LSAW steel pipe production process(QAPlan)

1 Steel plate inspection: steel plate into the production line, the first full-board ultrasonic inspection of the raw materials for steel production strictly.

2 Sharp-edge: Milling Machine by Automatic two longitudinal edges of the plate on both sides of milling, processing requirements to meet the board width, edge milling machine with automatic sheet in function, Head tracking with variable profiling can be According to the roughness of steel milling head position automatically ensure that both sides have the same bevel plate shape and size.

3 Pre-bending: the use of pre-bending machine plate edge pre-bending, side bending machine will board the pre-edge pre-bending to the right curvature to ensure that the geometry of the weld zone, and the subsequent forming, welding processes and Expanding to prepare.

4 Forming: JCO forming a multi-step method is progressive molded plate by the numerical control system to achieve the desired circular, uniform deformation of all parts of steel, no significant stress concentration, residual stress, evenly distributed. JCO machine after pre-bending on the first half of the plate after several step stamping, pressed into a "J" shape, then the other half of the same bent steel plate, pressed into a "C" shape, and finally the formation of the opening of the "O" shape .

5 Pre-welding: The two edges of the open seam pipe should be brought together by Pre-welding machine , in order to ensure internal and external multi-wire submerged arc welding quality basis. At the same time pre-welded using a high-power continuous active gas shielded arc welding (MAG), to ensure the quality of pre-welded, welded inside and outside welding is to lay a good foundation.

6 Internal welding: The pipe is welded from inside of the pipe by multipass tandem submerged-arc welding, which is characterized by: high efficiency, low porosity and slag, cracks tend to a small, good mechanical properties of joints, weld geometry easy to control

7 External welding: The pipe is welded from outside of the pipe by multipass tandem submerged-arc welding

8 Online ultrasonic flaw inspectionⅠ: Longitudinal inside and outside of the weld and weld both sides of the base material for one hundred percent of the UT automated testing.

9. X-ray detection Ⅰ: one hundred percent of the weld seam inside and outside the industrial X-ray TV inspection, using the image processing system to ensure detection sensitivity.

10 Expanding: The pipes are subject to full-length expansion to increase the precision of the pipe dimensions and improve the internal stress distribution

11 Hydrostatic test: hydrostatic testing machine after the pipe diameter of the expanded-by-root water pressure test. Hydraulic machine with automatic recording and storage of test pressure and time functions, the turbocharger to improve control of water pressure in a short time, meet the standard requirements of the test pressure, to ensure the quality of steel to meet the requirements.

12 chamfer angle: chamfering machine for pipe end beveling, the required size of pipe end beveling, pipe butt welding quality assurance.

13 ultrasonic flaw detection Ⅱ: once again by both sides of the root of the weld and base material for UT testing, inspection and Longitudinal in expanding, defects may arise after the water pressure.

14. X-ray detection Ⅱ: Each pipe after expansion and hydro test is subject to X-ray industrial TV inspection and pipe-end weld filming. to ensure the quality of the steel pipe

15, magnetic particle inspection: this check is to detect defects in the pipe ends

16 anti-corrosion and coating: according to user requirements after passing the steel pipe tested for corrosion and coating. After galvanization(HDG)of the external surface of all poles, coal tar pitch paint should be painted. The zinc layer would be checked by physical & chemical test.