GATE Past Year Questions: Casting | Manufacturing Engineering - Mechanical Engineering PDF Download
Q1: Aluminium is casted in a cube-shaped mold having dimensions as 20 mm×20 mm×20 mm. Another mold of the same mold material is used to cast a sphere of aluminium having a diameter of 20 mm. The pouring temperature for both cases is the same. The ratio of the solidification times of the cube-shaped mold to the spherical mold is ______ (answer in integer). (2024)
(a) 0.5
(b) 0.25
(c) 0
(d)1
Ans:(d)
Sol:
Given, D=20 mm for sphere
Volume of cube =20×20×20 mm 2
According chvorinov 's rule
Q2: The allowance provided to a pattern for easy withdrawal from a sand mold is (2024)
(a) Finishing allowance
(b) Shrinkage allowance
(c) Distortion allowance
(d) Shake allowance
Ans: (d)
Sol:
Types of allowances:
Draft/taper allowances.
Machining allowance/finishing allowance.
Distortion allowances/camber allowance
Shrinkage allowance/contraction allowances.
Shake allowance/rapping allowance.
Shake allowance
Before withdrawal from the sand mould, the pattern is wrapped all around the vertical faces to enlarge the mould cavity slightly, which facilitates its removal. Since it enlarge the final casting made, it is desirable that the original pattern dimensions should be reduced to account for this increase. There is no sure way of quantifying this allowance, since it is highly dependent on the foundry personnel and practices involved.
It is negative allowance and is to be applied only to those dimensions, which are parallel to the parting plane. One way of reducing this allowance is to increase the draft, which can be removed during the subsequent matching.
Draft/taper allowances
Once pattern is embedded in the moulding sand now it is required to withdrawing the pattern from moulding sand, for this propose a vertical force is required to lift the pattern. For easy removal of pattern from mould cavity there should be some degree or mm taper in the pattern.
If there is no taper in the pattern then more chance to break the mould cavity wall during withdrawing the pattern. Draft allowance varies with the complexity of job.
Machining or Finishing allowance
In sand casting operation machining/finishing allowances is given in the pattern as on solidification every metal get shrinked up to some extend and the outer surface of object (casting) is rough, therefore, to smoothing the outer surface of casting machining allowance is must.
Distortion allowance/Camber allowance
On just solidification of metal casting is weak, therefore, more chances to distorted casting. Chance of distortion are basically in U,V, then long section or complicated casting. Distortion can be minimized or eliminated by providing an allowance and constructed the pattern initially distorted, i.e. opposite in outer side direction. Among of distortion allowance varies from 1.520 mm.
It is the tendency of all metals that they shrink after cooling except bismuth, Shrinkage is only due to inter atomic vibration which are implified by increasing in temperature. Metal shrink or contract in three ways :
Liquid Contraction
Solidification Contraction
Solid Contraction
Q3: In a metal casting process to manufacture parts, both patterns and mould provide shape by dictating where the material should or should not go. Which of the option(s) given correctly describe(s) the mould and the pattern? (2023)
(a) Mould walls indicate boundaries within which the molten part material is allowed, while pattern walls indicate boundaries of regions where mould material is not allowed.
(b) Mould can be used to make patterns
(c) Pattern walls indicate boundaries within which the molten part material is allowed, while mould walls indicate boundaries of regions where mould material is not allowed.
(d) Patterns can be used to make mould
Ans: (a, b ,d)
Sol:
In some moulding processes like investment and full moulding, permanent moulds can be used for preparing the pattern.
Q4: Consider sand casting of a cube of edge length a. A cylindrical riser is placed at the top of the casting. Assume solidification time ts∝V/A, where V is the volume and A is the total surface area dissipating heat. If the top of the riser is insulated, which of the following radius/radii of riser is/are acceptable? (2022 SET 2)
(a) 
(b) 
(c) 
(d) 
Ans: (a, b)
Sol:
Riser should take more time for solidification than casting 
For top riser bottom area is not cooling surface and it is given that top cross section is also insulated. So only lateral area is cooling area.
Q5: A cast product of a particular material has dimensions 75 mm x 125 mm x 20 mm. The total solidification time for the cast product is found to be 2.0 minutes as calculated using Chvorinov's rule having the index, n = 2. If under the identical casting conditions, the cast product shape is changed to a cylinder having diameter = 50 mm and height = 50 mm, the total solidification time will be __________minutes (round off to two decimal places). (2021 SET2)
(a) 1.25
(b) 2.83
(c) 2.48
(d) 3.12
Ans:( b)
Sol:
Casting dimensions =75 mm×125 mm×20 mm
Total solidification time 
=2.0 min.
