Failure_Mechanisms_of_C-Steels_API_571_.xls_filename= UTF-8''Failure Mechanisms of C-Steels (API 571).xls

All about Failure Failure Mechanisms of C-steels according to API API 571 Failure Mechanism Creep and #tress -upture 0API &12 5A*I3M6

Mechanical Fatigue 0API &16 Corrosion Fatigue Crac8ing 05A*I3M6 consider also Therm. "i!ration Fatigue0API rosion2 ros rosio ion@ n@ Corrosion 0API &12 5A*I3M6

Description Creep at Temperature $%&'(C depending on material. Deformation may lead to a rupture -elated Mechanism7 1.#hort term overheat. #tress -upture ). -eheat crac8ing in heavy +all e:uipm. sudden, une;pected failure e;posed to cyclic stresses for an e;tented period

Affected Mat. Properties 1. All metals ). *o+ creep ductility %. Cut of remaining l i fe

Critical factors related to service 1. Material ). *oad %. Temperature

Appearance Affected Prevention Morphology Mitigation Units 1. eater tu!es 1. ardening 1. Design in fired heaters ). Creep voids ). Material ). Tu!e support at grain !ound. #election %. 3ther furnace %. % . fissures 4. P/ T internals 4. crac8s 4. A9 0!ulging6

Inspection Monitoring "isual UT,-T,C, / FMT

1. All metals

1. 5eometrie ). #tress level 0Temp.6 %. =um!er of cycles 4. Material strength . Material ardness >. Material Mi8rostruct.

1. small no<
concentric rings 0+aves6 emanating from the crac8 initiation site

1. 5ood Design ). Material #election %. Minimi
PT, MT and # / UT 0shear +ave U# testing6 "i!ration Monitoring

1."elocity ).Co ).Conc ncen entr trat atio ion n of impacting medium %. #i
1. ?ends ). Tees ees %. -educers 4. =o<. Pumps &. eate;ch.

locali
1. 5eometry ). Mate Materi rial al #election %. #urface ardening 4.Inhi!itors

1. "isual insp inspec ecttion ion of suspected areas ). UT, -T 0metal loss6

). Fatigue limit

-elated Mechanism7 %. ndurance "i!ration induced limit fatigue,Thermal fatigue

rosion7 mech mechan anic ical al remov emoval al of surface material rosion@ Corrosion7 removing protective films -elated Mechanism7 Cavitation, Fretting

1. All metals ). ).ar ardnes dness s of the surface %. Free corrosion potential 0"6

Failure Mechanism -eheat Crac8ing 0API &12 5A*I3M6

Description Crac8ing of a metal due to stress rela;ation during P/T or in service at elev elevat ated ed temp temper erat at.. It is most often o!served in heavy +all sections.

Affected Mat. Properties 1.*o+ alloy steels ). *oss of toughness %. Inte Interg rgra ran. n. crac8ing

Critical factors related to service 1. Chemical composit. ). Impurity elements %. 5rain si. =otches and stress concentrations

Affected Units 1. eavy +all vessels in areas of high restraint including no<< no<
Appearance Prevention Morphology Mitigation -eheat crac8ing 1. Minimi
1. 5eneral metal loss ). Crevice %. 5roove 4. Pitting

5alvanic Corrosion 0API &12 5A*I3M6

occur at the unction of dissimilar metals +hen they are oined together in a suita!le electrolyte. -elated Mechanism7 #oil corrosion

1. Free corrosion potential

1. lectrolyte ). T+o different materials 0anode2cathode6 %. lectrical connection !et+een the anode and cathode

any unit +here there is a conductive fluid and alloys are coupled.

Atmosph. corrosion 0API &12 5A*I3M6

occur from moisture moisture associated +ith atmospheric conditions. Marine environments are most severe.


1. Physical location location 0marine6 ). Moisture 0humidity6 %. Temperature

1. any unit ). under poor coating system %. lo+ temp. 4. not used component . open to atmosphere

-elated Mechanism7 Corrosion under isulation

Inspection Monitoring 1. #urface crac8s7UT,MT ). m!edded crac8s7 UT

1. no contact 1."isual ). Coating inspection 0the more no!le ). UT material should Thic8ness !e coated6 %. electric insulating 4. cathodic protection 1. general or or 1. #urface 1."isual local metal loss preperation inspection ). *ocali
Failure Mechanism Corrosion under Insulation 0CUI6 0API &12 5A*I3M6

Description resulting from +ater trapped under insulation fireproofing

Affected Mat. Properties 1. Free corrosion potential

Critical factors related to service 1. Design of insulation system ). Insulation typ %. Temperature 4. nvironment umidity, rainfall, chlorides from marine environment . 3perating !elo+ the +ater de+ point

Affected Units 1. any unit

Appearance Morphology often appears as loose, fla8y scale covering the corroded component

Prevention Inspection Mitigation Monitoring 1. igh :uality 1. Partial or coating full stripping ). #election ). UT@Thic8n. of insulation %. -eal@time material Profile B@ray 0closed@cell for small !ore foam glass piping !etter than 4. =eutron mineral +ool6 !ac8scater %. Calcium or I#ilicate insul. te t ermography contain identifying chlorides +et insulation 4. insp inspe ecti ction . 5ui 5uided plan +ave UT >. Deep penetrating ddy@current


1.Fluid Temperature 0increasing temp. tend to increase corr.@rate and fouling6 ). Type of +ater 0fresh, !rac8ish, salt6 $>'(C for fresh, $4>(C for !r !rac8ish and salt +ater cause scaling %. Type of cooling syst.

cooling +ater corrosion is a concern +ith +ater@ cooled heat e;changers and cooling to+ers in in al all applications

cooling +ater corrosion can result in many different forms of damage incl. 1. 5eneral corr. +hen dissolved o;ygen is present. ). *ocal corr.

1.Proper design Inspection ).3perat. Data depending %.Chem.treatm. on the 4./ater velocity Morphology .Periodic of Failure mechanical cleaning of tu!e IDs and 3Ds >. Minimi
-elated Mechanisms7 1. Atmospheric corrosion ). Crevice2Under Deposit

Cooling /ater Corrosion 0API &2 5A*I3M6 dont use

5eneral or locali
induced corrosion 0MIC6

Failure Mechanism continue Cooling /ater Corrosion 0API &2 5A*I3M6 dont use

C3) Corrosion 0API &12 5A*I3M6

Description

0once@through, open circulating, closed circ.6

Affected Mat. Properties

from under@ deposit, MIC

Critical factors related to service 4. 3;ygen content 0increasing o;ygen content tends to increase corr.@rates6 . Fluid velocities E1m2s are li8ely to result in fouling, sedimendation and increased corr.@rates. >. Fouling occur from mineral deposits, silt, suspended organic materials, corrosion products, mill scale, marine and mircro@ !iological gro+th

Affected Units

Appearance Morphology %. Pitting corr. 4. MIC . #CC >. Fouling

Prevention Mitigation

Inspection Monitoring

C3) Corrosion results 1. Free +hen C3) dissolves corrosion

1. Partial Pressure of C3). Increasing partial

1. /elds

1. *ocali
1. 3ptimi
1."T, UT and

). ?ends

thinning and2or

Process data

-T inspection

in +ater to form car!on acid 0)C3%6

pressure of C3)

%. -educer

pitting corrosion ). Corrosion

techni:ues

result in lo+er p condensate and higher rates of corrosion. ). Corrosion occurs in the li:uid phase, often at locations +here C3 )

4. Tees . =o<
). deep pitting and grooving in areas of tur!ulence

should focus on general or local loss in thic8ness +here +ater

). Chloride stress corrosion crac8ing %. 5alvanic corrosion

The acid may lo+er the p and sufficient :uantities may promote general corrosion and2or pitting corrosion

potential

condenses from the

regime6 >. ?ottom of

inhi!itors in steam condensate systems. %. material

selection +etting 0%'' series ## is anticipated.

Failure Mechanism continue C3) Corrosion 0API &12

Description


-elated Mechanisms 1. ?oiler +ater condensate corrosion ). Car!onate crac8ing

5A*I3M6

vapor phase. %. Increasing temperature increase

pipe2 e:uipment 0as the

Critical factors related to service corrosion rate up to the point +here C3) is

Affected Units density of

vapori
Flue@5as De+@Point Corrosion 0API &2 5A*I3M6

1. #ulfur and chlorine C@#teel, species in fuel +ill C@Cr@Mo@#t. form sulfur dio;ide, sulfur trio;ide and hydrogen chloride +ithin the com!ustion products. ). At lo+ enough temperature, these gases and the +ater vapour in the flue gas +ill condense to form

1. Concentration of contaminants 0sulfur and chlorides6 in the fuel ). 3perating Temp. %. De+point of sulf uric acid depends on the concentration of sulfur trio;ide 0a!out 1%(C6. 4. De+point of hydro@ chloric acid 0a!out 4(C6

Appearance Morphology

+ater is larger than of oil6.

are highly resistant6 4. increase of

). Preferential corrosion of +eld seams

Prevention Mitigation P $>

Inspection Monitoring may re:uire angle pro!e UT or -T.

&. Dead legs . Top surface of the pipe if condensation in +et gas systems is anticipated

1. All fired process heaters and !oilers that !urn fuels in the econo@ mi
1. 5eneral +astage often +ith !road, shallo+ pits, depending on the +ay the sulfuric acid condenses.

1. /all thic8@ ness7 UT

sulfurous acid, sulfuric acid and hydrochloric acid +hich can lead to severe corrosion.

