1
GATE PI 2008
MCQ (Single Correct Answer)
+2
-0.6
Two pipes of inner diameter $$100mm$$ and outer diameter $$110mm$$ each are joined by flash butt welding using $$30V$$ power supply. At the interface, $$1mm$$ of material melts from each pipe which has a resistance of $$42$$ Ohms.If the unit melt energy is $$64.4$$ $$MJ/{m^3}$$, then time required for welding (in $$S$$) is
2
GATE PI 2008
MCQ (Single Correct Answer)
+2
-0.6
Aluminium strips of $$2mm$$ thickness are joined together by resistance spot welding process by applying an electric current $$6000$$$$A$$ for $$0.15sec$$. The heat required for melting aluminium is $$2.9J/m{m^3}.$$ The diameter and thickness of the weld nugget are found to be $$5$$ $$mm$$ and $$2.5mm$$ respectively. Assuming the electrical resistance to be $$75$$ micro-ohms, the percentage of total energy utilized in forming the weld nugget is
3
GATE PI 2008
MCQ (Single Correct Answer)
+2
-0.6
Which of the following powders should be fed for effective oxy-fuel cutting of stainless steel
4
GATE PI 2007
MCQ (Single Correct Answer)
+2
-0.6
The $$DC$$ power source for arc welding has the characteristic $$3V + 1 = 240,$$ where $$V=$$ Voltage and $${\rm I}\,\, = $$ current in amp. For maximum arc power at the electrode, voltage should be set at
Questions Asked from Welding (Marks 2)
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