X52 large-diameter straight seam welded pipe main production process description:
Raw material inspection
Select steel billets or steel plates that meet API 5L X52 steel grade. After entering the site, check the appearance, measure the size, analyze the chemical composition with a spectrometer, and sample for mechanical property testing. Only qualified ones can be used.
Edge milling and pre-bending
Qualified materials are fine-trimmed with edge milling machines to remove excess and flat burrs to ensure straightness and parallelism; then use pre-bending machines to pre-bend the edges to obtain the initial curvature.
Pressing and forming
The pre-bent steel plate is placed in a JCO forming machine, half of which is pressed into a "J" shape and the other half into a "C" shape, and spliced into an approximately "O" shaped pipe billet, and the punching pressure is controlled to ensure accuracy.
Pre-welding and formal welding
The pipe billet is first pre-fixed by gas shielded welding, and then longitudinal multi-wire submerged arc welding is used inside, and the same type is used outside to weld according to the reference to ensure the quality of the weld.
Flaw detection
After welding, first ultrasonically check the weld and parent material, and then X-ray penetration imaging, carefully examine the welding quality, and ensure accurate defect detection.
Expansion
The qualified pipes are put into the expansion equipment for mechanical expansion and adjustment of pipe diameter, stress distribution, mechanical and dimensional stability.
Hydraulic pressure test
Water is injected into the expanded pipes one by one to increase pressure and maintain pressure, monitor leakage and deformation, and test pressure-bearing and sealing performance.
Chamfering
The pipes that pass the test are chamfered at the ends of the pipes according to the standards, and the angles are fine-tuned to meet the requirements of docking and assembly.
Secondary review
Use high-precision ultrasonic, new algorithm X-ray, and magnetic particle inspection to review the whole and the pipe ends and dig out potential defects.
Surface coating
Select anti-corrosion coatings and processes as needed, remove rust and clean, prime and spray, and enhance corrosion resistance and appearance.