Failure Mechanism Micro@ !iologically Induced Corrosion 0MIC6 0API &16 ?iological Corrosion 05A*I3M6

Description

Affected Mat. Properties corrosion caused !y 1. Free living organisms such corrosion as !acteria, algae or potential fungi. It often associated +ith the preence of tu!ercles or slimy organic su!stances -elated Mechanisms7 Cooling +ater corrosion

Critical factors related to service 1. /here +ater is present ). stagnant or lo+@flo+ %. 3rganisms can survive and gro+ under severe conditions incl. a. lac8 of o;ygen !. light or dar8 c. high salinity d. P range7 ' to 1) e. Temperature7 '( to )%(F 0@1&( to 11%(C6 4. 3rganisms thrive on different nutrients incl. inorganic su!stances 0e.g. sulfur, ammonia, )#6 and organic su!stances 0e.g. hydrocar!ons, organic acids6. In addition, all organisms re:uire a source of car!on, nitrogen and phosphor. for gro+th. . In@lea8age of process contaminants such as

Affected Appearance Units Morphology 1. eat 1. locali. Product storage tan8s and +ater cooled heat e;changers in any unit +here cooling +ater is not properly treated &. Fire +ater systems

Prevention Mitigation 1. Application of !iocides ). minimi
Inspection Monitoring 1. Measuring !iocide residual, micro!e counts and visual appearance. ). #pecial pro!es have !een designed to monitor for evidence of fouling +hich may precede or coincide +ith MIC damage %. An increase in the loss of duty of a heat e;chang. may !e indicative of fouling and potential MIC 4."T, UT and

hydrocar!ons or )#

-T

may lead to a massive increase in !iofouling and corrosion

Failure Mechanism #oil Corrosion dont use

Description The deterioration of metals e;posed to soils is refered to as soil corrosion.

-elated Mechanisms 5alvanic corrosion


Critical factors related to service 1. Temperature ). Moisture %. 3;ygen 4. #oil resistivity . #oil type >. Cathodic protection &. Coating type,age, condition . #oils having high moisture content, high dissolved salt concentr. and high acidity are usually the most corrosive. . #oil@to@air interface areas are often much more suscepti!le to corrosion than the rest of the structure !ecause of moisture and o;ygen availa!ility. 1'. corrosion rates increase +ith increasing metal temperature 11. 3ther factors a. galvanic corrosion

Affected Units 1. ?ottom of storage tan8s ). Production #eparator

Appearance Morphology 1.locali
Prevention Mitigation 1. Coating ). Cathodic protection

Inspection Monitoring 1."isual inspection ). UT, -T

!. dissimilar soils c. stray currents d. differential aeration corrosion cells e. MIC

Failure Mechanism Caustic Corrosion 0API &6 Caustic Corrosion and #CC 05A*I3M6 consider also Caustic #CC 0API &6

Description *ocali

Critical factors related to service 1. Presence of caustic 0=a3 or G36 ). Caustic is sometimes added to process streams for neutrali. ;posure to high solution strength caustic can result in general corrosion a!ove 1&(F 0&(C6 and very high corrosion rates a!ove )''(F 0%(C6

Affected Units 1. ?oilers ). #team generating e:uipments incl. heat e;changers %. /here caustic is added to crude unit charge 4. Accelerated locali
Appearance Prevention Morphology Mitigation 1.*ocali
Inspection Monitoring 1.For process e:uipment, UT thic8ness gauging is useful to detect general corrosion. *ocali
In vertical tu!es circumferential in hori
Failure Mechanism 3;idation 0API &16 igh Temperat. Corrosion 05A*I3M6

Description

#ulfidation 0API &16 igh Temp. )#

Corrosion of C@steel resulting from their reaction +ith sulfur

Corrosion

3;ygen reacts +ith C@steel at high temp. converting the metal to o;ide scale. It is most often present as o;ygen in the surrounding air used for com!ustion in fired heaters2!oilers

Affected Mat. Properties C@#teel, C@Cr@#teel

Critical factors related to service 1. Temperatur $%(C ). Alloy Composition.

Affected Appearance Units Morphology fired heaters and 1. 5eneral !oilers as +ell ). covered out@ as other side surface com!ustion +ith o;ide scale e:uipment

Prevention Mitigation 1. Material selection

Inspection Monitoring UT

C@#teel, C@Cr@#teel

1. Temperatur $)>'(C ). Alloy Composition. %. Concentration of

1.eaters fired +ith oil, gas ). ?oilers

1. Material selection

UT,-T


Initial stage7 ardness C Advanced stage7crac8s

compounds in high temp. environments.

05A*I3M6 Car!uri@
Car!on is a!sor!ed into a material at elevated temp. +hile in contact +ith a car!onaceous mater.

1.C@#teel, C@Cr@#teel ).loss of high temperature creep

or car!uri
1. 5eneral ). locali
corrosive sulfur comp. %. Piping 4. #ulfidation is primarily caused !y )#

erosion@corr. 4. sulfide scale

1. Temperatur $%(C 1.Fired heater ). Alloy Composition. tu!es %. Car!uri
1. Increase of hardness ). loss in ductility %. volumetric increase

-T,UT,MP

Failure Mechanism Decar!u@ ri
Initially, car!on diffuse into the component at a high rate and then tapper off as the depth of car!uri
%.loss of am!ient temp mech. Prop. 4. loss of +elda!ility . loss of corros. resis.

. *o+ 3) or steam

Description

Affected Mat. Properties 1.C@#teels C@Cr@#teels ). loss in room temp.

Critical factors Affected Appearance related to service Units Morphology 1. Time 1. Components 1.The decar!ur. ). Temperature e;posed to layer +ill !e free %. Car!on activity of the elevated temp., of car!ide process streamH gas heat treated or phases. phase 0), C3) 6 that e;posed to has a lo+ car!on activity f ire. so that car!on in the ). Piping in hot steel +ill diffuse to the hydrogen service surface to react +ith gas %. fired heater phase constituents. tu!es 4. Pressure vessel comp. hot formed

Prevention Mitigation 1. Material selection

Inspection Monitoring ardness

see Car!uri
see Car!uri
see Car!uri
A condition +here steel loses strength due the removal of car!on and car!ides leaving only an iron matri;. Dec ar!uri
tensile strength %. loss in creep strength

-elated Mechanism7 igh temperature ydrogen Attac8 0TA6 Metal Dusting 0API &12 5A*I3M6

Metal dusting is a see form of car!uri
see Car!uri
see Car!uri
dont use

occurs in car!uri
Failure Mechanism Corrosion Fatigue 0API &16 Corrosion Fatigue crac8ing 05A*I3M6 consider also Thermal and Mechanical Fatigue of API &1

Description

Affected Mat. Properties A form of fatigue 1. Free crac8ing in +hich corrosion crac8s develop under potential the com!ined affects ).ndurance of cyclic loading and limit corrosion. Crac8ing often initiates at a stress concentration such as a pit in the surface. Crac8ing can initiate at multiple sites. -elated Mechanisms7 Mechanical fatigue "i!ration induced fatigue

Critical factors Affected related to service Units 1. Corrosive environment 1. -otating ). Cyclic stresses :uipment %. Crac8ing is more ). Deaerators li8ely to occur in %. Cyclic ?oilers environments that 4. any e:uipm. promote pitting or su!ected to locali
Appearance Prevention Morphology Mitigation 1. The fatigue 1. Using fracture is !rittle coatings and and the crac8s and2or are most often inhi!itors transgranular, ). Minimi
Inspection Monitoring 1. crac8ing is generally detected +ith / FMT 0+et fluorescent magnetic particle testing ). Many of the crac8s are very tight and difficult to detect. %. Crac8ing may occur at the mem!ranes in the highly stressed regions, particularly corners at !uc8stays.

and often results in propagating of multiple parallel crac8s. . Crac8s initiation sites include concentrators such as pits, notches, surface defects, changes in section or fillet +elds.

Failure Mechanism Caustic #tress Corrosion Crac8ing 0Caustic m!rittle@ ment6 0API &16 Caustic Corrosion and #CC 05A*I3M6 consider also Caustic Corrosion 0API &16

Description

Affected Mat. Properties Caustic em!rittlement 1. Free is a form of stress corrosion corrosion crac8ing potential characteri
-elated Mechanisms7 Amine crac8ing Car!onate crac8ing

Critical factors related to service 1. Caustic #trength Crac8ing can occur at lo+ caustic levels if a concentrating mechan. is present. Concentration can occur as a result of alternating +et and dry conditions, locali
overload accompanied !y plastic deformation.

Affected Appearance Units Morphology 1. :uipment 1. crac8ing that handles typically caustic, incl. propagates )# removal parallel to the units. +eld in adacent ). :uipment !ase metal !ut that uses can also occur caustic for in the +eld neutrali
Prevention Inspection Mitigation Monitoring 1. P/ T 1. Although ). #teamout crac8s may of non@P/ Td !e seen car!on steel visually, crac8 piping and detection is e:uipment !est perfored should !e +ith /FMT avoided. 0+et flouresc. :uipment magnetic should !e particle test.6, +ater +ashed -T, ACFM !efore steam@ 0alternating out. current %. Proper magnetic design and flu; lea8age operation of the testing6. inection ).PT 0*i:uid system is penetrant re:uired to testing6 is not ensure that effective for caustic is finding tight,

crac8ing can !e residual that result from +elding or from cold +or8ing 0such as !ending and form formin ing6 g6 as +ell ell as applied stresses. 0Temp. and #tress causing caustic em!ritt. see Fig.4@6.

Failure Mechanism Ammonia #tress Corrosion Crac8ing 0API &16 Ammonia Corrosion and #CC 05A*I3M6

ydrogen m!rittlem. 06 0API &12

Description Car!on steel is is suscepti!le to #CC in anhydrous ammonia.

