Tubes for hydraulic cylinders


Tubes for mechanical machining – type HPZ are precision seamless tubes for the production of hydraulic cylinders or seals of piston rods. The inner working surface is obtained by mechanical machining, by honing or peeling and subsequent rolling.

Tubes intended for direct use in the cylinders – type HP are seamless tubes with a precisely machined inner surface, which are primarily intended for the manufacture of hydraulic cylinders. The inner working surface is achieved by peeling and subsequent rolling of the inner surface of the tubes.

Tubes intended for piston rods and telescopic cylinders – type HPK are cold drawn seamless tubes for piston rods, telescopic cylinders and cylinder liners. Use of tube piston rods and pistons is often preferable than the use of solid materials. Use of the tube material, which exhibits the same resistance to load stress, bending and in torsion, means a significant reduction in the weight of the cylinder.


Dimensions of hydraulic cylinder tubes

Precision tubes for mechanical machining – HPZ type

INNER DIAMETER (ID)40,0 – 115,0 mm
WALL THICKNESS (WT)5,0 – 10,0 mm
EUROPEAN STANDARDSEN 10305-1,
DIN 2391,
STN/ČSN 42 6711,
STN/ČSN 42 6712

Precision tubes machined to “ready to use” – type HP

INNER DIAMETER (ID)40,0 – 110,0 mm
WALL THICKNESS (WT)4,0 – 10,0 mm
EUROPEAN STANDARDSEN 10305-1,
DIN 2391,
STN/ČSN 42 6711,
STN/ČSN 42 6712

Precision tubes destined for piston rods – type HPK

OUTER DIAMETER (OD)40,0 – 120,0 mm
WALL THICKNESS (WT)5,0 – 10,0 mm
EUROPEAN STANDARDSEN 10305-1,
EN 10294-1,
DIN 2391
Dimensional standard SIZES (OD x WT) Dimensional table
EN10305-148.0 x 4.0 – 130.0 x 10.0 mm
DIN239148.0 x 4.0 – 130.0 x 10.0 mm
ČSN42 671148.0 x 4.0 – 130.0 x 10.0 mm
STN42 671248.0 x 4.0 – 130.0 x 10.0 mm
Dimensional standard SIZES (OD x WT) Dimensional table
EN10305-150.0 x 5.0 – 130.0 x 7.5 mm
DIN239150.0 x 5.0 – 130.0 x 7.5 mm
ČSN42 671150.0 x 5.0 – 130.0 x 7.5 mm
ČSN42 671250.0 x 5.0 – 130.0 x 7.5 mm

Steel grades for hydraulic cylinders

EN 10305-1E355
EN 10 294-120MnV6
STN/ČSN 42 026011 523
DIN 2391-2St52
DIN 17100St52-3
Standard TDC Steel grade (open product) Dimensional standard
DIN23912391
EN10305-110305-1
ČSN42 026042 6711
DIN171002391
STN42 026042 6712
STN42 026042 6711
ČSN42 026042 6712
Standard TDC Steel grade (open product) Dimensional standard
EN10305-110305-1
ČSN42 026042 6712
ČSN42 026042 6711
DIN23912391
STN42 026042 6711
DIN171002391
STN42 026042 6712

Tolerances for hydraulic cylinders

for mechanical machining – HPZ type

Tolerances of the outside diameter (OD) HPZ tubes meet the appropriate dimensional table standards. Tolerances values of the inside diameter (ID) are presented in the table .

Tolerance of the wall thickness is -/+ 7.5% of the wall thickness.
HPZ tubes eccentricity is included in the wall thickness tolerance

for HP tubes

Tolerances of the outside diameter (OD) HP tubes meet the appropriate dimensional table standards DIN 2391-1, EN 10305-1. Tolerances values of the inside diameter (d) H8 a H9 are presented in the table.

Tolerance of the wall thickness is -/+ 7.5% or 10% of the wall thickness.
HP tubes eccentricity is included in the wall thickness tolerance.

Length of tubes for hydraulic cylinders

(a), manufactured length of precision tubes in the range of 3 to 6 meters
(b), maximum precise length 6 meters

Tube testing

Selection of the tests is either according to standards or upon agreement with customer:

• cast / chemical analysis,
• tensile test,
• dimensional inspecti,
• visual inspection,
• NDT to find longitudinal defects.

Other tests are possible upon agreement.

Tubes ends

The tubes with deburred ends or ends customized for welding.
The tubes with deburred ends or ends customized for welding.
The ends are vertical to the longitudinal axis and are without burrs.
The ends are vertical to the longitudinal axis and are without burrs.

Upon agreement the tubes may be capped with plastic caps.

Cylinder tubes surface protection

The surface of the tubes is oiled.

Packaging tubes for hydraulic cylinders

Tube are packed in round or hexagonal bundles with weight max. 2 000 kg, fastened with steel strips.

Packaking-STANDARD-tubes bound with a steel band
Packaking-STANDARD-tubes bound with a steel band
Packaking-STANDARD-bundle tied down by steel strap underlaid by paper
Packaking-STANDARD-bundle tied down by steel strap underlaid by paper
Packaking-STANDARD-PLUS-paper tape and polyethylene foil
Packaking-STANDARD-PLUS-paper tape and polyethylene foil
Packaking-STANDARD-PLUS-the bundle placed into a wooden box
Packaking-STANDARD-PLUS-the bundle placed into a wooden box
Packaking-PREMIUM-B-into a wooden box in which the tubes are wrapped in foil
Packaking-PREMIUM-B-into a wooden box in which the tubes are wrapped in foil
Packaking-PREMIUM-C-the bandles are wraped into and plastic foil
Packaking-PREMIUM-C-the bandles are wraped into and plastic foil
Packaking-PREMIUM-D-placing the whole shipment into foil+vacuum sealed
Packaking-PREMIUM-D-placing the whole shipment into foil+vacuum sealed

Marking of tubes

The tubes are marked along the length of the tube where the following pieces of information are used:

(a), manufacturers’ logo,
(b), dimension (OD x ID),
(c), steel,
(d), heat number,
(e), the number of standard,
(f), other data as per the customers’ request.

Marked by a label
Marked by a label
Marked by stamping the data
Marked by stamping the data
Marked with spray either by a white or black color using InkJet
Marked with spray either by a white or black color using InkJet

According to EN 10 204 – 3.1.


Straightness of the tubes is 0,001 multiple of the tube length maximum, allowed straightness for one meter length is 1.0 milimeters.

The tubes are delivered as cold drawn and annealed to relieve the stress BKS (+SR).

Other delivery conditions are possible upon agreement.

Contact us

Are you interested in cooperation? Send us an inquiry, or order the goods directly from stock.
+421 48 6451111 | admin@zelpo.sk

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