Spiral Welded Pipe: These pipes are formed by rolling low-carbon carbon structural steel or low-alloy structural steel strips into a pipe blank at a specific spiral angle (known as the forming angle), and then welding the pipe seam to create the final product. They can produce large-diameter steel pipes using narrower strips. The specifications are indicated by outer diameter * wall thickness. The spiral welded pipes must ensure that the water pressure test, tensile strength of the weld seam, and cold bending properties meet the requirements.

Standard of Execution

Spiral seam submerged arc welded steel pipes for pressure fluid conveyance, SY5036-83, are primarily used for oil and natural gas pipelines; spiral seam high-frequency welded steel pipes for pressure fluid conveyance, SY5038-83, are those welded using high-frequency butt welding, suitable for pressure fluid conveyance. These steel pipes have high pressure-bearing capacity, good plasticity, and are easy to weld and shape. The general low-pressure fluid conveyance spiral seam submerged arc welded steel pipes, SY5037-83, are made by double-sided automatic submerged arc welding or single-sided welding and are used for conveying water, gas, air, steam, and other general low-pressure fluids.

Common standards for spiral steel pipes usually include: SY/T5037-2000 (Ministry Standard, also known as Spiral Seam Submerged Arc Welded Steel Pipes for Ordinary Fluid Conveyance), GB/T9711.1-1997 (National Standard, also known as Technical Conditions for Delivery of Steel Pipes for Petroleum and Natural Gas Industry Conveyance, Part 1: Grade A Steel Pipe (Grade B Steel Pipe with more stringent requirements as per GB/T9711.2)), API-5L (American Petroleum Institute, also known as Pipe Line Steel Pipe; divided into PSL1 and PSL2 two levels), and SY/T5040-92 (Spiral Seam Submerged Arc Welded Steel Pipes for Piling).

Material

Q235A，Q235B、16Mn、20#、40#

Specs

Spiral Pipe Φ219-2320x6-22mm

Application

Spiral-welded pipes are primarily used in domestic applications such as water supply projects, petrochemical, chemical, and power industries, agricultural irrigation, and urban construction. They are employed for liquid transportation, including water supply and drainage. For gas transportation, they are used for coal gas, steam, and liquefied petroleum gas. They also serve as structural materials for桩管(piling pipes), bridges, docks, roads, and building structures.

Production Process

Spiral-welded pipes are also a type of welding equipment, generally stronger than straight seam welded pipes. They can produce larger diameter pipes using narrower billets and can also produce pipes of different diameters with the same width billets. However, compared to pipes of the same length with straight seams, the weld length increases by 30~100%, and the production speed is slower. Therefore, smaller diameter pipes mostly use straight seam welding, while larger diameter pipes typically use spiral welding.

Spiral Steel Pipe Production Process: Raw materials are steel coil strips, which are formed through normal temperature extrusion. The spiral seam steel pipes are then焊接 using the automatic double-spiral double-sided submerged arc welding technique.

1. Raw materials, including steel coils, welding wire, and flux, must undergo rigorous physical and chemical testing prior to use.

2. Steel strip ends are joined using single or double wire submerged arc welding, followed by automatic submerged arc welding for reinforcement after the steel pipe is coiled.

3. Prior to forming, the strip steel undergoes leveling, trimming, edging, surface cleaning, conveyance, and pre-bending treatment.

4. The electric contact pressure gauge controls the pressure of the hydraulic cylinders on both sides of the conveyor, ensuring smooth steel strip transport.

5. Utilize external or internal roll forming.

6. Employ a weld gap control device to ensure that the weld gap meets welding requirements, with strict control over pipe diameter, misalignment, and weld gap.

7. Both inner and outer welding are performed using U.S. Lincoln welding machines for single or double wire submerged arc welding, ensuring consistent welding specifications.

8. All welded seams undergo online continuous ultrasonic automatic flaw detection, ensuring 100% non-destructive testing coverage for spiral welds. In the event of any defects, an automatic alarm is triggered and a marking is applied. Production workers adjust process parameters accordingly to promptly eliminate the defects.