What is Cold Drawn ERW Tube (CEW)？
The Cold Drawn ERW Tubes (CEW) are used in various applications requiring, high precision dimensional tolerances, better surface finish, high tensile properties and can be produced in ‘non standard’ sizes upon request.
What is CEW？
CEW is a welding process type. CEW stands for Cold Electric Welding. This method uses electricity to weld metals together.
Similar to CFS, this product starts as a welded tube and is subsequently cold drawn.The range is available in diameters from 6.35mm to 127.0mm.
Cold-drawn welded pipe is one of the best choices for producing multi-stage hydraulic cylinder pipes. Its process is the same as the cold-drawn process of precision seamless pipes. It is precision drawn by precision resistance welding (ERW) and is manufactured using EN 10305-2 EU mechanical cold drawn carbon steel welded pipe standard.
After the electric resistance welded pipe is welded, the entire pipe body is normalized to ensure that the weld and heat-affected zone are homogeneous in terms of metallographic structure and mechanical properties with the rest of the pipe; cold drawing and subsequent heat treatment (elimination of internal stress) have good dimensions with the steel pipe and mechanical properties.
Features of cold drawn erw tube
Diameter Range: Offered in sizes ranging from 6.35 mm to 127 mm.
Production Method: Manufactured through tube welding followed by cold drawing.
Typical Uses: Commonly applied in the petroleum, oil and gas, petrochemical, and various other industrial sectors.
Economic Advantage: Cold drawing minimizes machining needs and material waste, resulting in reduced production time and cost.
Cold drawn erw tube mechanical properties:
|
Condition |
Yield |
Tensile |
Elongation |
|
|
Re min N/mm2 |
Re min N/mm2 |
min % |
|
BK as drawn |
320 | 400 | 6 |
|
GBK annealed |
150 | 270 | 27 |
|
NBK normalised |
155 | 280 | 25 |
Material grades of cold drawn erw tube
Cold drawn erw tubes are made from various steel grades to meet specific application needs. Common carbon steel grades include ASTM A513, A178, and A179, offering good strength and machinability. Alloy steels like 4130 and 4140 provide higher strength for demanding uses. For corrosion resistance, stainless steel grades such as 304 and 316 are also available.
Manufacturing process of cold drawn erw tube
Cold drawn erw tubes are produced through a series of precise steps to ensure high dimensional accuracy and superior surface quality:
1. ERW Tube Formation:
A steel strip is formed into a tube and welded using high-frequency electric current without filler metal.
2. Weld Seam Normalizing (Optional):
The weld area may be heat-treated to improve uniformity and reduce stress.
3. Pickling & Cleaning:
The tube is acid-cleaned to remove scale and prepare for drawing.
4. Cold Drawing:
The tube is drawn through dies at room temperature to reduce size and enhance precision and finish. Multiple passes may be needed.
5. Heat Treatment (Optional):
Annealing or normalizing may follow to restore ductility and adjust mechanical properties.
6. Straightening & Cutting:
Tubes are straightened and cut to the desired lengths.
7. Inspection & Testing:
Final checks ensure dimensional accuracy, surface quality, and compliance with standards.
Read more: ERW Pipe VS. CEW Pipe
