UNIQUE WELDMENT JOINS DOUBLE PIPELINE.

The submerged arc fillet welds were made with L70, 1/8-in. solid wire (F72-EA1-A2) and 860 flux. Closure welds were made with L61 1/8-in. solid wire (F72-EM12K) and 860 flux. All submerged arc welding procedures were set at 450-500 A (DCEP), 28-30 V, with a travel speed of 19 ipm. Preheat of 150 degree F was required for the closure welds only, with a 350 degree F maximum interpass temperature allowable for all welds. Welds were inspected and tested ultrasonically and with magnetic particles. A localized hydrostatic test was also performed at 2900 psi to insure weld quality. In all, six fully automatic NA-3S submerged arc systems and nine semiautomatic welding machines were used on the project. The 7640 welds required were completed on schedule by fabricating a minimum of 24 pipes per day.