1
GATE ME 2012
+2
-0.6
In a $$DC$$ $$arc$$ welding operating, the length characteristic was obtained as $${V_{arc}} = 20 + 5l$$ where the $$arc$$ length $$l$$ was varied between $$5mm$$ and $$7mm.$$ Here $${V_{arc}}$$ denotes the arc voltage in volts. The $$arc$$ current was varied from $$400A$$ to $$500A.$$ Assuming linear power source characteristic, the open circuit voltage and the short circuit current for the welding operation are
A
$$45V, 450A$$
B
$$75V, 750A$$
C
$$95V, 950A$$
D
$$150V, 1500A$$
2
GATE ME 2010
+2
-0.6
Two steel bars each of diameter $$10mm$$ are coaxially friction welded end to end at an axial pressure of $$200MPa$$ and rotational speed of $$400rpm$$. The coefficient of friction between the mating faces of the rotating bars is $$0.50.$$ The torque is assumed to act at the $$3/{4^{th}}$$ radius of the rotating bar. The power (in $$kW$$) consumed at the interface of the welding is
A
$$12.33$$
B
$$16.44$$
C
$$18.50$$
D
$$24.66$$
3
GATE ME 2008
+2
-0.6
In arc welding of a butt joint, the welding speed is to be selected such that highest cooling rate is achieved. Melting efficiency and heat transfer efficiency are $$0.5$$ and $$0.7$$, respectively. The area of the weld cross section is $$5$$ $$m{m^2}$$ and the unit energy required to melt the metal is $$10\,\,J/m{m^3},$$ if the welding power is $$2$$ $$kW,$$ the welding speed in $$mm/s$$ is closet to
A
$$4$$
B
$$14$$
C
$$24$$
D
$$34$$
4
GATE ME 2007
+2
-0.6
A $$DC$$ welding machine with a linear power source characteristic provides open circuit voltage of $$80V$$ and short circuit current of $$800A,$$ during welding with the machine , the measured are current is $$500A$$ corresponding to an arc length of $$5.0$$ $$mm$$ and the measured are current $$460A$$ corresponding to an arc length of $$7.0$$ $$mm.$$ The linear voltage $$(E)$$ & arc length $$(L)$$ characteristic of the welding arc can be given as (where $$E$$ is in Volts and $$L$$ is in $$mm$$)
A
$$E=20+2L$$
B
$$E=20+8L$$
C
$$E=80+2L$$
D
$$E=80+8L$$
GATE ME Subjects
Engineering Mechanics
Strength of Materials
Theory of Machines
Engineering Mathematics
Machine Design
Fluid Mechanics
Turbo Machinery
Heat Transfer
Thermodynamics
Production Engineering
Industrial Engineering
General Aptitude
EXAM MAP
Joint Entrance Examination