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Spot welding of two steel sheets each 2 mm thick is carried out successfully by passing 4 kA of current for 0.2 seconds through the electrodes. The resulting weld nugget formed between the sheets is 5 mm in diameter. Assuming cylindrical shape for the nugget, the thickness of the nugget is _________ mm.
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- 3 mm
- 2.91 mm
- 2.91 mm
- 6 mm
Correct Option: C
t = 2 mm, I = 4 KA = 4000 A, t = 0.25 s
dn = 5 mm ,hn =?
Heat Generated = I² R t ...(1)
Heat utilized = Volume × δ × LH ...(2)
(1) = (2)
= 4000² × 200 × 10-6 × 0.2
= (π/4) 5² × 8000 × 1400
hn = 2.91 mm
