NHPC JE'21 ME: Daily Practices Quiz. 13-Oct-2021

Quiz: Mechanical Engineering
Exam: NHPC
Topic: Manufacturing

Each question carries 1 mark
Negative marking: 1/4 mark
Time: 6 Minutes

Q1. Which one of the following is the correct statements?
(a) Extrusion is used for the manufacture of seamless tubes
(b) Extrusion is used for reducing the diameter of round bars and tubes by rotating dies which open and close rapidly on the work
(c) Extrusion is used to improve fatigue resistance of the metal by setting up compressive stresses on its surface
(d) Extrusion comprises pressing the metal inside a chamber to force it out by high pressure through an orifice which is shaped to provide the desired form of the finished part

Q2. Which metal forming process is used for manufacture of long steel wire?
(a) Deep drawing
(b) forging
(c) Drawing
(d) Extrusion

Q3. The advantage of the welding process is
(a) It relieves the joint from residual stresses
(b) it helps in checking of distortion of work piece
(c) Large number of metals and alloys, both similar and/or dissimilar can be joined
(d) heat produced during the welding does not produce metallurgical changes.

Q4. Tool life is affected mainly with
(a) Feed
(b) Depth of cut
(c) Coolant
(d) Cutting speed

Q5. Flank wear occurs on the
(a) Relief face of the tool
(b) Rake face
(c) Nose of the tool
(d) cutting edge

Q6. Some high-speed steels have Cobalt (Co) added to them in amounts ranging from 2% to 15%, since this element improves the
(a) Cutting efficiency, especially at high temperature
(b) Depth hardening ability of the HSS tool
(c) Red hardness of the HSS tool
(d) Grain structure of the HSS tool

Solutions

S1. Ans.(a)
Sol. The correct option is (a)
The pipes and tubes can be seamless or with seam. Tube with seam is manufactured by the various welding techniques. Seamless tubes are made by Extrusion and Piercing methods.

S2. Ans.(c)
Sol. Drawing: The drawing operation is mainly used for reducing the diameter of bars and wires. The drawing speed varies from 10 m/min. for a large diameter to 1800 m/min for very thin wire.

S3. Ans.(c)
Sol. The advantage of the welding process is large number of metals and alloys, both similar and/or dissimilar can be joined.

S4. Ans.(d)
Sol. Sequence of parameters affecting tool life is:
Cutting speed > feed > depth of cut

S5. Ans.(a)
Sol. Flank wear occurs on the Relief face of the tool.

S6. Ans.(c)
Sol Cobalt improves hot hardness and wear resistance of high-speed steel.