This standard specifies several chemical methods of passivation for corrosion resisting steel (austeniticferriticmartensitic and precipitation hardenable) and of decontamination for nickel base alloy.

EN 2516 Passivation Treatment

This standard covers nitric acid and nitric acid / sodium dichromate solutions.
Like ASTM A380 it classifies types of stainless steel as suitable for specific treatment conditions according to
EN 2032-1 - Aerospace series - Metallic materials - Part1:Designation

Process ClassStainless Steel Types
C1 or C2Austeniticaustenitic precipitation hardening and duplex
C3High chromium martensitics
C4Ferriticmartensitics and martensitic precipitation hardening


The treatments are then defined by the process classes. In the case of classes C3 and C4, a two step process is defined, with a clean water rinse between the two steps, shown in the table below.


Process ClassSolution Concentration g/lTemp. Range CTime mins.Anodic voltage V



  Stainless Steel Tube/Pipe/TubingNickel Alloy TubingBrass Alloy TubingCopper Nickel Pipe Material Grades