History of Line Pipe Manufacturing in North America
4.0. Electric Resistance Welded Pipe
Electric resistance welded (ERW) line pipe is widely used for oil and gas pipelines. It is manufactured by cold-forming previously-hot-rolled strip to a circular shape, heating the two abutting edges by passing electric current through the interface as the edges come together, and effecting a bond between the edges as the molten or near-molten edges are forced together by mechanical means without the addition of any filler metal. The earliest ERW process (the “Parpart“ process(4-1) was developed in the 1910-1920 decade but the Johnson process which accounted for most of the ERW line pipe manufactured between 1930 and 1960...