Materials and Corrosion for Sour Service

Materials and Corrosion for Sour Service MP 55-P-19 July 1998 Scope This Mobil Engineering Practice (MEP) shall be used for the design of sour service materials for onshore and offshore production and processing facilities. This MEP covers general requirements for sour service materials used in upstream surface facilities, from the wellhead wing valve to sales. These include onshore and offshore offshore facilities as follows: •

ellsites

•

Production separation s!stems

•

Pipelines

•

"ompressor stations

•

#as processing plants

•

$il batteries

•

%n&ection s!stems

'll usiness ectors

* Mobil $il,+-

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MP 55-P-19

Materials and Corrosion for Sour Service

July 1998

Table of Contents



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MP 55-P-19


July 1998

1. Refer efere ences nces The following publications publications form a part of this Practice. 1nless otherwise specified specified herein, use the latest edition.

1.1. 1.1.

MPS MPS! !Mobi Mobill n" n"iineer neerin in" " Pra Pract ctiices ces

MP /23P3/0

Pressure "asting %nspection

MP ++3P3/+

4ired 5eaters 3 6esign and 4abrication

MP +03P3/+

Pressure 7essels36esign 8 4abrication

MP +23P3+/

hell 8 Tube 5eat E9changers36esign 8 "o "onstruction

MP +23P3+

'ir3"ooled 5eat E9changers36esign 8 "onstruction

MP +3P3/+

Piping3#eneral 6e 6esign

MP +3P3 3P32/ 2/' '

Pip Piping ing 3 Mat Mater eria ialls and and erv ervic icee "l "lassi assifi fica cati tio ons (M8; (M8;))

MP + +3P3
Piping34abrication, Er Erection, %n %nspection, 8 Te Testing

MP 0/3P3/+

$ffshore Pipeline 6esign

MP 0/3P3/0

=ine Pipe and end Material

MP 203P3/+

#eneral ;equirements for %nstrumentation

MP 23P3/+

Painting 3 #eneral ;equirements

MP 23P 23P33-+ +

Pain Painti ting ng 3 %nte %ntern rnal al "oat "oatin ings gs 3 Tan>s, n>s, 7essel ssels, s, Pipi Piping ng and and Tubula bulars rs

MP ?3P3/0

Pressure "o "ontaining Eq Equipment 3 elding 8 %nspection

1.#.

Mobil Tu Tutorials

EPT /23T3/

'cid #as ;emoval (E8P)

EPT /-3T3/2

Materials for our ervice

1.$. 1.$.

%P& %P&!%'e !%'eri rica can n Petr Petrol oleu eu' ' &nst &nstiitute tute

'P% 'P% T6 T6 + +

'ir3 'ir3"o "ool oled ed 5eat 5eat E9ch E9chan ange gers rs for for #en #ener eral al ;efi ;efine ner! r! erv ervic icee Thi Third rd Edit Editio ion n

'P% 'P% T6 T6 ++/< ++/<

eldin lding g of of Pip Pipel elin ines es and and ;el ;elat ated ed 4aci 4acili liti ties es Eigh Eighte teen enth th Edit Editio ion n



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1.(.


July 1998

%SM!%'erican Society of Mec)anical n"ineers

'ME 2+.2

Process Piping

'ME 2+.<

=iquid Transportation !stems for 5!drocarbons, =iquid Petroleum #as, 'nh!drous 'mmonia, and 'lcohols

'ME 2+.-

#as Transmission and 6istribution Piping !stems

'ME E" %%'

'ME oiler and Pressure 7essel "ode, ection %%: Materials@Part ': 4errous Material pecifications

'ME E" 7%%%

+ oiler 8 Pressure 7essel "ode + 'ddenda: Pressure 7essels

1.5.

%STM!%'erican Society for Testin" and Materials

'TM '+/A'+/M

tandard pecification for "arbon teel 4orgings for Piping 'pplications

'TM '+/

tandard pecification for eamless "arbon teel Pipe for 5igh3 Temperature ervice

'TM '0+A'0+M

tandard pecification for teel "astings, "arbon, uitable for 4usion elding, for 5igh3Temperature ervice

'TM '02
tandard pecification for Piping 4ittings of rought "arbon teel and 'llo! teel for Moderate and 5igh Temperature ervice

'TM '20A'20M

tandard pecification for teel "astings, 4erritic and Martensitic, for Pressure3"ontaining Parts, uitable for =ow3Temperature ervice

'TM '2?/ ;E7 '

tandard Test Methods and 6efinitions for Mechanical Testing of teel Products

'TM '<0/A'<0/M

tandard pecification for Piping 4ittings of rought "arbon teel and 'llo! teel for =ow3Temperature ervice

'TM '+A'+M

tandard pecification for Pressure 7essel Plates, "arbon teel, for Moderate 3 and =ower3Temperature ervice ;(+)

'TM '?-A'?-M

tandard pecification for traight3eam 1ltrasonic E9amination of Plain and "lad teel Plates for pecial 'pplications

'TM '?/2A'?/2M ;E7 '

tandard pecification for teel "astings, #eneral ;equirements, for Pressure3"ontaining Parts

'TM '?--

tandard pecification for teel 4orgings, #eneral ;equirements

'TM E<<

tandard 6efinitions of Terms ;elating to 5eat Treatments of Metal



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'TM E+
1.*.

July 1998

tandard 5ardness "onversion Tables for Metals, (;elationship 'mong rinell 5ardness, 7ic>ers 5ardness, ;oc>well 5ardness, ;oc>well uperficial 5ardness, Bnoop 5ardness, and clerscope 5ardness)

+%C!+ational %ssociation of Corrosion n"ineers

C'"E M;/+?

ulfide tress "rac>ing ;esistant Metallic Materials for $ilfield Equipment

C'"E TM/+??

=aborator! Testing of Metals for ;esistance to pecific 4orms of Environmental "rac>ing in 50 Environments Errata heet

C'"E TM/0-<

Evaluation of Pipeline and Pressure 7essel teels for ;esistance to 5!drogen3%nduced "rac>ing

#. ,eneral The design of sour service materials for onshore and offshore production and processing facilities shall be in accordance with requirements of this MEP, unless superceded b! more stringent local regulations. The Practice defines sour service for gas and multiphase s!stems. #uidance is also presented here on material aspects that help minimiDe the ris> of failures due to various forms of h!drogen damage, such as: •

ulfide stress crac>ing (")

•

5!drogen induced crac>ing (5%")

•

tress3oriented, h!drogen induced crac>ing ($5%")

This Practice also provides design, fabrication and inspection guidance, to ensure that the materials supplied are in a condition that minimiDes the ris> of damage from h!drogen.