Affected Mat. Properties 1. arness $ )) ?=

-elated Mechanism7 Mechanism7 not applica!le

A loss in ductility of high strength steels due to the penetration of atomic hydrogen

1.*oss of ductility ). C@#teel +ith L)) -C

Critical factors related to service 1. Anhydrous Anhydrous ammonia ammonia +ith E '.) +ater +ill cause crac8ing in C@#teels. ). P/ T eliminates suscepti!ility of most common steels 0E &' 8si K4) Mpa6 %. Contamination +ith air or o;ygen increases tendency to+ard crac8ing

Affected Units 1. Ammonia Ammonia is present as a process contaminant in some services or may !e intentionally added as an acid neutrali
properly dispersed !efore entering the high high@t @tem emp. p. crude preheat system.

scale@filled crac8s and should not !e used for dete detect ctio ion. n. %. Crac8 depths +ith shear +ave UT 0#/ UT6

Appearance Prevention Inspection Morphology Mitigation Monitoring 1. Crac8ing +ill +ill 1. P/T 1. /FMT occur at ). Addition of +elds inside e;posed non@ small :uantit. tan8s P/T +elds of +ater to the ). ;ternal and A9 ammonia 0'.) UT #hear %. ardness +ave J )) ?= 4. prevent ingress of o;ygen into storage facilities.

1.Crac8ing due to  can initiate su!@ surf ac ace, !ut in

1. Use lo+er strength steels ). P/ T %. Use lo+

1. For suface crac8ing use PT 0li:uid penetr.

5A*I3M6

can lead to !rittle crac8ing.  can occur during manufacturing, +elding, or from

ydrogen can come from ap a pplications /elding@if +et electrode have lo+ hard@ are used. ness and are igh temper. ydrogen usually not gas atmospheres. suscepti!le to /et )# or F acid.  0Pipe and

services that can charge hydrogen into

If the partial pressure of )# in the gas is

the steel in an a:ueous, corrosive, or a gaseous

Failure Mechanism continue ydrogen m!rittlem. 06 0API &12 5A*I3M6

Description

L ',% 8Pa 0',' psi6 ##C 0#ulfide stress


Critical factors related to service crac8ing6@ resistant steels, selected using Anne; A.) of I#3 11> Part ), shall not sho+ . ). #trength level and microstructure must !e suscepti!le to em!rittlement. ##C@ resistant steels shall not sho+ . %. A stress a!ove the threshold of  must !e present from residual stresses and2or applied stresses. 1. Type Type of amine used

environment. -elated Mechanisms7 1. hydrogen fla8ing ). under!ead crac8ing %. delayed crac8ing 4. hydrogen assisted crac8ing . hydrogen induced crac8ing. >. #ulfide stress crac8ing &. ydrogen stress corrosion crac8ing

Amine

general and2or and2or local

Primarily

Corrosion

corrosion that occurs

C@steel

most cases is hydrogen, dry surface !rea8ing electrodes and ).  occurs preheating at locations of methods. high residual or

testing6, MT 0magnetic particle test.6 or /FMT 0+et flouresc.

tri@a;ial stresses Pressure vessel 0notches,

magn. Part. testing6

steels classified restraint6 and as P@=o.1, +here the 5roup 1 and ). microstructure

). UT may also !e useful in finding 

Affected Units in #ection IB of A#M ?oiler a. Pressure vessel code. ). A9 of +elds if not P/T is done. %. ?olts and springs made of high stength steel are very prone to .

Appearance Prevention Morphology Mitigation is conducive, such as in +eld A9s 0J)) -C is accepta!le6.

Inspection Monitoring crac8s. %. -T often is not sufficiently sensitive to detect  crac8s

5eneral uniform 1. proper

1. visual and

thinning,

UT Thic8ness

1. all units to From most aggressiv to remove )#,

operation

0API &12 5A*I3M6

principally on car!on steel in amine treating processes. Corrosion is not caused !y the amine itself, !ut results from dissolved acid gases 0C3) and )#6, amine degradation products, eat #ta!le Amine #alts 0#A#6 and

Failure Mechanism continue Amine Corrosion 0API &12 5A*I3M6

Description


-elated Mechanisms7 Amine stress corr. crac8ing

Ammonium ?isulfide Corrosion

Aggressive corrosion occuring in hydro processing reactor

Car!on steel is less

0Al8aline #our /ater6 0API &12 5A*I3M6

effluent streams and in units handling al8aline sour +ater 0locali
resistant

other contaminants.

-elated mechanisms7 rosion2rosion corr.

C3) and

least7 MA,D5A,DIPA, DA,MDA ). Amin@Concentration $) #A# %. Temperature Corr. -ates increase +ith Temperature

mercaptans 0a sulfur@contain organic comp.6 ). -egenerator re!oiler and regenerator

4. Process stream velocity. Corrosion is generally uniform ho+ever high velocities

%.The rich amine or +ith side of the lean2 tur!ulence. reach e;changer hot lean amine

to #A#. 4. Filtration of solids and hydrocar!ons

such as the re!oiler feed and return line, the hot

Critical factors related to service 0$) m2s for rich amine and $> m2s for lean amine6 and tur!ulence +ill cause locali
Affected Appearance Units Morphology piping, hot rich amine piping, the amine solution pumps, reclaimer

Prevention Mitigation from amine solution. . Corrosion inhi!itors

Inspection Monitoring lean2rich amine piping, the stripper overhead condenser piping.

1. =4#@concentration 1. =4# salts

locali
). UT scans or profile radiography are used for e;ternal inspection. %. hot areas

precipitate in the reactor

1.5eneral metal loss +ith potential for

1. Flo+ regime 1. UT scans ). -elation and2or -T !et+een profile thic8n.

lead to underdeposit corrosion and fouling. %. 3;ygen and iron in the +ash +ater inected into hydroprocessing reactor effluent can lead

effluent streams +hen temperat. drop to +ithin the range of 4 to >>(C. ). Fouling and2 or velocity

e;tremely high locali
concentration and velocity. %. velocity !et+een % and > m2s. 4. C@steel may !e sucepti!le

to increased corrosion

accelerated

e;tremely

to high corr.

E ) +t solutions not generally corrosive. ). =4# salt deposits

of high and lo+ velocity areas. ). UT do+nstream of control valves at high =4#

and fouling.

Failure Mechanism continue Ammonium ?isulfide Corrosion 0Al8aline #our /ater6 0API &12 5A*I3M6 Ammonium Chloride Corrosion 0API &16 dont use

corr. may !e locali
that precipitated %. eat e;changers may sho+ plugging and

rates $ +t concentrat. . Properly %. -FC design and 0remote field maintain +ater eddy current +ash inection testing6 and +ith lo+ o;ygen flu; lea8age content.

inspection of steel air cooler tu!es.

Description


Critical factors related to service

Affected Units pressure separators. . ydrocar!on lines from reactor effluent separators due to entrained sour +ater.etc.

Appearance Prevention Morphology Mitigation loss of duty due to fouling.


5eneral or locali
1. Free

1. Crude to+er

1.The salts have 1. Crude Unit7

1. Accumulat.

corrosion, often pitting, normally occur under ammonium chloride or amine salt deposits, often in the a!sence of a free +ater phase

corrosion potential ). P- 0Pitting resistant e:uivalent6

1. Concentration7 0=%, Cl, )3 or

overheads7 to+er top, top trays, overhead piping, e;chang. may !e su!ect to fouling and corrosion.

a +hitish, greenish or !ro+nish appearance. /ater +ashing and2or steamout +ill remove

of ammonium chloride salts can !e very locali
amine salts6 ). Temperature7 Ammonium chloride salts may precipitate from high temperature streams as the they are

a.*imit salts !y limiting chlorides in the to+er feed through desalting and2 or the addition

-elated Mechanisms7 Cl corrosion

cooled, and may corrode Deposits may deposits so that piping and e:uipment occur in lo+ evidence of at temperature +ell flo+
of caustic to detect. the desalted ). -T, UT crude. tic8ness !. A +ater Monitoring +ash may !e re:uired in the crude to+er overhead line to flush the salt deposits. c. Filming amine inhi!itor are often added to control corr.

Failure Mechanism continue Ammonium Chloride Corrosion 0API &16

Description


Critical factors Affected related to service Units chlorides to form amine hydrochlorides that can act in a simular fashion. . Corr. -ates increase +ith increasing temp.

Appearance Morphology rates can !e e;tremely high

Prevention Inspection Mitigation Monitoring ).ydroprocess a.*imit chlorides in the hydrocar!on feed to the reactor and the ma8e@up hydrogen supply.

igh Temp. )2)#

The presence of hydrogen in )#

C@#teel,

1. Temperatur $)>'(C

1. ydro@

1. 5eneral

1. Material

C@Cr@#teel

streams increase the

Cr@Mo@#teel

). Alloy Composition. %. Prensence of  )

processing

Corrosion 0API &12

severity of high temp.

4. Concentration of  )#

5A*I3M6

sulfide corrosion.

/hen ) is present in

selection

UT,-T

dont use

significant :uantities, corrosion rates are higher than those associated +ith high temp. sulfidation in the a!sence of ).

-elated Mechanism7 #ulfidation

#our /ater Corrosion 0Acidic6

Corrosion of steel due C@#teel to acidic sour +ater cointaining )# at a

0API &12 5A*I3M6

p !et+een 4. and &. C3) may also !e present. #our +ater containing significant amounts of ammonia,

Failure Mechanism continue #our /ater Corrosion

Description

0Acidic6 0API &12 5A*I3M6

side the scope of this mechanism.

chlorides or cyanides may significantly affect p !ut are out@

1. )# content ). p %. "elocity 4. 3) concentration

1. 5eneral Thinning ). *ocali

UT,-T

Prevention Mitigation


%. under deposit

. E4. p corrosion >. $4. p thin Fe# layer limits corr. -ate a thic8er, porous Fe#


Critical factors Affected related to service Units layer can promote pitting under sulfide deposits. &. Cl and C3 ) lo+er p . Ammonia significantly increases p 0al8alin sour +ater and ammonia !isulfide corrosion6 . The presence of air or o;idants may increase the corrosion und usually pitting or under deposits.

Appearance Morphology

-emar8s acc. to API &1 and & API &17 Chapter7 4.). Ta!le 4@) Figure74@, 4@1' API &7 5.%. #u!surface Crac8. and Microfissuring Microvoid Format.

