Cold Drawn Seamless Cylinder Tubes

Seamless cold drawn cylinder tubes produced by ALTA spa have very high mechanical properties and are eventually available also n special steel grades. Dimensional tolerances, surface quality and roundness tolerance are as per UNI ISO EN10305-1 standards and cover a wide size range as per customer demand.

 

 

Final surface resulting in the cold drawn tubes is caused by the condition of the mother tube, because during its hot drilling the tube gains spiral shape (pic A) which is maintained even if reduced, after rolling and drawing (pic B).

Traditional finishing processes of honing and rolling follow this spiral trend, obtaining the requested tolerance and without modifying the spiral shape which is in direct opposition with the principal of concentricity for the specific group: PISTON TUBE/PISTON/TUBE.

Picture c, is demonstrating the extreme straightness of the inside finish, known as “ALTA finish”. The machining of a tube with a reduced inside stock allowance, is generating raw material spots (in the picture the darker spots) those areas are outside of the maximum tolerated straightness, due to the spiral shape of the tube.

To avoid these problems ALTA sources tubes with a higher stock allowance, over and above the norm (up to 3 mm in diameter) removing the necessary material, allowing a better straightness, roundness and surface cleaning finish, against the traditional systems

Fig. A
Fig. B
Fig. C

General Technical Data Sheet

 

NormEN 10305-1
Dimensional RangeFrom O.D. 42 mm to O.D. 305 mm | wall thickness from 5 mm to 25 mm
metric and imperial size range available
Lenghttill 12 m
fix or multiple length on demand
Feature+N
+SR
TypeReady for skiving
skived and roller burnished
SpecialChrome plated
tube rod
Telescopic
Inside TolerancesH8 | H9 | H10 | H11
Steel GradeE355 | E410
others on request
Test CertificateEN 10204:2004/3.1