#.1.

Criticality of Service

This Practice provides guidance on the criticalit! of the service for which a particular facilit! is being designed. The criticalit! of the service depends not onl! on the severit! of the production fluids, but also on the consequences of failure.



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July 1998

Selection of Materials

The selection of materials for use in sour service depends on man! factors in addition to the level of 50. $ther failure modes ma! be important, depending on the specific production condition. This Practice, however, does not specificall! address other failure modes that ma! be e9perienced in facilities as a result of other aggressive species. hen appropriate, cautionar! comments are provided with respect to other failure modes. Cevertheless, materials shall be selected in consultation with a material specialist and shall ta>e account of the effects of possible failure modes, in addition to those resulting from 50.

$. Sour nviron'ents $.1.

Sour ,as Service Materials shall be selected in accordance with this Practice if the gas being handled is at a total pressure of <<- >Paa ( psia) or greater and if the partial pressure of 5 0 in the gas is greater than 2< >Paa (/./ psia). 4igure + (or 0) provides a convenient method for determining whether the partial pressure of 5 0 in a sour environment e9ceeds 2< >Paa (/./ psia).



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MP 55-P-19


July 1998

Figure 1: Sour Gas Systems Customary !nits"

Figure #: Sour Gas Systems Metric !nits" 'll usiness ectors


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MP 55-P-19

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July 1998

Sour Multip)ase Service our multiphase fluids are fluids containing oil, gas and water in an! combination when an! one of the following criteria are met (4igures 2 and <): /./// percent@/./0 mol percent 5 0 in the gas and the partial pressure of 50 2< >Paa (/./ psia) •

0/./0 percent@ mol percent 5 0 in the gas and a total pressure +-0? >Paa (0 psia) •

•

@+ mol percent 5 0 in the gas and the partial pressure of 5 0  >Paa (+/

psia) •

+ mol percent 5 0 in the gas phase

Figure $: Sour Multi%&ase Systems Customary !nits"



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July 1998

Figure ': Sour Multi%&ase Systems Metric !nits" our multiphase service applies onl! to production equipment containing commingled or emulsified oil, gas and water. %n production equipment where phase separation occurs (e.g., separator, treater, 4B$, etc.), the environment is defined as sour service, in accordance with ection 2.+. 4or pressure equipment, when process conditions are such that a wet sour gas environment e9ists in one area but a Fnon3sourF multiphase s!stem e9ists in another area, the equipment shall be suitable for the more severe condition.

$.$.

Sour %ueous P)ase ometimes the dissolved 5 0, e9pressed as ppm b! weight, in an aqueous phase, becomes the criterion for sour service. 4or e9ample, where the partial pressures of 5 0 are not readil! available, Mobil uses / ppm b! weight 5 0 in aqueous phase, as a minimum, for defining sour service.

$.(.

Criticality of Sour Service Two categories of service are specified where the severit! of service is used to define the selection of materials, design, fabrication and inspection requirements.



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July 1998

The classification of severit! depends on the various factors associated with the probabilit! and consequences of failure, plus local considerations and economic impact.

$.(.1.

Ris %ssi"n'ent /actors =oss Prevention specialists provide guidance on the consequences of a failure, while material specialists give guidance on the li>elihood of a failure. ;is> assessments shall be made in consultation with these specialists to ensure optimum performance. 4actors associated with the assignment of ris> are as follows.

$.(.1.1.

Critical Sour Service

5igh pressure ( <<- >Paa ( psia) for gas s!stems and +-0? >Paa (0 psia) for sour oil and multiphase s!stems) •

•

5igh 50 partial pressure or high ppm in liquid

•

5igh environmental sensitivit!

•

Threat to people

•

5igh impact on production losses

•

=ong field life

$.(.1.#.

+on-Critical Sour Service

=ow pressure (G <<- >Paa ( psia) for gas s!stems and G +-0? >Paa (0 psia) for sour oil and multiphase s!stems) •

$.(.#.

•

=ow 50 partial pressure or low ppm in liquid

•

=ow environmental sensitivit!

•

;emote from personnel

•

=ow impact on production losses

•

hort field life

0a'ples of Sour Service Conditions 4ollowing are e9amples of conditions that are t!pical of critical and non3 critical sour service. The two e9amples presented are at the e9tremes of service ris>. %ndividual cases shall be reviewed to establish their criticalit! and how the material requirements shall be specified.

$.(.#.1.

Critical Service Conditions

1nder critical service conditions, ever! precaution is ta>en to avoid a failure.



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July 1998

Production fluids are ver! corrosive, are at high pressure and have high 50 content. •

The facilit! is close to habitation in an environmentall! sensitive area and a production shutdown would be environmentall! detrimental. •

$.(.#.#.

+on-critical Service Conditions

1nder non3critical service conditions, less stringent requirements are in effect for the materials of construction without compromising safet!. Production fluids are onl! mildl! corrosiveH the 5 0 content and pressure are low. •

The facilit! is far from habitation and a production shutdown would not be detrimental. •

$.5.

%crony's The following abbreviations and acron!ms are used in this MEP and also supplement those contained in C'"E M;/+?. 'dditional definitions related to heat treatment ma! be found in 'TM E<<. ()

utt elding

C*

"arbon Equivalent

CM+

"ement Mortar =ined (Pipe and Piping "omponents)

C,

"orrosion ;esistant 'llo!

C,-S

";'3olid

C,-C

";'3"lad, where ";' cladding is metallurgicall! bonded to a steel substrate

C,-.

";'35%P, where ";' powder is applied b! 5ot %sostatic Pressing (5%P)

C,-+

";'3=ined, where ";' liner is fitted to a steel substrate. %t is not metallurgicall! bonded to steel but ma! be a ver! tight shrin> fit, depending on the process of installation.

C,-/

";'3$verla!ed, where ";' is applied b! fusion welding and is metallurgicall! bonded to the substrate

C,-0

";'3Thermall! pra!ed, where a thin la!er of ";' is applied b! thermal spra!ingH it ma! or ma! not be metallurgicall! bonded

CS

"arbon teel

*,)

Electric ;esistance elded

F(*

4usion ond Epo9! (coating)



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MP 55-P-19


F,P

4iber ;einforced Plastic (t!picall! fiberglass)

.