API &17 Chapter7 4.).1> Fig. 4@) to %4 API &7 5.%.4 #urface connected crac8ing

API &17 Chapter74.).14 Ta!le7 4@% Fig. 4@)%,@)4,@) API &7 5.%.% *ocali
-emar8s acc. to API &1 and & API &17 Chapt.7 4.).1 API &7 5.%.4.2%.. #urface and #u!@ surface Crac8ing

API &17 Chapter7 4.%.1 Ta!le7 4@4 Fig. 4@%>2@%& API &7 5.%.% 5eneral or local metal loss, Pitting API &17 Chapter7 4.%.) API &7 5.%.% 5eneral or local metal loss, Pitting

-emar8s acc. to API &1 and & API &17 Chapter7 4.%.% Fig. 4@%2@% API &7 5.%.% 5eneral or local metal loss, Pitting

API &17 Chapter7 4.%.4 Fig. 4@4' API &7 5.%.). 5eneral 5.%.%. *ocali
-emar8s acc. to API &1 and &

API &17 Chapter7 4.%.> Fig.7 4@41 to 44 API &7 5.%.) 5eneral 5.%.% *ocali

API &17 Chapter7 4.%.& API &7 5.%.% *ocali
-emar8s acc. to API &1 and & API &17 Chapter7 4.%. Fig.7 4@4 to @' API &7 5.%.% *ocali
-emar8s acc. to API &1 and & API &17 Chapter7 4.%. Fig.7 4@1 to @%

-emar8s acc. to API &1 and & API &17 Chapter74.%.1' Fig.7 4@4 to  API &'7 Chapter7.%.1 Inection points

-emar8s acc. to API &1 and & API &17 Chapter 4.4.1 Ta!le 4@>7 Corrosion Rates Fig. 4@>) to 4.>4 API &7 5.%.). 5eneral metal loss API &174.4.) Fig. 4@>2>> Corr.@-ates Fig. 4@>& API &25.%.)2% 5eneral2*ocali2> API &25.%.> Metallurgical Changes

-emar8s acc. to API &1 and & API &17 Chapter 4.4.4 API &7 5.%.> 5.%.> Metallurgical Changes

see Car!uri
-emar8s acc. to API &1 and & API &17 Chapter7 4..) Fig.7 4@% to 4 API &7 5.%.4 #urface connected crac8ing

-emar8s acc. to API &1 and & API &17 Chapter7 4..% Fig.4@ to ) API &7 5.%.4 5.%.4 #urface connect. crac8ing

-emar8s acc. to API &1 and & API &17 Chapter7 4..4 Fig.7 4@% to  API &7 5.%.4 #urface connect. crac8ing

API &17 Chapter7 4..> Fig. 4@

I#3 11>@12) Petroleum and natural gas industries@ Materials for use in )# containing environments in oil and gas production Part 17

-emar8s acc. to API &1 and & 5eneral principles for selection of crac8ing@resistant materials. Part )7 crac8ing@resistant car!on and lo+ alloy steels, and the use of cast irons API &7 5.). Pre@#ervice Deficiencies 5.%. #u!surface Crac8ing API &17 Chapter7 .1.1

Fig. .1 API &7 5.%.% *ocali

API &17 Chapter7 .1.1.) Fig.7 @) API &75.%.% *ocali

API &17 Chapter7 .1.1.%


API &17.1.1. Fig. @%24 Corr.@-ates Ta!. @1 API &25.%.)

5eneral Metal loss

API &17.1.1.1' API &75.%.)2% 5eneral and *ocali

Exlanati Failure Mechanism Creep and #tress -upture

Thermal Fatigue

#hort Term 3verheating #tress -up. rosion2 rosion@ Corrosion

Cavitation

Failure Mechanism Mechanical Fatigue "i!ration@ Induced Fatigue -eheat Crac8ing

5alvanic Corrosion

Atmospher. Corrosion

Failure Mechanism Corrosion Under Insulation Cooling /ater Corrosion

?oiler /ater Condensate Corrosion C3) Corrosion

Flue 5as De+ Point Corrosion ?iological Corrosion

Failure Mechanism continue ?iological Corrosion

Caustic Corrosion

3;idation

#ulfidation

Car!uri@
Failure Mechanism Decar!uri@
Metal Dusting

Fuel Ash Corrosion

Corrosion Fatigue Caustic #CC

Failure Mechanism continue Caustic #CC

Ammonia #CC ydrogen m!rittle@ ment 06

Failure Mechanism Amin Corrosion

Ammonium ?isulfide Corrosion 0Al8aline #our /ater igh Temp )2)# Corrosion

#our /ater Corrosion

0Acidic6

Failure Mechanism Amine #CC

/et )# ?listering

#ulfide #tress Crac8ing 0##C6

Failure Mechanism continue #ulfide #tress Crac8ing 0##C6

#tress Corrosion Crac8ing 0#CC6

ydrogen Induced Crac8ing 0IC6

Failure Mechanism continue ydrogen Induced Crac8ing 0IC6

#tress 3riented ydrogen Induced Crac8ing 0#3IC6 #oft 9one Crac8ing 0#9C6

Crevice Corrosion

Failure Mechanism continue Crevice Corrosion

on of Failure Mechanisms ;planation At high temperature, metal components can sl o+ly and continuously deform under loa d !elo+ the yield stress. This time dependent deforma tion of stressed components is 8no+n as creep. The initial stages of creep damage can only !e identified !y scanning electron microscope metallography. Creep voids typically sho+s up at the grain !oundaries and in later stages form fissure and than crac8s. Threshold Temperature for Creep7 %&'(C for C@#teel and 4''(C to 4)(C for C@Mo and Cr@Mo@#teels. Thermal fatigue is the result of cyclic stresses caused !y variations in temperature. The process starts on the surface in areas of high local stresses caused !y notches 0such as the toe of a +eld6 and sharp corners 0such as the intersection of a no<
+hen the dissolved@gas content is high.

;planation Fatigue crac8ing is a mechanical form of degradation that occurs +hen a component is e;posed to cyclical stresses for an e;tended period, often resulting in sudden, une;pected failure !Exlanation# see (hermal Fatigue"% A form of mechanical fatigue in +hich crac8s are produced as the results of dynamic loading due to vi!ration, +ater hammer 0see rosion6, or unsta!le fluid flo+ !Exlanation# see (hermal Fatigue" Crac8ing of a metal due to stress rela;ation during P/T or in service at elevated temperatures. It is most often o!served in heavy +all sections. -eheat Crac8ing 0or #tress@ relief em!rittlement6 results in the loss of toughness +ithin the A9 and2or the +eld metal as a result of stress relieving of a +elded structure. -eheat crac8ing is also thought to !e caused !y the same mechanisms and leads to intergranular crac8ing +ithin the +eld
or in Crevices2Under Deposits.

;planation Corrosion of piping, pressure vessels and structural components resulting from +ater trapped under insulation or fireproofing. This is a special case of crevice Corrosion 0Exlanation# see Cre)ice* +nder ,eosit" 5eneral or locali
environment. This is termed fouling, or !io@fouling. Concentration cells form underneath the !arnacles and produce deep pits. Fouling on risers 0Tidal and su!merged
;planation accumulation occurs a lo+ fluit rates 0during shutdo+n periods6. Colonies of #ulfate@reducing ?acteria 0#-?6, gro+ only in a!sence of o;ygen #-? utili7 stimated Corrosion -ates for 3;idation Corrosion resulting from their reaction +ith sulfur compounds in high temperature environments. #ulfur is present in crude in the form of elementar #ulfur, )#, Aliphatic #ulfides, Aromatic #ulfides, Polysulfids, Disulfides, Mercaptans. If heated $%'(C produce  )#. The attac8 is chemical rather the electrochemical, i.e. independent of the presence of +ater7 Fe   )# K Fe#   ) API &1 Figure 4@>7 Corrosion -ates of different C@#teel, C@Cr@#teel and ## !et+een )%) and 4)&(C for '. +t  #ulfur. Car!uri
;planation Car!uri
caustic concentr. of ' to 1'' ppm are sufficient to cause crac8ing. #tresses that promote crac8ing can !e residual that result from +elding or from cold +or8ing 0such as !ending and f orming6 as +ell as applied stresses. Crac8 propagation rates increase dramatically +ith temperature and can sometimes gro+ through +all in a matter of hours or days during temperature e;cursions, especially if conditions promote caustic concentration. Concentrations can occur as a result of alternating +et and dry conditions, locali
;planation Caustic stress corrosion crac8ing typically propagates parallel to the +eld in adacent !ase metal !ut can also occur in the +eld deposit or A9. The pattern of crac8ing o!served on the steel surface is sometimes descri!ed as a spider +e! of small crac8s +hich often initiate at or inter@ connect +ith +eld@related fla+s that serve as local stress raisers. !see also Exlanation# $CC" API &1 Figure 4@7 -ecommended operating limits for C@#teels in caustic service C@#teel is suscepti!le to $CC in anhydrous 0E'.) +ater6. Consiteration must !e given to vapor spaces could have less than '.) +ater present due to partitioning of ammonia in +ater phase. !Exlanation# see $CC" Also 8no+n as hydrogen fla8ing, under!ead crac8ing, delayed crac8ing, hydrogen assisted crac8ing, hydrogen induced crac8ing 0IC6. ##C and ydrogen #tress Crac8ing @F are closely related forms of hydrogen em!rittlement. Three conditions must !e satisfied7 a. ydrogen must !e present at a critical concentration +ithin the steel. !. The strength level and microstructure of the steel must !e suscepti!le to em!rittlement !see I$ 1515-. 6 c. A stress a!ove the threshold for  must !e present from residual stresses and2or applied stresses. The hydrogen can come from / elding, Pic8ling, #ervice in high temperature hydrogen gas atmospheres, +et  )# or F acid services and CP. A fe+ ppm of hydrogen dissolved in steel can cause hairline crac8ing and loss of tensile ductility. ven +hen the :uantity of gas in solution is too small to reduce ductility, hydrogen@induced delayed fracture, sometimes called static fatigue, may occur. airline crac8ing usually follo+s prior@austenitic grain !oundaries and seems to occur +hen the damaging effect of dissolved hydrogen is superimposed on the stresses that accompany the austenitic@to@martensite transformation. #teels +ith tensile strenght E>' Mpa K1''8si appear to !e resistant to , and the structures made +ith such steels have !een used in service +ithout serious pro!lems in various environments that do not contain  )#. For 3.$ en)ironment see exlanation of $$C& $$C and 3IC% Mechanism7 The electrochemical conditions at the tip of a pit or an advancing crac8 are not the some as those of the !ul8 solution 0see crevice corrosion6. In a la!oratory study, +hen +edge@opening loading specimens +ere e;posed to sodium chloride solutions, the p value of the solution at the crac8 tip +as measured to !e a!out %. regardless of that of the !ul8 solution. At the crac8 tip, +here diffusion is limited, the p value of the

solution is lo+ered !y the acidic hydrolysis reaction, and in such a lo+@p solution, the cathodic partial reaction is the reduction of the hydrogen ion. As a result, nascent 0atomar6 hydrogen is generated at the tip of the pit or crac8 and a!sor!ed into the metal. It has also !een sho+n that hydrogen can !e generated at the crac8tips even +hen an anodic potential is applied to the !ul8 metal.

