The advent of rolling mill technology and its development during the first half of the nineteenth century also heralded in the industrial manufacture of tube and pipe. Initially, rolled strips of sheet were formed into a circular cross-section by funnel arrangements or rolls, and then butt or lap welded in the same heat (forge welding process). Toward the end of the century, various processes became available for the manufacture of seamless tube and pipe, with production volumes rapidly increasing over a relatively short period. In spite of the application of other welding processes, the ongoing development and further improvement of the seamless techniques led to the welded tube being almost completely pushed out of the market, with the result that seamless tube and pipe dominated until the Second World War. During the subsequent period, the results of research into welding technology led to an upturn in the fortunes of the welded tube, with burgeoning development work ensuring and wide propagation of numerous tube manufacturing processes. Of this figure, however, about one quarter takes in the form of so-called large-diameter line pipe in size ranges outside those which are economically viable in the seamless tube and pipe manufacturing.
Though the size of ranges for seamless and welded tube, the welded tube is predominantly manufactured in ranged characterized by small wall thickness and large outside diameters, while the seamless tube is produced mainly in the range extending from normal to very large wall thicknesses in the diameter range up to approx. 660m. The process of selection of the manufacturing process - especially in the overlap regions where there is a real choice between seamless and welded tube - is essentially dictated by the application of the tube, i.e. the associated material requirements and the service conditions.