5eat 'ffected Ione of eldment

.F

5ard 4aced (e.g., atellite)

.2C

5!drogen %nduced "rac>ing

22)

%nternational %nstitute of elding

2PC

%nternall! Plastic "oated (Pipe 8 4ittings)

+S

=ow 'llo! teel

M0

Magnetic Particle Testing (also >nown b! MP%)

Pcm

Parameter of "rac> Measurement

P*+

Pol!eth!lene =ined

P3,

Procedure Jualification ;eport for eldment

P0

=iquid Penetrant Testing (also >nown b! =P%)

P).0

Postweld 5eat Treatment

,0

;adiographic Testing

SCC

tress "orrosion "rac>ing

SM4S

pecified Minimum Kield trength

S/.2C

tress3$riented 5!drogen3%nduced "rac>ing

S/+

oc>olet

SSC

ulfide tress "rac>ing

S)

oc>et elding

0/+

Threadolet

!0

1ltrasonic Testing

)C

Tungsten "arbide

)FM0

et 4luorescent Magnetic Particle Testing

)/+

eldolet

July 1998

(. /errous Metals (.1.

Carbon and o2 %lloy Steels (.1.1.

Carbon Steels •


"arbon steels shall be in accordance with the attached appendices.


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July 1998

hen required b! equipment tables later in this Practice, carbon steel plate shall meet the requirements of 'ppendi9 ',  or ", as applicable. •

(.1.#.

Carbon uivalent 3C4 "arbon equivalent is a measure of the hardenabilit! of carbon and low allo! steels as a result of welding. The "E is based on the content of specific elements in the parent metal. The %% formula for "E is: "E L

M n

.



( Cr + Mo + V ) :



( Ni + Cu ) +:

here the elements are in weight percents

(.1.$.

Cracin" Para'eter 3Pc'4 7er! low carbon steels (G /.+/ weight percent carbon) are usuall! micro3 allo!ed in order to achieve desired strength. %n those cases, "E is not a good measure of hardenabilit! and the use of a crac>ing parameter (P cm) is recommended instead. Pcm L " 

Si 2/



( Mn + Cu + Cr ) 0/



Ni ./



Mo +:

 

here the elements are in weight percents

(.1.(.

Cold /or'ed ends 'll cold formed bends in carbon steel, including 13tubes for heat e9changers and fired heaters, shall be stress3relieved at a minimum temperature of +/N" (++2/N4) or full! normaliDed, if the as3bent hardness e9ceeds 00 5 or if the plastic strain used during bending e9ceeds  percent.

(.#.

Micro-%lloyed Steels (.#.1.

6anadiu'7 +iobiu' and Titaniu' %lloyed /erritic Steels 4or vanadium, niobium and titanium allo!ed ferritic steels, the vanadium content shall not e9ceed /./ percent, the niobium /./ percent, the titanium /./0 percent and their combined content shall not e9ceed /.+/ percent. hen these elements are used for allo!ing, the soluble aluminum to nitrogen ratio shall not be less than 0:+, with the nitrogen less than /./+ percent.



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(.#.#.

July 1998

Pipeline Steels Micro3allo!ed steels used in the manufacture of line pipe shall meet the requirements of the appropriate sections of MP 0/3P3/0.

(.$.

/ree Mac)inin" Steels 4ree machining steels, including all free machining grades of stainless steels, shall not be used.

(.(.

Cast &ron Con3ductile forms of cast iron shall not be used for pressure containing parts in sour service.

(.5.

%ustenitic Stainless Steels %n addition to the limitations outlined in C'"E M;/+?, the 2// series stainless steels, including their low carbon grades, shall not be used in services where the temperature and chloride concentration fall within the stress3crac>ing region defined b! 4igure . #as>ets are e9empted from this requirement for operating temperatures of +0/N" (0/N4) or less. oc>et welds or threaded connections that present a crevice on the process side shall be avoided.



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July 1998

Figure 5: C&loride Stress Cracing ,egion for ustenitic 0P $6' 7 0P $1 Stainless Steel

(.*.

/erritic Stainless Steels 4erritic stainless steels that meet the requirements of C'"E M;/+? are acceptable. 5owever, special considerations appl! to their selection, manufacture and use. Prior to purchase or use of these materials, a Mobil material specialist shall be consulted.

(..

Martensitic Stainless Steels Martensitic stainless steels that meet the requirements of C'"E M;/+? are usuall! acceptable. 5owever, special consideration applies to the selection, manufacture, heat treatment and use of these allo!s. "onsequentl!, a Mobil material specialist shall be consulted prior to their use.

(.8.

Precipitation ardenin" Stainless Steels Precipitation hardening stainless steels that meet the requirements of C'"E M;/+? are generall! acceptable. 5owever, special consideration applies to the selection, manufacture, heat treatment and use of these allo!s. "onsequentl!, a Mobil material specialist shall li>ewise be consulted prior to their use.



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(.9.


July 1998

:uple0 Stainless Steel 6uple9 stainless steels that meet the requirements of C'"E M;/+? are generall! acceptable. 5owever, duple9 stainless steels are fairl! new and >nowledge about their use changes rapidl!. ' Mobil material specialist shall be consulted before selection and establishment of fabrication techniques regarding these materials.

5. +on-/errous Metals The non3ferrous metals shown in C'"E M;/+? are acceptable. 'n! applicable Mobil modification for these materials is listed below.

5.1.

+icel-Copper %lloys Cic>el3copper allo!s shown in C'"E M;/+? are acceptable. Cic>el3copper allo!s such as 1C C/<
5.#.

;t)er +icel-ase %lloys Man! nic>el3chromium, nic>el3iron3chromium and nic>el3iron3chromium3mol!bdenum allo!s are acceptable for sour service according to C'"E M;/+?. election of these allo!s is suggested when chlorides are present and "" of the 2// series stainless steels is li>el! to occur. 5eat treatment and hardness requirements of C'"E M;/+? shall be strictl! adhered to in order to prevent crac>ing in sour service, due to h!drogen absorption b! galvanic coupling andAor corrosion.

5.$.

Copper %lloys "opper3nic>el allo!s, such as 1C "?/// (/A+/ "uACi) and 1C "?+// (?/A2/ "uACi) allo!s, are acceptable under C'"E M;/+?H however, the! have high corrosion rates in sour service. "opper allo!s such as brass and bronDe shall not be used in process streams containing amines, ammonia or 50, nor in applications where atmospheric e9posure to 5 0 occurs.



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July 1998

ead and ead %lloys =ead, lead allo!s and lead3bearing (free machining) allo!s shall not be used in sour service.

5.5. 5.5.

:iss :issi' i'il ilar ar Meta Metals ls and and ,alv ,alvan anic ic Coup Coupli lin" n" "oupling of dissimilar metals in a corrosive environment might lead to problems of crevice corrosion, h!drogen h!drogen charging or pitting attac>. ith ith dissimilar metals coupled, the more anodic metal ma! ma! suffer crevice corrosion andAor andAor pitting. %n some cases, the more anodic metal might corrode and cause h!drogen charging of the more cathodic (corrosion resistant) resistant) metal. This charging ma! lead to crac>ing of the more resistant metal. "oupling of dissimilar dissimilar metals is onl! a problem problem when the more anodic metal, b! itself, will corrode in a specific environment.