;planation Amine corrosion refers to the general and2or locali m2s for lean amine 0MDA6. Aggressive corrosion occuring in units handling al8aline sour +ater 0Ammonium ?isulfide = 4#6 Ammonium ?isulfide 0=4#6 concentration, velocity and2or locali'(C. This form of sulfidation usually results in a uniform loss in thic8ness associated +ith hot circuits in hydroprocessing units. Corrosion +ill appear as a uniform loss in thic8ness from the process side and is accompanied !y the formation of an iron sulfide scale. #cale is a!out  times the volume of lost metal and may !e in multiple layers. API &1 Fig. @%24 Corrosion rates in  )2)# service Corrosion of steel due to acidic sour +ater containing  )# at a p !et+een 4. and &.'. C3 ) may also !e present. #our +aters containing significant amounts of ammonia, chlorides or cyanides may significantly affect p !ut are outside of the scope of this mechanism.

)# content, p, temperature, velocity and o;ygen concentration are all critical factors. )# is solu!le in +ater, its a:ueous solution !ehaves as a +ee8 acid  )# K   #@. )# corrosion is called N#ourN. -ole of  )# in corrosion7 The produced acidity 0  ions6 drives on the hydrogen evolution reaction at the cathode site, thus the cyclic corrosion process continues. Com!ination of  )# and C3 ) is more aggressive than  )# alone. Com!ination of  )# and 3 ) is highly corrosive. The overall corrosion rate of 3 ) is a!out &) times higher than C3 ) and )'' times higher than  )# at lo+ concentrations 0E) ppm 3) and E)''ppm  )#6 and 4'' times higher at high concentrations 0 ppm 3 ) and ''ppm  )#6

;planation Amin #CC is a form of Al8aline #CC. Caustic #CC and Car!onate #CC are t+o other forms of Al8aline #CC 0A#CC6 that are similar in appearan@ ce.The critical factors are the level of tensile stress, amine concentration and temperature.Crac8ing is more li8ely to occur in lean MA and DA service !ut is also found in most amines including MDA and DIPA 0ADIP6. It is most often found at or adacent to non@P/Td C@#teel +eld@ ments or in highly cold +or8ed parts. The appearance of the crac8s on the surface may !e similar to those caused !y +et  )# crac8ing. Exlanation# see $$C ydrogen@induced !listering is most prevalent in lo+@strenght alloys, and it is o!served in metals that have !een e;posed to hydrogen@charging conditions, for e;ample, acid pic8ling or corrosion in environments containing hydrogen sulfide. /hen hydrogen is a!sor!ed into metal and diffuses in+ard, it can precipitate as molecular hydrogen  ) at internal voids, laminations, matri; interfaces, and it can !uilt up pressure great enough to produce internal crac8s. If these crac8s are ust !elo+ the surface, the hydrogen@gas pressure in the crac8s can lift up and !ulge out the e;terior layer of the metal so that it resem!les a !lister. Corrosion@generated hydrogen causes !listering of steel in oil@+ell e:uipment and in petroleum@storage and refinery e:uipment. In storage vessels !listering is generally at the !ottom or in the vapor space +here +ater is present. The hydrogen is generated on the surface of the steel !ecause of a corrosion reaction. Iron reacts +ith  )# to form Fe )#% and   . This hydrogen is generated in atomic form on the surface, +here it can com!ine to form  ) and leave the surface as !u!!les or the  can diffuse into the steel. This latter process may result in h2drogen enbrittlement !3E" or $$C . It is important to note that +ater !e present for this mechanism to occurH +ithout it, ##C +ill not !e o!served, !ecause the ioni
!6 ffect to p /ith decreasing p, the corrosion rate of the steel tends to increase, +hich causes more hydrogen to !e produced. It is generally agreed that increasing the p a!ove  is !eneficial in reducing the tendency to+ard ##C. During drilling operations in sour reservoirs, the p is usually maintained in the 1' to 11 rage, thus providing the opportunity to use high@strength steels. c6 Temperature As temperatures increases, the resistance to ##C also increases. This is due to a reduction in the hydrogen@permeation rate at elevated temperatures. This effect allo+s materials that are suscepti!le to ##C at room temperature to !e used at elevated temperature. It has !een found

;planation that ##C is most severe at room temperature !elo+ room temperature, resistance to ##C again !egins to increase. d6 #trength *evel 0E )) -C6 The microstructure of the steel is very important and essentially controls the o!served ##C properties. It has !een found that the microstructure that provides the !est ##C resistance is that of tempered martensiteH other transformation products reduce ##C resistance. Conse:uently, it is very important to ensure through hardening in the component. It is common practice +hen :uenching tu!ular products for this application to implement !oth side :uenches. d6 Cold@/or8 It is +idely 8no+n that cold +or8 can adversely affect the ##C resistant of materials. The hardness is locally increased, and residual stresses can also !e generated. ardness that greatly e;ceed )) -C 0some as high as 4' -C have !een measured6 can !e produced !y inproper straightening and handling. ven idendification stamping has !een reported to cause enough cold +or8 to initiate ##C. e6 #tress 0applied and residual6 Threaded connections7 igh stress, stress concentrations /ith this mechanism of degradation, a tensile stress is re:uired 0li8e ##C6, together +ith a suscepti!le material and an environment that promotes crac8ing. In the oil and gas industries, the material that are most generally found to !e suscepti!le to ##C are austenitic stainless steel and nic4el-base allo2s are used in oil and gas production !ecause they form protective films and therefore have very lo+ corrosion rate. Mechanism7 Chloride ions 0Cl @6, either in com!ination +ith hydrogen sulfide 0 )#6 or alone, can attac8 this film, causing smallpits to form. These small pits act as anodes, +hile the remainder of the o;ide film acts as a cathodeH the unfavora!le area ratio causes the pit to gro+. Also, the solution inside the pit 0see Mechanism of 32drogen Embrittlement 3E 6 is acidified !ecause of the corrosion reaction, +hich also tends to increase the corrosion rate. Finally, a crac8 is initiated at the !ase of the pits !ecause of the stress concentration, and propagation occurs !ecause of the tensile stress. The crac8 often gro+s along grain !oundaries !ecause grain !oundaries are electrochemically more active than the !ul8 grain. Chloride #CC is usually o!served at temperature e;ceeding >( to (C.

Factors that influence #CC7 Temperature, Chloride Concentration,  )# concentration, lementar #ulfur, p and P- 0Pitting -esistance :uivalent6. IC is also called step+ise crac8ing or !lister crac8ing. IC is primarily found in lo+er@strength steels, typically +ith tensile strengths less than a!out ' MPA 0' 8si6, primarily found in line@pipe steels. In 5UPC3 reha! proect +e use7 A 1'> ? 0>' 8si6, #A 1' 0&' 8si6, 1> 5r.&' 0&' 8si6, A )%4 /P? 0>' 8si6, API * 5r.? and B4) 0>' 8si6, API 5r.B) 0>> 8si6 and API 5r. B>' 0& 8si6.

;planation Mechanism7 This type of degradation also !egins +ith a reaction !et+een steel and hydrogen sulfide 0 )#6 in the presence of +ater. Again, hydrogen atoms enter the steel, !ut +ith IC, as opposed to $CC& these hydrogen atoms com!ine to form )@gas at internal defects. These internal discontinuities can !e hard spots of lo+@temperature transformation products or laminations. o+ever, manganese sulfide inclusions are the primary site for this to occur. These inclusions tend to !ecome elongated during pipe manufacture and give rise to high stresses at the tip of the inclusion +hen hydrogen gas forms there. As crac8s initiate and propagate, they !egin to lin8 up +ith others, and a series of step+ise crac8s can propagate through the material. Factors that affect IC7 Concentration of )#, #hape control of Mn#, Addition of Calcium ma8es the sulfides spherical, -educing of #@content, Addition of Cu up to a!out '.) 0no tensile stress re:uired6. #taggered small crac8s formed appro;imately perpendicular to the principal stress 0residual or applied6 resulting in a Nladder@li8eN crac8 array lin8ing pre@e;isting 3IC6s% The mode of crac8ing can !e catogori
A crevice in a metal surface at a oint !et+een t+o metallic surfaces or !et+een a metallic and a nonmetallic surface or a crevice !eneath a particle of solid matter on a metallic surface provides conditions that are conducive to the development of the type of concentration@ cell corrosion called crevice corrosion. Crevice corrosion can progress very rapidly. For e;ample, a sheet of stainless steel can !e cut 0corroded6 into t+o pieces simply !y +rapping a ru!!er !and around it, then immersing the sheet in sea+ater or dilute ferric chloride solution 0FeCl % 6. The open surface +ill pit slo+ly, !ut the metal under the ru!!er !and +ill !e attac8ed rapidly for as long as the crevice !et+een the ru!!er and the steel surface e;ists. In a metal@ion concentration cell, the accelerated corrosion occurs at the edge of or slightly outside of a crevice. In an o;ygen@concentration cell, the accelerated corrosion usually occurs +ithin the crivice !et+een the mating surfaces.

