Materials and Corrosion Curriculum
Mod 8 - Material Selection
Module from the Materials and Corrosion Curriculum curriculum.
MATERIAL SELECTION GUIDELINES · Learning Objectives · 1. Apply corrosion allowance, design temperature, and hardness criteria 2. Specify PWHT and hardness limits for sour service 3. Balance initial cost vs life-cycle cost in material selection 4. Reference API 571 for damage mechanism-driven selection · Material Selection by Service — Typical Refinery Applications
| Service | Temperature | Pressure | Typical Material | Alternative (Upgrade) | Corrosion Allowance | Notes |
|---|---|---|---|---|---|---|
| Crude Overhead (desalted) | <250°F | 100 psig | CS + inhibitor injection | Mo2 SS if TAN >0.5 | 1/8" (3 mm) | Cl⁻ control critical, no upper cutline moisture |
| Crude Unit HVGO / Fractionator | 600-750°F | 50 psig | 5Cr-0.5Mo (9Cr) | 317L SS for TAN >2.0 | 1/16" | Sulfur + naphthenic acid corrosion |
| Hydroprocessing Reactor | 650-800°F | 1500-2500 psig | 2.25Cr-1Mo V-mod (SA 336) | 2.25Cr-1Mo + 347 SS weld overlay | 1/8" | H2 attack resistance, temper embrittlement |
| Amine Absorber (lean/rich) | 100-150°F | 150 psig | CS PWHT + HIC plate | 316 SS if corrosion severe | 1/4" (6 mm) | Wet H2S + amine degradation products |
| Sour Water Stripper | 250-350°F | 50 psig | CS PWHT + 410SS weld overlay | Duplex 2205 for severe | 1/4" | High CO2 + H2S + NH3, SSC + corrosion |
| Alkylation (sulfuric acid) | 40-120°F | 150 psig | Monel 400 (piping), CS PWHT (vessels) | Alloy 625 for severe | 1/16" | Acid type-dependent material |
| FCC Regenerator | 1250-1350°F | 30 psig | CS with refractory lining | None upgraded | Refractory dependent | High temp + oxidation — refractory protects |
| Cooling Water | 85-125°F | 150 psig | CS + inhibitor + biocide | Cu-Ni (90/10) for seawater | 1/16" | Microbiological + corrosion + erosion |
| Source: API 571 Damage Mechanisms, Materials_Selection_Guide_v1.xlsx, IPE-EP-10 series (20 documents) |
Source: Materials_and_Corrosion_Curriculum_v1.xlsx · Sheet: Mod 8 - Material Selection
© 2026 Inflection Point Engineering, LLC. All rights reserved. The content of this page — including calculation methods, reference data, written analysis, interactive tools, and source code — is the intellectual property of Inflection Point Engineering, LLC and is protected under applicable copyright, trademark, and trade secret laws. Unauthorized reproduction, redistribution, modification, or derivative use in whole or in part is prohibited without prior written consent.
Disclaimer. This material is provided for informational and educational purposes only and does not constitute professional engineering advice. Calculations, reference data, and methodologies are based on published standards and accepted engineering practice but are not a substitute for engineering judgment, site-specific analysis, or review by a licensed Professional Engineer. Inflection Point Engineering, LLC makes no warranties, express or implied, regarding the accuracy, completeness, or fitness for a particular purpose of any content presented here, and shall not be liable for any direct, indirect, incidental, or consequential damages arising from its use. Users assume all risk associated with applying this content to real-world design, operations, or decisions.
© 2026 Inflection Point Engineering, LLC. All rights reserved.