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
