Differences in manufacturing processes

• DOM tubes are made by first curling hot-rolled steel sheets, welding them by high-frequency resistance welding (ERW), and then cold drawing them through a mandrel for finishing. After cold drawing, they are plastically deformed to eliminate the weld.
• Cold-drawn seamless tubes are made by perforating solid round steel billets to form blank tubes, which are then cold-drawn/cold rolled in multiple passes, and the outer diameter tolerance is controlled directly by the die.

 

Advantages and disadvantages of DOM tubes and CDS tubes

• Due to the mandrel drawing, the inner surface of the DOM tube is very smooth like a mirror, while the CDS tube may have some irregularities or roughness.
• Because the DOM tube is first made into a welded tube, the wall thickness deviation accuracy is not as high as that of a cold-drawn seamless tube.
• In terms of cost, DOM raw materials use ERW welded pipes, which have lower manufacturing costs. However, DOM tubes have potential defects in the weld matrix, so under non-extreme working conditions, DOM tubes have significant cost-effectiveness advantages.

 

Differences between DOM tubes and CDS tubes in application areas

• In the application of hydraulic cylinder barrels, DOM tubes are suitable for medium and low pressure systems due to the hidden dangers of welds; CDS seamless structures have no weld weak areas, have a higher pressure limit, and can be used in high pressure systems.
• In automotive industry applications, DOM tubes are suitable for exhaust brackets, seat rails, body frame connectors, etc.; cold-drawn seamless (CDS) tubes are ideal for high-precision fuel injection pipes, new energy vehicle braking systems, etc.
• For food and medical equipment, cold-drawn seamless tubes are more suitable for sanitary pipes often required in pharmaceutical or dairy equipment.

 

 

Conclusion

In conclusion, DOM tubes and cold drawn seamless tubes each have their own advantages and disadvantages, and the choice should be made based on the specific application.