1
GATE PI 2001
MCQ (Single Correct Answer)
+5
-1.5
A weld is made using $$MIG$$ welding process with the following welding parameters: Current: $$200A;$$ Voltage: $$25V;$$ Welding speed: $$18$$ $$cm/min;$$ wire diameter: $$1.2$$ $$mm;$$ Wire feed rate: $$4$$ $$m/min;$$ Thermal efficiency of the process: $$65\% $$
The area of cross section of weld bead in $$m{m^2}$$ is:
2
GATE PI 1995
Subjective
+5
-0
Two plates with symmetrical $$V$$ joint penetration of $$V$$ angle $$60deg$$ are to be arc welded in a single pass. The power $$P(kW)$$-arc length $$L$$ $$(mm)$$ characteristic is given by $$P=4+0.8L-0.1$$$${L^2}$$. Assuming that the top surface of the weld is flat & flush with the plate top surface, & the energy losses are $$20\% $$, the density of filler material is $$8gm/cc$$ and the energy required to melt $$1$$ $$gm$$ is $$1400$$ joules. The plate dimensions are $$1000mm$$ length & $$5mm$$ thickness. The maximum welding speed is .......................
3
GATE PI 1993
Subjective
+5
-0
The voltage-arc length characteristics of a power source is $$V=20+40L,$$ where $$V=$$ operating voltage in volts and $$L=$$ arc length in $$cm.$$ The open circuit voltage and short circuit current for arc lengths ranging from $$3$$ to $$5mm$$ and current from $$400$$ to $$500$$ amps during welding operation are
4
GATE PI 1992
Subjective
+5
-0
In $$MIG$$ welding the power source characteristics is $${V_p} = 36 - {\rm I}/60$$ and the arc characteristics is $${V_a} = 2{L_a}\,\,\,\, + 27.$$ Find the change in power of the arc if the arc length changed from $$2mm$$ to $$4mm.$$ If the maximum current capacity of the power source is $$300$$ Amps, the maximum arc length sustainable is
Questions Asked from Welding (Marks 5)
Number in Brackets after Paper Indicates No. of Questions
GATE PI Subjects
Fluid Mechanics
Metrology
Theory of Machines
Engineering Mathematics
Machine Tools and Machining
Industrial Engineering
Engineering Mechanics
Strength of Materials
Thermodynamics
Machine Design
Casting
Joining of Materials
Metal Forming