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.
The allowed pressure rates and temperatures are the responsibility of the customer in accordance with the state of the art and in application of the safety coefficients specified in the application regulations, codes or standards.
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.
Chemical composition(%) of EN 10305-1
|C(% max)||Si(% max)||Mn(% max)||P(% max)||S(% max)|
Mechanical and technological properties of EN 10305-1
The tubes are supplied in the following quality grades :
|BK||No heat treatment after the last cold-forming process. The tubes therefore have only low deformability.|
|BKW||After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits.|
|Annealed||GBK||After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum.|
|Normalized||NBK||The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum.|