GATE ME Questions on Casting process(Production Engineering)

Question #1

The part of a gating system which regulates the rate of pouring of molten metal is

(A) pouring basin

(B) runner

(C) choke

(D) ingate

[GATE 2016 Set 1, 1 mark]

Question #2

Heat is removed from a molten metal of mass 2 kg at a constant rate of 10 kW till it is completely solidified. The cooling curve is shown in the figure

The latent heat of fusion of the metal(in kJ/kg)is ______

[GATE 2016 Set 1, 2 marks]

Question #3

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

(A) 150

(B) 200

(C) 100

(D) 125

[GATE 2016 Set 1, 2 marks]

Question #4

Gray cast iron blocks of size 100 mm × 50 mm × 10 mm with a central spherical cavity of diameter 4 mm are sand cast. The shrinkage allowance for the pattern is 3%. The ratio of the volume of the pattern to volume of the casting is _________

[GATE 2016 Set 2, 2 marks]

Question #5

Equal amounts of a liquid metal at the same temperature are poured into three moulds made of steel, copper and aluminum. The shape of the cavity is a cylinder with 15 mm diameter. The size of the moulds are such that the outside temperature of the moulds do not increase appreciably beyond the atmospheric temperature during solidification.

The sequence of solidification in the mould from the fastest to slowest is
(Thermal conductivities of steel, copper and aluminum are 60.5, 401 and 237 W/m-K, respectively. Specific heats of steel, copper and aluminum are 434, 385 and 903 J/kg-K, respectively. Densities of steel, copper and aluminum are 7854, 8933 and 2700 kg/m3, respectively.)
(A) Copper – Steel – Aluminum
(B) Aluminum – Steel – Copper
(C) Copper – Aluminum – Steel
(D) Steel – Copper – Aluminum

[GATE 2016 Set 3, 1 mark]

Question #6

The solidification time of a casting is proportional to $(\frac{V}{A})^2$, where V is the volume of the casting and A is the total casting surface area losing heat. Two cubes of same material and size are cast using sand casting process. The top face of one of the cubes is completely insulated. The ratio of the solidification time for the cube with top face insulated to that of the other cube is
(A) 25/36
(B) 36/25
(C) 1
(D) 6/5

[GATE 2015 Set 1, 2 marks]

Question #7

A cube and a sphere made of cast iron (each of volume 1000 cm3) were cast under identical conditions. The time taken for solidifying the cube was 4 s. The solidification time (in s) for the sphere is __________

[GATE 2015 Set 2, 2 marks]

Question #8

In full mould (cavity-less) casting process, the pattern is made of
(A) expanded polystyrene
(B) wax
(C) epoxy
(D) plaster of Paris

[GATE 2015 Set 3, 1 mark]

Question #9

The dimensions of a cylindrical side riser (height = diameter) for a 25 cm × 15 cm × 5 cm steel casting are to be determined. For the tabulated shape factor values given below, the diameter of the riser (in cm) is ________

 shape factor 2 4 6 8 10 12 Riser volume/casting volume 1 7 0.55 0.5 0.4 0.35

[GATE 2015 Set 3, 2 marks]

Question #10

Ratio of solidification time of a cylindrical casting (height = radius) to that of a cubic casting of side two times the height of cylindrical casting is ________

[GATE 2015 Set 3, 2 marks]

Question #11

An aluminium alloy (density 2600 kg/m3) casting is to be produced. A cylindrical hole of 100 mm diameter and 100 mm length is made in the casting using sand core (density 1600 kg/m3). The net buoyancy force (in newton) acting on the core is ______

[GATE 2014 S1, 2 marks]

Question #12

Match the casting defects (Group A) with the probable causes (Group B):

 Group A Group B P: Hot tears 1: Improper fusion of two streams of liquid metal Q: Shrinkage 2: Low permeability of the sand mould R: Blow holes 3: Volumetric contraction both in liquid and solid stage S: Cold Shut 4: Differential cooling Rate

[GATE 2014 Set 3, 1 mark]

Question #13

The hot tearing in a metal casting is due to

(A) high fluidity

(B) high melt temperature

(C) wide range of solidification temperature

(D) low coefficient of thermal expansion

[GATE 2014 Set 3, 1 mark]

Practice other topics from Production Engineering:

Theory of Metal cutting

Machining

Welding