HPL Tubes

HPL Tubes are seamless cold-drawn precision steel tubes mainly used as pressure lines in hydraulically or pneumatically operated systems. Installation is carried out by detachable and non-detachable connections.

During the operation of hydraulic systems, changes in velocity and pressure of the flowing medium occur under operating conditions. The changes in velocity cause pressure surges that lead to a superposition with the static internal pressure. Thus, the tubing is usually subjected to pulsating stresses. When designing the tubes for such systems, the actual stress profile under service conditions must be taken into account. If lightweight construction requirements or maximum operating pressures are of importance, we will be pleased to inform you about our HPL +N Duro solutions. Furthermore, we offer MW-protect® - an optimized corrosion protection with a particularly long-lasting protective effect.

The dimensions and requirements of the tubes on this website are aligned with EN 10305-4 "Seamless cold-drawn tubes for hydraulic and pneumatic power systems".

Dimensions

Outside diameter	4 - 120 mm*
Wall thickness	1.0 - 12.5 mm
Standard length	6 m +10/-0 mm
Other dimensions on request *Dimensions and deviation limits at 4 mm ≤ OD ≤ 80 mm according to DIN EN 10305-4; Dimensions and deviation limits at OD > 80 mm according to DIN EN 10305-1 Table 5.

Detailed dimensions & tolerances

The detailed delivery program, including dimensions and tolerances, was created in accordance with EN 10305-4 "Seamless cold drawn tubes for hydraulic and pneumatic power systems“ and also takes into account established dimensions in hydraulics and pneumatics.

The design of HPL tubes can be carried out according to the calculation basis of DIN 2413. We are pleased to be at your service for questions regarding the design according to DIN 2413 taking into account your operating conditions.

Deviation Limits

For outside diameter and inside diameter, the specifications of the detailed delivery program including dimensions and tolerances apply.
Straightness in accordance with EN 10305-4.
For tubes ordered by outside diameter and inside diameter, the maximum permissible eccentricity is 7.5%.
The tubes are supplied in lengths of 6,000 mm -0/+10 mm, shorter lengths down to 4,000 mm are bundled seperately.

Materials

HPL tubes in accordance with EN 10305-4 are supplied in steel grades E 235 oder E 355.

Chemical composition*

Steel grade
	C %	Si %	Mn %	P %	S %
E235	≤ 0.17	≤ 0.35	≤ 1.20	≤ 0.025	≤ 0.015
E355	≤ 0.22	≤ 0.55	≤ 1.60	≤ 0.025	≤ 0.015

* Minimum Al_ges-content is regulated for both steel grades, except for additions of nitrogen-binding elements such as Nb, Ti and V, which are left to the manufacturer's discretion. The proportion of these elements shall be specified where applicable. When Ti is used, the following applies: (Al + Ti/2) ≥ 0.020 %.

Mechanical properties at room temperature*

Steel grade	Tensile strength	Yield strength	Elongation
	R_m MPa	R_eHMPa min	A % min
E235	340 - 480	235	25
E355	490 - 630	355	22

*For tubes with outside diameters ≤ 30 mm and wall thicknessses ≤ 3 mm, the R_eHminimum values are 10 MPa lower than the values given in this table.

Optimized fatigue strength: +N Duro

For applications with particularly high demands on operating pressures, service life or lightweight construction, Mannesmann has developed HPL tubes with increased fatigue strength: E355 +N Duro.

At constant operating pressure, a weight reduction of over 30% is possible. Alternatively, the operating pressure can be increased by more than 50% while maintaining the same cross-sectional dimension. In both cases, product safety remains at the highest level.

For more information click here.

Workability

Cold workability
Due to the final heat treatment, HPL tubes are suitable for cold working. In the case of bending, there is a decrease in wall thickness and out-of-roundness in the bending area. Corresponding reduction factors for the calculation of the bends and non-circular cross-sections are given in DIN 2413 Part 2. We are happy to support you in the design of tube bends, taking into account your operating conditions.

Weldability
The tubes are weldable without preheating and aftertreatment using standard welding techniques.

Surface conditions & protection

Technical delivery conditions
The tubes are normalized (+N) in a controlled atmosphere in accordance with EN 10305-4.

