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 millisecond. A spherical fusion zone extending up to the full thickness of each sheet is formed. The properties of the metallic sheets are given as :ambient temperature = 293 Kmelting temperature = 1793 K density = 7000 kg/m3latent heat of fusion = 300 kJ/kg specific heat = 800 J/kgKAssume : 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 ; andiii) the complete weld fusion zone is at the melting temperature.The melting efficiency (in %) of the process is

Two metallic sheets, each of 2.0 mm thickness, are welded in a lap joi

1.	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 millisecond. A spherical fusion zone extending up to the full thickness of each sheet is formed. The properties of the metallic sheets are given as :ambient temperature = 293 Kmelting temperature = 1793 K density = 7000 kg/m3latent heat of fusion = 300 kJ/kg specific heat = 800 J/kgKAssume : 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 ; andiii) 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» D. 80.37