**1. What is welded steel pipe used for?**
Welded steel pipes are widely used in construction, oil and gas transportation, water supply systems, automotive manufacturing, and structural applications (e.g., bridges, scaffolding). They are ideal for low-to-medium pressure environments and cost-effective projects requiring long, continuous piping. They are also employed in industrial machinery, HVAC systems, and fencing due to their versatility and availability in large diameters.
**2. What is the difference between welded and seamless pipe?**
Welded pipes are made by rolling steel coils/sheets into shape and welding the seam, while seamless pipes are produced by piercing solid steel billets and extruding them into hollow tubes. Seamless pipes have no welded joints, making them stronger and more reliable for high-pressure, high-temperature, or corrosive applications (e.g., oil refineries). Welded pipes are cheaper, easier to produce in large sizes, and suitable for moderate conditions.
**3. What is the difference between ERW and welded pipe?**
ERW (Electric Resistance Welding) is a type of welded pipe. The term "welded pipe" includes all pipes made by welding, such as ERW, SAW (Submerged Arc Welded), and EFW (Electric Fusion Welded). ERW specifically uses high-frequency electric current to bond the seam without filler material, creating a smooth joint. It is commonly used for low-pressure fluid transport. Other welded pipes, like SAW, use external filler material and are suited for thicker walls or heavy-duty applications.
**4. What is the difference between welded and threaded pipes?**
"Welded pipe" refers to the manufacturing process (seam-welded tubes), while "threaded pipe" describes a connection method. Welded pipes are joined permanently via welding, ideal for high-pressure systems. Threaded pipes have screw-like ends for detachable connections, often used in low-pressure plumbing or where disassembly is needed. Threading weakens the pipe wall, making welded joints stronger for critical applications.
**5. What are the advantages of welded pipe?**
Key advantages include:
- **Cost-effectiveness**: Lower production costs than seamless pipes.
- **Availability in large sizes**: Easily manufactured in long lengths and large diameters.
- **Versatility**: Suitable for diverse applications (structural, fluid transport).
- **Efficiency**: Faster production and customizable wall thicknesses.
- **Improved technology**: Modern welding (e.g., laser, automated processes) ensures high strength and reliability, narrowing the quality gap with seamless pipes.
