Metal separations in electric resistance welded pipe (ERW)A type of steel pipe that is manufactured using the electric resistance welding (ERW) process. It involves the application of pressure and the passage of an ele… or flash weldLocalized coalescence of metals produced by heating the materials to the welding temperature, with or without the application of pressure, or by the application… (FW) pipe, resulting from imperfections at the edge of the plate or skelpA strip of steel, typically in coil form, used to form the tube or cylinder of welded pipe., parallel to the surface, which turn toward the inner diameter (ID) or outer diameter (OD)The diameter of a pipe that extends from the outside edge of one wall through the center point to the outside edge of the opposite wall. pipe surface when edges are upset during welding.