*. +on-Me +on-Metal tallic lic Materi Materials als *.1.

lasto'ers The equipment supplier shall be consulted with respect to elastomer recommendations (and supporting test data and service service e9perience) for the pro&ect service conditions. These service conditions need to be clearl! identified for this selection process. Table Table + lists service and temperature ranges for several elastomers commonl! used as $3 rings and other components.

0ale 0ale 1: Service and 0em%erature 0em%erature ,anges for Common *lastomers itrile (una-" ote "

;iton FM<" ote 5"

0eflon P0F*" ote '"

*t&ylene Pro%ylene *P=M"

flas

NC

30/ to +0/ (Cote 0)

30/ to +/

C.;.

C.;.

30/ to 0//

30/ to 0/

NF

/ to 0/ (Cote 0)

/ to 2//

C .; .

C.;.

/ to
/ to //

NC

C.;.

30/ to +/

30/ to +/

C.;.

30/ to 0//

30/ to 0/

NF

C.;.

/ to 2//

/ to 2//

C.;.

/ to
/ to //

ote 1" .#S

C/#



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MP 55-P-19

mines 7 2n&iitors


July 1998

;iton FM<" ote 5"

0eflon P0F*" ote '"

*t&ylene Pro%ylene *P=M"

flas

ote 1"

itrile (una-" ote "

NC

30/ to 

30/ to 

C .;.

30/ to +/

30/ to 0//

30/ to 0/

NF

/ to 0//

/ to 0//

C .;.

/ to 2// (Cote 2)

/ to
/ to //

/0*S:

+. Tempera Temperature ture conversion conversionss used used above above are are appro9im appro9imate. ate. 0. 'ccept 'cceptabl ablee when when part partial ial pres pressur suree of 5 0 G . >Paa (+ psia). 2. ME' ME'A6E' A6E' onl! onl!.. <. Plastic Plastic flow flow under under shearing shearing stress stress shall shall be considered considered.. . 7iton iton ma! ma! show show embri embrittl ttleme ement nt due due to 5 0 induced vulcaniDation effects. . $ther $ther s!nthetic s!nthetic rubbers rubbers li>e Ceopren Ceoprenee ma! be acceptable, acceptable, sub&ect sub&ect to agreemen agreementt with the Mobil Mobil material specialist.

*.#.

/iber Re Reinforced Pl Plastic 4iber reinforced plastic plastic (4;P) ma! be used for some sour water water service. 5owever, the the variet! of 4;Ps and their various conditions warrant careful consideration prior to their use. Their low fire resistance resistance ma! preclude use in some some locations.

*.$.

,asets #as>et materials shall be selected in accordance with MP +3P32/'.

*.(.

Pacin" Pac>ing materials shall be selected in accordance with piping, valve and equipment guides.



+- of /

MP 55-P-19


July 1998

. oltin" .1.

0posed oltin" FE9posed boltingF boltingF under C'"E M;/+? is Folting that is e9posed to the sour environment or that is buried, insulated, equipped with flange protectors or otherwise denied direct atmospheric e9posure OF here a facilit! has both sour and non3sour production equipment, equipment, all process bolts and nuts are considered FE9posed oltingF under C'"E M;/+?. here a facilit! requires low temperature bolts and nuts, all process bolts and nuts are considered low temperature service. Table Table 0 outlines the appropriate material specification.

0ale 0ale #: Material S%ecifications S%ecificati ons for Selection of *?%osed (olting Material an and S Seervice

(olting S% S%ecification

ut S% S%ecification

tandard temperature, critical or non3critical sour service (Cotes + and 0)

'+2 '+2A' A'+ +2M 2M #r. #r.?M ?M

'+< '+
=ow temperature, critical or non3critical sour service (Cotes + and 0)

'20/A 20/A' '20/M 20/M #r #r.=?M =?M

'+
Caron Steel

/0*S:

+. tandard tandard temperatu temperature re service service refers to operatio operation n at temperatures temperatures from from +0/N" (0/N4) (0/N4) to @0N" (3 0/N4). =ow temperature service refers refers to operation at temperatures temperatures in the range of @<N" (3/N4) (3/N4) to @0N" (30/N4). hen selecting the operating operating temperature, consideration shall shall be given to code requirements, local climatic conditions and process conditions, including the effects of upset, startup and shutdown. 0. hen pressur pressureAtem eAtemperat perature ure ratings ratings cannot cannot be achieved achieved using ?M or =?M boltin bolting, g, high allo! allo!,, precipitation hardenable, hardenable, high strength bolting bolting shall be used. used. pecial ordering instructions instructions ma! be necessar! to satisf! satisf! the strength requirements requirements of the equipment standard standard and the heat treatment treatment and hardness requirements requirements of C'"E M;/+?. "onsult !our !our materials specialist.



+ of /

MP 55-P-19


July 1998

8. Platin"s and Coatin"s 8.1.

Metallic Coatin"s Metallic coatings (electroplated, electrol!ses and thermal spra!) shall not be allowed as a stress corrosion crac>ing control method. here plating is used for corrosion or wear resistance, the material upon which the plating is deposited (substrate) shall conform to this Practice. "admium and galvaniDed Dinc plating is unsuitable for h!drogen sulfide service, due to rapid corrosion.

8.#.

+on-Metallic Coatin"s %n non3critical sour service applications at lower operating temperatures, under 2N" (0//N4), the use of non3metallic coatings, such as epo9ies or phenolics, ma! be considered. The coating specified shall be compatible with the process conditions. The installation and J'AJ" requirements shall be individuall! specified for the application and be in accordance with MP 23P3-+.

9. /abrication 9.1.

,eneral These guidelines supplement MP ?3P3/0 for sour service.

9.1.#.

Set-on +o==les et3on noDDles with inside diameters equal to the diameter in a vessel or pipe wall are limited to a ma9imum diameter of +// mm (< in). The weld attaching the noDDle to the vessel shall penetrate completel! through the noDDle nec> and ma! be either single or double welded.

9.1.$.

ac2eldin" ac>welding to correct root bead welding defects or misalignment on the inside (process side) of pipe is not permitted.



0/ of /

MP 55-P-19


9.1.(.

July 1998

9.#.

Post2eld eat Treat'ent 3P<T4 9.#.1.

Materials Reuirin" P<T P5T is required for some carbon steels, low allo! steels, martensitic steels and other transformation hardenable metallic materials e9posed to higher temperatures, such as e9perienced in welding or air3arc gouging.

