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# BARC 2020: Manucfacturing Nuclear quiz 4

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Question 1

Which of the following represent surface roughness on a drawing?

Question 2

An EDM process which uses a RC relaxation circuit, a hole of 10 mm diameter is made in a steel plate of 50 mm thickness using a graphite tool and the dielectric is kerosene. The discharge time is negligible. The following parameters are measured:

Resistance= 30 Ω

Capacitance= 25μF

Supply voltage= 220 V

Discharge Voltage= 110 V

Average power input is :

Question 3

Medium carbon steel is turned on a lathe machine with a cutting velocity of 50m/min, feed rate of 0.8mm/rev and depth of cut of 1.5mm. If machining is done on workpiece having 100mm diameter and 100mm length. If density of medium carbon steel is 7850 kg/m3. Then after one cut the weight loss of the part (in grams) and material removal rate (in mm3/min) of machining are respectively

Question 4

Metal is to be poured in a cubical cavity of side 400 cm in which a cubical core of size 200cm is placed centrally. The densities of metal and sand are 8000 kg/m3 and 1600 kg/m3 respectively. Then the minimum weight which should be placed above the core (in kN) to prevent lifting of cope box is:

Question 5

Tool life testing on a lathe under dry cutting conditions gave n and C of Taylor tool life equation as 0.12 and 130 respectively. When a coolant was used, C increased by 10%. Find the percent increase in tool life with the use of coolant at a cutting speed of 90 m/min.

Question 6

A 200 mm long workpiece is used to cut a 25 mm deep slot with the help of HSS side and slab cutter whose diameter is 150 mm and it has 15 teeth. The cutting speed is 75 m/min and feed is 0.3 mm per teeth, then time required to machine the slot will be______.

Question 7

A 30mm thick steel plate is to be rolled to 1.4cm in a mill having roll diameter of 680mm. If the yield stress is 200MPa and the thickness of sheet at neutral point is 17.2mm, the forward slip and backward slip are respectively

Question 8

In a wire drawing operation the 12 mm dia. wire is reduced to 8 mm. Mean flow stress is taken 500 MPa, drawing load and stress required for wire drawing operation respectively_______.

Question 9

Shafts of diameter mm are assembled interchangeably with holes of diameter mm. The minimum clearance in the assembly will be

Question 10

During a steady-state gas metal arc welding with direct current electrode positive, the welding current, voltage and welding speed are 150A, 30V, 6 m/min. A metallic wire electrode of diameter 1.2 mm is being feed at a constant rate of 12 m/min. The density, specific heat, and melting temperature of the wire electrode are 7000 kg/m3, 500 J/kg, 1530 °C. Assuming ambient to be 30 °C and neglect latent heat of melting, further consider that (2/3)rd of the total electrical power is available for melting. The melting efficiency of the wire electrode (%) is
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