Resistance projection welding is used to simultaneously weld two thin, steel plates together at four\nlocations. One of the pieces of steel plate is pr
Resistance projection welding is used to simultaneously weld two thin, steel plates together at four
\r\nlocations. One of the pieces of steel plate is preformed with projections that have a diameter of 0.25
\r\nin and a height of 0.20 in. The duration of current flow during the weld is 0.30 sec and all four
\r\nprojections are welded simultaneously. The plate steel has a unit melting energy of 140 Btu/in3 and
\r\na resistance between plates of 90.0 micro-ohms. Experience has shown that 55% of the heat is
\r\ndissipated by the metal and 45% melts the weld nugget. Assume the volume of the nuggets will be
\r\ntwice the volume of the projections because metal from both plates is melted. How much current is
\r\nrequired for the process?