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.

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. 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. 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. 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. 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. 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. 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.  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. 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. 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. 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. 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. 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. Temperature: Hydrogen ion would dissolve easily
in high temperature  Brittle as cool down
Exposure time: More uncover more chance to
corrosion
Impacting Factor

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. 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.  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. 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. Hardness & Strength
Brinell Hardness:
Rockwell Hardness: F0+F1 on test
material (9 scale: HRX)
Vicker’s Hardness:
Conversion: ASTM E140 table

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. 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. 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. 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. 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. 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. 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. 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.  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