Surface condition
In accordance with EN 10305-4 the tubes exhibit smooth inside and outside surfaces with roughness of n R_a ≤ 4 μm.

Passivation
High-performance passivated HPL-tubes are externally galvanized with a zinc coating with a standard thickness of 12 to 15 μm plus a passivation layer (other coating thicknesses on request).
With its high-performance passivation, Mannesmann Precision Tubes has a Cr(VI)-free coating processs that fully complies with the requirements of Directive 2000/53/EG, which has been in force since 2007.
The coatings of the high-performance passivated tubes have a transparent, colorless appearance. The resistance to white rust (salt spray test to ISO 9227) is ≥ 300 h for tubes with an outer diameter < 20 mm and ≥ 200 h for tubes with an outer diameter ≥ 20 mm (this value applies to straight tube sections and decreases after deformation).
The resistance to red rust (salt spray test ISO 9227) is ≥ 400 hours for all dimensions.

White rust is a white deposit that can form on galvanized parts (zinc surfaces) stored in an insufficiently ventilated environment. Loose white rust provides no protection to the surfaces.

Red rust is a corrosion product that forms during the atmospheric corrosion of iron. It is black or brown to red and has a loose, porous condition.

Unless otherwise specified, the tubes will be coated and tested according to ISO 2081. The designation according to ISO 2081 should be given as in the following example:

Galvanic Coating ISO 2081-Fe/Zn12/A

This example specifies a galvanic zinc coating on ferrous material (Fe) with a minimum coating thickness of 12 μm (Zn12) and a transparent, colorless appearance (A).

Temporary Corrosion Protection

All tubes are provided with an inhibitor-containing mineral oil coating as temporary corrosion protection:

HPL tubes, black:
2 mm ≤ ID < 6 mm: oil coated internally and externally
ID ≥ 6 mm: oil coated internally and externally or phoshated and oiled internally and externally

HPL tubes, galvanized:
with an OD < 8 mm or ID < 4 mm: non-greased, unoiled
with an OD ≥ 8 mm or ID ≥ 4 mm: oiled internally and externally

MW-protect®: Excellent surface protection

Mannesmann has developed an improved coating system for increased corrosion protection of HPL tubes.
MW-protect^®for seamless hydraulic and pneumatic precision steel tubes for according to DIN EN 10305-4 and surface protection with test according to DIN EN ISO 9227 in connection with DIN EN ISO 2081.

The designation according to ISO 2081 should be given as in the following example:

Galvanic Coating ISO 2081-Fe/Zn12/A/T2

Details on the increased protection can be found in the data sheet MW-protect^®.

Tube ends

Standard: Smooth unmachined
Exception: High-performance passivated tubes with outside diameters < 8 mm or with an inside diameter < 4 mm: "Ends pinched off", i. e. the ends are sheared off and slightly oval.

End seal (non-pinched-off ends only):

Tubes with inside diameters ≤ 4 mm are closed with plastic end caps.
Tubes with inside diameters > 4 mm are sealed with plastic plugs.
Tubes ≤ 42 mm in outside diameter and lengths other than 6000 + 10/- 0 mm are delivered with open ends protected with blue plastic bags.

Testing

Testing
Tests in accordance with DIN EN 10305-4. Additional inspections can be agreed upon.

Inspection certificates
HPL-Tubes are supplied with an inspection certificate 3.1 according to EN 10204 as standard. A 3.2 inspection certificate can be agreed upon.

Marking

Continuous full-length marking is applied to all tubes. The marking includes:

Manufacturer‘s mark
Tube type
Dimensions
Delivery standard
Steel grade
Delivery condition
Batch number
Additional information
Country of Origin

Marking example:

MPT-BR HPL 15 x 11 x 2 EN 10305-4 +N 3484711 Cr6-free MADE IN GERMANY

Packaging

Tubes ≥15 mm outside diameter are packed in steel strapped hexagonal bundles.

Short lengths, residual quantities and all tubes < 15 mm are supplied in round bundles.

Other packaging (e.g. crates, cardboard tubes, bundle ends with foil) by agreement. We recommend crate packing forthin-walled tubes and overseas shipments.