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 press and weld the squeeze roll under pressure Realize production. In the 1950s, the high-frequency resistance welding method was applied to the production of welded pipes. In the past ten years, its production technology has become more and more perfect, and the quality of its products has continued to improve. First, the quality of the raw materials used in ERW production has been significantly improved. Low-carbon, low-phosphorus, low-sulfur steel parts design, microalloying; converter smelting, ladle refining, vacuum degassing, continuous casting and other new technologies in the smelting process. Controlled rolling and controlled cooling are used in the rolling process The technology has greatly improved the appearance size, appearance quality and physical and chemical properties of the hot rolling mill. Rolled steel strips for large and medium-sized ERW steel pipes. The pipeline steel produced by Baosteel Co., Ltd., which represents the highest level of hot-rolled steel strip in China, has reached the requirements of the API 5L standard of the American Petroleum Institute and is at the international leading level.
Secondly, the computer’s automatic control is realized in the production process of large and medium-caliber ERW steel pipe forming welding heat treatment, and the computer’s automatic compensation system effectively controls the heat input energy in the high-frequency welding process; preventing the welding heat input energy from being low due to high heat Input energy causes cold welding, false welding and overheating. The control of the intermediate frequency heat treatment temperature enables the heat treatment process to achieve the best effect according to the process requirements, thereby effectively ensuring the quality of the weld and the heat-affected zone.
In addition, the advancement of inspection technology has realized the damage of online or offline all-welded ultrasonic or eddy current exploration. The hydraulic test can also be tested and stabilized according to requirements under the supervision of a computer. The promotion and implementation of ISO9000 series standards and APIQ1 specifications have ensured the quality of the entire process for the production, inspection, sales and service of large and medium diameter ERW steel pipes. In recent years, countries are actively studying the use of ERW steel pipes instead of seamless steel pipes and spiral steel pipes. In industrially developed countries, the diameter is less than Φ610mm, and the proportion of ERW has reached about 70%.
In the past ten years, Japan’s ERW welded pipe has developed rapidly. Nippon Steel, Sumsei Metals and Wakayama Iron Works all have 508 mm (20 inches) ERW welded pipe production plants; Kawasaki Chita Steel and Japan Steel Keihan Steel each have a 609 mm (24 inches) 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 output of spiral welded submerged arc welded pipe is 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, 8 of which are ERW welded pipe production lines, and orders for only one spiral submerged arc welded pipe are decreasing. The main reason is that the number of long-distance oil and gas pipelines constructed by spiral welded submerged arc welded pipes is decreasing year by year, and some countries do not even allow the use of spiral welded submerged arc welded pipes in important long distances. Oil and gas pipelines. According to the regulations of American Amoco Company, the use of spiral seam submerged arc welded pipes on long-distance oil and gas pipelines is not allowed.
The Argentine Siat company has one RBE direct submerged arc welded pipe production line, two ERW long seam welded pipes and a spiral groove submerged arc welded pipe production line. According to Siat, in Argentina, spiral seam submerged arc welded pipes are usually only used for water transport and piling. The main pipelines for long-distance transmission of oil and gas use RBE longitudinal submerged arc welded pipes, and some branch lines use ERW welded pipes.
Seversky Tubeworks in Russia has 6 ERW welded pipe production lines. The first production line was built in 1962. The newest workshop was built in 1993. The diameter of the steel pipe is 6-32mm, 10-76mm and 20-76mm. It can produce 20-102mm, 73-219mm, 102-220mm galvanized steel pipes as required, with a total annual output of 920,000 tons.
American GENEVA steel, CSI steel pipe products IPSCO TUBULARS LONESTAR, Newport Steel, TUBACERO INTERNATIONAL and American STEEL TUBULAR products all have ERW welded pipe production lines.
In China, large-diameter 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.
Post time: May-26-2021