NEWS

1. Steel plate inspection of hf welded steel pipe mill line: before the steel plate is processed, it will be ultrasonically inspected to effectively prevent unqualified steel plates from entering the production line;

　　1. Steel plate inspection of hf welded steel pipe mill line: before the steel plate is processed, it will be ultrasonically inspected to effectively prevent unqualified steel plates from entering the production line;

　　2. Blanking: Mill the edges on both sides of the steel plate by an edge milling machine. Since the reducing tube is one big and the other small, the steel plate is also wide at one end and narrow at the other after cutting, so as to achieve the required width and edge of the steel plate. parallelism and bevel shape;

　　3. Pre-bending of hf welded steel pipe mill line: use a pre-bending machine to pre-bend the edge of the plate, which meets the requirements of curvature, and can use a press for pre-bending if the thickness is larger.

　　4. Forming: First, on the forming machine, half of the pre-bent steel plate is rolled several times to make it into a "J" shape, and then the other half of the steel plate is pressed into a "C" shape by the same operation. Open "O" shape

　　5. Pre-welding of hf welded steel pipe mill line: the formed high-frequency straight seam welded steel pipe will be welded by secondary welding

　　6. Internal welding: use tandem multi-wire submerged arc welding (up to four wires) to weld on the inner side of the large-diameter welded pipe factory;

　　7. External welding of hf welded steel pipe mill line: use tandem multi-wire submerged arc welding to weld high-frequency straight seam welded steel pipes,

　　8. Trimming: Trimming the entire welded steel pipe to ensure the precise size required by customers and to improve the distribution of internal stress in the steel pipe;

　　9. Inspection of hf welded steel pipe mill line: Ultrasonic inspection or X-ray inspection, hydrostatic test, anti-corrosion and coating can also be performed on high-frequency straight seam welded steel pipes according to customer requirements.