160519531-nace
TRANSCRIPT
N.A.C.E FOR SULFIDE ENVIRONMENT
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N.A.C.E MR-0175-2000
LECTURE
ON
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Corrosion
This is defined as chemical or electrochemical reaction between a material,usually a metal and its environment that produces a deterioration of the materialand its properties.
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Crevices corrosion : Localized corrosion of a metal surface at ,or immediately adjacent to, an
area that is shielded from full exposure to the environment because of close proximity between
the metal and the surface of another material
Pitting: Forming small sharp cavities in surface due to localized corrosion, wear or any other mechanically
assisted degradation.
Inter-granular corrosion: Corrosion occurring preferentially at grain boundaries, usually with slight or
negligible attack on adjacent grain.
Selective leaching: Corrosion in which one element is preferentially removed from an alloy ,leaving a residue
(often porous) of the elements that are more resistant to the particular environment (decarburization,
decobaltification, denickelification , dezincification and graphitic corrosion)
.Erosion corrosion: A conjoint action involving corrosion & erosion in the presence of a moving corrosive fluid,
leading to accelerated loss of material.
Stress corrosion: Preferential attack of areas under stress in a corrosive environment, where such an
environment alone could not have caused corrosion.
.Hydrogen damage: In the presence of hydrogen environment in certain material hydrogen induced
embrittlement, cracking & blistering occurs this is called hydrogen damage.
Uniform attack: In this form of corrosion the corrosion proceeds at the same rate over the metal surface.
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The Basics of Sulfide Stress Cracking
Sulfide -stress cracking is basically a hydrogen-embrittlement phenomenon .Atomic hydrogen enters the steel to
cause cracking. The hydrogen is generated on the surface of the steel because of a corrosion reaction. Iron
reacts with h2s to form iron sulfide and hydrogen .This hydrogen is generated in atomic form on the steel surface
,where it can either combine to form molecular hydrogen and leave the surface as bubbles or diffuse into steel
.This latter process may result in hydrogen embrittlement .Hydrogen sulfide prevents hydrogen recombination &
thus promote entry of atomic hydrogen into steel .It is important to note that water must be present for this
mechanism to occur ;without it SSC will not be observed ,because the ionization of the hydrogen sulfide is
required.
SSC develops in aqueous solutions as corrosion takes place on the surface of a material. Hydrogen ions
are a product of many corrosion processes. These ions pick up electrons from the base material producing
hydrogen atoms. At that point, two hydrogen atoms may combine to form a hydrogen molecule. Most molecules
will eventually collects, for hydrogen bubbles and float away harmlessly. However, some percentage of the
hydrogen atoms will diffuse into the base metal and embrittle the crystalline structure. When a certain critical
concentration of hydrogen is reached and combined with a tensile stress exceeding a threshold level, SSC will
occur. H2S does not actively participate in the SSC reaction; however, sulfides act to promote the entry of the
hydrogen atoms into the base material.
In many instances, particularly among carbon and low alloy steels, the cracking will initiate and propagate along
the grain boundaries. This is called intergranular stress cracking. In other alloy systems or under certain specific
conditions, the cracking will propagate through the grains. This is called transgranular stress corrosion cracking.
