High-frequency straight seam welded pipe (ERW) is a hot-rolled coil formed by a forming machine, which uses the skin effect and proximity effect of high-frequency current to heat and melt the edge of the pipe blank, and then perform pressure welding under pressure. Squeeze rolls to achieve production. The high frequency resistance welding method was used in the production of welded pipes in the 1950s. In the past ten years, its production technology has been improved day by day, and the quality of its products has been continuously improved. The first is that the quality of raw materials used in the production of explosive remnants of war has been significantly improved. Low C, low P, S, and microalloying in the design of steel components; new technologies such as converter smelting, ladle refining, vacuum degassing, and continuous casting are used in the smelting process. The appearance size, appearance quality and physical and chemical properties of hot rolled steel are analyzed. Rolled steel strips for large and medium diameter ERW steel pipes. The pipeline steel produced by Baoshan Iron and Steel Company represents the highest level of hot-rolled strip steel in China, and meets the requirements of the American Petroleum Institute API 5L standard, and is at the international leading level.

Secondly, in the production process of large and medium diameter ERW steel pipe forming welding heat treatment, automatic control of the computer is realized. The automatic compensation system of the computer effectively controls the heat input energy during the high-frequency welding process to prevent the welding heat input energy from being low and high heat input Cold welding, false welding and overheating caused by energy. The control of the intermediate frequency heat treatment temperature enables the heat treatment process to achieve the best effect according to the process requirements, and effectively guarantees the quality of the weld and the heat-affected zone.

In addition, advances in inspection technology have achieved online or offline full weld ultrasonic or eddy current flaw detection. The hydraulic test can also be tested and stabilized as required under the supervision of a computer. The promotion and implementation of ISO9000 series standards and APIQ1 norms make the production, inspection, sales and service of large and medium-diameter ERW steel pipes in the whole process of quality assurance. In recent years, countries have been actively researching the use of ERW steel pipes to replace seamless steel pipes and spiral steel pipes. In industrially developed countries, where the diameter is less than φ610mm, the proportion of ERW has reached about 70%.

In the past ten years, Japan's ERW welded pipe has developed rapidly. Nippon Steel & Steel Corporation, Sumsei Metals and Wakayama Ironworks each have a 508 mm (20 inch) ERW welded pipe production plant; Kawasaki Chita Steel Works and Japan Steel Pipe Keihan Steel Plant each have a 609 mm (24 inch) ERW welded pipe production line. At present, the output of ERW welded pipe has accounted for 70-75% of the total output of Japanese steel pipe, while the spiral seam submerged arc welded pipe has been relatively small.

South Korea’s ERW welded pipe has begun to develop rapidly and has replaced many seamless steel pipes. Busan Steel Pipe Company and Hyundai Steel Pipe Company each have 9 welded pipe production lines, of which 8 are ERW welded pipe production lines, and orders for only 1 spiral submerged arc welded pipe are decreasing. The main reason is that the number of long-distance oil and gas pipelines constructed with spiral seam submerged arc welded pipes has decreased year by year, and some countries do not even allow the use of spiral seam submerged arc welded pipes on important long-distance pipelines. Oil and gas pipelines. The American Amoco company stipulates that spiral seam submerged arc welded pipes are not allowed to be used in long-distance oil and gas pipelines.

The Argentine Siat company has one RBE LSAW pipe production line, two ERW LSAW pipe production lines and a spiral groove submerged arc welded pipe production line. According to Siat, in Argentina, spiral seam submerged arc welded pipes are generally only used for water delivery and piling. The main pipeline of long-distance oil and gas transportation adopts RBE longitudinal submerged arc welded pipe, and some branch lines adopt ERW welded pipe.

Russia Seversky Tubeworks has 6 ERW welded pipe production lines. The first production line was built in 1962, and the latest workshop was built in 1993. The diameters of steel pipes are 6-32mm, 10-76mm, and 20-76mm. , 20-102mm, 73-219mm, 102-220mm, galvanized steel pipe can be produced as required, with a total annual output of 920,000 tons.

American GENEVA STEEL, CSI TUBUL AR PRODUCTS IPSCO TUBULARS LONESTAR, NEWPORT STEEL, TUBACERO INTERNATIONAL and US STEEL TUBULAR PRODUCTS all have ERW welded pipe production lines.

In China, large and medium-caliber ERW steel pipes appeared in the late 1980s and early 1990s, but their development was extremely rapid, and the market coverage of their products was increasing. Industrial fields, such as urban pipe networks and building structures.

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