;planation Mechanism of Concentration@Cell Corrosion 0Crevice Corrosion67 If a piece of metal is immersed in a electrolyte and there is a difference in concentration of one or more dissolved compounds or gases in the electrolyte, t+o areas of metal in contact +ith solution differing in concentration +ill ordinarily differ in solution potential, forming a concentration cell 0see also 3E6.

Failure Mechanisms# Comarison of 9A:IM& API 571 and others Failure Mechanisms

Discription of the Failure

Failure Mechanism of 5A*I3M

acc.follo+ing #tandards

Mechan% and Metallurg% Failures 5raphiti
-emar8s to the Failure Mechanisms of 5A*I3M

API &1

#pheroidi
?etter7 5raphiti
API &1

#pheroidi
?etter7 #oftening 0#pheroidi
API &1

Temper m!rittlement

API &1

#train Aging

API &1

(F04&4(C6 m!rittlement

API &1

#igma O Chi Phase m!rittlement

API &1

?rittle Fracture

API &1

Creep@#tress -upture

API &1

Thermal Fatigue Crac8ing

?etter7 Thermal Fatigue

API &1

rosion@#olids and rosio n Droplets

API &1 incl. impact from solids, li:uids, va por or any com!inations

API &1

Cavitation

?etter7 #igma Phase m!rittlement

API &1 API &1 API &1 API &1

API &1 API &1 API &1 API &1

-eheat Crac8ing

API &1

5alvanic C-

API &1

Atmospheric Corrosion

API &1

C- Under Insulation2Fire proofing

?etter7 Corrosion Under Ins ulation

API &1

Cooling /ater C-

?etter7 Cooling /ater Corrosion

?etter7 5alvanic Corrosion

API &1

?oiler /ater2Condensate C-

?etter7 ?oiler /ater Condensate Co rrosion

API &1

C3) Cr

?etter7 C3) Corrosion

API &1

Flue 5as De+ Point C-

?etter7 Flue 5as De+ Point Corrosion

API &1

?iological Corrosion

?iological Corrosion inclu de ?iofouling, MIC and #-? Corrosion

#oil Corrosion

Failure Mechanisms

API &1


#oil Corrosion



+niform or :ocalied Metal :oss Caustic Corrosion Dealloying 5raphitic Corrosion 3igh (emeratur Corr%!;<<=F*.<;=" 3;idation #ulfidation Car!uri

API &1 API &1

Dealloying

API &1 API &1 API &1

igh Temperature Corrosion igh Temperature )# Corrosion

API &1

Car!uri
API &1

De@Car!uri
API &1

Metal Dusting

?etter7 #ulfidation

API &1 API &1

=itriding

API &1

Chloride #tress C- Crac8ing 0#CC6

?etter7 Chloride #tress Corrosion Crac8ing or Chloride #CC

API &1

C- Fatigue Crac8ing

?etter7 Corrosion Fatigue Crac8ing

API &1

Caustic C- and #tress C- Crac8ing

are different mechanism2morphology and pr o!a!ility of failure 0P3F6

API &1

Ammonia C- and #CC

API &1

*i:uid Metal m!rittlement Crac8ing

API &1

ydrogen m!rittlement

API &1

Amine C-

?etter7 Amine Corrosion

API &1

Ammonia ?isulfide C-

?etter7 Ammonium ?isulfide Corrosion

API &1

Cl C-

?etter7 ydrochlorid Acid 0Cl6 Corrosion

API &1

igh Temp. )2)# Corrosion

?etter7 *i:uid Metal m!rittlement

Refining Industr2 Failure +niform or :ocalied Metal :oss Amine Corrosion Ammonium ?isulfide Corrosion 0Al8aline #our /ater6 Ammonium Chloride Corrosion ydrochlorid Acid 0Cl6 Corrosion igh Temp. )2)# Corrosion

API &1

ydrofluoric 0F6 Acid Corrosion =aphthenic Acid Corrosion 0=AC6

Failure Mechanisms

API &1

ydrofluoric Acid C-

?etter7 ydrofluoric 0F6 Acid Corrosion

API &1

=aphtenic Acid C-

?etter7 =aphtenic Acid Corrosion



acc.follo +ing #tandards

+niform or :ocalied Metal :oss Phenol 0Car!onic Acid6 Corrosion Phosphoric Acid Corrosion #our /ater Corrosion 0Acidic6 #ulfuric Acid Corrosion En)ironment-Assisted Crac4ing Polythionic Acid #tress Corr. Crac8ing Amine #tress Corrosion Crac8ing /et )# ?listering #ulfide #tress Crac8ing 0##C6 #tress Corrosion Crac8ing 0#CC6 ydrogen Induced Crac8ing 0IC6 #tep+ise Crac8ing 0#/C6 #tress 3rient. ydr. Induc. Cr.0#3IC6 #oft 9one Crac8ing 0#9C6 ydrogen #tress Crac8ing@F 5alv. Induc. ydr. #tress Cr.05#C6 Car!onate #tress Corr. Crac8ing ther Mechanisms igh Temp. ydrogen Attac8 0TA6 Titanium ydriding


API &1

Phenol2=MP Corrosion

API &1

Phosphoric Acid Corrosion

?etter7 Phenol 0Car!onic Acid6 Corrosion

API &1

#our /ater Corrosion

API &1

#ulfuric Acid Corrosion

API &1

Polythonic #tress Corrosion Crac8ing

?etter7 Polythonic Acid #tress Corrosion Crac8ing

API &1

Amine #tress C- Crac8ing

?etter7 Amine #tress Corrosion Crac8ing or Amine #CC

#ulfide #tress Crac8ing

?etter7 #ulfide #tress Crac8ing 0##C6

?etter7 #our /ater Corrosion 0Acidic6

API &1 I#3 11> I#3 11>, API &1 I#3 11>, API &1

ydrogen Induced Crac8ing 0IC6

I#3 11> I#3 11>, API &1

#tress oriented ydr. Induc. Crac8ing 0#3IC6

I#3 11> I#3 11>, API &1

ydrofluoric Acid Crac8ing

?etter7 ydrogen #tress Crac8ing@F

I#3 11> API &1

Car!onate #tress C- Crac8ing

API &1

igh Temperature  ) Attac8

?etter7 igh Temperature ydrogen Attac8 0TA6

API &1

ydriding >listering

?etter7 Titanium ydriding 0other hydrogen diffuses7 IC, ##C,etc6 ?listering include Coating@, Deposit@, Delamination und pressure 0 )6

?rittleness due to high temp. aging

#hould !e removed7 already incl. in Temper and (F m!rittlement

Car!ide precipitate em!rittlement

#hould !e removed7 already incl. ?rittle Fracture 0Intergranular6

Chloride*$odium 32ochlorite CR

Chloride and #odium ypochlorite 0=a3Cl6 +aste+ater treatment

Creep Crac8ing

#hould !e removed7 already incl. Creep@#tress -upture

Cre)ice* +nder deosit

Crevice2Under deposit incl. Cooling /ater, MIC, Caustic,Amine@Corr.

Failure Mechanisms


C2anide $tress Crac4ing !3C?"

Cyanide are respons. for accelerated corr. and @charging of steel

Fatigue

Fatigue incl. Corrosion@ Thermal@ and Mechanical Fatigue 0API &16

Flue 9as CR

Flue 5as Corr. Incl. Flue 5as De+ Point and Flue Ash Corrosion


-emar8s to the Failure Mechanisms

)2)# #ulfidation

of 5A*I3M #hould !e removed7 already incl. in igh Temper. )# corrosion

3ardening

ardening can !e a prere:uisite of a failure mechanism li8e aging


ot 3;idation

#hould !e removed7 no difference to Nigh temperature 3;idationN

ydrogen Attac8

#hould !e removed7 already incl. in IC, ##C, #C, #3IC,5#C,

Incipient Melting

In@ection oint CR Inorganic Chloride C-

If do not 8no+ the chemicals 0no failure mechanism6 #hould !e removed7 already incl. in Cl Corrosion, Chloride #CC, Ammonium Chlorid Corrosion

3rganic Chloride C-

#hould !e removed7 or *iterature ;amples shall !e given

rganic $ulfur CR

Mercaptans are a group of sulfur@containing organic chem. #u!st.

3;ygen Pitting2Car!onic Acid Corrosion

#hould !e removed7 already incl. in Phenol 0Car!onic Acid6 Corr.

)erload !Plastic Collase"

also !uc8ling

Polysulfide@ /ater Corrosion

#hould !e removed7 already incl. in Ammonium ?isulfide Corrosion 0Al8aline #our /ater6

#liding /ear #oftening due to overaging

>etter# Fretting or Fretting Corrosion #hould !e removed7 already incl. in 5raphiti
Thermal ratcheting et 3.$ Corrosion

#hould !e used for general or locali
/et )# Crac8ing

#hould !e removed7 already incl. in ydrogen m!rittlement, /et )# ?listering, ##C, IC, #CC,etc.

Failure Mechanisms affecting to C- and lo0 allo2 $teel* different units at the oil and gas roduction and refining indust Failure Mechanisms

Mechan% and Metallurg% Failures 5raphitation #oftening Temper m!rittlement #train Aging (F 04&4(C6 m!rittlement #igma Phase m!rittlement ?rittle fracture Creep2#tress -upture Thermal Fatigue #hort Term 3verheating@#tress -upture #team ?lan8eting Dissimilar Metal /eld 0DM/6Crac8ing Thermal #hoc8 rrosion2 rosion@Corrosion Cavitation Mechanical Fatigue "i!ration@Induced Fatigue -efractory Degradation -eheat Crac8ing +niform or :ocalied Metal :oss 5alvanic Corrosion Atmospheric Corrosion Corrosion Under Insulation 0CUI6 Cooling /ater Corrosion ?oiler /ater Condensate Corrosion C3) Corrosion Flue 5as De+ Point Corrosion ?iological Corrosion

Components

oil2gas

Parameter

product. "acuum Co8er

eater eater eater vessel +alls

vessels eater@tu!es eater eater eater

Crude

Delayed Fluid cat.