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PARAMETERS AFFECTING THE RATE OF SSC
— HYDROGEN SULFIDE CONCENTRATION
— Ph OF THE SOLUTION
— TEMPERATURE OF THE SOLUTION
— STRENGTH OF THE MATERIAL
—COLD WORK ON THE MATERIAL
—STRESS ON THE MATERIAL
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History of NACE
NACE STANDS FOR NATIONAL ASSOCIATION OF CORROSION ENGINEERS
•1959 T-1B COMMITTEE BY WESTERN CANADA ENGINEERS
•1963 ISSUE OF SPECIFICATION 1B163 ― RECOMMENDATION OF MATERIAL
FOR SOUR SERVICE‖
•1965 NATION WIDE COMMITTEE FORMED T-1F-1
•1966 T-1F-1 RELEASED SPECIFICATION 1F166
•1975 T-1F-1 RELEASED SPECIFICATION MR0175
•NOW ANNUALLY IT IS RELEASED BY T-1 COMMITTEE WHICH CONSTITUTE
OF 500 ENGINEERS
•LATEST REVISION IS MR0175-2000
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•INTENDED FOR OILFIELD EQUIPMENT
•NOW APPLIED IN OTHER PLACES LIKE LNG PLAN,REFINERIES ETC
•ONLY SULFIDE STRESS CRACKING IS ADDRESSED
•NOT A DESIGN STANDARD
–ONLY A GUIDELINE FOR MATERIAL SELECTION & PROCESSING METHOD
–DECISION ON THE USER
–HOWEVER IN SOME PART OF WORLD MANDATORY AS PER LEGISLATION
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•ADDRESSES:
– HEAT TREATMENT OF MATERIALS
– ALLOWABLE HARDNESS LEVELS
– MECHANICAL WORK HARDENING
– POST WELD HEAT TREATMENT
– FABRICATION TECHNIQUES
– BOLTING MATERIALS
– PLATING & COATINGS
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APPLICABILITY OF MR175-2000
•MR0175 shall be applicable only when the partial pressure of HYDROGEN SULFIDE
in a wet gas phase of a gas , gas condensate ,or crude oil system is equal to or
exceeds 0.05 psia
•It is not applicable for following condition
1. When the total pressure is less than 65psia
2. When the total pressure is less than 265psia ,the max. gas/oil ratio(scf/bbl)is 5,000
or less, and the H2S content is less than 15mol% and the H2S partial vapour pressure
content is less than 10psia.
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EXAMPLE
Given below an example taken from GNFC gasifier project.
Composition in KG-MOL/HR
COMPONENT FLUID RATE IN KG-MOL/HR
CO 1075.92
H2 1076.502
CO2 106.706
H2O 2406.187
C1 10.058
AR 8.621
N2 5.559
H2S 3.778
COS 0.094
NH3 3.262
TOTAL 4696.687
PARTIAL PRESSURE OFA GAS IN AN MIXTURE IS CALCULATED AS FOLLOW
MOLAR WT. OF THE GAS/TOTAL MOLAR WT) X TOTAL PRESSURE
i.e P.P OF H2S =(3.778/4696.687) * 81.978 KG/CM2
= 0.006594284 KG/CM2
= 0.941125 PSIA
In the above example the partial pressure of H2S is greater than 0.05 psia so for this service
NACE is applicable
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NACE REQUIREMENT FOR VARIOUS MATERIAL
The requirement of NACE MR0175 is described in two basic form of materials
1.FERROUS METAL
2.NON-FERROUS METAL
The evaluation of this materials for pipelines & pressure vessel steel has to be performed
as per procedure given in NACE standard TM0284 & testing of metals for resistance to
sulfide stress cracking at ambient temperatures in NACE standard TM0177
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FERROUS METAL
The material having iron as principal component.This is having below listed categories
•CARBON & LOW-ALLOY STEEL
•FREE MACHINING STEEL
•CAST IRON
•AUSTENITIC STAINLESS STEEL
•FERRITIC STAINLESS STEEL
•MARTENSITIC STAINLESS STEEL
•PRECIPITATION HARDENING STAINLESS STEEL
•DUPLEX STAINLESS STEEL
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CARBON STEEL & LOW ALLOY STEEL
Carbon steel
•CARBON CONTENT LESS THAN 1%( LOW CARBON STEEL LESS THAN
0.3%,MEDIUM CARBON STEEL 0.3 TO 0.6 %,HIGH CARBON STEEL 0.6 TO 1%) Low Alloy steel
•TOTAL ALLOYING ELEMENT CONTENT GREATER THAN
2.07%(NICKEL,CHROMIUM,MOLYBDENUM)
•TOTAL CHROMIUM LESS THAN10%
REQUIREMENT OF NACE
•HARDNESS LESS THAN 22HRC
•NICKEL PERCENTAGE LESS THAN1%
•POST WELD & COLD HEATTREATMENT TO BE DONE
•MATERIALS
–SA216 GRADE WCB & WCC
–SA105
–SA352 GRADES LCB &LCC
As per KRUPP UHDE standard ES-AD 3 MAX cold shaping of the metal allowable
is 5%
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CAST IRON
• CAST FERROUS ALLOYS
•THE CARBON CONTENT EXCEED THE SOLUBILITY OF CARBON IN AUSTENITE AT
THE EUSTECTIC TEMPERATURE
•CAST IRON CONTAINS AT LEAST 2% CARBON PLUS SILICON AND SULFUR AS
MINIMUM.
