1. **What is an ERW pipe?**
An ERW (Electric Resistance Welded) pipe is a type of steel pipe manufactured by forming flat steel strip (skelp) into a cylindrical shape and then welding the longitudinal seam using heat generated by the electrical resistance of the steel as high-frequency current passes through it, combined with pressure to forge the edges together; it's a high-speed, cost-effective process for producing pipes in a wide range of sizes, commonly used for lower-pressure fluid transport and structural applications.
2. **What is the difference between ERW and CEW tubes?**
The main difference lies in the welding process and historical context: ERW (Electric Resistance Welding) uses high-frequency electrical current to heat and forge the seam under pressure, producing a cleaner weld with minimal filler material, while CEW (Continuous Electric Welding) is an older, largely obsolete term often referring to early resistance welding methods using lower frequencies or different techniques, which typically resulted in a coarser weld bead and potentially more heat-affected zone issues; modern "ERW" encompasses advanced high-frequency techniques (HFW) that produce superior quality compared to older CEW methods.
3. **What is an LSAW pipe?**
An LSAW (Longitudinal Submerged Arc Welded) pipe is a large-diameter steel pipe manufactured by bending and forming steel plates into a cylindrical shape, creating a single longitudinal seam which is then welded on both the inside and outside using the submerged arc welding (SAW) process, where the arc is shielded under a blanket of granular flux; this process is well-suited for thicker walls and larger diameters (typically over 24 inches), often used in demanding applications like oil and gas transmission pipelines, and involves plate forming methods like UOE or JCO pressing.
4. **What does ERW mean?**
ERW stands for **E**lectric **R**esistance **W**elding (or **W**elded). It refers to the specific manufacturing process where the longitudinal seam of the pipe is created by applying pressure and using heat generated by the electrical resistance of the steel itself as an electrical current (usually high-frequency) passes through the contacting edges.
5. **Which is better, seamless or ERW pipe?**
Neither is universally "better"; the choice depends on the application requirements. Seamless pipe, made by piercing a solid billet, has no welded seam, offering potentially superior strength uniformity, pressure containment, and corrosion resistance in critical, high-pressure, high-stress, or corrosive service (e.g., high-pressure steam, deep-well oil & gas). ERW pipe is generally more cost-effective, readily available in common sizes, and has significantly improved in quality due to modern HFW technology; it performs excellently in many medium-pressure fluid transport, structural, and mechanical applications where the inherent seam weakness is not a critical factor. Cost and specific performance needs dictate the selection.
