EN 10305

EN 10305 european standard specifies the technical delivery conditions for seamless cold drawn steel pipe of circular cross section used in hyhydraulic and pneumatic power systems.

• EN10305-1 E215
• EN10305-1 E235
• EN10305-1 E355

Tubes according to this EN 10305 European standard are characterised by having precisely defined tolerances on dimensions and a specified surface roughness.

EN 10305 seamless precision steel tube shall be manufactured from hot finished seamless tubes by cold drawning. Other suitable methods of cold working are permitted. The tubes shall be delivered in the delivery condition +N which means that after the final cold drawing operation the tubes are normalized in a controlled atmosphere.

NBK means protective heat-treating under the non-oxidation enviroment to get a bright and smooth surface for the tubes.

Seamless, cold-drawn precision steel tubes have a particularly high dimensional tolerance with regard to the outer and inner diameter and/or the wall thickness. The excellent dimensional accuracy is achieved through an additional work step, known as “cold drawing”, after the actual tube production. This also vastly improves the surface.

Because the dimensions of the tube are changed during drawing, you can also order relatively small quantities within the size range and thereby also represent intermediate sizes economically compared to an otherwise necessary machining situation.

While the variety of materials is far greater than with welded tubes, the manufacturing process is more complex and thus more expensive on the whole.

Chemical composition(%) of EN 10305-1

Steel grade Name	Steel Number	C(% max)	Si(% max)	Mn(% max)	P(% max)	S(% max)
E215	1.0212	0.10	0.05	0.70	0.025	0.015
E235	1.0308	0.17	0.35	1.20	0.025	0.015
E355	1.0580	0.22	0.55	1.60	0.025	0.015

Mechanical and technological properties of EN 10305-1

Yield strength	Tensile strength	Elongation
(min Mpa)	(min Mpa)	(min %)
215	290-430	30
235	340-480	25
355	490-630	22

The pipes are used to manufacture hydraulic and pneumatic power systems of the I generation and they are also used in the pipelines of hydraulic and pneumatic systems. They are manufactured as seamless cold drawn tubes. They are provided in the +N delivery condition (normalized in a controlled atmosphere).

Note:

• The yield point for the annealed (GBK)condition on delivery is at least 50% of the (ultimate) tensile strength. Depending upon the degree of deformation in the drawing operation, the yield point of tubes delivered in the cold-finished/hard (BK)and cold-finished/soft(BKW) conditions, may be increased to a level close to the tensile strength.
• In calculating the yield point, the following values are recommended : cold-finished/hard condition on delivery ≥ 80% of the tensile strength, cold-finished/soft condition on delivery ≥ 70% of the tensile strength.

The tubes are supplied in the following quality grades :

1. precision steel tubes intended primarily for mechanical stressing, without any particular quality requirement and without acceptance test certificate.
2. precision steel tubes intended primarily for mechanical stressing, with special quirement and exclusively with acceptance test certificate.
3. precision steel tubes with special requirement according to section 12. Theses requirements and corresponding tests must be agreed, with the customer having to specify his requirements at the time of enquiry and on ordering.

Welded, cold-drawn precision steel tubes have a particularly high dimensional tolerance with regard to the outer and inner diameter and/or the wall thickness. The excellent dimensional accuracy is achieved through an additional work step, known as “cold drawing”, after the actual tube production. This also vastly improves the surface.

Because the dimensions of the tube are changed during drawing, you can also order relatively small quantities within the size range and thereby also represent intermediate sizes economically compared to an otherwise necessary machining situation.

Some materials cannot be welded as a result of production, and this is where using seamless tubes can be absolutely vital.

Welded, size-rolled precision steel tubes have a good dimensional tolerance and fantastic surfaces due to the manufacturing process.

These tubes can also be put to good use for the furniture industry and for decorative purposes, due to the continuous use of high-quality tape material.

In addition to a particularly high dimensional tolerance, seamless, cold-drawn HPL precision steel tubes have good formability and corrosion resistance due to downstream phosphatising or electrogalvanising.

These tubes are mainly used as lines in hydraulic or pneumatic installations.