Gray, austenitic and white cast irons cannot be used for any pressure retaining parts, due
to low ductility. Ferritic ductile iron to ASTM A395 is acceptable when permitted by ANSI,
API or other industry standards.
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FREE MACHINING STEEL
•ALLOYING ELEMENT LIKE SULFUR,SELENIUM OR LEAD ADDED TO IMPROVE
MACHINING CHARACTERISTIC
AS PER NACE THIS MATERIAL IS NOT ALLOWED
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STAINLESS STEEL
•STEEL CONTAINING MORE THAN 10% CHROMIUM
•FIVE CATEGORIES
– MARTENSITIC STAINLESS STEEL
–FERRITIC STAINLESS STEEL
–AUSTENITIC STAINLESS STEEL
–PRECIPITATION HARDENING STAINLESS STEEL
–DUPLEX STAINLESS STEEL
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304 (“18-8”)
Fe-18 to 20 Cr.
8 to 10 Ni
Add CR and Ni for
strength and
oxidation resistance
309, 310, 314,
330
Add Ni for corrosion resistance in high
temperature environment
Ni-Cr-Fe Alloys
Add Mo for pitting resistance
316
Add more Mo for pitting
resistance
317
Superferritic
stainless steels
Add Cr.
430
No Ni, ferritic
Add Nb + Ta to reduce
sensitization
347
Add Ti to reduce
sensitization 321
Lower C to
reduce
sensitization
316l
317l
304l
Add Ni, Mo, N for
corrosion resistance
Superaustenitic
stainless steel
Add S or Se for
machinability
Increase Cr,
lower Ni for
higher strength
Add Cu, Ti, AI, lower
Ni for precipitation
hardening
Add Mn and N,
lower Ni for higher
strength
No Ni addition,
lower Cr,
martensitic
303, 303 Se
Duplex
stainless
steel
Precipitation
hardening
stainless steels
201, 202
403, 410,
420
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MARTENSITIC STAINLESS STEEL
•MARTENSITE MICRO STRUCTURE
•STRUCTURE FORMED DUE TO FAST COOLING
•CHROMIUM 10.5 TO 18%, CARBON GREATER THAN 1.2%
•NACE REQUIREMENT
– HARDNESS MAX 22HRC
•HEAT TREATMENT PROCEDURE
–NORMALISE OR AUSTENITIZE & QUENCH
–TEMPERING TWICE AT 620 DEG. CEL.AND THEN COOLING TO AMBIENT TEMP.
