The ERW steel pipe, which is the Electric Resistance Welded steel pipe, begins as a coiled plate of steel with appropriate thickness and specific width in its processing. This kind of welded steel pipe is cold formed. In the manufacturing process, pull the ribbon through a series of rollers to form it into a cylindrical tube. An electric charge should be used to heat the edges so that they can be welded together when the edges of the cylindrical plate come together. The electric resistance welded steel pipe can be produced at a high speed in continuous lengths up to 115'. The wall thicknesses and outside dimensions that the pipe produces is uniform, and the electric resistance welded pipe can be made in a variety of specifications. However, sometimes this kind of pipe needs minimum tonnage so that it can be set up on a specific size and has long lead times.
The name of the submerged arc welded steel pipe comes from the process that the welding arc is submerged when it happens. When the welding temperatures are heated, the flux is useful for preventing the weld area from impurities in the air. Only when the inside welds and outside welds are performed and the welding be accomplished in separate processes. Therefore, the pipe then can be looked as double submerged arc welded. This kind of process is suitable for three common types of pipe: U&O Press, Rolled and Welded, Spiral weld.
The spiral welded steel pipe, which is in a spiral form, has a DSAW seam the entire length. We can apply the angle of the steel that is de-coiled against the forming head to determine the outside diameter of the spiral welded pipe. The angle that is used is more acute, and then the diameter that is determined will be greater. The spiral welded pipe can be used in more places because of the production of large, hot rolled coils of sufficient width and the development of dependable non-destructive testing methods. The lengths up to 115 feet in either ID or OD dimensions up to 144 inches are suitable for the roll of the spiral welded pipe. The contractor may have an advantage of short term changes because of the slow manufacturing process. However, the slow manufacturing process may have a bad effect if the large tonnages are needed with a short lead time. The spiral welded steel pipe has limit specifications.