Cylindrical casting =H=D=50 min
Total solidification Time 
=? Chvorinov's rule, 
Q6: A true centrifugal casting operation needs to be performed horizontally to make copper tube sections with outer diameter of 250 mm and inner diameter of 230 mm. The value of acceleration due to gravity, g=10m/ s2 If a G-factor (ratio of centrifugal force to weight) of 60 is used for casting the tube, the rotational speed required is _____rpm (round off to the nearest integer). (2021 SET 1)
(a) 124
(b) 284
(c) 662
(d) 847
Ans: (d)
Sol:
Q7:A mould cavity of 1200 c m 3 volume has to be filled through a sprue of 10 cm length feeding a horizontal runner. Cross-sectional area at the base of the sprue is 2cm 2 Consider acceleration due to gravity as 9.81m/s2 .Neglecting frictional losses due to molten metal flow, the time taken to fill the mould cavity is _______ seconds (round off to 2 decimal places). (2020 SET 2)
(a) 10.6
(b) 2.24
(c) 4.28
(d) 15.3
Ans: (d)
Sol:
Volume of mould cavity (V)=1200cm 3
Height of sprue (hs)=10cm
Area of sprue at the bottom (As)=2cm2
g=9.81m /s2
Sprue is feed a horizontal runner: Filling time required (tt)=?
Q8: The figure shows a pouring arrangement for casting of a metal block. Frictional losses are negligible. The acceleration due to gravity is 9.81 
(a) 12.55
(b) 45.28
(c) 28.92
(d) 36.28
Ans: (c)
Sol: 
At point (3) is open to atmosphere so (3) is the choke. 
Q9: The fluidity of molten metal of cast alloys (without any addition of fluxes) increases with increase in (2019 SET 2)
(a) viscosity
(b) surface tension
(c) freezing range
(d) degree of superheat
Ans: (d)
Sol:
Fluidity increases with increase of degree of super heat
Q10: Match the following sand mold casting defects with their respective causes. (2019 SET 2)
(a) P-4, Q-3, R-1, S-2
(b) P-3, Q-4, R-2, S-1
(c) P-2, Q-4, R-1, S-3
(d) P-3, Q-4, R-1, S-2
Ans: (d)
Sol:
Blow hole ⇒ ⇒ Poor Permeability
Misrun ⇒ ⇒ Insufficient Fluidity
Hot tearing ⇒ ⇒ Poor Collapsibility
Wash ⇒ ⇒ Mold erosion
Try yourself: The fluidity of molten metal of cast alloys (without any addition of fluxes) increases with increase in [ME 2019,Set-2]
Try yourself: In full mould (cavity-less) casting process, the pattern is made of [ME 2015:Set-3]
Try yourself: The hot tearing in a metal casting is due to [ME 2014,Set-3]
Try yourself: Match the casting defects (Group A) with the probable causes (Group B): Group-A Group-B [ME 2014,Set-3]
P. Hot tears
Q. Shrinkage
R. Blow holes
S. Cold shunt
1. Improper fusion of two streams of liquid metal
2. Low permeability of the sand mould
3. Volumetric contraction both in liquid and solid stage
4. Differential cooling rate
Try yourself: During solidification of a pure molten metal, the grains in the casting near the mould wall area [ME 2013 :Set-2]
Try yourself: Green sand mould indicates that [ME 2011]
Try yourself: Two streams of liquid metal which are not hot enough to fuse properly result into a casting defect known -as [ME 2009]
Try yourself: While cooling, a cubical casting of side 40mm undergoes 3%, 4% and 5% volume shrinkage during the liquid state, phase transition and solid state, respectively. The volume of metal compensated from the riser is [ME 2008]
Try yourself: Which of the following engineering materials is the most suitable candidate for hot chamber die casting? [ME 2007]
Try yourself: An expendable pattern is used in [ME 2006]
Try yourself: Misrun is a casting defect which occurs due to [ME 2004]
Try yourself: The primary purpose of sprue in casting mould is to [ME 2002]
Try yourself: In centrifugal casting, the lighter impurities are [ME 2002]
Try yourself: Shrinkage allowance on pattern is provided to compensate for shrinkage when [ME 2001]
Try yourself: Disposable patterns are made of [ME 2000]
Try yourself: Centrifugally casted products have [ME 1993]
Try yourself: In a green sand moulding process, uniform ramming leads to [ME 1992]
Try yourself: Increase in water content in moulding sand causes [ME 1989]
Try yourself: Which of the following casting processes uses expandable pattern and expandable mould? [PI 2011]
Try yourself: In sand casting fluidly of the molten metal increases with [PI 2011]
Try yourself: Hot chamber die casting is not suited for [PI 2009]
Try yourself: In hollow cylindrical parts made by centrifugal castings, the density of the part is [PI 2008]
Try yourself: Which one of the following is not a property of a sand mould? [PI 2003]
Try yourself: Electrical switches made out of thermoset materials are produced by [PI 1992]
Try yourself: Ceramics slurry is used in making the moulds for [PI 1991]
Try yourself: For casting of turbine blades made of high temperature and high strength alloys, the most suitable process is [PI 1990]
Try yourself: Green strength in powder metallurgy refers to the strength of [PI 1989]
Try yourself: For the same material, powder metallurgy process in superior to casting for [PI 1989]
Try yourself: The process by which shell like casting (like toys) are made is [PI 1989]
Try yourself: Negative allowance is provided on the pattern to take care of [PI 1989]
