be the range of pressure (in MPa) under which molten metal is pressed to form the castings by squeeze casting method?
a) 10 to 50
b) 50 to 140
c) 140 to 240
d) 240 to 300
View Answer
Explanation: In squeeze casting, the punch portion of the upper die is forced into the cavity by displacing the molten metal under pressure until it fills the annular space between the die and the punch. Normally, the metal is kept under pressure of 50 to 140 MPa to avoid the formation of shrinkage defects.
4. At the starting of the casting process, the punch should be lowered down in such a way to form a tight seal.
a) True
b) False
View Answer
Explanation: The punch and die portion are separated at the initial of the casting process and the holding furnace holds the molten metal at the requisite temperature. After the pouring of molten metal into the cavity, the punch is lowered down in such a way that it forms a tight seal to avoid inclusion of any gases to the castings.
5. Shrinkage cavities cannot be reduced by application of pressure; it can only be avoided by having a tight seal in the casting system.
a) True
b) False
View Answer
Explanation: After pressing of punch onto the molten metal, melt loses heat rapidly because of its contact with the metallic die. Then solidification occurs, this solidification under pressure is mainly claimed to be responsible for the reduction in the shrinkage cavities in the resulting castings.
6. The method of squeeze casting is very expensive to use because of its less productivity.
a) True
b) False
View Answer
Explanation: The squeeze casting has very low gas entrapment, lower shrinkage cavities, lower die costs, and very high quality of surface with fine details of castings. Also, it produces fine grain size to improve the mechanical properties of the castings. Aluminum and copper alloys component can be manufactured easily by this method with high productivity.
7. Which of the following methods of casting is also known as the liquid metal forging?
a) Die casting
b) Continuous casting
c) Permanent mould casting
d) Squeeze casting
View Answer
Explanation: Squeeze casting is also known as the liquid metal forging, which combines the advantages of casting and forging processes. This process is widely used for the production of quality castings; this is mainly achieved by improving the contact between the molten metal and the die by pressurization.
8. In squeeze casting, the instant contact between the melt and the die results into the formation of ductile castings of coarse structure due to slow rate of cooling.
a) True
b) False
View Answer
Explanation: The cooling rate of the molten metal is mainly increased during the solidification stage of the squeeze casting. The instant contact between the melt and the die surface produces a rapid heat transfer condition that makes the casting of good harden-ability with fine grain structure.
9. An intermediate feeding component takes part in the in-direct type of squeeze casting.
a) True
b) False
View Answer
Explanation: Generally, squeeze casting has two types of ways for performing casting operation. Direct and in-direct, in direct squeeze casting, pressure is directly applied to the metal, while in in-direct squeeze casting; pressure is applied on the molten metal through an intermediate feeding part.
10. Which of the following factors is not considered for the determination of pressure level in the squeeze casting?
a) Shape of the casting
b) Fluidity of the alloy
c) Freezing range of alloy
d) Moulding material
View Answer
Explanation: In squeeze casting, time duration is mainly determined by the casting configuration, alloy type and heat transfer conditions. After the completion of the solidification process, pressure is no longer required in the operation. Then the casting is safely taken out from the die for the further process of machining.
11. Extension of holding time of casting under the punch leads to more strength of the castings.
a) True
b) False
View Answer
Explanation: Extended holding time never makes the castings of good strength; even it may cause wall cracking and problems with punch withdrawal due to thermal contraction of the casting. So a rule is set in the squeeze casting that the maximum holding time is about one second per mm of section thickness.
12. In squeeze casting, die preheating temperature is maintained within close limits and very precise.
a) True
b) False
View Answer
Explanation: In squeeze casting, the die temperature has to be monitored within close limits, because too low preheating temperature of die may result in quick solidification and cold laps in the castings. And too high temperature may cause the surface defects and welding of the die with casting.
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Practice 1000+ Multiple Choice Questions and Answers on Metal Casting and Metal Forming and Welding.
