API RP 581 - 3rd Ed.2016 - Add.2-2020 - Risk-Based Inspection Methodology

2.B-24 API RECOMMENDED PRACTICE 581
Table 2.B.3.7—High Temperature Sulfidic and Naphthenic Acid Corrosion—Estimated Corrosion
Rates for 12 % Cr Steel (mpy)
Sulfur
(wt%)
TAN
(mg/g)
Temperature (°F)
≤450 500 550 600 650 700 750 >750
0.7 1 1 1 1 1 1 2 2
1.1 1 1 1 1 1 2 4 5
0.2
1.75 2 2 2 4 4 5 8 10
3.0 5 10 15 20 25 30 25 40
4.0 10 15 20 25 30 25 40 45
0.7 1 1 1 1 1 2 3 3
1.1 1 1 1 1 1 2 3 3
0.4
1.75 1 2 2 2 2 4 5 5
3.0 2 3 3 3 3 5 10 15
4.0 3 4 5 8 10 12 15 20
0.7 1 1 1 1 1 2 3 4
1.1 1 1 1 1 1 2 3 4
0.8
1.75 2 2 4 5 6 6 7 8
3.0 3 3 5 8 10 12 15 20
4.0 4 5 5 8 10 15 20 25
0.7 1 1 1 1 2 3 4 5
1.1 1 1 1 1 2 3 4 5
1.5
1.75 2 2 3 5 7 8 10 10
3.0 3 3 5 8 10 12 15 20
4.0 5 8 10 12 15 20 25 30
0.7 1 1 1 1 2 3 5 6
1.1 1 1 1 1 2 3 5 6
2.5
1.75 2 5 7 9 10 12 15 15
3.0 3 8 10 15 20 20 25 30
4.0 5 10 15 20 25 30 35 40
0.7 1 1 1 1 2 4 5 6
1.1 1 1 1 1 2 4 5 6
3.0
1.75 3 5 7 9 10 12 15 15
3.0 4 8 10 15 20 20 25 30
4.0 5 10 15 20 25 30 35 40