The inspection process of spiral welded pipe, the implementation standard of spiral welded pipe

Spiral seam submerged arc welded steel pipe SY5036-83 for pressure fluid transportation is mainly used for pipelines transporting oil and natural gas; Spiral seam high-frequency welded steel pipe SY5038-83 for pressurized fluid transportation is welded by high-frequency lap welding method and is used for spiral seam high-frequency welded steel pipe for pressurized fluid transportation. The steel pipe has strong pressure-bearing capacity and good plasticity, which is easy to weld and process; Spiral seam submerged arc welded steel pipe SY5037-83 for general low-pressure fluid transportation is made of double-sided automatic submerged arc welding or single-sided welding method for submerged arc welded steel pipe for general low-pressure fluid transportation such as water, gas, air and steam.

The common standards for spiral steel pipes are generally divided into: SY T5037-2000 (Ministry standard, also known as spiral submerged arc welded steel pipe for ordinary fluid transmission pipelines), GB national standard, also known as the first part of the technical conditions for the delivery of steel pipes for oil and gas industry transportation: A-grade steel pipes (GB B-grade steel pipes with strict requirements)), API-5L (American Petroleum Institute, also known as pipeline steel pipes; It is divided into two levels: PSL1 and PSL2), and SY T5040-92 (spiral seam submerged arc welded steel pipe for pile).

Uncoiler: Double cone head uncoiler, which can disassemble 32 tons of heavy steel coils.

Steel belt squeaming machine: it is a seven-roller slender, and the plate thickness can reach 20mm

Shearing machine: can cut 2000mm*20mm coiled board.

Butt welding machine: welding just has head and tail.

Disc shear: cut off the burr of the steel plate to reach the specified size.

Edge milling machine: process the 10mm steel plate into the required bevel vertical roller device: ensure that the steel plate runs along the delivery line.

Conveyor: The two-roller conveyor is the main power for molding.

Guide plate: Ensure that the steel plate is balanced into the molding machine.

Forming machine and bridge, output roller table, three-stick bending plate, outer roller sizing forming machine can form 219-2520mm steel pipe internal and external welding device: internal welding single wire, external welding double wire, Lincoln welding machine, and infrared thermal imaging internal welding tracking control system.

Flux device: Post-weld flux.

Automatic external repair welding device: repair weld defects.

Flat-to-edge machine: to ensure that the standard pipe end requirements are met.

Hydrostatic testing machine: 100% hydrostatic test.

Weighing and measuring device: weighing and measuring the length of steel pipes.

Automation of equipment on spiral welded pipe production lines.

cosa=b/（пd）

Where: a - helix angle.

b - plate width.

Pi. d——Overview of the process flow of seamless steel pipe with steel pipe diameter.

a. Hot rolling (extruded seamless steel pipe): round tube billet heating perforation three-high oblique rolling, continuous rolling or extrusion depipe sizing (or reducing diameter) cooling billet pipe straightening hydrostatic test (or flaw detection) marking warehousing.

b. Cold drawn (rolled) seamless steel pipe: round tube blank heating, perforation, heading, annealing, pickling, oiling (copper plating), multi-pass cold drawing (cold rolling) billet tube, heat treatment, straightening, hydrostatic test (flaw detection), marking and warehousing.

Hot rolling and cold rolling are both sections or steel plate forming processes, they have a great impact on the structure and properties of steel, the rolling of steel is mainly based on hot rolling, cold rolling is only used to produce small section steel and thin plates.

Spiral welded pipe: It is made by rolling low-carbon structural steel or low-alloy structural steel strip into a pipe blank according to a certain spiral angle (called forming angle), and then welding the pipe seam, which can produce large-diameter steel pipes with narrower strip steel. Its specifications are expressed by the outer diameter * wall thickness, and the welded pipe should ensure that the hydraulic test, tensile strength and cold bending performance of the weld should meet the regulations.

Spiral welded steel pipe refers to a steel pipe with joints on the surface after bending and deforming the steel strip or steel plate into a round, square and other shapes. According to different welding methods, it can be divided into arc welded pipe, high-frequency or low-frequency resistance welded pipe, gas welded pipe, furnace welded pipe, bondi pipe, etc. According to the shape of the weld, it can be divided into longitudinal welded pipe and spiral welded pipe.

Welded steel pipes are used in oil drilling and machinery manufacturing. Furnace welded pipes can be used as water gas pipes, etc., and large-diameter longitudinal welded pipes are used for high-pressure oil and gas transportation; Spiral welded pipes are used for oil and gas transportation, pipe piles, bridge piers, etc. Welded steel pipes have lower cost and higher production efficiency than seamless steel pipes.

The production process of longitudinal welded pipe is simple, the production efficiency is high, the cost is low, and the development is fast. The strength of spiral welded pipes is generally higher than that of longitudinal welded pipes, and welded pipes with larger diameters can be produced with narrower blanks, and welded pipes with different diameters can also be produced with blanks of the same width. However, compared to the same length of straight seam pipe, the weld length is increased by 30 100%, and the production speed is lower.

Therefore, most of the smaller-diameter welded pipes are welded longitudinally, while the larger-diameter welded pipes are mostly spiral welded.

Industrial TV internal inspection equipment: inspect the appearance quality of internal welds. Magnetic Particle Flaw Detector:

Inspect near-surface defects of large-diameter steel pipes. Ultrasonic Automatic Continuous Flaw Detector: Inspect the transverse and longitudinal defects of the full-length weld of the spiral steel pipe.

Ultrasonic manual flaw detector: re-inspection of large-diameter steel pipe defects, inspection of repair welds and weld quality after hydropressure. X-ray automatic flaw detector and industrial TV imaging equipment:

Check the internal quality of the full-length weld of the spiral steel pipe, and the sensitivity is not less than 4%. X-ray imaging equipment: inspect the original weld and repair weld, and the sensitivity is not less than 2%.

2200 tons of hydraulic press and microcomputer automatic recording system: check the pressure quality of each large-diameter steel pipe.

In general, the following tests are done:

1. Chemical properties of materials.

2. Mechanical properties.

3. Dimensions, geometric tolerances.

4. Metallographic structure of matrix and weld, grain size.

5. Other weld requirements such as metal inclusions, hands-free damage detection, etc.

6. Appearance, burr.

7, 30 degree bending test.

The above items are to be based on your specific requirements, you get what you pay for, the higher the requirements are to be shipped to the east, the more expensive the west, the quality is costly, and you can choose independently.