Hydraulic Seamless Tubes
Seamless
Hydraulic Tubes as per DIN
2391 for hydraulic
applications
A hydraulic system is a
complex combination of an
arrangement of hydraulic
pumps, various types of
hydraulic valves, power pack
accessories, fittings,
seamless hydraulic tubes and
hoses. The seamless tube
carries the hydraulic fluid
or oil from one part of the
hydraulic system to another.
Hence the Seamless Hydraulic
Tube becomes an essential
part of the Hydraulic
system. The Tubes used in
the system are specially
engineered tubes which have
a particular chemical
composition and physical or
mechanical properties to
fulfil the requirements of
the hydraulic system
Hydrofit
Engineers offer Seamless
Hydraulic Tubes as per DIN
2391 standards which are
manufactured by Cold Drawn
process and precision
manufactured to very close
tolerances and having smooth
Inside and outside finish.
To achieve the desired
mechanical properties the
tubes are Heat Treated which
involves the process of
Normalizing, Stress
Relieving, Annealing and
Tempering in Bright
Annealing Furnace. Bright
Annealing provides the
required Ra values of Inside
and Outside surface finish
The pipes are then subjected
to Straightening on Multiple
Roll Straitening machines.
Accuracy of Straightness
achieved is 1mm : 1000mm
Straightness
Chemical properties of Seamless hydraulic Tube Din 2391:
| C | Si | Mn | P | S | Ni | Cr | Mo | Others | ||
|---|---|---|---|---|---|---|---|---|---|---|
| ST 35 | 0.17 Max | 0.35 Max | 0.40 Max | 0.050 Max | 0.050 Max | – | – | |||
| ST 45 | 0.21 Max | 0.35 Max | 0.40 Max | 0.050 Max | 0.050 Max | – | – | |||
| ST 52 | 0.22 Max | 0.55 Max | 1.60 Max | 0.050 Max | 0.050 Max | – | – |
Applications of Cold drawn bright annealed Seamless Tubes are :
-
• Automobiles
-
• Hydraulics
-
• Tractors
-
• Earth Movers
-
• General Engineering
The cold drawn seamless tubes are subject to the following annealing processes :
Annealing –
GBK – After the cold forming process the
tubes are subjected to annealing in
controlled atmosphere or in vacuum
Normalizing
– NBK – The tubes are annealed above the
upper transformation point in a
controlled atmosphere or under vacuum
The finished Seamless Tubes are subjected to the following Mechanical Tests :
-
• Tensile Test
-
• Hydrostatic pressure Test
-
• Eddy Current Test
-
• Flattening, Flaring, Bending Test
-
• Surface roughness Test
-
• Hardness Test
-
• Burst Test
-
• Salt spray Test to test Phosphating/Plating
-
• Chemical Composition
-
• Metallurgical & Stereo Microscopy
-
• Dimensional Checks
Small diameter tubes with high thickness for low flow but
high pressure applications