Try yourself: 50. In sand casting of hollow part of lead, a cylindrical core of diameter 120 mm and height 180 mm is placed inside the mould cavity. The densities of core material and lead are 1600 kg/m3 and 11300 kg/m3 respectively. The net force (in N) that tends to lift the core during pouring of molten metal will be [PI 2008]
Try yourself: The mould filling time is seconds is [PI 2007]
Try yourself: The volume flow rate (in mm3/s) is [PI 2007]
Try yourself: Cold shut is a defect in casting due to [PI 2006]
Try yourself: The shape factor for a casting in the form of an annular cylinder of outside diameter 30 cm, inside diameter 20 cm and height 30 cm (correction factor k = 1.0) will be [PI 2005]
Try yourself: Wood flour is added to core sand to improve [PI 2004]
Try yourself: A casting of size 100 mm × 100 mm × 50 mm is required. Assume volume shrinkage of casting as 2.6%. If the height of the riser is 80 mm and riser volume desired is 4 times the shrinkage in casting, what is the appropriate riser diameter in mm? [PI 2003]
Try yourself: Gating ratio of 1 : 2 : 4 is used to design the gating system for magnesium alloy casting.This gating ratio refers to the cross-section areas of the various gating elements as given below: The sequence of the above elements in the ratio 1 : 2 : 4 is [PI 2003 : 2 Marks]
1. Down sprue
2. Runner
3. Ingates
Try yourself: A 10 mm thick steel bar is to be horizontally cast with two correctly top risers of adequate feeding capacity. Assuming end effect without chill, what should be the theoretical length of the bar? [PI 2002]
Try yourself: Proper gating design in metal casting P. Influences the freezing range of the melt [PI 2002]
Q. Compensates the loss of fluidity of the melt
R. Facilitates top feeding of the melt S. Avoids misrun
Try yourself: The permeability of moulding sand was determined using a standard AFS sample by passing 2000 cc of air at a gauge pressure of 10 g/cm2. If the time taken for the air to escape was 1 min, the permeability number is [PI 2002]
Try yourself: The height of the down sprue is 175 mm and its CS are at the base is 200 mm2. The CS area of the horizontal runner is also 200 mm2.Assuming no losses, indicate the correct choice for-the time (second) required to fill a mould cavity of volume 106mm3. (Use g = 10 m/s2) [PI 2002]
Try yourself: Chaplets are placed between mould in order to [PI 1992]
Try yourself: The primary function of a riser is to [PI 1992]
Try yourself: The optimum pouring time for a casting depends on several factors. One important factor among them is [PI 1991]
Try yourself: A cylindrical job with diameter of 200 mm and height of 100 mm is to be cast using modulus method of riser design. Assume that the bottom surface of cylindrical riser does not contribute as cooling surface. If the diameter of the riser is equal to its height, then the height of the riser (in mm) is [ME 2016,Sat-1]
Try yourself: The part of a gating system which regulates the rate of pouring of molten metal is [ME 2016,Set-1]
Try yourself: In a gating system, the ratio 1:2:4 represents [ME 2010]
Try yourself: A 200 mm long down sprue has an area of crosssection of 650 mm2 where the pouring basin meets the down sprue (i.e. at the beginning of the down sprue). A constant head of molten metal is maintained by the pouring basin. The molten metal flow rate is 6.5 × 105 mm3/s. Considering the end of down sprue to be open to atmosphere and acceleration due to gravity of 104 mm/s2, the area of the down sprue in mm2 at its end (avoiding aspiration effect) should be [ME 2007]
Try yourself: In a sand casting operation, the total liquid head is maintained constant such that it is equal to the mould height. The time taken to fill the mould with a top gate is tA. If the same mould is filled with a bottom gate, then the time taken is tB. Ignore the time required to fill the runner and frictional effects, Assume Atmospheric pressure at the top molten metal surfaces. The relation between tA and tB is [ME 2006] tB = 2tA
Try yourself: A mould has downsprue whose length is 20 cm and the cross sectional area at the base of the downsprue is 1 cm2. The downsprue feeds a horizontal runner leading into the mould cavity of volume 1000 cm3. The time required to fill the mould cavity will be [ME 2006]
Try yourself: Gray cast iron blocks 200 x 100 x 10 mm are to be cast in sand moulds, Shrinkage allowance for pattern making is 1%. The ratio of the volume of pattern to that of the casting will be [ME 2004]
Try yourself: Hardness of green sand mould increases with [ME 2003]
Try yourself: Light impurities in the molten metal are prevented from reaching the mould cavity by providing [ME 1996]
Try yourself: Converging passage is used for feeding the liquid molten metal into the mould to [ME 1991]
Try yourself: The pressure at the in-gate will be maximum with the gating system [ME 1990]
Try yourself: Riser is designed so as to [ME 1987]
FAQs on GATE Past Year Questions: Casting
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| 2. How do I identify which casting process to use in a GATE past year problem? | |
| 3. Why does metal shrinkage during solidification matter in casting design? | |
| 4. What's the difference between a feeder and a riser in casting processes? | |
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