Precision tubes machined to “ready to use” - type HP
Standards and steel grades,
Precision tubes are produced by the cold drawing process. The rolled seamless tubes are used as the semi-finished product. “Ready to use” precision tubes type HP are used directly for production of the hydraulic cylinders. The inside surface is machined by stripping and subsequent rolling at Zeleziarne Podbrezova a.s. Precision tubes HP type are made from carbon and alloyed steel. Overview of dimensional standards and technical-delivery conditions for the HP tubes is presented in a separate overview.
separate overview. Steels are produced in electric arc furnace and it is fully killed. Upon agreement it is possible to deliver other types of steel.
Delivery condition and thermal treatment of the HP tubesTubes are delivered as cold drawn and annealed to relieve the stress BKS (+SR). Other delivery conditions are possible upon agreement. Overview of other conditions may be found here .
Length of HP tubes- manufactured length of HP tube is in the range of 3 to 6 meters
- maximum precise length 6 meters
Tolerances of HP tubesTolerances of the outside diameter (OD) HP tubes meet the appropriate dimensional table standards DIN 2391-1, EN 10305-1, STN and ČSN 426712. 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.
Straightness of HP tubes1 mm / m (1 : 1 000) measured on the outside surface.
Condition of the HP tubesAccording to the DIN 2391 directives, the precision tubes have the outside surface smooth.
Ends of the HP tubesEnds of the tubes are square to the longitudinal axis of the tubes. Upon agreement the tubes may be capped with plastic caps.
Marking of the HP tubesThe tubes are marked along the length of the tube where the following pieces of information are used: manufacturers’ logo, dimension (OD x ID), steel, heat number and the number of standard or other data as per the customers’ request.
Surface protection of the HP tubesThe surface of the tubes is oiled.
Testing of HP tubesSelection of the tests is either according to standards or upon agreement with customer: chemical analysis, tensile test, dimensional test, visual inspection and nondestructive testing (eddy current). Other tests are possible upon agreement.
Certificates for HP tubesAccording to the following standards: EN 10 204 - 3.1 or DIN 50049 - 3.1.B