ERW Pipe: electric resistance welding pipe. It uses hot rolled wide steel coil as raw material. The production process is pre-bending, continuous forming, welding, heat treatment, sizing, straightening, cutting process, etc. Compared with SSAW, ERW pipe has shorter seam, higher dimensional accuracy, and uniform wall thickness and better surface. ERW can also bear higher pressure than SSAW Pipe. The disadvantage of ERW is that it can only make small diameter pipe with thin thickness. The seam may has greyness, incomplete fusion and trench corrosion defects. It is widely used in delivering city gas, crude oil and oil products.
SSAW Pipe: spiral submerged arc welding pipe. It is made of hot rolled and cold rolled coil, the forming and welding are at the same time. The welding seam is spiral. The advantage of SSAW is that it can produce different sizes of pipe with same size material. The seam can avoid main stress of pipe, so it can bear lots of pressure. The disadvantage of SSAW is that its geometric dimension is not very good, and it has longer seam comparing with LSAW. SSAW pipe may also cause cracks, porosity, slag, weld defects and so on. Generally speaking, SSAW pipe for oil and gas delivering is only used in ordinary city.
LSAW Pipe: longitudinally submerged arc welding. It uses cut deal as raw material, and then put the cut deal in the mold or molding machine to roll, by using double-sides submerged arc welding and expansion, so that to get the products. LSAW has a wide range of dimension with good toughness, plasticity, uniformity and densification. The advantage of LSAW pipe is that it can be with big diameter and high thickness. It can also bear high pressure, low temperature and resist corrosion. It is widely used in making high tensile, high tenacity and high quality oil and gas pipe.
According to API Specification, LSAW pipe is the only kind of pipe which is allowed in delivering oil and gas in very cold area, in the sea and in big city.
Shanghai Katalor is a professional steel producer and stockiest. We have different kinds or ERW pipe for you to choose. Don't hesitate to contact us if you need it.