**1. Does ERW pipe have a seam?**
Yes, ERW (Electric Resistance Welded) pipes have a seam. The seam is formed by welding the edges of a rolled steel strip using electric resistance heating. However, the weld seam is often smoothed and blended, making it less visible compared to other welded pipes.
**2. Where are ERW and seamless pipes used?**
- **ERW Pipes**: Commonly used in low-to-medium pressure applications, such as water distribution, structural purposes, fencing, and automotive exhaust systems.
- **Seamless Pipes**: Used in high-pressure, high-temperature, or critical applications, such as oil and gas pipelines, power plants, chemical industries, and machinery requiring superior strength and reliability.
**3. Which is better, ERW or EFW?**
ERW (Electric Resistance Welded) and EFW (Electric Fusion Welded) differ in welding methods. ERW uses high-frequency current to weld seams, making it cost-effective for thinner pipes. EFW typically involves submerged arc welding (SAW) for thicker walls or larger diameters. Neither is universally "better"-selection depends on application requirements (e.g., pressure, thickness, budget). ERW is often preferred for general purposes, while EFW suits heavy-duty applications.
**4. What is the difference between seam and seamless pipe?**
- **Seam Pipes**: Manufactured by welding rolled steel plates or coils (e.g., ERW, EFW, LSAW). They have a visible weld seam and are generally cheaper but may have weaker points at the weld.
- **Seamless Pipes**: Made by extruding solid billets without welding. They lack seams, offering uniform strength, higher pressure tolerance, and better corrosion resistance, but are more expensive.
**5. What are seamless pipes?**
Seamless pipes are tubular products manufactured without any welding seam. They are produced by piercing a solid steel billet to form a hollow shell, which is then elongated and rolled to achieve the desired dimensions. These pipes excel in high-stress environments due to their homogeneous structure, making them ideal for critical applications in oil and gas, petrochemicals, and high-pressure hydraulic systems.
