Formic acid has proven to be highly corrosive at concentrations over 50% especially if contaminated by
acidic oxidizing
chloride. Because of its corrosive nature at high concentrations material
selection can be a challenge.
Stainless Steel,
Nickel base alloys and
Zirconium's Corrosion in Formic Acid.
Formic acid is corrosive to many alloys including Stainless steel,
Nicel alloys and Zirconium. Formic acid as a reducing agent and attacks stainless steel unless an oxidizing agent is added. Nickel base alloys perform better than SS
316, but are attacked if an oxidizing agent is present.
Zirconium has been applied sucesfully in some formic acid applications but is sensitive to attack from
acidic acids oxidizing chlorides and other contaminants such as FeCl3 and CuCl2 and the Use of zirconioum is not recommended in these media and these materials should be avoided.
Lmunity in Formic Acid up to 150°C. Tantaline is the only commercial available metal that is not sensistive to corrosion attack from formic acids in any concentration up to 150*C where impurities like FeCl3 or CuCl2may be present.
Corrosion of in Formic Acid above 150°C
showing very good
corrosion reistance in formic acid acid at
temperature in the range 150°C to 300°C. The specific composition of the media will have to be evaluated to estimate the exact corrosion rate.
Materials in Formic Acid HCCOH
| Conc. HCOOH% |
0.5 |
1 |
1 |
2 |
2 |
2 |
5 |
5 |
5 |
5 |
| Temp. °C |
70 |
20 |
40 |
20 |
40 |
100 |
20 |
80 |
95 |
100=BP |
| Grade or type of alloy: |
|
|
|
|
|
|
|
|
|
|
| Carbon steel |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
| 13Cr |
0 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
| 304/304L |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
1 |
2 |
2 |
| TP316/316L |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
1 |
| 18Cr13Ni3Mo/317L |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
1 |
| 17Cr14Ni4Mo / 1.4439 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| 904L / N08904 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| Sanicro 28 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| 254 SMO |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| 654 SMO |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| SAF 2304 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| SAF 2205 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| SAF 2507 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| Titanium (CP Ti) |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| Conc. HCOOH % |
80 |
90 |
90 |
90 |
90 |
90 |
90 |
100 |
100 |
100 |
| Temp. °C |
107 =BP |
20 |
40 |
60 |
80 |
100 |
106 =BP |
20 |
60 |
101 =BP |
| Grade or type of alloy: |
|
|
|
|
|
|
|
|
|
|
| Carbon steel |
2 |
2 |
2 |
2 |
2 |
2 |
2 |
1 |
2 |
2 |
| 13Cr |
2 |
1 |
2 |
2 |
2 |
2 |
2 |
1 |
1 |
2 |
| 304/304L |
2 |
0 |
0 |
1 |
2 |
2 |
2 |
0 |
0 |
1 |
| TP316/316L |
1 |
0 |
0 |
0 |
0 |
1 |
2 |
0 |
0 |
1 |
| 18Cr13Ni3Mo/317L |
1 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
1 |
| 17Cr14Ni4Mo / 1.4439 |
1 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
1 |
| 904L / N08904 |
1 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
0 |
| Sanicro 28 |
1 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
0 |
| 254 SMO |
1 |
0 |
0 |
0 |
0 |
|
1 |
0 |
0 |
0 |
| 654 SMO |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| SAF 2304 |
2 |
0 |
0 |
0 |
0 |
|
2 |
|
|
1 |
| SAF 2205 |
1 |
0 |
0 |
0 |
0 |
0 |
2 |
|
|
1 |
| SAF 2507 |
1 |
0 |
0 |
0 |
0 |
0 |
1 |
0 |
0 |
1 |
| Titanium (CP Ti) |
1 |
0 |
0 |
0 |
0 |
1 |
1 |
0 |
0 |
1 |
| SAF 2906 |
1 |
|
|
|
|
0 |
1 |
|
|
1 |
| SAF 2707 HD |
1 |
|
|
|
|
0 |
0 |
|
|
1 |
| SAF 3207 HD |
1 |
|
|
|
|
0 |
1 |
|
|
1 |
Symbol clarification
These corrosion tables use a number of symbols, having the following meanings:
| Symbol |
Description |
| 0 |
Corrosion rate less than 0.1 mm/year. The material is corrosion proof. |
| 1 |
Corrosion rate 0.1—1.0 mm/year. The material is not corrosion proof, but useful in certain cases. |
| 2 |
Corrosion rate over 1.0 mm/year. Serious corrosion. The material is not usable. |
| p, P |
Risk (severe risk) of pitting and crevice corrosion. |
| c, C |
Risk (Severe risk) of crevice corrosion. Used when there is a risk of localised corrosion only if crevices are present. Under more severe conditions, when there is also a risk of pitting corrosion, the symbols p or P are used instead. |
| s, S |
Risk (Severe risk) of stress corrosion cracking. |
| ig |
Risk of intergranular corrosion. |
| BP |
Boiling solution. |
| ND |
No data. (Used only where there are no actual data to estimate the risk of localised corrosion instead of p or s). |
Selection of Stainless Steel fo Handling Sulphur Dioxide SO2 and Sulphur Trioxide SO3
Selection of Stainless Steel for Handling Phosphoric Acid H3PO4
Selection of Stainless Steel for Handling Hydrofluoric Acid HF
Selection of Stainless Steel for Handling Citric Acid C3H4OH (COOH)3
Selection of Stainless Steel for Handling Ammonia NH3
Selection of Stainless Steel for Handling Chlorine Cl2 and Chlorine Dioxide ClO2
Selection of Stainless Steels For Handling Hydrochloric Acid HCl
Selection of Stainless Steel for Handling Sulphuric Acid H2SO4
Selection Stainless Steel for Handling Sodium Hydroxide NaOH
Selection of stainless steels for handling acetic acid (CH3COOH)
Selection of stainless steels for handling sodium hypochlorite (NaOCl)
Selection of stainless steels for handling nitric acid (HNO3)
NACE MR 0175/ISO 15156 for Corrosion Resistant Alloys for Sulphide Service
Selection of stainless steel in water supply and waste water treatment