9.#.#.

Materials +ot Reuirin" P<T +. Materials not requiring P5T are low carbon seamless pipes with the following conditions: a) Ma9imum carbon content of /.0/ percent. b) "E ≤ /.<2. c) MK G2/,/// >Pa (0,/// psi). d) eld procedure qualification shall be carried out with ma9imum hardness in the surve! of 0<- 57 +/. 0. P5T is onl! required in high ris>, severe sour service.

9.#.$.

Te'perature>Ti'es +ecessary for P<T +. The heat treatment temperatures for the respective materials are given in Table 2. The holding time at temperature shall be a minimum of + hour per 0 mm (+ in) of thic>ness, with a minimum time of + hour. The actual heat treatment time and temperature to ensure that the acceptable hardness limit is met will depend on the actual material. 0. This requirement for P5T is in addition to and does not preclude the use of P5T, as specified b! the relevant construction and fabrication industr! codes.



0+ of /

MP 55-P-19


July 1998

0ale $: Post@eld .eat 0reatment for Ferritic Materials Material

P).0 0em%erature ,ange

ominal nalysis"

P-umer

C

"arbon teel

+

+/@

++2/@+02/

Manganese@Mol!bdenum

2

0/@?0/

++/@+20

"@ +A0 Mo

2

0/@?0/

++/@+20

A0 "r@ +A0 Mo

2

0/@?0/

++/@+20

+ "r@ +A0 Mo

<

?/@?<

+2//@+2?

++A< "r@ +A0 Mo

<

?/@?<

+2//@+2?

0+A< "r@+ Mo



?0/@?/

+20@+
2 "r@+ Mo



?0/@?/

+20@+
 "r@ +A0 Mo



?0/@?/

+20@+
? "r@ +A0 Mo



?0/@?/

+20@+
 "r@+ Mo



?0/@?/

+20@+
+0 "r (martensitic)



?0/@?/

+20@+</

+0 "r (ferritic)

?

Cone

Cone

0+A< Ci

'

@2

++//@++?

2+A0 Ci



@2

++//@++?

 Ci

++'

/@-

+/0@+/-

 Ci

++'

/@-

+/0@+/-

+

F

/0*S:

+. Temperature of an! part of weldment during P5T shall not be less than shown above. Minimum holding time at temperature shall be one hour. 0. This table does not appl! to normaliDed and tempered materials or to quenched and tempered materials. P5T of such materials shall be approved b! Mobil. %t shall be such that the weld and 5'I hardnesses do not e9ceed 00 5 (02- 57 +/) and the mechanical properties are not less than the specification minimum.

9.#.(.

P<T of TMCP Steels elds in TM"P steels shall not be postweld heat treated.



00 of /

MP 55-P-19


9.#.5.

July 1998

P<T of ?uenc)ed and Te'pered Steels elds in quenched and tempered steels shall not be postweld heat treated at a temperature above the tempering temperature. hen in doubt, the steel supplier shall be contacted to determine a satisfactor! heat treatment procedure.

9.$.

ardness Testin" 9.$.1.

ardness Scales /or Sour Service C'"E M;/+? uses the ;oc>well " (5;") scale of hardness as the scale for measurement, control and acceptabilit! of hardness for materials in sour service. Mobil recommends the use of the 7ic>ers 57 +/ scale for measuring of hardness in weld procedure qualification testing. Mobil recommends the rinell  scale (5) for production testing of weldments and the ;oc>well ", when practical, for procurement and production testing of materials. 5ardness conversions between the three scales are given in 'TM E+
9.$.#.

ardness Testin" of en at locations suitable for determining ma9imum hardness of each Done of both sides of the weldment (refer to 4igure ). The ma9imum weld hardness at an! location in the weldment shall be 0<- 57 +/.



02 of /

MP 55-P-19


July 1998

Figure : .ardness Survey

9.$.$.

ardness Testin" of Production
4or carbon steels, the hardness shall not e9ceed 0// 5.

4or pipeline steels with MK equal to or greater than </,/// >Pa (,/// psi), the hardness shall not e9ceed 00 5. •

5ardness tests of carbon steel shall be performed on the deposited weld metal after heat treatment (if applied) using an indentation t!pe hardness testing instrument for which an 'TM standard e9ists. •

4or each weld tested, two hardness readings, separated b! a distance greater than the weld length divided b! three, shall be ta>en. −

here accessible, all hardness readings shall be performed on e9ternal (non3process side) weld surfaces. −



0< of /

MP 55-P-19

9.(.


July 1998

T)readed Connections Threaded connections are not permitted in sour service for primar! process piping greater than CP 2A<. •

Threaded connections are permitted for secondar! lines, such as for instruments that are downstream of flanged bloc> valves, connected b! welded fittings on the primar! process piping, but their use shall be minimiDed. •

1se of thread connections in other applications ma! be approved on a case3 b!3case basis b! the Mobil pro&ect engineer. •

9.5.

&dentification and Sta'pin" of Material Materials and fabrications ma! be identified using the following: +. ;aised lettering integral to hot forming or casting operations. 0. =ow stress, interrupted dot stamps applied to e9ternal surfaces not e9posed to the sour environment. 2. 6ie stamps applied at a temperature above N" (++//N4) or applied prior to final heat treatment at a minimum temperature of N" (++//N4). <. harp 7ee, rounded 7ee or interrupted dot stamps applied to the low stress area on the outer rim of flanges. . %ndelible mar>ers that are free of chlorides, sulfides and heav! metals such as lead ma! be used where stamping is not permitted or is impractical.



0 of /

%ppendi0 %@ Pressure Pipin"

1A. Pressure Pipin" and Co'ponent Material 0ale A: Pressure Pi%ing and Com%onent MaterialB =esignB )eldingB Farication and on-=estructive *?amination /%tions for ;arious Sour Service Categories SM* ($1$" ote 1"

Critical Service

on-Critical Service

eam welded pipe to 'ppendi9 $ (Cote +/)

ame as for critical service

Material election $ptions Pipe

eamless pipe to 'TM '+/ #; (Cote ++) rought 4ittings

elded carbon steel to 'ppendi9 PH or

ame as for critical service

";' or ";' clad " to match pipe eamless fittings to 'TM '+/A'+/M or 'TM '02
"arbon steel to 'TM '+/A'+/M (Cote ++)

1se materials listed in MP +3 P32/' for sour service

";' or ";' clad " to match pipe 7alves

olting

"A5%" resistant steel ('ppendi9 C)

'll valve parts to meet C'"E M;/+?

";', ";' clad

od! to be casting meeting qualit!@=evel 2 or forgings. od! to be heat treated after welding.

