Stainless steel (aisi 304) ball bearings, which have uniformlybeen heated to 850 c, are hardened by quenching them in an oil baththat is maintained at 40 c. the ball diameter is 20 mm, andthe convection coefficient associated with the oil bath is 1000w/m2*k.
(a) if quenching is to occur until the surface temperature ofthe balls reaches 100 c, how long must the balls be kept in theoil? what is the center temperature at the conclusion of thecooling period?
(b) if 10,000 balls are to be quenched per hour, what isthe rate at which energy must be removed by the oil bath coolingsystem in order to maintain its temperature at 40 c?