This standard specifies several chemical methods of passivation for corrosion resisting steel (austenitic, ferritic, martensitic 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
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 Class |
Solution Concentration g/l |
Temp. Range C |
Time mins. |
Anodic voltage V |
| HNO3 |
Na2Cr2O7.2H2O |
| C1 |
200-250 |
20-30 |
50-55 |
20-40 |
without |
| 20-30 |
30-60 |
| C2 |
200-500 |
- |
20-30 |
30-60 |
without |
| C3 |
200-250 |
20-30 |
50-55 |
2-3 |
3-5 |
| - |
40-60 |
60-70 |
30-40 |
without |
| C4 |
200-250 |
20-30 |
50-55 |
20-40 |
without |
| - |
40-60 |
60-70 |
30-40 |
without |
|