Q.60. Two metallic sheets, each of 2.0 mm thickness, are welded in a lap joint configuration by resistance spot welding at a welding current of 10 kA and welding time of 10 milli second. A spherical fusion zone extending up to the full thickness of each sheet is formed. The properties of the metallic sheets are given as:
(i) contact resistance along sheet – sheet interface is 500 micro-ohm and along electrode – sheet interface is zero;
(ii) no conductive heat loss through the bulk sheet materials; and
(iii) the complete weld fusion zone is at the melting temperature.
The melting efficiency (in %) of the process is
(A) 50.37
(B) 60.37
(C) 70.37
(D) 80.37
Answer: (C)
Explanation:
