A method for determining the position and size of an impedance resistor for the production of straight seam welded pipes

Abstract

The present invention relates to a method for determining the position and the size of an impedor for producing a longitudinally welded pipe. According to the technical scheme, the impedor (3) is located in the longitudinally welded pipe (2) which passes through the interior of an induction ring (4); the axis of the impedor (3) is parallel with the axis of the longitudinally welded pipe (2); the front end of the impedor (3) and the plane where the center line of an extruding roller (1) of a welding extruding machine set are a same vertical plane; and the tail end of the impedor (3) and the tail end of the induction ring (4) are a same vertical plane. The area of the cross section of the impedor (3) is 42-84% of the area of the cross section of an inner cavity of the longitudinally welded pipe (2); a gap a between the outer surface of the impedor (3) and the inner wall of the longitudinally welded pipe (2) where a weld seam (5) is located is equal to (1-2) delta, and delta represents the wall thickness of the longitudinally welded pipe (2), mm. By means of the method, a magnetic rod material of the impedor (3) is saved, the service life of the impedor (3) is prolonged, acquired induction eddy current and corresponding welding heat are dense on a V-shaped to-be-welded surface, and the welding efficiency and the quality of a weld seam joint are improved.

Description

technical field [0001] The invention belongs to the technical field of straight seam welded pipe welding. In particular, it relates to a method for determining the position and size of an impedance for producing straight seam welded pipes. Background technique [0002] High-frequency induction welded pipes are processed by uncoiling, straightening, butt jointing, edge processing and other processes of raw material coils, and then rolled into tube blanks in the forming unit, and then use the "skin effect" and "proximity effect" of high-frequency current "The edge of the tube blank is rapidly heated to the welding temperature for extrusion welding. Therefore, the efficient utilization of high-frequency current "skin effect" and "proximity effect" is a problem that must be paid attention to in the production of high-frequency induction welded pipes. When the tube blank passes through the induction coil with high-frequency current, two high-frequency induced eddy currents will...

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Problems solved by technology

"On the Structure and Configuration of Inductors and Impedors in High Frequency Induction Welding" (Tong Lianxun, Bi Jingdong, Qi Huijuan. On the Structure and Configuration of Inductors and Impedors in High Frequency Induction Welding [J]. Welded Pipe, 1996, 19(3 ): 18-25.) and "Analysis of Influencing Factors of ERW Induction Welded Pipe Weld Quality" (Song Zhiqiang, Meng Qiang, Qu Deqiang. Analysis of Influencing Factors of ERW Induction Welded Pipe Weld Quality [J]. Steel Pipe, 2012, 41(4) : 37-41.) believed that the ratio of the cross-sectional area of ​​the impedance to the internal cross-sectional area of ​​the welded pipe should be as large as possible, "Three links in the quality control of the high-frequency welded pipe production process" (Chen Ying, Yang Chenqin. High-frequency welded pipe production process Three links of quality control [J]. Welded Pipe, 2003, 26(2): 53-55.) thinks that the ratio should not be less than 70%, however, the actual production shows that most of the welded pipe production is difficult to achieve this value

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