For the general enterprise, advantages of the SSAW steel pipe are that it is suitable for the manufacture of medium and below wall thickness (20mm), large diameter (1-3mm) and medium grade (X70). Its limitations are due to the spiral around the tube, the weld in the curved surface position, thus the welding is more difficult, and improving the welding speed is also not easy, the residual stress is larger. Therefore, it is difficult to improve the steel grade (X80) and to improve the wall thickness (20 mm). When the wall thickness is large (for example, 25 mm), the weight due to the weight of the coil can be manufactured, but the yield is low.
In order to overcome the limits of SSAW steel pipe, foreign SSAW steel pipe manufacturer adopted some measures. To eliminate the residual stress, Russia adopted the whole body heat treatment method, Canada adopted the whole pipe body mechanical expansion method; in the process of forming the process to overcome the low speed of submerged arc welding problem On the use of two-step method, that is, pre-precision welding method is to take 3-4 fine welding line to meet the pre-welding speed increase. Therefore, the pre-precision welding method is mainly to improve the production capacity of spiral submerged arc generator (production), of course, it also improves the quality of molding and welding. Not all of foreign countries requires two-step method, Russia and Central Asian countries, there is no such requirements, because the two-step method and one-step production of steel pipe physical quality, as long as the standards are qualified, no difference. West-East Second Line, three-wire SSAW steel pipe are produced by one-step method.
On the two-step method, there are several hot topics. One, it must be stably shaped, to create conditions for precision welding tracking. Second, requiring the concentrate, strip geometric size to be more accurate. Third, the technical performance of the molding equipment to keep up with the requirements of high speed, especially milling machine (preferably two milling - rough milling and fine milling) is a bottleneck. Four, A full set of imported advanced foreign pre-refined welding production line, investing about 500 million yuan. Therefore, the general SSAW steel pipe business, if there is no limit in the short term and a large number of demand orders, under normal circumstances can adapt to the rhythm of market demand, do not blindly on the two-step method. Five is already on the two-step business, to digest the introduction of technology, correctly grasp the operating norms, and spare parts as much as possible (especially milling cutter) made, efforts to reduce efficiency, open up domestic and foreign markets.
Prime Steel Pipe is a leading manufacturer and exporter for SSAW steel pipe and other kinds of carbon steel pipe, we have the most advanced technology to produce the most high-quality SSAW steel pipe, more detailed information will be provided for you if you send email to us.