–AFTER COLD WORK STRESS RELIEVED AT 620 DEG CEL
• COMMON MATERIAL APPROVED BY NACE AND ARE COMMONLY USED ARE
–UNS S41000 (410 stainless steel SST) (FORGE)
–A217 GR CA 15 (CASTINGS)
–A486 CL CA6NM(CASTINGS)
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FERRITIC STAINLESS STEEL
•HAVING FERRITIC MICROSTRUCTURE
•COMPOSITION MAINLY CHROMIUM 11 TO 30%
•NOT USUALY USED FOR INSTRUMENTATION ONLY FOR PIPES & AUTOMOTIVE
PARTS
•SUPERALLOYED FERRITE HAVING GOOD RESSTANCE AGAINST SSC
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AUSTENITIC STAINLESS STEEL
•AUSTENITE MICRO STRUCTURE(FACE CENTRE CRYSTALLINE PHASE)
•COMPOSITION CHROMIUM 16 TO 26% ,NICKEL LESS THAN 35%, MANGENESE
LESS THAN 15%
•NACE REQUIREMENT
–MAX HARDNESS 22HRC
–GOOD RESISTANCE TO SSC IN ANNEALED CONDITION
–COMMONLY USED MATERIAL IN CAST FORM & WROUGHT FORM ARE
302,304,304L,305,308,309,310,316,316,316L,317,321,347 AND UNSN08020(ALLOY 20-
UPTO 32HRC)
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PRECIPITATION -HARDENING STAINLESS STEEL
• CHROMIUM NICKEL GRADE STEEL HARDENED BY AGEING (AUSTENITIC (A-286),
SEMI AUSTENITIC(17-7PH), MARTENSITIC(17-4PH))
•HIGH YIELD STRENGTH,GOOD DUCTILITY & TOUGHNESS
•NACE REQUIREMENT
– 17-4PH CAN BE USED IN WROUGHT FORM(S17400) ALSO IN CAST FORM
(CB7Cu-1) FOR MAX 33HRC
–S66268(A286 GRADE 660) FOR MAX 35HRC
–S20910 (NITRONIC 50) FOR MAX 35 HRC COMMONLY USED FOR SHAFTS,STEM
&PINS
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DUPLEX STEEL
•CONSIST OF TWO MICROSTRUCTURES(AUSTENITIC / FERRITIC)
•TYPICAL COMPOSITION CARBON LESS THAN
0.3%,MOLYBDENUM,NITROGEN,TUNGESTEN,COPPER,CHROMIUM(20 TO 30%) &
NICKEL (5 TO 8%)
•HIGH STRENGTH,DUCTILITY,GOOD RESISTANCE TO CHLORIDE SSC & PITTING
•GENERALLY NOT USED IN INSTRUMENT APPLICATION USED MOSTLY FOR VESSEL
MANUFACTURING DUE TO HIGH STRENGTH THIN WALL THICKNESS REQUIRED
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FERRITIC MARTENSITIC PRECIPITATIONHARDENING
AUSTENITE DUPLEX(AUSTENITIC/FERRITIC)(WROUGHTCONDITION ONLY)
AISI AISI ASTM AISI UNS-S31260
405 410 A453 GR 660 302 UNS-S31803
430 501 A638 GR 660 304 UNS-S32404
304L UNS-S32550
305 UNS-S32760
308 UNS-S39274
309 UNS-S39277
310
316
316L
317
321
347
ASTM ASTM UNS S17400 ASTM CAST DUPLEX
A268 A217GRCA15 UNS S45000 A182 (AUSTENTIC/FERRITIC)
TP405,TP430
A268 GR TP410 UNS S66286 A193 STAINLESS STEEL
TPXM27,TPXM33
A743 GR CA 15M GR B8R,B8RA,B8 Z6 CNDU 28.08 M
A487 CI CA 15M B8M,B8MA NF A320-55 FRENCH
A487 CI CA6NM A194 NATIONAL STANDARD
UNS S42400 GR 8R,8RA,8A,8MA UNS J93380
A320 UNS J93404
GR B8,B8M
A351
GR CF3,CF8,CF3M
CF8M,CF7M
A743
GR CN7M
A744
GR CN7M
B463
B473
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NONFERROUS ALLOYS
• The nickel-base alloys are acceptable to a maximum hardness level of 35 HRC. All have
excellent resistance to SSC.
• Commonly used acceptable materials of nickel copper alloys MONEL 400,MONEL R405
M35-1 and M35-2 (cast alloy 400) and and the precipitation hardening alloy MONEL K500.
• The nickel chromium alloys include alloys INCONEL 600 and INCONEL X750).
