ERW steel pipe
ERW pipe (electric resistance welded pipe) and CDW pipe (cold drawn welded pipe) are two different production processes for welded steel pipes.
1. Production process
| Comparison items | ERW pipe (electric resistance welded pipe) | CDW pipe (cold drawn welded pipe) |
| Full name | Electric Resistance Welded Pipe | Cold Drawn Welded Pipe |
| Forming process | The edge of the steel plate is heated by high-frequency current and pressurized and welded into shape | First welded into pipes, then cold drawn (cold deformation treatment) |
| Welding method | High Frequency Resistance Welding (HFW/ERW) | ERW or argon arc welding (TIG) is usually used for welding |
| Subsequent processing | Directly sizing and cutting after welding | Cold drawing (cold rolling) finishing after welding |
2. Performance characteristics
ERW pipe
Dimensional accuracy: General (±0.5%~1% outer diameter tolerance)
Surface quality: The weld is slightly obvious and needs to be polished
Mechanical properties: Strength depends on the parent material, and there may be softening in the weld area
Residual stress: Low (only simple heat treatment after welding)
CDW pipe
Dimensional accuracy: extremely high (within ±0.1mm, suitable for precision purposes)
Surface quality: smooth surface, no oxide scale (polished after cold drawing)
Mechanical properties: cold working hardening, strength increased by 20%~30%
Residual stress: high (annealing is required to eliminate cold drawing stress)
3. Application scenarios
ERW: oil/gas pipelines, building structure pipes (scaffolding), low-pressure fluid pipes (GB/T 3091)
CDW: hydraulic cylinders, precision mechanical parts (such as bearing sleeves), automobile transmission shafts (areas with high dimensional accuracy requirements)
Common standards of types
ERW: API 5L (pipeline pipe), ASTM A53 (structural pipe), EN 10219 (European standard welded pipe)
CDW: ASTM A519 (precision cold-drawn pipe), DIN 2391 (German standard high-precision pipe)
CDW pipe = ERW pipe + cold drawing, with more precise dimensions and higher strength, but also higher costs.
ERW pipe is suitable for general structural purposes, while CDW pipe is used in the field of high-precision machinery.
If the performance of CDW pipe needs to be further improved, annealing treatment can be added (to eliminate cold working stress).
Post time: Apr-01-2025
