Two square shaped steel plates A and B have thickness of 4 and 8 cms respectively. They are sand cast under identical conditions. Plate A takes 10 minutes to solidify. Plate B would solidify in . . . . . . . . minutes.
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The operation not associated with casting is
A. Gating
B. Fettling
C. Stack moulding
D. Calendaring
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A vertical tapered sprue of 16 cms length is, kept full during pouring. To just avoid any aspiration, the cross-sectional areas at the centre and the bottom of the sprue must be in the ratio of
A. 1 : 1
B. √2 : 1
C. 2 : 1
D. 4 : 1
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In hot chamber method of die casting . . . . . . . .
A. Only low melting point metals can be cast
B. High melting point metals can be cast
C. Die is kept hot by electrical heating
D. Die is kept cold by circulating water
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The process of formation of new stable tiny particle of product phase in the parent phase during phase transformation process.
A. Solidification
B. Nucleation
C. Growth
D. All of these
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The machining allowances for medium section cast steel
A. 3 mm
B. 4.5 mm
C. 8 mm
D. 12 mm
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A cope and drag pattern is another form of
A. Single piece pattern
B. Sweep pattern
C. Split pattern
D. Segmental pattern
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In which of the following methods, close fitting cores are pushed in the cavities?
A. Permanent mould casting
B. Semi-permanent mould casting
C. Slush casting
D. Pressed casting
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Ferrous alloys are usually cast by . . . . . . . .
A. Hot chamber machine
B. Cold chamber machine
C. Die casting machine
D. None of the above
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Draft allowance given to patterns is for
A. compensating the liquid state shrinkage
B. easy removal of pattern from the mould cavity
C. providing support for the core placement
D. compensating the solidification shrinkage
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For casting a cylindrical aluminum bloom having a length of 1000 mm and diameter of 700 mm. the approximate solidification time (in minutes) estimated using Chvorinov's rule is
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The shrinkage allowance for zinc is . . . . . . . . mm.
A. 17
B. 24
C. 20.8
D. 12.5 - 15
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Riser is not required for the casting of
A. grey cast iron
B. white cast iron
C. Al- 4% Cu
D. Al-12% Si
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Assertion 'a' : During casting of aluminium, grain refinement can be achieved by addition of certain alloying elements.Reason 'r' : The addition of the alloying elements may result in the formation of deoxidation products or intermetallic compounds which may act as nucleation sites for grain refinement.
A. Both 'a' and 'r' are true, but 'r' is not the reason for 'a'
B. Both 'a' and 'r' are true and 'r' is the reason for 'a'
C. 'a' is true but 'r' is false
D. 'a' is false but 'r' is true
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In foundary practice, the fluidity of an alloy does not increase with increasing
A. superheat
B. channel size
C. flow velocity
D. heat transfer coefficient
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Fly wheels, track wheels and gears can be produced by
A. true centrifugal casting
B. semi centrifugal casting
C. centrifuged casting
D. none of the above
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In a casting, cold shut defect is caused by
A. low pouring temperature
B. melt-mould reaction
C. faulty gating system
D. very low mould permeability
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For designing a pressurised gating system in sand casting, the gating ratio should be
A. 1 : 0.75 : 0.50
B. 1 : 1 : 1
C. 1 : 2 : 4
D. 1 : 3 : 3
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. . . . . . . . is the strength of the sand (of mold cavity) above 100°C
A. Hot strength
B. Green strength
C. Dry strength
D. None of these
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Eutectic Al-Si castings are modified by
A. Na
B. P
C. S
D. none of these
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