• The acceptable nickel-chromium-molybdenum alloys include alloys INCONEL625 ,
HASTEALLOY C276 and HASTEALLOYC ( cast alloy C). The precipitation hardening
grade INCONEL 718 is also acceptable to 40 HRC.
• Where high strength levels are required along with good machinability, valve
manufacturer uses N05500, N07718, N07750 or N07725 (alloy 725). They can be drilled
or turned, then age hardened.
• Several cobalt base materials are acceptable, including R30035 (alloy MP35N), R30003
(Elgiloy) and R30605 (Haynes 25‖ or L605).
•Aluminum base and copper alloys may be used for sour service, but the user is cautioned
that severe corrosion attack may occur on these materials. They are seldom used in direct
contact with H2S.
•Several wrought titanium grades are now included in MR0175. The only common
industrial alloy is wrought R50400 (grade 2). Cast titanium is not included in MR0175.
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NICKEL-COPPER ALLOYS
.UNSN05500 – MONEL K500 OR K MONEL
.UNSN04400 – MONEL 400 OR ALLOY 400
.UNSN04405 - MONEL R405 R 405
NICKEL-IRON-CHROMIUM ALLOYS
.UNSN08800- INCOLOY 800 OR ALLOY 800
NICKEL-CHROMIUM ALLOYS
.UNS N06600 –INCONEL 600
.UNS N07750 – INCONEL X750 OR ALLOY X750
NICKEL –CHROMIUM –MOLYBDENUM ALLOYS
.UNS N06625 – INCONEL 625
.UNS N10002 – HASTELLOY C
.UNS N10276 – HASTELLOY C276
.UNS N07718 – INCONEL 718 OR ALLOY 718
.UNS N06002 - HASTELLOY X
.UNS N06975 – HASTELLOY G-3
.UNS N07031 – PYROMET 31
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COBALT-NICKEL-CHROMIUM-MOLYBDENUM ALLOYS
.UNS R30035 – MP35N
.UNS R03004 - HAVAR
.UNS R03003 – ELGILOY
COBALT-NICKEL-CHROMIUM –TUNGSTEN ALLOYS
.UNS R30605 – HAYNES ALLOY 25
COBALT-NICKEL-CHROMIUM-MOLYBDENUM-TUNGSTEN ALLOYS
UNS R30260 – DURATHERM 2602
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INSTRUMENTATION & CONTROL DEVICE
•For instrumentation & control device component directly exposed to sour environments
shall be of materials as described above. However AISI Type SS316 Stainless steel
compression fittings and instrument tubing can be used though it does not satisfy the
hardness criteria as explained why explaining the austenitic stainless steel.
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BOLTING
• The most commonly used fasteners for ―exposed‖ applications are ASTM A193 grade
B7M bolts and A194 grade 2M nuts. They are tempered and hardness tested versions
of the B7 and 2H grades. HRC 22 is the maximum allowable hardness.
•Many consultant (E.I.L) use only B7M bolting for bonnet, packing box, and flange
joints. This reduces the likelihood of SSC if a leak develops and goes undetected or
unrepaired for an extended time.
•Since B7M has lower strength using of this material requires pressure vessel de-rating.
Some vendors offers special S17400 double H1150 bolting at the full B7 rating to
overcome the de-rating problem.
•ENC(electrolyses nickel) coating is acceptable on pressure retaining and non pressure
retaining fasteners.
•As per EIL standard only below listed materials to be used for studs & nuts
.STUDS: ASTM A193 GR B7M/ASTM A320 GR L7M
.NUTS: ASTM A194 GR 2HM/ ASTM A194 GR 7M
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COATINGS
Coatings, plating and overlays may be used provided the base metal is in a condition,
which is acceptable per MR0175. The coatings may not be used to protect a base material,
which is susceptible to SSC. Coatings commonly used in sour service are chromium
plating, electroless nickel (ENC) and nitriding. Overlays and castings commonly used
include CoCr-A (Stellite or carbide alloys are acceptable in the cast, cemented or thermally
sprayed conditions such as welding, silver brazing or spray metallizing systems. Ceramic
coatings such as plasma sprayed chromium oxide are also acceptable. However during this
above thermal procedure the substrate should not get heated up beyond critical temp. and
stress gets created. Valve manufacturer often uses ENC as a wear resistant coating. As
required by MR0175, it is applied only to acceptable base metals. ENC has excellent
corrosion resistance in sour, salt containing environments.
