Development process of ERW steel pipe technology at home and abroad

High frequency welded pipe (ERW) is the hot rolled plate after molding machine molding, using high frequency current skin effect and proximity effect, make the edge of tube billet heating melt, in the role of squeezing roller pressure welding to achieve production.

High-frequency resistance welding method in the 50 s applied to welded pipe production. In nearly a decade, and its production technology improvement, continuously improve product quality. First is the quality of the ERW production materials have obvious difference, the steel composition design of the low C and low P, S, micro alloying; Smelting process of converter smelting, ladle refining, vacuum degassing, continuous casting and the adoption of new technology; In the process of rolling the use of controlled rolling and controlled cooling technology makes the appearance of the large and medium caliber ERW steel pipewith hot rolled steel belt size, appearance quality, physical and chemical performance is greatly improved.

Followed by the large and medium caliber ERW steel tube forming welding heat treatment process such as the production process to achieve the automatic computer control, high frequency welding heat input energy along with the computer in the process of automatic compensation system has been effectively controlled, prevent the welding heat input energy on the low side caused by cold welding, virtual welding, and heat input energy on the high side and burnt.

Medium frequency heat treatment temperature control of heat treatment process can according to the technological requirements to achieve the best effect, effectively guarantee the quality of welding seam and heat affected zone. In addition, the progress of detection technology, realized the full weld ultrasonic or online or offline eddy current exploration and hydrostatic test can also be under the monitor of the computer, pressure testing and regulated in accordance with requirements. ISO9000 series standards and the promotion and implementation of APIQ1 specification, the large and medium caliber ERW pipe production, testing, sales and service in a whole process of quality assurance. In recent years, countries are actively research using high frequency welded pipe (ERW) pipe instead of seamless pipe and spiral welded pipe, in the industrial developed countries, high frequency welded pipe under $ 610 mm diameter, ERW proportion has reached 70%.