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

RISK-BASED INSPECTION METHODOLOGY, PART 2—PROBABILITY OF FAILURE METHODOLOGY 2-47
6.10 Figures
280
260
240
Area 'C'
Application of Nickel Alloys to Be Considered in This Area
220
Nickel Alloy Trim for Valves
In Areas 'B' & 'C'
200
Area 'B'
180
Carbon Steel
Stress Relieve Welds & Bends
Temperature, F
160
140
120
Area 'A'
100
80
Carbon Steel
No Stress Relief Necessary
60
40
20
0
0 10 20 30 40 50
Concentration NAOH, % By Weight
Figure 6.1—Susceptibility of Caustic Cracking in Carbon Steel