; ; ; ;

; ; ; ; ;

crac8ing

Catalytic

ydro@

small pipes2no<<

; ; ; ;

P/T thic8 +all

;

heat e;changer

; ; ; ; ;

Pumps small pipes2no<<

lo+ temp. +ater trapped ead e;changer Feed+ater heat Feed+ater heat fired eater Tan8s,etc.

; ; ;

Amine

#ulfur

#our +ater

Isomeri

Treating

-ecover

stripper

; ; ;

;

;

; ; ;

;

;

; ;

; ; ;

; ; ;

; ; ; ; ; ; ;

; ?end, "elocity

Al8ylation

-eforming process. F2#ulfur

;

; ; ;

;

;

;

;

;

;

; ; ;

; ;

;

; ;

;

;

; ;

;

; ; ;

#oil Corrosion

Failure Mechanisms

+niform or :ocalied Metal :oss Caustic Corrosion Dealloying 5raphitic Corrosion 3igh (emeratur Corr%!;<<=F*.<;=" 3;idation #ulfidation Car!urisation Decar!uri
Tan8s

;

Components

oil2gas

Parameter


Causticeater

;

Crude

Delayed Fluid cat. crac8ing

Catalytic

ydro@

Al8ylation


;

Amine

#ulfur

#our +ater

Isomeri

Treating

-ecover

stripper

;

;

;

eater eater eater eater eater eater

; ; ; ; ; ;

; ;

; ; ;

; ; ; ;

; ; ;

;

;

overhead cond.

; ; ;

A9,+elding

;

re!oiler

; ;

cyclic heater A9,eater

; ;

;

; ; ;

;

; ;

;

;

; ;

;


air cooler

Crude, ydropr.

; ;

Piping high temp

;

Crude, ydropr.

; ;

; ; ;

;

;

; ;

; ;

;

;

; ;

;

;


Failure Mechanisms

+niform or :ocalied Metal :oss Phenol 0Car!onic Acid6 Corrosion Phosphoric Acid Corrosion #our /ater Corrosion 0Acidic6 #ulfuric Acid Corrosion En)ironment-Assisted Crac4ing Polythionic Acid #tress Corr. Crac8ing Amine #tress Corrosion Crac8ing /et )# ?listering #ulfide #tress Crac8ing 0##C6 #tress Corrosion Crac8ing ydrogen Induced Crac8ing 0IC6 #tep+ise Crac8ing 0#/C6 #tress 3riented ydrogen Induced Crac8ing 0#3IC6 #oft 9one Crac8ing 0#9C6 ydrogen #tress Crac8ing @F 5alvanically induced ydrogen #tress Crac8ing 05#C6 Car!onate #tress Corr. Crac8ing ther Mechanisms igh Temp. ydrogen Attac8 0TA6 Titanium ydriding

; ;

Components

oil2gas

Parameter


; ;

A9

;

+et )#

; ;

; ;

; ;

; ;

;

; ; ;

;

+et )# +et )# A9,+et )# +et )# A9,+et F

;

Catalytic

ydro@

Al8ylation Amine


;

Treating

!elo+ scru!!er

; ; ; ;

#our +ater

Isomeri

-ecover

stripper

;

;

; ;

; ;

; ;

; ;

; ;

;

;

;

;

;

;

;

;

;

;

;

;

;

; ;

;

; ;

+ater treatm.

#ulfur

; ;

;

Cre)ice* +nder deosit C2anide $tress Crac4ing !3C?"

crac8ing

; ;

A9,+et )#

;

Delayed Fluid cat.

A9

P 4,@&,)#

>listering Chloride*$odium 32ochlorite CR

Crude

;

;

Fatigue Flue 9as CR

Failure Mechanisms

eater

oil2gas


Inection unit all Compon. +et )#

; ; ; ; ;

Crude

;

Parameter

rganic $ulfur CR )erload !Plastic Collase" et 3.$ Corrosion

;

Components

3ardening In@ection oint CR

; ;

Delayed Fluid cat. crac8ing

Catalytic

ydro@

Al8ylation


Amine

#ulfur

#our +ater

Isomeri

Treating

-ecover

stripper

2 ydrogen -eforming

;

; ; ; ; ; ; ;

; ;

; ;

ydrogen -eforming

;

;

;

;


; ;

;


Failure Mechanisms# shall used and Influence Parameter Failure Mechanisms 0FM6 of API &12I#3 11> Mechan% and Metallurg% Failures 5raphitation #oftening Temper m!rittlement #train Aging (F 04&4(C6 m!rittlement #igma Phase m!rittlement ?rittle fracture Creep2#tress -upture Thermal Fatigue #hort Term 3verheating@#tress -upture #team ?lan8eting Dissimilar Metal /eld 0DM/6Crac8ing Thermal #hoc8 rrosion2 rosion@Corrosion Cavitation Mechanical Fatigue "i!ration@Induced Fatigue -efractory Degradation -eheat Crac8ing +niform or :ocalied Metal :oss 5alvanic Corrosion Atmospheric Corrosion Corrosion Under Insulation 0CUI6 Cooling /ater Corrosion ?oiler /ater Condensate Corrosion C3) Corrosion Flue 5as De+ Point Corrosion ?iological Corrosion

FM

FM

affected units,etc

used

press.

(C

+ater

Temp.

cut

A9, eater

no

$4)&

eater

no

44'2&>'

A9, eater

no

%4%2%

vessel +alls

no

;

no

%1>24'

no

%24

vessels

psi )#

psi C3)

psi

dissolv.

susp.

Chemic.

P

Fe

#olids

Inect.

no

eater@tu!es

;

$%&'

eater

no

s+ing%

eater

no

eater

no

;

no no ?end, "elocity

;

Pumps

no

small pipes2no<<

;

s ma ll p ip es 2n o<<

no

; ; ; ; ;

; ;

; ;

no P/T thic8 +all

;

heat e;changer

;

lo+ temp.

;

+ater trapped

;

heat e;changer

no

Feed+ater heat

no

Feed+ater heat

;

fired eater

;

Tan8s,etc.

;

;

; ; ; ; ; ; ;

; ;

;

; ;

;

; ;

; ;

; ;

;

;

;

#oil Corrosion

Failure Mechanisms 0FM6

Tan8s

;

no

FM

FM

(C

+ater

affected units,etc

used

press.

Temp.

cut

;

;

;

Causticeater

psi )#

psi C3)

psi

dissolv.

susp.

Chemic.

P

Fe

#olids

Inect.

;

;

;

; ;

;

;

; ;

; ;

no no eater

;

$4)

eater

;

$)>'

eater

;

$%

;

eater

;

eater

no

4)21>

;

eater

no

$%

no

$%1>

;

no cyclic heater

no

A9,eater

;

overhead cond.

; ;

; ;

; no

A9,+elding

;

;

;

E'.)

; ;

Refining Industr2 Failure +niform or :ocalied Metal :oss Amine Corrosion Ammonium ?isulfide Corrosion 0Al8aline #our /ater6 Ammonium Chloride Corrosion ydrochlorid Acid 0Cl6 Corrosion igh Temp.  )2)# Corrosion

; ;

re!oiler

;

air cooler

;

Cr ude, ydr opr.

no

Cr ude, ydr opr.

no

; ;

Piping high temp

no

$)>'

;

;

; ;




no Cr ude high temp

no

FM

FM

affected units,etc

used

phenol e;traction

no

polymeri
no

A9

;

;

(C

+ater

press.

Temp.

cut

psi ) #

psi C3)

psi

dissolv.

susp.

Chemic.

P

Fe

#olids

Inect.

;

; ;

;

; ;

;

;

;

;

;

E&2$&

; ; ;

; ; ;

; ; ;

; ; ;

;

; ; ;

no A9

;

;

;

+et )#

no

;

-T21'

A9,+et )#

;

no

E)

;

;

E

+et )#

;

+et )#

no

;

;

A9,+et )#

; no

; ;

-T21'

+et )#

; ;

; ;

; ;

; ;

A9,+et F

no

A9

no no

;

;

;

;

;

>listering

pipe, vessel

no no no

;

;

;


+ater treatm.

no

heate;changer

;

stripper

no

; ;

; ;

; ;


-T21'

;

;

;

; ; ; ;

; ;

; ; ; ; ;

Fatigue Flue 9as CR

Failure Mechanisms 0FM6 In@ection oint CR

heater,no<<.

no

eater

no

;

;

;

;

;

psi )#

psi C3)

psi

dissolv.

susp.

Chemic.

P

Fe

#olids

Inect.

FM

FM

(C

+ater

used

press.

Temp.

cut

no

;

;

; ;

; ;

Inection unit

;

no all Compon. +et )#

no no

;

$%

affected units,etc rganic $ulfur CR )erload !Plastic Collase" et 3.$ Corrosion

;

;

;

;

;

;

Failure Mechanisms# affected Material& :ocations& Insecti Failure Mechanisms 0FM6

FM

FM

Material

affected units,etc used

Mechan% and Metallurg% Failures 5raphitation #oftening Temper m!rittlement #train Aging (F 04&4(C6 m!rittlement #igma Phase m!rittlement ?rittle fracture Creep2#tress -upture Thermal Fatigue #hort Term 3verheating@#tress -upture #team ?lan8eting Dissimilar Metal /eld 0DM/6Crac8ing Thermal #hoc8 rrosion2 rosion@Corrosion Cavitation Mechanical Fatigue "i!ration@Induced Fatigue -efractory Degradation -eheat Crac8ing +niform or :ocalied Metal :oss 5alvanic Corrosion Atmospheric Corrosion Corrosion Under Insulation 0CUI6 Cooling /ater Corrosion ?oiler /ater Condensate Corrosion C3) Corrosion Flue 5as De+ Point Corrosion Micro!iologically Induced Corr. 0MIC6

A9, eater

no

C@2'.Mo #teel

eater

no

C@2'.Mo @Cr

A9, eater

no

).)Cr@1Mo

vessel +alls

no

C@2'.Mo #teel

no

#tainless #t.

no

#tainless #t.

vessels

no

C@#teel

eater@tu!es

;

C@2Cr@Mo #t.

eater

no

C@#teel

eater

no

C@2Cr@Mo #teel

no

C@2Cr@Mo #teel

no

C@#teel2##

eater

no

C@#teel

?end, "elocity

;

C@#teel

Pumps

no

C@#teel

small pipes2no<<

;

C@#teel

no

C@#teel

small pipes2no<<

no P/T thic8 +all

;

C@2Cr@Mo #teel

heat e;changer

;

#teel2Cooper

lo+ temp.

