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

RISK-BASED INSPECTION METHODOLOGY, PART 2, ANNEX 2.B—DETERMINATION OF CORROSION RATES 2.B-9
Table 2.B.2.6—HCl Corrosion—Estimated Corrosion Rates for Alloy B-2 and Alloy 400 (mpy)
Alloy
Cl −
Concentration
(wt%)
Temperature (°F)
100 125 175 200
Oxygen/Oxidants Present?
No Yes No Yes No Yes No Yes
Alloy B-2 0.50 1 4 1 4 2 8 4 16
0.75 1 4 1 4 5 20 20 80
1.0 2 8 5 20 10 40 25 100
Alloy 400 0.50 1 4 3 12 30 120 300 999
0.75 2 10 5 20 80 320 800 999
1.0 19 40 25 100 150 600 900 999
Table 2.B.2.6M—HCl Corrosion—Estimated Corrosion Rates for Alloy B-2 and Alloy 400 (mm/y)
Alloy
Cl −
Concentration
(wt%)
Temperature (°C)
38 52 79 93
Oxygen/Oxidants Present?
No Yes No Yes No Yes No Yes
Alloy B-2 0.50 0.03 0.1 0.03 0.1 0.05 0.2 0.1 0.41
0.75 0.03 0.1 0.03 0.1 0.13 0.51 0.51 2.03
1.0 0.05 0.2 0.13 0.51 0.25 1.02 0.64 2.54
Alloy 400 0.50 0.03 0.1 0.08 0.3 0.76 3.05 7.62 25.37
0.75 0.05 0.25 0.13 0.51 2.03 8.13 20.32 25.37
1.0 0.48 1.02 0.64 2.54 3.81 15.24 22.86 25.37