A continuous weld is to be made around the circumference of a round steel tube of diameter = 6.0 ft, using a submerged arc-welding operation under automatic control at a voltage of 25 V and current of 300 A. The tube is slowly rotated under a stationary welding head. The heat transfer factor for SAW is = 0.95 and the assumed melting factor = 0.7. The cross-sectional area of the weld bead is 0.12in2. If the unit melting energy for the steel = 150 Btu/in3, determine
(a) the rotational speed of the tube and
(b) the time required to complete the weld.