GATE 2019 ME (ME2) – Question 61
Gas tungsten arc welding uses 250 A, 20 V and travel speed 5 mm/s. Arc efficiency is 70%. Find net heat input per weld length (kJ/mm), to one decimal place.
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Correct answer: .7 to .7
Explanation
Useful heat input is $\eta VI=0.7(20)(250)=3500$ J/s. Divide by travel speed 5 mm/s to obtain 700 J/mm, or **0.7 kJ/mm**.