NACE introduction and related terms


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NACE is the corrosion engineer institute. As now, material corrosion exist in our daily life, no matter in the industry application or usual commercial product. They all suffer corrosion impact. As one of member valve industry, I would like to introduce NACE and its related code in upstream and downstream area for stimulating more idea and opponent for make our working environment safe and green.

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NACE introduction and related terms

  1. 1. S H A W N H S U 1 2 / 2 2 / 2 0 1 2 NACE MR0175/MR0103 主要 差異與其關聯簡稱
  2. 2. Outline 1. NACE Brief Introduction and its history 2. MR0175/ISO 15156, MR0103. comparison and description 3. Carbon steel and other alloy (Austenltic, Martensite ) criterion 4. The Corrosion feature of steel in petroleum and refinery industry 5. Other related term sketch (Cracking, Hardness, Strength and Welding) 6. Summary
  3. 3. 1. NACE Brief Introduction  Goal: Protecting people, assets and the environment from the effects of corrosion.  Seeking : Education, Establish, Promote, Advocate  Founding : 11 engineers establish the association which solely focused from cathode protection to material selection and design in all kind of industries.  Training: Originally, NACE was training un- experienced or no background people, then developes to confer the experienced persons for advanced training.
  4. 4. Founding Member 1. NACE Brief Introduction Technical Committees W.R. Whitney Award Propose Ballot (every spring) New Material Add All Positive One Reject NACE Chairman approve NACE monthly publication (MP)
  5. 5. 1. NACE Brief Introduction Annual Conference NACE Certification Quotation Mars Fontana once said that : solving a corrosion problem involved 25% knowledge, 50% experience, and 25% luck. Evolution membership
  6. 6. 1. NACE Brief Introduction  Hydrogen Embrittlement : is the process by which metal, most high-strength steel, become brittle and fracture following exposure to hydrogen.  Counteraction: 1. De-Hydrogenation 2. Hydrogen killer 3. Inhabitation doping
  7. 7. NACE MR 0175/MR 0103 MR : Material Requirement 01 : version number 75/03 : 1975 / 2003 year Scope: MR0175upstream (Oil & Gas production) MR0103downstream (refining and Gas production) Target: Control sour service environment which includes H2S to select resistance of SSC (Sulfide Stress Cracking) material
  8. 8.  Major Difference between MR0103 & MR0175:  1. The refinery standard guidelines for determining whether an environment is “ sour” are quite different from the version of MR0175  2. The refinery standard does not include environment restriction on material  3. Ammonia’s concentration in downstream is higher than upstream so it will increase solubility of H2S  4. Because welding is prevalent in refinery piping and equipment, MR0103 would put emphasis on controlling it, especially carbon steel. NACE MR 0175/MR 0103
  9. 9. MR0175 sour service  MR0175: All gas phase, condense and oil within H2S equal or over 0.05psia should apply. (Total pressure should over limitation) Single gas phase Multi phase (gas, oil, water..)
  10. 10. MR0103 sour service  MR0103: 1. >50ppmw dissolved H2S in the free water 2. A free water PH<4 and some dissolved H2S present 3. A free water PH>7.6 and >20ppmw hydrogen cyanide ion and some H2S dissolved in the free water 4. >0.05 psia partial pressure H2S in a process with gas phase (no limitation)
  11. 11. NACE MR0175/MR0103  MR0103 cover a broad range of sour service so guideline are based on:  1.User’s plant experience and practices  2.Existing NACE and industry recommended practice and reports  3.A fundamental theory of atomic hydrogen generation in sour service area. **User would be allowed supply their own experience or risky analysis to determine plant operating scenarios
  12. 12. H2S impact in production area H2S leads to SSC(Sulfide Stress Cracking) SSC impacting factors:  1. Metal Feature (composition, strength, microstructure )  2. Environment PH value  3. H2S concentration and partial pressure  4. Temperature & Exposure time
  13. 13. Impacting Factor PH value: Acid concentration in refinery area is lower than oil production. H2S partial pressure: It is over 0.05 psia or 50 ppmw apply the NACE code. C.S. 5Cr-0.5Mo Alloy A.S.
  14. 14. Temperature: Hydrogen ion would dissolve easily in high temperature  Brittle as cool down Exposure time: More uncover more chance to corrosion Impacting Factor
  15. 15. Related term sketch SSC (Sulfide Stress Cracking): It is a form of Hydrogen Embrittlement. Alloy would form metal sulfide and atomic hydrogen as corrosion by product.
