What is DOM Tubing?

DOM tubing is the abbreviation of drawn over mandrel tubing, which means that the welded steel pipe is processed by deep drawing or cold rolling, and the high quality steel pipe with small dimensional tolerance and good mechanical properties is obtained. Due to its small dimensional tolerance and good mechanical properties, the steel pipe is well applied in automotive applications, high-pressure pumping pumps, high-speed roller tubes, and drafting tubes for textile machines.

1. Performance

The DOM tubing is obtained by cold drawing (or cold rolling) from a welded pipe. The cold drawing process is the process of yielding and plastic deformation of the pipe metal, which will cause work hardening of the pipe metal. After cold drawing, the mechanical properties generally deteriorate. Cold drawing causes the plasticity of the pipe to decrease, and the strength and hardness are improved. These performance changes of the tube after cold drawing will reduce the bearing capacity of the DOM tubing and reduce the safety of use. In the cold drawing process, if the process parameters are not properly selected, it is easy to micro-crack on the surface of the pipe body, which significantly reduces the bearing capacity of the DOM tubing. In severe cases, the pipe body will break during the cold drawing process.

2. Geometric accuracy

Undoubtedly, the DOM tubing is produced by cold drawing (or cold rolling) of the base pipe, and its geometric precision is high.

3. Steel grade of DOM tubing

DOM Tubing (Drawn Over Mandrel) is typically made from cold-drawn steel grades 1020 to 1026 or ST52.3. This electric resistance welded tube undergoes a process that removes all flash before being drawn to size, resulting in higher yield and tensile strengths.

How is DOM Tubing Made? 

The manufacturing process for DOM tubing is similar to that for other electric resistance welded (ERW) tubing. First, the steel coil is cut into strips of the desired size. Next, an electric resistance welder joins the edges of the strips under pressure to form the tubing shape. Afterwards, the tube is quality tested to ensure it meets industry standards and then cut to the required lengths. While standard ERW tubes are usually finished at this stage, the manufacturing of DOM tubing requires additional steps to improve quality.

ERW Introduction:
Electric resistance welding (ERW) is a process that uses pressure and heat generated by high-frequency electric current to form a strong weld. Specifically, cold-pressed electric resistance welding (CERW) is the first step in the manufacturing of DOM tubing. This method ensures that the edges of the steel are effectively fused together, laying the foundation for the subsequent processes of the DOM tubing.

After the ERW process is complete, the flash weld is removed from the tube and it is then cold drawn over a mandrel, which is how DOM Tubing gets its name – “Drawn Over Mandrel”. This cold drawing process reshapes the metal, enhancing the alignment of its crystal structure, making the tube longer and stronger. It also precisely controls the inner and outer diameters, producing a tube with uniform thickness, high strength and a high weight ratio.

While DOM Tubing looks similar to other steel pipes and has a smooth surface, it actually has an internal seam. However, when manufactured properly, this seam is almost invisible due to the welding process.

The DOM process makes the steel tube highly adaptable and strong, making it ideal for a variety of mechanical applications. According to the Steel Tube Association, DOM Tubing is not only more cost-effective, but also stronger, has tighter tolerances, is more machinable, and is available in a wider range of sizes and thicknesses.

Common Uses and Applications of DOM Tubing:

DOM Tubing is known for its reliability, cost-effectiveness and smooth surface, and is suitable for a wide range of applications. From racing car frames and roll cages to hydraulic cylinders and agricultural machinery, DOM tubing is a versatile choice.

1. Automotive Industry
Due to its excellent strength-to-weight ratio, DOM Tubing is commonly used in automotive parts such as axles, steering columns, gear shifters, airbag inflators, power seat mechanisms, engine mounts, fuel rails, and fuel injection components. It is also used to secure vehicle components such as headrests and seat frames. If you examine a removable headrest in a vehicle, you may find that DOM tubing was used in its manufacturing process.

However, the application range of DOM tubing is not limited to automobiles. Experts generally agree that it is an ideal material for making roll cages. It is also essential in hydraulic presses, torque wrenches, and snowmobiles.

2. Construction Industry
In the construction field, DOM tubing is used for augers, chassis, and crane boom tie-downs. It can also be used inside buildings as structural members such as columns and railings.

3. Energy Industry
Another unexpected application of DOM tubing is in the energy field, where it helps to harness clean energy in solar racks and wind turbines. It is also used in coal, nuclear, and power plants throughout the United States. Because DOM tubing can be used in both static and dynamic applications and can be extensively processed after production, it can effectively replace many types of steel pipe.

4. Medical equipment 
Surgical instrument tubes: high cleanliness (inner wall Ra ≤0.4 μm), in line with ISO 13485 standard.
Medical gas pipelines: such as oxygen delivery pipes, require leak-free design.

5. Special applications
Semiconductor equipment: ultra-high purity stainless steel pipes (such as ASTM A270) to prevent contamination.
Ship hydraulic systems: salt spray corrosion resistance (such as Duplex 2205 duplex steel).

Is DOM tubing right for you?

If you need a steel pipe with uniform wall thickness, a strong grain structure, high yield and tensile strength, excellent processing properties, and a smooth, clean surface, DOM tubing may be the ideal choice for your project. Unlike other steel pipes, DOM tubing is mandrel-drawn, which results in the highest weld strength.

Every project has unique requirements, but if your needs match the uses and versatility of DOM tubing discussed earlier, it is likely to be a solid choice for you.

Read more: Cold Drawn Seamless Tubing or Cold Drawn ERW Pipe