Time Left - 15:00 mins
GATE ME 2021 || Manufacturing Quiz 8 (App update required to attempt this test)
Attempt now to get your rank among 585 students!
Question 1
The voltage length characteristic of a direct current (dc) arc is given by
V = (20 + 40 L) Watts
Where, L is the length of the arc in cm. The power source characteristic is approximated by a straight line with an open circuit voltage = 80 V and a short circuit current = 1000 amp. The optimum arc length is _________ (in cm).
Question 2
Welding of two 8 mm thick plates placed at a distance of 20 mm is done. It is carries out at 20 V, 400 A and the heat required to melt the plate is 25 J/mm3. The melting and heat transfer efficiency are 0.625 and 0.80 respectively. Find the speed of welding _______.
Question 3
For resistance spot welding of two sheets each of 2 mm thickness, a current of 3000 ampere was passed for 0.2 s. The total resistances was 50 micro-ohms. The heat energy utilised for welding is 72.88 J and the melting energy per unit volume is 2.9 J/mm3. The weld nugget can be
Question 4
Which theory explains microscopic level of surfaces that has crevices, cracks and pores?
Question 5
Two 8 mm thick steel plates are placed 5 mm apart and welded by a butt joint. Welding is carried out at 20 V. Heat transfer efficiency is 0.80. If the heat required to melt steel is 10 J/mm3 and melting efficiency is 0.625. The weld current is 200 A. The welding speed (in mm/s) is ___________.
Question 6
Resistance spot welding is performed on two plates of 1.5 mm thickness with 6 mm diameter electrode, using 15000 A current for a time duration of 0.25 seconds. Assuming the interface resistance to be 0.0001Ω, the heat generated( W-sec) to form the weld is
- 585 attempts
- 1 upvote
- 9 comments
Sep 27ESE & GATE ME