;efer to ection ?

;efer to ection ?

=esign and Farication ote #"



0 of /

MP 55-P-19


ote 1"

July 1998

Critical Service


utt elds

4ull penetration

4ull penetration

mall ore Pipe elds

 (Cote 2)

 preferred,  acceptable (Cote 2) for pipe siDes CP ++A0 and less

ranch "onnection

 tees preferred

 tees preferred

4ull penetration welds for $=s and $=s, if permitted (Cote 2)

4ull penetration welds for $=s, $=s and T$=s (Cotes 2 and <), if permitted

PAPJ; 5ardness

7ic>ers surve! required (Cote ) ;efer to ection .2

urve! required (Cote ) ;efer to ection .2

P5T

;efer to ection .0.0

ee ection .0.+

Production 5ardness

hall be considered . ;efer to ection .2.2

Ma! be considered ee ection .2.2

utt elds

+// percent ;T (Cote -)

Per MP +3P3
ranches

+// percent MT (Cote +/)

+/ percent MT (Cote +/)

Material election $ptions

on-=estructive *?amination

/0*S:

+. ;efer to ections 0 and 2 and EPT /-3T3/2, Materials for our ervice, for a discussion of factors influencing service categor! and t!pical classification of equipment. 0. ;efer to ection  of this Practice for design and fabrication details. 2. ecause of the difficult! of inspecting soc>et welds and due to the problem of crevice corrosion with them, the use of soc>et welds () is discouraged. henever possible, the use of butt welding () connections is recommended. <. MinimiDe use of threaded connections. . 7ic>ers indentor load shall be ≤+/ >g. . 5ardness surve! ma! be b! an! indentation method for which there is an 'TM standard, e9cept rinell. ?. 'pplies to non3clad ". "lad " receives P5T in accordance with 'ME 2+.2, 'ME 2+.< or 'ME 2+.-. -. %nterpret using 'ME 2+.2 for severe c!clic conditions with the e9ception of undercut (1"). 1" shall remain as for +// percent ;T. . %nterpret using 'ME E" 7%%%, 6ivision +, 'ppendi9  or equivalent. +/. piral weld pipe shall not be used.



0? of /

MP 55-P-19


July 1998

++. "E ≤/.<2. Material for hub t!pe connectors shall match the pipe material chemical and mechanical properties. "ompression seal rings used with hub t!pe connectors shall meet the requirements of C'"E M;/+?. (;efer to MP +3P32/'.)

11. ranc) Connections ranch connections in corrosive two3phase environments shall be made from the top of the main header. (;efer to MP +3P3/+.)

1#. /lan"ed Connections 4or corrosive andAor erosive services, provision of a solid Teflon insert for the annular space inside the ;T or spiral wound gas>et shall be considered. The %6 of the insert shall match the pipe bore and the $6 shall match the %6 of the gas>et. (;efer to MP +3P3/+.)

1$. :rains %n the presence of 5 0, all drains shall be hard3piped to a closed drain s!stem. (;efer to MP +3P3 /+.)

1(. Coatin"s E9ternal and internal protective coating s!stems for platform piping and risers shall conform to MP 23P3/+.

15. 6alves and C)oes tainless steel is the preferred internal trim for carbon steel valves. hen hardfacing is required for erosion control, it shall be applied over stainless steel.



0- of /

MP 55-P-19


July 1998

7alve parts that are not freel! vented to the atmosphere shall conform to the sour service requirements of this Practice. This includes insulated valves, buried valves, bolts inside flange protectors or bolting otherwise denied free access to the atmosphere. eld repair of castings shall be minimiDed. 'll valve springs, including those used in bellows3sealed relief valves, shall be made of materials resistant to ". 'cceptable spring materials are listed under clause -.2 of C'"E M;/+?. Elastomers and pac>ings for valves are discussed in ection  of this Practice.



0 of /

%ppendi0 @ Pressure 6essels and To2ers 0ale (A: Caron Steel Pressure ;essel MaterialB =esignB )eldingB Farication and on-=estructive *?amination /%tions For ;arious Sour Service Categories 0y%ically SM* S*C ;222B =ivision 1" ote 1"

Critical Service


5%" tested plate to 'ppendices B and =H or

Billed carbon steel with grid 1T of plate to 'TM '?-A'?-M =evel 0 (Cote 2)

";' "lad Plate (Cote 0)

;estricted chemistr! material withAwithout coating (Cotes < and )

Billed carbon steelH or

Billed carbon steel

Material Selection /%tions

hell and 5eads

Pipe, 4ittings and 4orgings

";' or ";' clad or overla!ed " to match Tubes

;efer to ection 

;efer to ection 

=esign 7 Farication ote "

elds

4ull penetration welds (Cotes ? and -)

4ull penetration welds (Cotes ? and )

CoDDles

;adiographable vessoletsAsweepolets designs preferred

CoDDle design per "ode

et3in or set3through designs acceptable

et3in or set3through designs

et3on designs allowed for openings ≤< CP, on shells and heads with t ≤/ mm (0 in). ;efer to ection .+.0

et3on designs allowed for openings ≤ CP. ;efer to ection .+.


7ic>ers surve! required (Cote +/). ;efer to ection 

urve! required (Cote ++). ;efer to ection 

P5T

;equired, +/N" (++2/N4) min (Cote +0)

;equired, +/N" (++2/N4) min (Cote +0)

Production 5ardness

"onsider

Cot required



2/ of /

MP 55-P-19

ote 1"


Critical Service

July 1998



=ong. 8 #irth elds

4ull ;T (Cote +2)

C6E per MP +03P3/+

4ull 1T if t/ mm (0 in) (Cote +<) 4MT (Cote +) welds e9posed to process CoDDle elds

4MT (Cote +) welds e9posed to process

C6E per MP +03P3/+

4ull 1T if  CP < (Cote +<) /0*S:

+. ;efer to the tutorial EPT /-3T3/2, Materials for our ervice, for a discussion of factors influencing service categor! and t!pical classification of equipment. 0. Economic decisions with respect to use of ";' or carbon steel shall consider life c!cle costs, including e9tended periods between shutdowns and elimination of 4MT during shutdowns and possible elimination of P5T. 2. 1T performed to 'TM '?-A'?-M +.+ and 0.0. 'n! area with one or more discontinuities, which produce a continuous total loss of bac> reflection and cannot be encompassed within a 0 mm (+ in) diameter circle, is unacceptable. <. The qualit! of the coating &ob shall be closel! monitored. . acrificial anodes shall also be considered for use with coatings, in order to supplement corrosion protection. . ;efer to ection  of this Practice for design and fabrication details. ?. 'pplies to all longitudinal seams, circumferential seams and noDDle connections ('ME "ategor! 6 connections). -. 4or critical service, internal attachment welds connecting pressure containing parts shall be full penetration to avoid interface for 5 0 collection (refer to MP +03P3/+). . 4or moderate and mild service, as a minimum, welds connecting non3pressure to pressure parts shall be continuous to seal the perimeter of the part and prevent corrosion behind the attachment (;efer to MP +03P3/+). +/. 7ic>ers indentor load shall be ≤+/ >g. ++. 5ardness surve! ma! be b! an! indentation method for which there is an 'TM standard, e9cept rinell. ;efer to ection .2. +0. 'pplies to non3clad ". 4or clad ", P5T per 'ME E" 7%%%, 6ivision +. +2. ;T to 'ME E" 7%%%, 6ivision +, Paragraph 1+ or equivalent.



