The straight seam steel pipe can be divided into high -frequency straight steel pipes and buried arc welding straight seam steel pipes according to the production process. Here are the most common high -frequency straight seam steel pipes and buried arc welding straight seam steel pipes.
Buried arc welding
After the steel plate used to create a large -caliber buried arc welding straight seam steel pipe enters the production line, the full board ultrasonic inspection is performed first; double -sided milling on both edges of the steel plate through the milling machine, so that it can meet the requirements of the plate width, parallel parallel and parallel parallel, and the parallel parallel degree and parallel parallel. The shape of the slopes; use the pre -bending machine for the pre -bending of the board to make the edge of the board have a curved curvature; first on the JCO molding machine, the half of the steel plate after the pre -curved bending has been stamped multiple times and pressed it into a "J" shape. Then the other half of the steel plate is also bent, pressed into a "C" shape, and finally the "O" shape of the opening.
Make the forming straight seam welded steel pipes and seams and use gas protection welding (MAG) for continuous welding; use the column -to -wire buried arc welding (up to four wires) on the inside of the straight steel pipe to weld; Buried arc welding is welded outside the outside of the straight arc welded steel pipe. After the welding is completed, the first ultrasonic inspection (mainly inspection of welds and the mother material on both sides), the first X -ray examination (check the sensitivity of the detection), the test of the diameter, and the water pressure (water pressure Press test opportunities automatically save records).
Then process the inspection of the inspection of the steel pipes to the size that meets the requirements, and then perform the second ultrasonic inspection, the second X -ray inspection, the tube end magnetic powder test, anticorrosive and coating, and complete the entire processing process.
High -frequency welding
High -frequency welding is based on the electromagnetic induction principle and AC charge in the conductor, the adjacent effect, and the vortex thermal effect of the edge of the weld to the melting state, and then squeeze it with a roller to enable the seam to achieve indirect crystals in the seams. , To achieve the purpose of welding welding. High -frequency welding is an inductive welding (or pressure contact welding). It does not require welding seam filling, no welding splash, welding thermal affecting narrowing area, beautiful welding molding, and good welding mechanical performance. Therefore, it is subject to the production of steel pipes. Wide application.
The high -frequency welding of the steel pipe uses the skin's skin -tending effect and the neighboring effect of AC power. After the steel (with steel) is rolled and forming, a cross -section disconnected circular tube blank is formed. Or a set of impedance (magnetic rods), an electromagnetic induction circuit is formed at the opening of the impedance and the opening of the duct. Under the action of the skin tendency and the neighboring effect, the edge of the tube's mouth has a strong and concentrated thermal effect, so that the edge of the welded seams can make the edge of the welded seams. After quickly heating to the temperature required for welding, after the pressure roller is squeezed, the metal of the melting state achieves indirect crystal convergence, and a solid docking weld is formed after cooling.
