ERW (ERW straight seam welded steel pipe) is a hot rolled coil after forming machine. It uses skin effect and proximity effect of high frequency current to make the edge of the pipe heated and melted under the pressure of extrusion roll to realize production.


High frequency resistance welding method used in pipe production in 1950s. In the past ten years, the production technology has become more and more mature, and the quality of products has been continuously improved.


First, ERW steel pipes for raw material quality have been significantly improved, steel components are designed with low C, P, S and microalloying; smelting process, ladle refining, vacuum degassing, continuous casting and other new processes; ERW pipe-ERW rolling process control rolling, control cooling technology makes the appearance size, appearance quality and physical and chemical properties of large and medium ERW steel pipes greatly improved. The steel pipe produced by Baoshan Iron and Steel Company, representing the highest level of hot rolled strip steel, has reached API 5L standard of American Petroleum Association and is at the international level.


Secondly, the steps of longitudinal forming welding and heat treatment of medium and large diameter ERW are realized by computer automatic control in the production process. The heat input energy of high frequency welding process and the computer automatic compensation system are effectively controlled to prevent the low temperature caused by the heat input energy of cold welding and the high energy caused by the heat input and excessive combustion of welding. IF heat treatment temperature control allows the heat treatment process to achieve the best results according to process requirements, effectively ensuring the quality of weld and heat affected zone of steel pipe.


In addition, the progress of ERW pipeline-ERW detection technology has realized the complete online or off-line ultrasonic or eddy current welding hazard. Hydraulic pressure test can be monitored by computer to meet the requirements of pressure test and adjustment. Implement and implement ISO9000 APIQ1 standards and specifications to ensure the quality of medium and large diameter ERW straight seam steel pipe in the whole process of production, testing, sales and service.


In recent years, our country is actively using ERW straight seam welded pipe and spiral welded pipe seamless pipe in place. In industrialized countries, ERW straight pipe 610mm below, ERW pipe has reached about 70% of the proportion. Our vertical ERW production capacity is also increasing.