What is the Difference Between DOM and CDS Tubing?

What is DOM Tubing?

DOM (Drawn Over Mandrel) tubing is a type of mechanical tubing that starts as hot-rolled steel, which is then cold drawn through a die and over a mandrel.

• The mandrel process improves the surface finish, concentricity, and dimensional accuracy.

• It is technically not a “seamless” tube, but the welding seam from the original ERW tube is completely refined and nearly invisible after the drawing process.

• Known for smooth inner and outer surfaces, tight tolerances, and high strength.

Typical Uses: automotive drive shafts, hydraulic cylinders, racing roll cages, industrial machinery components.

What is CDS Tubing?

CDS (Cold Drawn Seamless) tubing is made from a seamless steel billet (no weld seam at all), which is pierced and then cold drawn to final dimensions.

• Since there’s no weld, CDS is considered a true seamless tube.

• It offers uniform strength around the circumference and excellent mechanical properties.

• Generally has higher pressure ratings compared to DOM.

Typical Uses: high-pressure hydraulic systems, mechanical and automotive components, aerospace parts, precision machinery.

Key Differences Between DOM and CDS Tubing

Expansion Questions for Customers

1. Which tubing is better for high-pressure hydraulic systems?
   → CDS tubing is generally preferred because it has no weld seam, offering maximum uniform strength and reliability under pressure.

2. If I need tubing for roll cages in motorsports, should I choose DOM or CDS?
   → DOM tubing is the standard choice. It offers excellent strength, smooth finish, and cost-effectiveness. Many racing organizations specifically approve DOM for roll cage construction.

3. Is CDS always superior to DOM?
   → Not necessarily. While CDS is seamless and slightly stronger, DOM provides nearly equivalent strength and precision at a lower cost. For many structural and automotive uses, DOM is the practical and economical choice.

Conclusion

• DOM Tubing = Welded + drawn → strong, accurate, affordable → perfect for structural and automotive uses.

• CDS Tubing = Seamless + drawn → superior uniform strength → best for high-pressure and critical applications.