DOM-Rohre geschweißtDOM tubes
DOM-Rohre geschweißtDOM tubes

DOM = Drawn Over Mandrel

Our North American and European partners in the manufacture of DOM mechanical Tubing, having

produced this product for many decades.

During this period, they have forged a reputation for innovation and technical superiority in its production and use.

DOM Tubing is available in a diameter range up to 304.80 mm OD and a maximum wall thickness of 15.88 mm. It is supplied in as-drawn condi-tion unless otherwise specified. A specia-lized product, TuffDOM Tubing, is designed for the most demanding applications, in particular those involving fluid power.

The lengthy experience in the manufacture of DOM Tubing has allowed to reduce the guaran-teed machining, honing and centerless grinding allowances for this product as much as 50 % from normal industry standards, and to guarantee OD and ID tolerances that are tighter than commercial standards.

We also deliver quenched and tempered DOM Tubing for specialized applications, as in the field of Hydraulics and lattice booms for the crane industry.

Most commonly we supply the European market with products of low and medium carbon steels such as TuffDOM 520 (comparable to E355) and TuffDOM 620 (comparable to STE 460). As a matter of course we also offer other steel grades.

Wall Uniformity and Concentricity
Uniform wall thickness is the most important characteristic of DOM Tubing.

Seamless Tubing, formed by forging a rotating, heated, solid-steel round over a piercing point, inherently possess some spiraling eccentricity, since it is not possible to hold the piercing point to the exact center of the round.


DOM Tubing usually does not display such eccentricity and shows very little wall variation for several basic reasons. The tube is formed from high-quality, flat-rolled steel with very little gauge variation. Any minor deviation in the raw material will run naturally in the same plane throughout the tube length, leaving the bore very straight and true.

DOM Tubing is preferred for those numerous applications that require uniform wall thickness (a prerequisite for concentricity) and a straight bore.

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Advantages of DOM Tubing
Our DOM Tubing are produced acc. to ASTM A 513/ EN 10305-2 by using the Electric Resis-tance Welding (ERW) process.This process produces the highest weld strength possible. Because it is cold-drawn after forming, DOM Tubing also offers a number of other advantages:

  • The uniform wall thickness of DOM Tubing, with closer OD and ID tolerances, provides maximum concentricity of +/- 2.5 % in most cases.
  • Thermal treatment prior to cold drawing crystallizes the grain structure of the tubing and weld area, giving it a uniform, controlled hardness.
  • Cold working gives DOM Tubing higher yield and tensile strength than as-welded products. Thermal treatment after drawing can give increased ductility when desired.
  • The OD and ID surfaces of DOM Tubing are cleaner, smoother and more dense than as-welded products. The reduction of the tube during cold drawing removes in most cases all dimensional evidence of the weld.
  • DOM Tubing can be manufactured to an almost infinite range of diameters and walls by varying the sizes of the die and mandrel. This size range allows end users to achieve mate-rial savings and lower machining costs through selection of a size that matches the dimensions of the finished product.
  • The tight tolerances, controlled mechanical properties and uniform, dense surface of DOM Tubing all result in good machining characteristics and make further machining, e.g. hard chrome plating after appropriate preparation possible as well.

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DOM Mechanical Tubing Applications
DOM Tubing is the preferred choice for a wide range of static and dynamic applications. Some of these are among the industry’s most demanding:

  • Hydraulic applications including telescopic cylinders, barrels and plungers
  • Accumulators
  • Axles and high-speed shafts (cardan shafts)
  • Shock absorbers
  • Gas springs
  • Printing, textile and paper mill rolls
  • Bearing races and spacers
  • Machined tubular parts of many types
  • Lift industries

Primary markets for DOM Tubing in these appli-cations include automotive and trucks, construc-tion equipment, farm machinery, oil and gas industry tooling, and industrial machinery.

The American DOM Tubing products can be compared to the European products also be purchased – in relative small mill production quantities.

Wall Thickness Tolerances

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Mechanical Properties and Chemical Analysis
DOM Tubing is manufactured to ASTM A 513 or EN 10305-2. This product has tensile properties that are comparable to cold drawn seamless steel Tubing of the same steel analysis and normal size. In addition the DOM Tubing has superior concentricity and a high degree and uniformity in wall thickness.

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Quench and Temper Heat Treating (Q + T)
For special applications we offer quench and temper heat treatment for DOM Tubing products. This tubing is used in oil drilling and production, automotive, industrial, agricultural and construc-tion equipment and other applications. This tubing 

is available for tubing with an OD up to 203.2 mm with wall thicknesses up to 10.16 mm maximum and with lengths up to 12 meters.

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Surface Finish
The excellent surface finish of DOM Tubing can substantially reduce finishing costs of many parts and, with the added advantage of close concentricity, may eliminate finishing operations altogether. Prior to cold drawing, the as-welded tubing is cleaned thoroughly to produce clean, bright inside and outside surfaces. During cold drawing, the cross-sectional reduction is precisely controlled to enhance the surface quality even further.

Commercial Quality DOM Tubing may be used as received for many applications. It is produced to the OD and ID tolerances shown in the tables on page 32, and to confirm to the mechanical properties shown on page 20/21. When sur-faces are to be machined, refer to the tables on pages 24 -– 31 for stock allowances that assure 100% clean up of surface imperfections.

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Size Ranges
DOM Tubing is produced in one of the world‘s most extensive size ranges – 19.00 through 304.80 mm OD and 1.25 through 15.88 mm wall thickness. 

Many intermediate metric or inch sizes may be ordered to your specifications without penalty of tool costs or delivery time.

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Machining Qualities
The widespread use of DOM Tubing for machined parts is due primarily to its remarkable concentricity. This reduces or eliminates certain machining operations and their costs. The machinability of DOM Tubing is similar to that of seamless tubing of the same size and analysis. As-drawn DOM Tubing has clean, bright surfaces, high strength and excellent machinability. 

The Rockwell hardness of Tuff DOM 520/E355 steel typically will run to Rb 85 minimum, ideal for honing, centerless grinding and other machining. 

Many users have realized that their specified finished sizes are available as rough sizes. Thus, it is not necessary to machine those tubes. 

Even though the diameter of the finished product needs to provide a concentricity with tight tolerances, there is just needed a small stock allowance in order to remove possible surface imperfections.

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Ovality 
The ovality shall be within the on page 32 mentioned tolerances except when the wall thickness is less than 3 % of the OD. In such cases, the additional ovality shall be added as follows in the table left, but the mean diameter shall be within the specified tolerance. 

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DOM Sizes Metric

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Machining Allowances for DOM Tubing

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Centerless Grinding Allowances for DOM Tubing

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Honing Allowances for DOM Tubing

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Skiving Allowances for DOM Tubing

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Tolerances

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Ovality

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