Straight seam submerged arc welding pipe (LSAW) based on single Zhang Zhonghou plate as raw material, the steel in the mold or molding machine medium-voltage (roll) into the pipe, using double-sided submerged arc welding and ChengJinHang production of hole enlargement. Its finished product specification range is wide, the toughness of the weld, plasticity, good uniformity and compactness, with large pipe diameter, wall thickness, strong resistance to high pressure, low temperature corrosion resistance, etc. In the construction of high strength, high toughness, high quality of long distance oil and gas pipeline, the steel tube are mostly straight seam submerged arc welding of large diameter thick wall pipe. According to the provisions of the API standard in large oil and gas pipelines, when the elevations, sea and city populated area in class 1, 2, straight seam submerged arc welding pipe is the only specify the applicable type. Can be divided into the UOE welded pipe molding in different ways: single plate after edge bending, after U shape, O forming, welding, welding, mechanical cold expanding process of JCOE welded pipe: as \"J - E - C - O\" after welding, forming, welding process by cold hole diameter, etc. HME welded pipe: the mandrel rolling method according to the \"C - C - O\" after forming, welding process by cold hole diameter, etc.
Double-sided submerged arc welding and straight seam steel pipe (LSAW) production process 1. Board revisited: steel plate into the production line, after the first full plate ultrasonic inspection, the production of steel raw materials are strictly controlled. 2. The edge milling: through two longitudinal edge of the steel plate automatic edge milling machine double-sided milling, make it meet the machining requirements of plate width, edge milling machine has the steel plate automatic for the function, milling head floating contour tracking function, can be adjusted automatically according to the pingdu situation of steel plate milling head position, ensure the steel plate on both sides have the same groove shape and size. 3. The bending edge: the use of bending machine for plate bending, flanging machine will edge bending curvature where appropriate, to ensure that the weld region geometric shape, and for the next process such as forming, welding and hole enlargement. 4. Shape: JCO displayed is moulded gradual multi-step, steel plate by nc system to achieve ideal circular, each part of the steel plate uniform deformation, no obvious stress concentration, residual stress is small, uniform distribution. JCO forming machine in the first half after bending of the plate after many step punching, pressure into a \"J\" shape, and the other half of the steel plate bending, same pressure into a \"C\" shape, eventually forming the opening 5. \"O\" shape preweld: on the quick joint prediction in opening of the welder on the steel pipe welding, in order to ensure the internal and external wire submerged arc welding quality foundation. At the same time preweld adopted high-power continuous reactive gas shielded arc welding (MAG), to ensure the welding quality, for the welding and welding laid a good foundation. 6. The welding: welding using columns within multi wire submerged arc welding was carried out in steel pipe inside welding, its features are: high efficiency, low porosity and slag, cracks tend to be small, joint mechanical performance is good, weld geometry is easy to control. 7. Welding: f how wire submerged arc welding welding using columns in the side of the straight seam submerged arc welding steel pipe welding 8. Ⅰ: ultrasonic flaw detection of straight seam welded pipe inside and outside weld and weld on both sides of the base of one hundred percent of UT inspection; 9. X-ray flaw detection Ⅰ: one hundred percent of inside and outside weld X-ray industrial TV inspection, using image processing system in order to protect the flaw detection sensitivity; 10. Hole enlargement: expanding machine of straight seam submerged arc welding steel pipe (LSAW) length of hole enlargement, the whole circle, straightening, in order to improve the precision of steel tube geometry size, and can improve steel pipe internal stress distribution condition 11. Hydraulic pressure test: steel pipe after hydrostatic testing machine for hole enlargement by root water pressure test. Hydraulic press with automatic recording and storing the function of the test pressure and time, the supercharger in a short period of time to improve pipe pressure, meet the standard requirements of test pressure, ensure the quality of steel pipe is achieved. 12. Chamfering: chamfering machine for steel pipe groove processing, meet the requirements of tube end groove size, ensure the steel pipe butt welding quality. 13. Ultrasonic testing Ⅱ: once again by the root to UT inspection of weld and parent metal on both sides, inspection after the straight seam welded pipe in the hole diameter, water pressure may produce defects;