Stainless Steel Hydraul Tubes Seamless EN 1.4435
The austenitic steel with designation 1.4435 is a so-called acid resistant grade containing chromium, nickel and molybdenum just like 1.4432, but in the case of 1.4435, the contents of chromium and nickel are somewhat higher. In terms of strength, 1.4435 is marginally higher than 1.4432.
Seamless tubes for lines in hydraulic systems must be amenable to bending without splitting or cracking, at the same time as they can on occasion be subjected in service to high internal pressure. Such seamless tube in stainless steel is standardised in EN 10216-5. Tibnor’s offer encompasses tubes with outside diameters in the range 6-30 mm and wall thicknesses between 1.0- and 4.0-mm. Seamless stainless tubes for hydraulic lines are manufactured by extrusion followed by cold drawing and bright annealing. All tubes are pressure tested.
In comparison with 1.4404, the higher content of molybdenum means that the grade 1.4435 shows somewhat better immunity to attack by weak acids and chloride-containing water so long as the chloride concentration is not too high. Seamless tube in 1.4435 is a suitable choice for hydraulic lines in systems that are exposed to aggressive environments, such as are commonplace in the marine and offshore segments.
1.4435 has good formability and weldability and if needed bending, cold forming or welding of seamless hydraulic tube can be performed without any special issues. The tubes are subjected to extensive testing in order to ensure that there is no risk for cracking in the event the tubes are bent or processed via cold forming.
Seamless tubes for hydraulic lines that can be supplied in grade 1.4435 have been bright annealed in protective atmosphere and their surface is metallically clean. The tolerances on outer diameter (D) and wall thickness (T), which are stipulated in detail in EN 10305-1 and EN-ISO 1127, are ±0.8 mm for D and ±10% for T. Straightness is good with height of arc at most 0.002 times length. The greatest permitted internal pressure to which the tubes can be subjected depends on operating temperature and (of course) diameter and wall thickness, and is calculated following a procedure specified in EN 13480-3.