Spiral Welded Pipe: This is a type of pipe produced by rolling low-carbon carbon structural steel or low-alloy structural steel strips into a pipe blank at a specific spiral angle (referred to as the forming angle), and then welding the pipe seam to form the pipe. It allows for the production of large-diameter steel pipes using narrower strips. The specifications are indicated by outer diameter * wall thickness. The welded pipe must ensure that the water pressure test, tensile strength of the weld seam, and cold bending properties meet the requirements.
Standard Implementation
Spiral-welded steel pipes with submerged arc welding, SY5036-83, are primarily used for pipeline transportation of oil and natural gas; spiral-welded steel pipes with high-frequency welding, SY5038-83, are high-frequency butt-welded and used for pressure fluid transportation. These pipes have high pressure-bearing capacity, good plasticity, and are easy to weld and shape. Generally, spiral-welded steel pipes with submerged arc welding, SY5037-83, are used for low-pressure fluid transportation and are made by double-sided automatic submerged arc welding or single-sided welding methods, suitable for transporting water, coal gas, air, and steam.
Common standards for spiral steel pipes generally include: SY/T5037-2000 (Ministry Standard, also known as Spiral 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 Pipes (Grade B Pipes with stricter requirements are GB/T9711.2)), API-5L (American Petroleum Institute, also known as Pipe Line Steel Pipe; which includes two grades: PSL1 and PSL2), SY/T5040-92 (Spiral Submerged Arc Welded Steel Pipes for Piling).
Material
Q235A，Q235B、16Mn、20#、40#
Specs
Spiral Pipe Φ219-2320x6-22mm
Usage
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 used for liquid transportation: water supply and drainage. For gas transportation: coal gas, steam, liquefied petroleum gas. For structural purposes: pile driving pipes, bridges; wharfs, roads, and building structural pipes, etc.
Production Process
Spiral-welded pipes are also a type of welding equipment, generally with higher strength 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 generally use spiral welding.
Spiral Steel Pipe Production Process: Made from steel coil as raw material, it is formed by normal temperature extrusion and welded into spiral seam steel pipes using automatic double-sided submerged arc welding with double wires.
1. Raw materials include steel coils, welding wire, and flux. All must undergo rigorous physical and chemical inspections prior to use.
2. Steel coil ends are joined with single or double wire submerged arc welding, followed by automatic submerged arc welding for patching after rolling into steel pipes.
3. Prior to forming, the strip steel is straightened, trimmed, deburred, surface cleaned, conveyed, and pre-bent.
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. Utilize a weld gap control device to ensure the weld gap meets welding requirements; strict control is maintained over pipe diameter, misalignment, and weld gap.
7. Both inner and outer welding are performed using 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 case of defects, an automatic alarm is triggered and marked with paint, allowing production workers to adjust process parameters in real-time and promptly eliminate the defects.
