The straight seam steel pipe is a steel pipe with a longitudinal parallel of welding seams and steel pipes. It is generally divided into public welding steel pipes, welding thin wall pipes, transformer cooling oil pipes, and so on. The production process of straight steel pipes is simple, high production efficiency, low cost, and rapid development. The strength of the spiral welded pipe is generally higher than that of the straight seam steel pipe. The welded pipe with a large pipe diameter can be produced with a narrow square billet. The steel pipes of different pipe diameters can be produced at the same square billet width. The weld length increased by 30 % and 100 %, respectively, and the production speed was lower.
Welding frequency
High frequency will affect the distribution uniformity of the current inside the steel plate. When choosing a high -frequency welding frequency, you must consider both heat permeability and the neighboring effect. Generally, the current frequency can be appropriately increased, which can not only save electrical energy, but also improve the quality of welded seams and reduce the size of the weld heat -influencing area. In terms of welding efficiency, high frequencies are used as possible. The high -frequency current of 100KHz can penetrate 0.1mm of ferrous steel, and 400kHz can only penetrate 0.04mm, that is, the current density distribution on the surface of the steel plate, the latter is nearly 2.5 times higher than the former.
In production practice, the frequency of 350 ~ 450kHz can generally be selected when welded with carbon steel; welding alloy steel materials can be used for 50 ~ 150kHz when the plate is thick for 10mm or more, because the chromium contained in alloy steel, the chromium contained in alloy steel, The skin collection effect of zinc, copper, aluminum and other elements is different from steel.
Welding power
The power of the tube of the slopes is insufficient for too early hours, and the welding temperature cannot be achieved, which will cause unprooped defects such as virtual welding, welding, and welding. The temperature is greatly higher than the temperature required for welding, causing severe splash, pinhole, residue and other defects. This defect is called over -burning defects. The input power during high -frequency welding should be adjusted and determined according to the thickness and molding speed of the tube wall. Different forming methods, different unit equipment, and different material steel grades need to be summarized and optimized by practice.
In addition to the above factors, it also includes the speed of welding, the method of welding, the welding squeeze pressure, and the impedance used by the impedance. Mastering the quality control elements of these high -frequency welded pipes can make better boutiques.