  16. 16. HIC (Hydrogen Induce Cracking): H2S encounter with steel to form surface blister and diffuse to internal site then trapped. With more H+ accumulating, the stress increase to cross boundary line. Fe + H2S  FeS + 2H+ 2H+ + 2e-  H2 (g) Cracking
  17. 17.  SCC(Stress Corrosion Cracking): is the cracking induced from the combined influence of tensile stress and a corrosive environment. Model: Step- Wise Cracking Cracking
  18. 18. Hardness & Strength Tensile Strength: is the maximum stress that material withstand while being stretched or pulled before necking Yield Strength: the point as the stress at which a material begins to deform plastically.
  19. 19. Hardness & Strength Brinell Hardness: Rockwell Hardness: F0+F1 on test material (9 scale: HRX) Vicker’s Hardness: Conversion: ASTM E140 table
  20. 20. Welding  HAZ(Heat Affecting Zone): The area which execute welding and then subsequently re-cooling process causes the heat energy diffuse to lower zone, until terminate to temperature sensitivity area.  WPQ(Welding Performance Qualification):is a kind of process to evaluate the welding performance.
  21. 21. Welding  PWHT(Post Welding Heat Treatment): is stress relief and a kind of method for reducing and redistributing residual stress by welding.  PERN: %chromium+3.3X%molybdenum+(16 to 30)X% nitrogen. Chromium: Increase oxidation ability and corrosion Molybdenum: Help Cr stable and increase hardness Nitrogen: Stabilize lattice structure and increase the mechanical property
  22. 22. NACE MR0175 & MR0103 Requirement Category MR0175 / ISO 15156 MR0103 Carbon Steel Max Hardness: HRC 22 Conditions: Annealed, Normalized, Normalized & Tempered, Quenched & Tempered, Stress Relieved Welding: Vickers Hardness survey regardless of whether PWHT or not Suggestion regarding "other controls" detected. Max Hardness: HRC 22 Conditions: Annealed, Normalized, Normalized & Tempered, Quenched & Tempered Welding: Vickers Hardness survey regardless of whether PWHT or not Suggestion regarding "other controls" detected. Alloy Steel Max Hardness: HRC 22 Conditions: Annealed, Normalized, Normalized&Tempered, Quenched&Tempered,Stress Relieved Welding: Vickers Hardness suvey regardless of wheather PWHT or not Max Hardness: For P numbered steel Conditions: Annealed, Normalized&Tempered, Quenched&Tempered Welding: Vickers Hardness suvey regardless of wheather PWHT or not Austenitic Stainless Max Hardness: HRC 22 Conditions: Solution Heat Treated Welding: Vickers Hardness suvey Max Hardness: HRC 22 Conditions: Solution Heat Treated Welding: No specific control Martensitic Stainless Max Hardness: HRC 22 Conditions: Annealed, Normalized, Normalized&Tempered, Quenched&Tempered,Stress Relieved Welding: Vickers Hardness suvey Max Hardness: HRC 22 Conditions: Quenched & Double-Tempered Welding: No specific control Suggestion regarding "other controls" detected.
  23. 23. Steel Category definition  Carbon Steel content: Carbon content(<2%), Manganese (<0.25%), no requirement for other metal element. Low Carbon Steel (0.16%~0.29%): Medium Carbon Steel(0.3%~0.59%): High Carbon Steel(0.6%~0.99%):  Alloy Steel: Generally define chromium content less than 10% and total alloying element content exceed 10%. MR0175 especially notify nickel content because nickel would reduce the resistance of SSC
  24. 24. Steel Category definition  Austenitic Stainless content (FCC): C(<0.15%),Cr(>16%),Ni(8%),Manganese(<2%),Silic on(<2%), Major item stainless in industry.  Martensitic Stainless content (BCC): Cr(12~14%),Mo(0.2~1%),Ni(<2%),C(~1%) :Magnetic & strong. Austenitic Martensitic
  25. 25. Heat Treatment  Anneal : is a kind of heat treatment that material would be altered its properties like hardness and ductility. Re-crystallized distorted structure.  Normalized : is an annealing process in which a metal is cooled in air after heating for relieving stress.  Quenched : it is the rapid cooling of workforce to obtain material properties. Like strength and hardness of iron-based alloy.  Tempered : it uses to increase toughness of iron- based alloy and usually combine with Quenched process.
  26. 26. Corrosion in oilfield  Because the H2S will dissolve into H2 & S which will combine with H2O around the environment and generate H2SO4 and HCl. Then these two chemical compounds will react with metal and corrode.
  27. 27. Corrosion in oilfield 2HCl (aq)+Fe (s) FeCl2+H2(g) **Pickling agent: It is an important application by using hydrogen acid to remove rust or iron oxide scale : Fe2O3+Fe+6HCl  3FeCl2+3H2O Typically 18% concentration
  28. 28.  NACE code use to define material selection to resistance SSC feature and H2S corrosion.  H2S would cause outer & internal damage of steel in upstream or downstream.  Internal corrosion: SSC, HIC,SCC…..  Outer corrosion: Hydrogen acid, Sulfide acid corrosion  Effectively control H2S environment or correctly select material for equipment or related facility. Summary