Welding
Exam Duration: 45 Mins Total Questions : 20
An example of fusion welding is
- (a)
gas welding
- (b)
arc welding
- (c)
thermit welding
- (d)
forge welding
a welding, a flux is used to
- (a)
permit perfect cohesion of metals
- (b)
remove the oxides of the metals formed at high temperature
- (c)
None of the above
- (d)
Both (a) and (b)
The welding process in which two pieces to be joined are overlapped and placed between two electrodes, is called
- (a)
projection welding
- (b)
spot welding
- (c)
butt welding
- (d)
seam welding
The temperature of arc in flame within the range of
- (a)
2000oC to 4000°C
- (b)
4000°C to 6000oC
- (c)
below 1000oC
- (d)
above 6000oC
A consumable electrode is used in
- (a)
MIG welding
- (b)
TIG welding
- (c)
submerged arc welding
- (d)
All of these
Welding process, in which electrode is not consumed is
- (a)
Tungsten Inert Gas (TIG) welding
- (b)
MIG welding
- (c)
Both (a) and (b)
- (d)
None of the above
In gas welding, maximum flame temperature occurs at
- (a)
inner cone
- (b)
outer cone
- (c)
tip of the flame
- (d)
same at each point
Carburising flame is obtained by supplying
- (a)
equal volumes of oxygen and acetylene
- (b)
more volume of acetylene and less volume of oxygen
- (c)
more volume of oxygen and less volume of acetylene
- (d)
None of the above
Neutral flame is obtained by supplying
- (a)
equal volumes of oxygen and acetylene
- (b)
more volume of acetylene and less volume of oxygen
- (c)
more volume of oxygen and less volume of acetylene
- (d)
None of the above
Oxidising flame is obtained by supplying
- (a)
equal volumes of oxygen and acetylene
- (b)
more volume of acetylene and less volume of oxygen
- (c)
more volume of oxygen and less volume of acetylene
- (d)
None of the above
Arc length in arc welding should be equal to
- (a)
half the diameter of electrode rod
- (b)
1.5 times the rod diameter
- (c)
twice the rod diameter
- (d)
2.5 times the rod diameter
In MIG welding, helium or argon is used in order to
- (a)
provide cooling effect
- (b)
act as flux
- (c)
act as shielding medium
- (d)
All of these
When the work piece is connected to the negative terminal and the electrode holder to the positive terminal, the welding set up is said to have
- (a)
straig ht polarity
- (b)
reversed polarity
- (c)
Both (a) and (b)
- (d)
None of these
In coated electrode in arc welding
- (a)
coating melts first and then rod melts
- (b)
rod melts first and then coating melts
- (c)
Both rod and coating melt simultaneously
- (d)
None of the above
In which of following welding techniques, a vacuum environment required?
- (a)
Plasma arc welding
- (b)
Ultrasonic welding
- (c)
Laser beam welding
- (d)
Electron beam welding
Identify the label B in arc welded joint as shown in figure.
- (a)
Slag
- (b)
Reinforcement
- (c)
Weld preparation
- (d)
Penetration
For welding of a steel plate of thickness 20 mm, the required current is 200 A. While the thickness of plate is 40 mm then the value of current is 450 A. What is value of current when plate thickness is 10 mm?
- (a)
75 A
- (b)
60 A
- (c)
80 A
- (d)
100 A
In arc welding of steel with a potential of 40 V and current is 500 A, the welding speed is 6 mm/s and the cross-sectional area of the joints is 30 mm2, heat required to melt steel is 5 J/mm3 and heat transfer efficiency is 80%. The value of melting efficiency is
- (a)
5.625%
- (b)
6.25 %
- (c)
8.025%
- (d)
7.75%
The given figure shows linear power characteristic. The voltage and arc length is related to each other by a linear equation V = 20 + 2 t, what is the value of current, when arc length is 5 mm (l in mm)?
- (a)
300 A
- (b)
400 A
- (c)
500 A
- (d)
600 A
In an arc welding process, the current and voltage are 300 A and 25 V respectively. The arc heat transfer efficiency is 0.85 and welding speed is 8 mm/s. The net heat input in J/mm is
- (a)
797
- (b)
64
- (c)
1103
- (d)
79700
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