TABLE FOR ALLOWABLE MATERIALS FOR COATING & OVERLAYS
1 Co-Cr-W ALLOYS AS IN A.W.S(American Welding Society) A5.13-80
2 Ni-Cr-B ALLOYS AS IN A.W.S(American Welding Society) A5.13-80
3 Tungsten Carbide Alloys
4. CERAMICS
5 Ni-B ALLOYS
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SPRINGS
Springs in compliance with NACE represent a difficult problem. To function properly,
springs must have very high strength (hardness) levels. Normal steel and stainless steel
springs would be very susceptible to SSC and fail to meet MR0175.
In general, very soft, low strength materials must be used. Of course, these materials
produce poor springs. The two exceptions allowed are the cobalt based alloys, such as
R30003 , which may be cold worked and hardened to a maximum hardness of 60 HRC
and alloy N07750 which is permitted to 50 HRC.
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HEAT TREATMENTS
Stress Relieving
•Mainly intended for relieving locked in stresses in weld joints & cold working stresses in
base metal by heating the metal below critical temperature holding the constant temp. and
then cooling slowly.No change in microstructure.
•Many people have the misunderstanding that stress relieving following machining is
required by MR0175. Provided good machining practices are followed using sharp tools
and proper lubrication, the amount of cold work produced is negligible. SSC resistance will
not be affected.
MR0175 actually permits the cold rolling of threads, provided the component will meet the
heat treat conditions and hardness requirements specified for the given parent material.
Cold deformation processes such as burnishing are also acceptable. Below table gives the
details of temperature at which the metal has to be heated as per MR0175.(BASED ON
THICKNESSES ASME SECTION VIII HAS ALSO TO BE REFFERED )
Sno. MATERIAL TEMPERATURE DEG CEN.
1 CARBON STEEL 595 (min)
2 MARTENSITIC STEEL 620 (MIN)
3 LOW CARBON MARTENSIC STEEL 620 (MIN)
3 LOW CARBON MARTENSIC STEEL 620 (MIN)
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ANNEALING
Annealing is a generic term denoting a treatment that consists of heating to and holding at
a suitable to a suitable temperature followed by cooling at an appropriate rate,primarily for
softening of metallic materials.As the hardness of steel increases during cold working,
ductility decreases and additional cold reduction becomes so difficult that the material
must be annealed to restore its ductility.In this procedure the heating is above the critical
temperature and due to this micro structure changes occur.
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NORMALISING
Heating a ferrous alloy to a suitable temperature above the transformation range and then
cooling in air to a temperature substantially below transformation range. With this process
basically the steel microstructure is getting uniformly distributed and the mechanical
properties are changing (e.g. carbon steel normalization leads to higher strength )
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SOLUTION ANNEALING
For stainless steel when heated chromium- carbide gets precipitated at the boundary of the
grains which in turns make the steel ineffective against corrosive attack. Above heat
treatment is done at temp. at1150 deg cel. And the temp. is brought below 300 deg cel.
within 3minutes by putting it into chloride free water.This process disintegrates chromium
carbide and chromium goes back into the steel.This heat treatment is mandatory for SS if
any hot operation is done on the steel.
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CODES AND STANDARDS BESIDES MR-0175 TO BE USED FOR H2S SERVICE
Some related standards are given below which are related to MR0175.
