Iso-Corrosion Diagrams
Each of these iso-corrosion diagrams was constructed using numerous corrosion rate values, generated at different acid concentrations and temperatures. The blue line represents those combinations of acid concentration and temperature at which a corrosion rate of 0.1 mm/y (4 mils per year) is expected, based on laboratory tests in reagent grade acids. Below the line, rates under 0.1 mm/y are expected. Similarly, the red line indicates the combinations of acid concentration and temperature at which a corrosion rate of 0.5 mm/y (20 mils per year) is expected. Above the line, rates over 0.5 mm/y are expected. Between the blue and red lines, corrosion rates are expected to fall between 0.1 and 0.5 mm/y.
Hydrobromic Acid
Concentration |
50°F |
75°F |
100°F |
125°F |
150°F |
175°F |
200°F |
225°F |
Boiling |
Wt. % |
10°C |
24°C |
38°C |
52°C |
66°C |
79°C |
93°C |
107°C |
2.5 |
- |
- |
- |
- |
<0.01 |
- |
<0.01 |
- |
<0.01 |
5 |
- |
- |
- |
- |
<0.01 |
0.13 |
0.6 |
- |
- |
7.5 |
- |
- |
- |
- |
<0.01 |
<0.01 |
0.93 |
- |
- |
10 |
- |
- |
- |
- |
0.15 |
0.82 |
- |
- |
- |
15 |
- |
- |
<0.01 |
0.3 |
0.64 |
- |
- |
- |
- |
20 |
- |
0.1 |
0.16 |
0.33 |
0.65 |
- |
- |
- |
- |
25 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
30 |
- |
- |
0.11 |
0.21 |
0.34 |
0.72 |
- |
- |
- |
40 |
- |
- |
0.08 |
0.15 |
0.25 |
0.42 |
0.79 |
- |
- |
All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254.
Data are from Corrosion Laboratory Job 17-04.
All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.
Hydrochloric Acid
Concentration |
50°F |
75°F |
100°F |
125°F |
150°F |
175°F |
200°F |
225°F |
Boiling |
Wt. % |
10°C |
24°C |
38°C |
52°C |
66°C |
79°C |
93°C |
107°C |
1 |
- |
- |
- |
- |
- |
<0.01 |
<0.01 |
- |
0.23 |
1.5 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
2 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
2.5 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
3 |
- |
- |
<0.01 |
<0.01 |
<0.01 |
2.07 |
- |
- |
- |
3.5 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
4 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
4.5 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
5 |
- |
- |
<0.01 |
<0.01 |
- |
4.65 |
- |
- |
- |
7.5 |
- |
- |
0.07 |
0.49 |
- |
- |
- |
- |
- |
10 |
<0.01 |
0.15 |
0.3 |
1.16 |
- |
- |
- |
- |
- |
15 |
0.06 |
0.19 |
0.4 |
1.06 |
- |
- |
- |
- |
- |
20 |
0.06 |
0.16 |
0.36 |
0.82 |
- |
- |
- |
- |
- |
All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254.
Data are from Corrosion Laboratory Jobs 56-97 and 3-98.
All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.
Sulfuric Acid
Concentration |
75°F |
100°F |
125°F |
150°F |
175°F |
200°F |
225°F |
250°F |
275°F |
300°F |
350°F |
Boiling |
Wt. % |
24°C |
38°C |
52°C |
66°C |
79°C |
93°C |
107°C |
121°C |
135°C |
149°C |
177°C |
1 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
2 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
3 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
4 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
5 |
- |
- |
- |
- |
<0.01 |
0.06 |
- |
- |
- |
- |
- |
0.4 |
10 |
- |
- |
- |
- |
0.01 |
0.24 |
- |
- |
- |
- |
- |
1.05 |
20 |
- |
- |
- |
- |
0.02 |
0.58 |
- |
- |
- |
- |
- |
2.84 |
30 |
- |
- |
- |
0.01 |
0.03 |
0.68 |
- |
- |
- |
- |
- |
- |
40 |
- |
- |
<0.01 |
0.02 |
0.58 |
- |
- |
- |
- |
- |
- |
- |
50 |
- |
- |
- |
0.01 |
0.89 |
- |
- |
- |
- |
- |
- |
- |
60 |
- |
- |
<0.01 |
0.48 |
0.92 |
- |
- |
- |
- |
- |
- |
- |
70 |
- |
<0.01 |
0.23 |
0.63 |
- |
- |
- |
- |
- |
- |
- |
- |
80 |
- |
0.05 |
0.31 |
0.91 |
2.54 |
- |
- |
- |
- |
- |
- |
- |
90 |
<0.01 |
0.17 |
1.26 |
- |
6.97 |
- |
- |
- |
- |
- |
- |
- |
96 |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
- |
All corrosion rates are in millimeters per year (mm/y); to convert to mils (thousandths of an inch) per year, divide by 0.0254.
Data are from Corrosion Laboratory Jobs 57-97 and 4-98.
All tests were performed in reagent grade acids under laboratory conditions; field tests are encouraged prior to industrial use.