Electro welded cold drawn tubes RTU H9 (+C, +SR, +N)

The distinctive properties of the electro welded cold drawn tubes has precise dimensional tolerances, high concentricity and a unique inside finish. These tubes comply with the European norm EN 10305 and are for suitable for precision uses.



These are obtained thanks to a manufacturing process in which the thickness of the coil is obtained through a lamination process and is rigidly controlled. The extremities of the coil are prepared in a specific way to obtain the optimum contact during the welding operation and the cold deformation of the coil begins until it reaches the desired circular section.

The high quality of the welding operation, after the deformation, creates a specific temperature, fusing the edges of the coil with no added materials.  A continuous tube is formed, with no variation of the chemical composition in the welding area, giving a safety factor V=1. The result is a tube that has a clean and defect free surface with optimal tolerances on thickness and concentricity, ideal for the next operation of cold drawing.

The Cold Drawing process, follows the deformation and welding of the tube, guarantees an excellent surface finish of the product, obtaining precise dimensional tolerances.

Thus, optimal quality of the raw tube, together with a heat treatment, give the drawn tube remarkable mechanical properties and resilience.

Finally the high quality of the electro welded cold drawn tube is also guaranteed by regular destructive and non-destructive lab tests, including dimensional controls and measurement of the surface finish.

Today, the cold drawn electro welded tube is the best product for the manufacture of high quality hydraulic cylinders at lower costs.

TUBES EN 10305

The electro welded cold drawn tubes produced by ALTA comply with the UNI EN 10305-2 standard, a detailed item of the more generic EN 10305. In particular, EN 10305-2 characterizes cold-drawn welded tubes with high dimensional accuracy, excellent surface quality and definable mechanical properties. These tubes are therefore highly suitable for precision applications.

General Technical Data Sheet


NormEN 10305-2
Dimensional RangeFrom OD 42 mm to OD 305 mm and thickness from 5 mm to 25 mm
Available from stock metric and imperial sizes
LenghtUp to 12 m.
Upon request fix or cut lengths
Feature+C | +N | +SR
Piston Tube
Telescopic Tube
Inside ToleranciesH9
Steel GradeE355
others upon request
Test CertificateEN 10204:2004/3.1