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...