Spiral Welded Pipe: It involves rolling low-carbon carbon structural steel or low-alloy structural steel strips into a billet at a specific helical angle (known as the forming angle), followed by welding the seam to create the pipe. This method allows for the production of large-diameter pipes using narrower strips. The specifications are indicated by outer diameter x wall thickness. The welded pipes must ensure compliance with the required hydrostatic tests, tensile strength of the weld seam, and cold bending properties.
Execution Standards
Spiral-welded steel pipes for pressure fluid conveyance, SY5036-83, are mainly used for oil and natural gas pipeline transportation; Spiral-welded steel pipes for pressure fluid conveyance, SY5038-83, are high-frequency butt-welded pipes used for conveying pressurized fluids. These pipes have high pressure-bearing capacity, good plasticity, and are easy to weld and shape; Generally, spiral-welded steel pipes for low-pressure fluid conveyance, SY5037-83, are made by double-sided automatic submerged arc welding or single-sided welding and are used for conveying low-pressure fluids such as water, coal gas, air, and steam.
Common standards for spiral steel pipes generally include: SY/T5037-2000 (Ministry Standard, also known as Spiral Seam Submerged Arc Welded Steel Pipe for Ordinary Fluid Transportation), GB/T9711.1-1997 (National Standard, also known as Technical Conditions for Delivery of Steel Pipes for Petroleum and Natural Gas Industry Transportation - Part 1: Grade A Steel Pipe (for stricter requirements, see GB/T9711.2 Grade B Steel Pipe)), API-5L (American Petroleum Institute, also known as Pipeline Steel Pipe; divided into PSL1 and PSL2 levels), and SY/T5040-92 (Spiral Seam Submerged Arc Welded Steel Pipe for Piling).
Material
Q235A，Q235B、16Mn、20#、40#
Specs
Spiral Pipe Φ219-2320x6-22mm
Application
Spiral-welded pipes are primarily used in China for water supply projects, petrochemical, chemical, and power industries, agricultural irrigation, and urban construction. They are used for liquid conveyance: water supply and drainage. For gas conveyance: coal gas, steam, and liquefied petroleum gas. As structural materials: for pile driving, bridges, wharfs, 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 straight seam pipes of the same length, 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 usually employ spiral welding.
Spiral Steel Pipe Production Process: The process involves using coil steel as raw material, forming the spiral seam steel pipe through normal temperature extrusion, and then welding it using the automatic double-sided submerged arc welding technique with two wires.
1. Raw materials include steel coils, welding wire, and flux. All must undergo rigorous physical and chemical inspections 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 rolling into steel pipes.
3. Prior to forming, the steel strip undergoes leveling, trimming, edge dressing, surface cleaning and pre-bending processing.
4. The输送机sides' pressure cylinders are controlled by an electrical contact pressure gauge, ensuring smooth steel strip conveyance.
5. Utilize external or internal roll forming.
6. Utilize a welding gap control device to ensure that the weld gap meets welding requirements; the pipe diameter, misalignment, and weld gap are all strictly controlled.
7. Both internal and external welding processes utilize Lincoln welding machines for single or double wire submerged arc welding, ensuring stable welding specifications.
8. All welded seams undergo online continuous ultrasonic automatic flaw detection, ensuring 100% non-destructive testing coverage for spiral welds. In case of defects, an automatic alarm is triggered and marking is applied. Production workers adjust process parameters accordingly to promptly eliminate any defects.