;

C@#teel

+ater trapped

;

C@#teel

heat e;changer

no

C@#teel

Feed+ater heat.

no

C@#teel

Feed+ater heat.

;

C@#teel

fired eater

;

C@#teel

Tan8s,heat e;.

;

C@#teel

#oil Corrosion


Tan8s

no

C@#teel

FM

FM

Material


Causticeater

;

C@#teel

no no

cast iron

eater

;

C@2Cr@ #teel

eater

;

C@2Cr@ #teel

eater

;

C2Cr@#teel

eater

;

C2Cr@#teel

eater

no

C2Cr@#teel

eater

no

C2Cr@#teel

no

C2Cr @Mo #teel

no

##, =i@!ase

cyclic heater

no

C2Cr@#teel

A9,eater

;

C2Cr@#teel

overhead cond. A9,+elding

;

C@#teel

no

C@#teel

;

C@#teel


re!oiler

;

C@#teel

air cooler

;

C@#teel

Crude, ydropr.

no

C@#teel

Crude, ydropr.

no

C@#teel

Piping high temp

no

C@#teel



no Cr ude high te mp

no

FM

FM

Material



phenol e;traction

no

polymeri
no

overhead syst.

;

C@#teel

A9

;

C@#teel

no A9

;

+et )#

no

C@#teel

A9,+et )#

;

C@#teel

no +et )#

;

C@#teel

+et )#

no

C@#teel

A9,+et )#

;

C@#teel

+et )#

no

C@#teel

A9,+et F

no

Amine proc.

no no

>listering

pipe, vessel

no no no


+ater treatm.

no


C@#teel

?oiler tu!es

heat e;changer

;

stripper

no

C@#teel C2Cr@Mo #teel

C@#teel

Fatigue

heater,no<<.

no

C@#teel

Flue 9as CR

fired eater

no

C@#teel

FM

FM

Material



In@ection oint CR

Inection unit

)erload !Plastic Collase" et 3.$ Corrosion

no

no

rganic $ulfur CR all Compon. +et )#

no no

on methods *ocation of Falures A9 and regions +ith signif. plastic deformation 0+or8 hardening or !en ding67 metallograpic e;am Fired heater tu!esH metallographic o!servation, a reduction of tensile strength and2or hardness can !e identified !y up+ard shift of ductile@!rittle transition temperatue 0Charpy "@notch impact test6 Mostly older 0pre 1'6, cold +or8ed +ithout stress relieving, vessels +allsH metallographic e;am.

Thic8 +all e:uipment, +ith lo+ Charpy@values, high ductile@!rittle transition temprature A9, =o<
?end, Tee, -educer, =o<
Tan8 !ottom, 5eneral and locali
*ocation of Falures ?oiler, steam gen. e:uipment, heat e;ch., Inspect. Points 0API &'6, *ocal.Corr.H"T,UT,-T,!oroscope

Presence of air, outside of furnace tu!es, internal furnace componentsHgeneral corr.HUT piping in sulfur@containing 0$'.)6 streams, heaters fired +ith oil, gasHgeneral and locali
ID of tu!es, opposite !uc8stay attachment on the 3D 0 stress concentration6HUT A9, eat transfer e:uipment, Caustic treating section, caustic service, mercaptan treatm.H"T,C,-T, overhead condensat. +here ammonia is a neutrali
Amine treat. units, lo+ velocity general and at high velocity or under deposit locali'(C sulfide corrosion. Uniform corr.HUT,"T and -T

*ocation of Falures

P 4,@&,)#H general, locali
A9 in lean amine serv. incl. contactors, a!sor!ers, stripp., regenerators, heat e;.7"T,/FMT,ACFM on the ID,3D or +ithin the +all thic8ness of pipes or pressure vesselsH"T /eld cover passes and attachment +elds +hich are not tempered, A9, high hardnessH/FMT,C,-T vapor recovery system, sour +ater stripper and amine regenerator overhead systemH "T,/FMT vapor recovery system, sour +ater stripper and amine regenerator overhead systemH "T,/FMT A9, vapor recovery system, sour +ater stripper amine regenerator overhead syst.H"T,/FTM,C Form of ##C, occur +hen #teels contain a local Nsoft
=ot P/T, A9, near +eld , +eld, P $&.>

?listering include Coating@, Deposit@, Delamination und Pressure 0 )6 if do not 8no+ the chemicals of +aste +ater treatment Chlorine or =a3Cl Crevice2Under deposit incl. Cooling /ater@, MIC@, Caustic@,Amine@, Ammonium ?isulfide@Corrosion vapor recovery system, sour +ater stripper and amine regenerator overhead system 0see +et  )#6

see thermal@, mechanical and corrosion fatigue see flue gas de+ point and flue ash corrosion

*ocation of Falures If do not 8no+ the chemicals 0no failure mechanism6 use Inection point Corrosion 0see API &'6 Mercaptans are a group of sulfur@containing organic chem. #u!st. 0see caustic corrosion2crac8ing6 #hould !e used for general or locali
Failure Mechanisms affecting to C-&lo0 allo2 $teel and Coer * different units at the oil and gas roduction Failure Mechanisms 0FM6

FM

FM

used

need

Mechan% and Metallurg% Failures 5raphitation A9, eater #oftening eater Temper m!rittlement A9, eater #train Aging vessel +alls (F 04&4(C6 m!rittlement #igma Phase m!rittlement ?rittle fracture vessels Creep2#tress -upture eater@tu!es Thermal Fatigue eater #hort Term 3verheating@#tress -upture eater #team ?lan8eting eater Dissimilar Metal /eld 0DM/6Crac8ing Thermal #hoc8 rrosion2 rosion@Corrosion ?end, "elocity Cavitation Pumps Mechanical Fatigue small pipes2no<< "i!ration@Induced Fatigue small pipes2no<< -efractory Degradation -eheat Crac8ing P/T thic8 +all +niform or :ocalied Metal :oss 5alvanic Corrosion heat e;changer Atmospheric Corrosion lo+ temp. Corrosion Under Insulation 0CUI6 +ater trapped Cooling /ater Corrosion heat e;changer ?oiler /ater Condensate Corrosion Feed+ater heat C3) Corrosion Feed+ater heat Flue 5as De+ Point Corrosion Micro!iologically Induced Corr. 0MIC6

#team

#team

eating Cooling Cooling

/ater

Condensate

+ater

Treatm.

#team

#team


Condensate

/ater

no no no no no no no ;

;

; ; no no no ;

;

;

; ; ;

; ; ;

;

;

;

;

no ; ; no ; ; ; ;

; ;

; ;

;

;

;

; ; ;

fired eater

;

Tan8s,etc.

;

;

;

;

#oil Corrosion


+niform or :ocalied Metal :oss Caustic Corrosion Dealloying 0selective leaching6 5raphitic Corrosion 3igh (emeratur Corr%!;<<=F*.<;=" 3;idation #ulfidation Car!urisation Decar!uri
Tan8s

no

FM

FM

used

need

Causticeater

; no

#team


/ater

Condensate

+ater

Treatm.

; ;

;

#team

#team


Condensate

;

/ater

;

;

no eater

;

eater

;

eater

;

eater

;

eater

;

eater

;

; no no

cyclic heater

;

A9,eater

;

overhead cond.

; no

A9,+elding

;

Refining Industr2 Failure +niform or :ocalied Metal :oss Amine Corrosion Ammonium ?isulfide Corrosion 0Al8aline #our /ater6 Ammonium Chloride Corrosion ydrochlorid Acid 0Cl6 Corrosion igh Temp.  )2)# Corrosion

#team

re!oiler

;

air cooler

;

Crude, ydropr.

;

Crude, ydropr.

;

Piping high temp

;

; ; ;

;

;

;

;




no Cr ude high te mp

no

FM

FM

#team


/ater

used

need

Condensate

+ater

Treatm.

phenol e;traction

no

;

polymeri
no

A9

;

#team Condensate

eating Cooling Cooling /ater

;

no A9

;

+et )#

;

A9,+et )#

;

no +et )#

;

+et )#

;

A9,+et )#

; ;

A9,+et F

no

A9

no ;

>listering

pipe, vessel

;


+ater treatm.

;

heate;changer

;

stripper

;

C2anide $tress Crac4ing !3C?"

#team

;

+et )#

Cre)ice* +nder deosit

#team

;

;

;

;

;

;

;

Fatigue Flue 9as CR

Failure Mechanisms 0FM6 In@ection oint CR

heater,no<<.

;

eater

;

FM

FM

used

need

Inection unit

;

all Compon. +et )#

;

rganic $ulfur CR )erload !Plastic Collase" et 3.$ Corrosion

;

;

#team

;

;

#team


/ater

Condensate

+ater

Treatm.

#team

;

;

#team


Condensate

/ater

/ater Treatm.

/ater Treatm.

/ater Treatm.

/ater Treatm.

Failure_Mechanisms_of_C-Steels_API_571_.xls_filename= UTF-8''Failure Mechanisms of C-Steels (API 571).xls

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