API 6A ―Specification for valve and wellhead equipment‖
API 6D ―Specification for pipeline valve,steel gate ,plugs,ball &check valve ‖
This standard requires manufacturers of API equipment to produce and maintain a
document control system must
API 941 ―Steel for Hydrogen service at elevated temperatures and pressures in petroleum
& petrochemical plants‖
This standard gives the selection of material based on partial pressure of hydrogen &
temperature and also explain the mechanism of hydrogen induced corrosion
ES-AD 3 ― Additional requirements for Hydrogen and/or Sour Gas Service.‖
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UIL EXPERIENCE WITH PREVIOUS PROJECT
a. Additional requirement asked for the PETROFAC & L&T SRU jobs
1.All steel shall be killed (steel treated with strong deoxidizing agent such as silicon or
aluminum in order to reduce the oxygen content to such a level that no reaction occurs
between carbon and oxygen during solidification and fine grained.
2.All steels shall be manufactured by either basic oxygen or electric furnace process only.
3.The following treatments during steel making are mandatory:
Steel shall be made by low sulfur & low phosphorus refining process and shall be
vacuum degassed while molten
Steel shall be calcium treated for inclusion morphology control to determine the
effectiveness of calcium treatment ―Inclusion count check ― shall be performed as per
ASTM E-45
Steel shall be specifically treated to control non-metallic inclusions like metallic oxide
clusters, silicates & magnesium sulfide etc
Carbon equivalent shall be computed as per the following formulae depending upon the
carbon content.
.If C=<0.12 : Pcm = C + Si/30 + (Mn+Cu+Cr)/20 + Ni /60 + Mo/15 +V/10
.If C> 0.12 :CE = C + Mn/6 + (Cr+Mo+V)/5 + (Ni+Cu)/15
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REQUIRED CHEMICAL COMPOSITION
ELEMENT PERCENTAGE
C 0.23% MAX
Mn 1.35% MAX
Si 0.10% TO 0.35%MAX
P 0.02% MAX
Ni 0.2% MAX
S 0.01 % MAX
Other element AS PER ASTM
Pcm 0.21 MAX
CE 0.4 MAX
• FOR ASTM A105,A216 GR WCB,A350 GR LF2,A352 GR LCB.THIS WAS ASKED
SINCE THE ABOVE COMPOSITION HAS GOOD WELDABILITY PROPERTY
• HOWEVER THE VALVE VENDORS WERE UNABLE TO DELIVER THE CASTING
WITH THIS COMPOSITION INSTEAD THE VENDOR SUPPLIED A351 CF8M
• EIL HAD APPROVED SOME FOUNDRYS AND PRE -QUALIFICATION OF FOUNDRY
MANDOTRY
N.A.C.E FOR SULFIDE ENVIRONMENT
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b. UIL EXPERIENCE WITH GNFC PROJECT
In this project only two line classes had NACE requirement i.e KE61WA & KE62WA
And the material used in this project used are listed below
FOR KE61WA (900#)/KE62WA(1500#)
SR.NO. COMPONENTS MATERIAL
1. PIPE A335 GR P11
2. FLANGE A182 GR F11
3. GASKET A182 GR FR5(90-125BHN)
4. VALVE BODY A217WC6
5. TRIM MATERIAL A182 GR F321
6. NUT A193 GRB16
7. BOLTS A194 GR 4
N.A.C.E FOR SULFIDE ENVIRONMENT
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CONCLUSION:-
1.INSTRUMENT ENGG. SHOULD CHECK WITH PROCESS ENGG. THE APPLICABILITY OF THE
STANDARD IF ANY H2S GAS IS PRESENT & ALSO CHECK IN PIPING SPECIFICATION.
2.IN G.E.S THE REQUIREMENT OF NACE SHOULD BE GIVEN.
3. MATERIAL SELECTED SHOULD BE AS PER NACE
4. WHILE CHECKING VENDOR TEST REPORT THE FINAL HARDNESS SHOULD BE CHECKED
OR STRESS RELIEVING PROCEDURE IS AS PER NACE
5. DURING EVALUATION VENDOR’S MANUFACTURING PROCEDURE
SHOULD BE REVIEWED.