1. **Are CEW and CDW the same?**
No, CEW (Cold Expanded Welded) and CDW (Cold Drawn Welded) are **not** the same. While both start as welded pipe (usually ERW or EFW), CEW undergoes cold expansion to improve roundness and dimensional tolerance, whereas CDW undergoes cold drawing to achieve tighter dimensional tolerances, improved surface finish, and higher strength.
2. **What is ERW in pipe?**
ERW stands for **Electric Resistance Welded**. It's a manufacturing process where steel strips or coils are formed into a cylindrical shape and the longitudinal seam is welded using heat generated by the electrical resistance of the steel itself as current passes through it, often combined with pressure.
3. **What is the use of CDW pipe?**
CDW (Cold Drawn Welded) pipe is used in applications requiring **high dimensional accuracy, excellent surface finish, tighter tolerances, and higher strength** than standard welded pipe. Common uses include precision mechanical components, instrumentation, hydraulic cylinders, bearing sleeves, and specialized automotive parts.
4. **Is 3074 ERW 1?**
Yes, **IS 3074 Part 1** specifically covers **ERW (Electric Resistance Welded) steel pipes** intended for structural purposes like water, gas, sewage transmission, and general engineering applications.
5. **Is ERW tube seamless?**
No, an **ERW (Electric Resistance Welded) tube is NOT seamless**. It has a distinct longitudinal weld seam formed during the manufacturing process where the edges of the steel strip are fused together using electrical resistance heating and pressure. Seamless tubes are produced without any welding seam.
