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Precision seamless tubes for hydraulic and pneumatic pressure circuits (HPL type)


EN 10305-4 Steel tubes for precision applications. Part 4: Seamless cold drawn tubes for hydraulic and pneumatic power systems.
DIN 2391-1 Seamless precision steel tubes. Part 1: Dimensions.

Steel grades:

according to EN: E215 (1.0212), E235 (1.0308), E355 (1.0580)
according to DIN: St 44.4, St 37.4, St 52.4

Mechanical properties in room temperature

Steel grade Yield limit  ReH
min. MPa
Tensile strenght Rm
min. MPa
Elongation A min. %
E215 215 290 to 430 30
E235 235 235 to 480 25
E355 355 490 to 630 22

Note. For tubes with outside diameter ≤ 30 mm and wall thickness ≤ 3 mm, minimum values of ReH are 10  MPa lower than given above.

Delivery condition

+N (EN); NBK (DIN) Normalized (after the last cold drawing process the tubes are normalized in a controlled atmosphere)

Coarseness of the outer and inner surface (starting with ID 15 mm) Ra ≤ 4 μm


– the length of the maufactured precision tubes is 6 000 mm (tolerances at the standard length is 0+50 mm and at the exact length is 0+10 mm)
– exact length can be from the range of 3 000 mm – 9 000 mm


Total deviation: max 0,0015 L
Local deviation: max 3 mm / 1 m

Ends of the tubes

The ends of the tubes are smooth and enclosed with plastic caps.


The electromagnetic nondestructive testing of leak tightness is always performed according to EN 10246-1 or other corresponding standards. Selection of the tests is defined in EN 10305-1. The NDT test and the flattening or drift expanding test is possible.


Each tube is marked by the InkJet system along the whole length according to standards or according to customer requirements. Tube bundles are marked by tags.

Surface protection

– oiled
– phosphated and oiled
– electrolytically galvanized and chrome-coated


The HPL tubes are delivered in bundles with either circular or hexagonal cross-section weighting maximum 2000 kilograms. The tubes are tied with a steel band. Upon agreement it is possible to protect the surface with paper lining or protect the ends of the bundle with PCV foil.

Certificates for HPL tubes

According to the following standards: EN 10 204 or DIN 50049
– nonspecified testing – 2.2
– specified testing 3.1.B or 3.1
– upon agreement – 3.1.C or 3.2

Dimensions, cross sectional area and weight of HPL tubes

 Tables of pressures for hydraulic tubes (MPa)

Table of pressures for hydraulic tubes, E355 without specific testing

Table of pressures for hydraulic tubes, E355 with specific testing

Table of pressures for hydraulic tubes, E235 without specific testing

Table of pressures for hydraulic tubes, E235 with specific testing