Seam welding is commonly used during the manufacturing of round, square and rectangular steel tubing. The steel strip is unwound from coils and side-trimmed to control width and condition the edges for welding. The strip then passes through a series of contoured rollers which cold-form the material into a circular (square or rectangular) shape. The edges are forced together under pressure as a butt joint and then welded by heating the material to temperatures above 2000° F. The flash weld that has formed is now removed from the outside diameter of the tube. Once the weld has been tested the tube then passes through a series of sizing rolls to attain its precise finished size, after which the tube is then straightened and cut to length.

U. S. Steel Tubular Products high frequency electric weld (ERW) line pipe and standard electric resistance weld pipe products are smoothly finished and thin-walled. They are produced by continuously forming coiled hot rolled strip into a tube and welding the longitudinal seam using high-frequency electric resistance welding. Chemical and mechanical property requirements are as prescribed by current API 5L and applicable ASTM standards.