2+ of /

MP 55-P-19


July 1998

+<. 1T to 'ME E" 7%%%, 6ivision +, 'ppendi9 +0 or equivalent. +. here accessible, after h!drotest 4MT welds are e9posed to the process according to 'ME E" 7%%%, 6ivision +, 'ppendi9  or equivalent. This is in addition to the requirements of MP +03P3/+.



20 of /

%ppendi0 C@ S)ell and Tube eat 0c)an"ers 3Refer to MP 1$-P-1A4

1*. S)ell and Tube eat 0c)an"er Material 0ale CA: S&ell and 0ue .eat *?c&anger MaterialB =esignB )eldingB Farication and on-=estructive *?amination /%tions for ;arious Sour Service Categories 0*M and SM* S*C ;222B =ivision 1" ote 1"

Critical Service


5%" tested plate to 'ppendices B and =

Billed carbon steel with grid 1T of plate to 'TM '?-A'?-M =evel 0H (Cote 2)

";' "lad Plate (Cote 0)

;estricted chemistr! material

Billed carbon steel

Billed carbon steel


hell, 5ead and "hannel

Pipe, 4ittings and 4orgings

";' or ";' clad or overla!ed " to match Tubes

;efer to ection <

;efer to ection <

elds

4ull penetration welds (Cotes  and )

4ull penetration welds (Cotes  and ?)

CoDDles

;adiographable vessoletsAsweepolets designs preferred

et3in or set3through designs preferred

et3in or set3through designs acceptable

et3on designs allowed for openings ≤ CP <

=esign 7 Farication ote '"

et3on designs allowed for openings ≤ CP <, on shells and heads with t ≤/ mm (0 in) Construction



22 of /

MP 55-P-19


July 1998

ote 1"

Critical Service



7ic>ers surve! required (Cote -)

urve! required (Cote )

P5T

;equired, +/N" (++2/N4) min (Cote +/)

;equired, +/N" (++2/N4) min (Cote +/)

Production eld Test

+// percent required

+/ percent required

4ull ;T (Cote ++)

4ull ;T (Cote ++)

4ull 1T if t/ mm (0 in) (Cote +0)

4MT (Cote +2)


=ong. and "irc. elds

4MT (Cote +2) CoDDle "at. 6 elds

4MT (Cote +2)

4MT (Cote +2)

4ull 1T if  CP < (Cote +0) Tube to Tubeplate elds

4MT ferrous metals, PT non3magnetic metals

4MT ferrous metals, PT non3 magnetic metals

/0*S

+. ;efer to the tutorial EPT /-3T3/2, Materials for our ervice, for discussion of factors influencing service categor! and t!pical classification of equipment. 0. Economic decisions with respect to use of ";' or carbon steel shall consider life c!cle costs, including e9tended periods between shutdowns and elimination of 4MT during shutdowns and possible elimination of P5T. 2. 1T performed to 'TM '?-A'?-M +.+ and 0.0. 'n! area with one or more discontinuities, which produce a continuous total loss of bac> reflection and cannot be encompassed within a 0 mm (+ in) diameter circle, is unacceptable. <. ;efer to ection  of this Practice for design and fabrication details. . 'pplies to all longitudinal seams, circumferential seams and noDDle connections ('ME "ategor! 6 connections). . 4or critical service, internal attachment welds connecting pressure containing parts shall be full penetration to avoid interface for 5 0 collection (refer to MP +03P3/+). ?. 4or moderate and mild service, as a minimum, welds connecting non3pressure to pressure parts shall be continuous to seal the perimeter of the part and prevent corrosion behind the attachment (;efer to MP +03P3/+). -. 7ic>ers indentor load shall be ≤+/ >g. . 5ardness surve! ma! be b! an! indentation method for which there is an 'TM standard, e9cept rinell. ;efer to ection .2. +/. 'pplies to non3clad ". 4or clad ", P5T per 'ME E" 7%%%, 6ivision +.



2< of /

MP 55-P-19


July 1998

++. ;T to 'ME E" 7%%%, 6ivision +, Paragraph 1+ or equivalent. +0. 1T to 'ME E" 7%%%, 6ivision +, 'ppendi9 +0 or equivalent. +2. here accessible, after h!drotest 4MT welds are e9posed to the process according to 'ME E" 7%%%, 6ivision +, 'ppendi9  or equivalent. This is in addition to the requirements of MP +03P3/+.

1. :issi'ilar Materials Tubes shall not be anodic to the tube sheet or shell.



2 of /

%ppendi0 :@ %ir-Cooled eat 0c)an"ers 3Refer to MP 1$-P-154

18. %erial Cooler Material 0ale =A: erial Cooler MaterialB =esignB )eldingB Farication and ondestructive *?amination /%tions For ;arious Sour Service Categories P2 S0= 1" ote 1"

Critical Service


5%" resistant plate to 'ppendi9 =H

Billed carbon steel with grid 1T of plate to 'TM '?-A'?-M =evel 0 (Cote 2)


5eader o9 and Tube Plate

";' "lad Plate (Cote 0)H ";' plate Pipe, 4ittings and 4orgings

Billed carbon steel

Billed carbon steel

";' or ";' clad Tubes

"arbon steel or ";'

"arbon steel

elds

4ull penetration welds (Cotes  and )

4ull penetration welds (Cotes  and ?)

