The high-frequency resistance welding method has been used in the production of welded pipes since the 1950s. In the past ten years, its production technology has become more and more perfect, and its product quality has been continuously improved. First of all, the quality of the raw materials used in ERW production has been significantly improved. Low C, low P, S, micro-alloying in the design of steel components; converter smelting, ladle refining, vacuum degassing, continuous casting and other new technologies in the smelting process The use of controlled rolling and controlled cooling technology in the rolling process has greatly improved the appearance size, appearance quality, and physical and chemical properties of hot-rolled steel strips for large and medium-diameter ERW steel pipes.
In addition, with the advancement of detection technology, online or offline full-weld ultrasonic or eddy current exploration can be realized, and the water pressure test can also be tested and stabilized as required under the monitoring of the computer. The promotion and implementation of ISO9000 series standards and APIQ1 specifications make the production, inspection, sales and service of large and medium diameter ERW steel pipes in a whole process of quality assurance. In recent years, all countries are actively studying the use of high-frequency welded (ERW) steel pipes to replace seamless pipes and spiral welded pipes. In industrially developed countries, the diameter of high-frequency welded pipes is below Ф610mm, and the proportion of ERW has reached about 70%.
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