1
GATE ME 2008
MCQ (Single Correct Answer)
+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
$$34$$
2
GATE ME 2007
MCQ (Single Correct Answer)
+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
$$E=80+8L$$
3
GATE ME 2007
MCQ (Single Correct Answer)
+2
-0.6
Two metallic sheets, each of $$2.0$$ $$mm$$ thickness are welded in lap joint configuration by resistance spot welding at a welding current of $$10$$ $$KA$$ and welding time of $$10$$ milliseconds. A spherical fusion zone extending up to the full thickness of each sheet is formed. The properties of the metallic sheets are given below:
Ambient temp $$=293$$ $$K$$
Melting point temp $$=1793$$ $$K$$
Density $$ = 7000kg/{m^3}$$
Latent heat of fusion $$=300$$ $$kJ/kg$$
Specific heat $$=800$$ $$J/kgK$$

Assume:
(i) Contact resistance along sheet - sheet interface is $$500$$ micro-ohm and along
$$\,\,\,\,\,\,$$electrode-sheet interface is zero.:
(ii) No conductive heat loss through the bulk sheet material; and
(iii) The complete weld fusion zone is at the melting temperature, the melting
$$\,\,\,\,\,\,\,\,\,$$efficiency (in %) of the process is .........

A
$$50.37$$
B
$$60.37$$
C
$$70.37$$
D
$$80.37$$
4
GATE ME 2006
MCQ (Single Correct Answer)
+2
-0.6
In arc welding process, the voltage and current are $$25V$$ and $$300A$$ respectively. The arc heat transfer efficiency is $$0.85$$ and welding speed is $$8$$ $$mm/sec$$. The net heat input (in $$J/mm$$) is
A
$$64$$
B
$$797$$
C
$$1103$$
D
$$79700$$
GATE ME Subjects
Turbo Machinery
EXAM MAP
Medical
NEET
Graduate Aptitude Test in Engineering
GATE CSEGATE ECEGATE EEGATE MEGATE CEGATE PIGATE IN
CBSE
Class 12