Tubular Operations sits on the original site of national tube Works. Steel arrives at the facility in coils that are unrolled, cut and welded into a continuous strip before entering the mill. the strip steel passes through a series of forming rolls, which transform the strip from flat steel to a round pipe section. the fin pass section of the mill finishes the rounding process and contours the edges of the strip for seam welding. the high-frequency welder heats the edges of the rolled strip to approximately 2,600°F. Pressure rolls then squeeze the heated edges together to form a fusion weld. the weld is inspected by an ultrasonic non-destructive inspection unit.the pipe then enters the seam normalizer where the weld area is heat treated as per API specification to remove welding stresses and produce a uniform normalized grain structure. the weld is cooled in air below transformation temperature and then water-cooled to near ambient before passing through the sizing mill, where idler side-closing rolls straighten the pipe and size it to the correct outside diameter. as the continuous length of pipe moves down the mill, the flying cut-off cuts lengths of pipe without interrupting the production line. each pipe is hydrostatic tested to ensure rated strength and weld integrity under pressure. after  hydrotesting, any bow in the pipe is removed by passage through a multi-stand straightener. the pipe enters the finishing floor where the weld is ultrasonically inspected and the pipe is examined by automated electromagnetic inspection. after being cut to customer-specified lengths, the pipe is finished and prepared for shipment.