High-frequency straight seam resistance welded steel pipe is produced by using the skin effect and proximity effect of high-frequency current to heat and melt the edge of the pipe blank after the hot-rolled coil is formed by the forming machine, and then pressure welded under the action of the extrusion roller. The product.
High-frequency resistance welded steel pipes are different from the welding process of ordinary welded pipes. The weld seam is melted from the base material of the steel strip body, and its mechanical strength is better than that of ordinary welded pipes. The appearance is smooth, the precision is high, the cost is low, and the weld reinforcement is small, which is beneficial to the coating of 3PE anti-corrosion coating. The welding methods of high-frequency welded steel pipes and submerged arc welded pipes are significantly different. Since welding is completed instantaneously at high speed, ensuring welding quality is much more difficult than with submerged arc welding.
The so-called high frequency in high-frequency welding refers to the current with a frequency of 50KHz-400KHz. Such a current will have two effects on the metal. One is the skin effect: unevenness occurs when high-frequency current passes through a conductor. And the density of the conductor surface is large but the inside is small, which is the skin effect; one is the proximity effect, where high-frequency current flows in opposite directions between adjacent conductors. Even if the other side is shorter, the current will be concentrated to the edge. Will flow to the shorter side, creating a proximity effect. These two effects are the basis of high-frequency welding. High-frequency welding uses the skin effect to concentrate high-frequency current on the working surface, and uses the proximity effect to control the loop position and range of the high-frequency current, thereby heating and melting adjacent steel plates to complete the welding.
