HydroFluoric acid
Hydrofluoric acid (HF) is very corrosive and can react with many metals, including cast iron, to generate hydrogen gas. Common stainless steel types, like 304 and 316, are not resistant to HF at any concentration or temperature. Higher grades of stainless steel may have some resistance, but they can still be attacked locally.
Corrosion rates in Hydroflouric Acid (HF)
Corrosion rates in Hydroflouric Acid (HF)
| Alloy | Notes | Concentration, % | Temperature | Time | Corrosion Rate | Ref | ||
|---|---|---|---|---|---|---|---|---|
| C | F | mm/yr | mils/yr | |||||
| 316 | — | 3 | 21 | 70 | — | 1.25 | 49.1 | 1 |
| 316 | — | 5 | 21 | 70 | — | 2.33 | 91.8 | 1 |
| 316 | — | 5 | 40 | 104 | — | 7.8 | 306 | 1 |
| 316 | — | 1 | 50 | 122 | — | 1.82 | 71.8 | 1 |
| 316 | — | 2 | 50 | 122 | — | 5.3 | 209 | 1 |
| 316 | — | 5 | 50 | 122 | — | 15.9 | 626 | 1 |
| 904L | — | 3 | 21 | 70 | — | 0.125 | 4.9 | 1 |
| 904L | — | 5 | 21 | 70 | — | 0.18 | 7.2 | 1 |
| 904L | — | 5 | 40 | 104 | — | 0.73 | 28.8 | 1 |
| 904L | — | 1 | 50 | 122 | — | 0.23 | 9.2 | 1 |
| 904L | — | 2 | 50 | 122 | — | 0.71 | 28 | 1 |
| 904L | — | 3 | 50 | 122 | — | 0.85 | 33.5 | 1 |
| 904L | — | 4 | 50 | 122 | — | 1.36 | 53/5 | 1 |
| 904L | — | 5 | 50 | 122 | — | 1.82 | 71.6 | 1 |
| 904L | — | 1 | 70 | 158 | — | 0.99 | 39 | 1 |
| 904L | — | 2 | 70 | 158 | — | 2.0 | 80.2 | 1 |
| 904L | — | 3 | 70 | 158 | — | 3.31 | 130 | 1 |
| AL-6XN | — | 3 | 21 | 70 | — | 0.08 | 3.2 | 1 |
| AL-6XN | — | 5 | 21 | 70 | — | 0.20 | 8.0 | 1 |
| AL-6XN | — | 5 | 40 | 104 | — | 0.82 | 32.4 | 1 |
| AL-6XN | — | 1 | 50 | 122 | — | 0.10 | 4.1 | 1 |
| AL-6XN | — | 2 | 50 | 122 | — | 0.43 | 16.9 | 1 |
| AL-6XN | — | 3 | 50 | 122 | — | 0.98 | 38.4 | 1 |
| AL-6XN | — | 4 | 50 | 122 | — | 1.42 | 55.9 | 1 |
| AL-6XN | — | 5 | 50 | 122 | — | 2.0 | 78.7 | 1 |
| AL-6XN | — | 1 | 70 | 158 | — | 0.54 | 21.1 | 1 |
| AL-6XN | — | 2 | 70 | 158 | — | 1.98 | 78 | 1 |
| AL-6XN | — | 3 | 70 | 158 | — | 3.05 | 120 | 1 |
| C-276 | — | 2 | 70 | 158 | — | 0.23 | 9 | 7 |
| C-276 | — | 5 | 70 | 158 | — | 0.25 | 10 | 7 |
| C-22 | — | 2 | 70 | 158 | — | 0.23 | 9 | 7 |
| C-22 | — | 5 | 70 | 158 | — | 0.36 | 14 | 7 |
| 625 | — | 2 | 70 | 158 | — | 0.51 | 20 | 7 |
| 625 | — | 5 | 70 | 158 | — | 0.41 | 16 | 7 |
| 400 | saturated with air | 25 | 30 | 86 | 24hr | 1 | 37 | 17 |
| 400 | saturated with air | 25 | 80 | 176 | 24hr | 0.28 | 11 | 17 |
| 400 | saturated with air | 50 | 30 | 86 | 24hr | 0.2 | 8 | 17 |
| 400 | saturated with air | 50 | 80 | 175 | 24hr | 1 | 39 | 17 |
| 400 | purged with nitrogen | 25 | 30 | 86 | 48hr | 0.005 | 0.2 | 17 |
| 400 | purged with nitrogen | 25 | 80 | 176 | 48hr | 0.061 | 2.4 | 17 |
| 400 | purged with nitrogen | 50 | 30 | 86 | 48hr | <0.003 | <0.1 | 17 |
| 400 | purged with nitrogen | 50 | 80 | 176 | 48hr | 0.01 | 0.5 | 17 |