CoDDles

;adiographable vessoletAsweepolet designs preferred

CoDDle design per 'ME E" 7%%%, 6ivision +

=esign 7 Farication ote '"

et3in designs acceptable et3on designs allowed for openings ≤ CP <, on header bo9es with t≤/ mm (0 in) PAPJ; 5ardness

urve! required (Cote -)

urve! required

P5T, 5eader o9

;efer to ection  (Cote )

;efer to ection 

Production eld Tests



2 of /

MP 55-P-19


ote 1"

July 1998

Critical Service


5eader o9 elds

4ull ;T or 1T long seams and end plate welds (Cotes ++ and +0)

;efer to MP +23P3+ (Cote +/)

CoDDle elds

4ull 1T if  CP < (Cote +0)

;efer to MP +23P3+ (Cote +/)


4ull MT all noDDles /0*S:

+. ;efer to ection 2 of this Practice for a discussion of factors influencing service categor! and t!pical classification of equipment. 0. Economic decisions with respect to the use of ";' or carbon steel shall consider life c!cle costs, including e9tended periods between shutdowns and elimination of 4MT during shutdowns. election of ";' depends on actual service conditions and shall be done in consultation with a materials specialist. 2. 1T performed to 'TM '?-A'?-M +.+ and 0.0. 'n! area with one or more discontinuities that produce a continuous total loss of bac> reflection and cannot be encompassed within a 0 mm (+ in) diameter circle is unacceptable. <. ;efer to ection  of this Practice for design and fabrication details. . 'pplies to all longitudinal seams, end plate welds, circumferential seams and noDDle connections ('ME "ategor! 6 connections.) . 4or critical service, welds connecting attachments shall be full penetration, to avoid interface for 50 collection. ?. 4or non3critical service, as a minimum, welds connecting attachments shall be continuous to seal the perimeter of the part and prevent corrosion behind the attachment. -. 5ardness surve! ma! be b! an! indentation method for which there is an 'TM standard, e9cept rinell. here 7ic>ers indenter is used, the load shall be ≤+/ >g. . 'pplies to non3clad ". 4or clad ", P5T in accordance with 'ME E" 7%%%, 6ivision +. +/. ;T to 'ME E" 7%%%, 6ivision +, Paragraph 1+ or equivalent. ++. 1T to 'ME E" 7%%%, 6ivision +, 'ppendi9 +0 or equivalent. +0. MT welds to 'ME E" 7%%%, 6ivision +, 'ppendi9  or equivalent.

18.1. +o==les and Connections Equipment shall have flanged noDDles or connections. lip3on flanges and seal and bac>welded threaded connectors shall not be used. Threaded plugs ma! be used as closures for tube3rolled openings in headers.



2? of /

MP 55-P-19


July 1998

18.#. Plu" S)eet Plu"s Plug threads shall be coated with a mol!bdenum disulfide base lubricant.



2- of /

%ppendi0 @ Plate Type eat 0c)an"ers Plate t!pe heat e9changers shall not be used in critical, sour or to9ic service where gas>et lea>s pose an unacceptable ris>. E9perience shows that plate heat e9changers are ver! reliable and do not have man! lea>age problems. 5owever, due to the large number of gas>ets, there is a potential for lea>age and therefore an unacceptable ris> in critical service.



2 of /

%ppendi0 /@ /ired eaters 6esigns and materials requirements for fired heaters are covered in MP ++3P3/+. 5eater tube materials for 50 service shall also meet all the requirements of C'"E M;/+? and this Practice.



%ppendi0 ,@ Pipelines 3Refer to MP #A-P-A14

19. ,as Pipelines 0ale GA: Gas Pi%eline MaterialB =esignB Construction and on-=estructive *?amination /%tions for ;arious Sour Service Categories Critical Service


5%" tested bare steel pipe (Cote +) with 5%" resistant steel components (Cote +/)H

are steel s!stem (Cote )

Material Selection

Pipe and "omponent Material !stem

";'3 s!stem ";'3" pipe with ";'3, ";'3" or ";'3$ components =esign

ranches

 tees (Cotes 0 and 2)



7ic>ers surve! required (Cote ). ;efer to ection 

5ardness surve! required (Cote ). ;efer to ection 

;epair elds

PJ; required

PJ; required

ac>weld not permitted

ac>weld not permitted



P5T

Per "ode

Per "ode

Production 5ardness

hall be considered

Ma! be required



#irth elds

+// percent ;T (Cote ?)

+// percent ;T

$3=ets

+// percent MT (Cote -)


Construction ote '"




<+ of /

MP 55-P-19


July 1998

/0*S:

+. ;efer to MP 0/3P3/0 for procurement of 5%" resistant and 5%" tested pipe. 0. $3lets shall not be used in siDes greater than CP <. hen $3lets are permitted in lieu of butt welding () tees for outlet siDes equal to or less than CP <, full penetration welds are required for the $3let to run connection. 2. hen pigging facilities are included in the design, barred tees shall be used. elding of bars shall satisf! the requirements of this MEP. <. Table #+ refers to mainline construction. 4or above ground piping (e.g., at wellsites, valve stations, pigging facilities, test facilities, compressor stations or pump stations) refer to ection of this Practice. . 7ic>ers indentor load shall be ≤+/ >g. . 5ardness surve! ma! be b! an! indentation method for which there is an 'TM standard, e9cept rinell. ?. %nterpret using 'ME 2+.- and 'P% T6 ++/< or equivalent, e9cept incomplete penetration greater than +2 mm ( +A0 in), is not permitted. Co burnthroughs are permitted. -. %nterpret using 'ME E" 7%%%, 6ivision +, 'ppendi9  or equivalent. . %nhibitor s!stem ma! be required. +/. P G /./0 percent,  G /./+/ percentH ma9imum !ield strength shall not e9ceed / MPa (-/ >si)H macrohardness ≤00 5;"H microhardness ≤0<- 57 (//)H E; pipe ≥ CP 0 shall be sub&ected to the root guided3bend test.

#A. iuid Multip)ase Pipelines 0ale GA: +iDuid Multi%&ase Pi%eline MaterialB =esignB Construction and on=estructive *?amination /%tions for ;arious Sour Service Categories Critical Service


5%" tested bare steel pipe (Cote +) with 5%" resistant steel components (Cote +/)

are standard steel s!stem (Cote )

";'3 s!stem

"M= steel s!stem

";'3" pipe and ";'3, ";'3" or ";'3$ components

%P" steel s!stem


Pipe 'nd "omponent Material !stem



PE= steel s!stem

<0 of /

MP 55-P-19


July 1998

Critical Service



Per "ode


7ic>ers surve! required (Cotes  and )

7ic>ers surve! required (Cotes  and )

P5T

Per 'ME Piping "ode


Production 5ardness

$ptional

Cot required

#irth elds

+// percent ;T (Cote ?)


$3lets


Per 'ME Piping "ode@ comment on min. +/ percent ;T good practice

=esign

ranches Construction '"


/0*S:

+. ;efer to 'ppendices B and = for guidance with the procurement of 5%" resistant and 5%" tested pipe. 0. hen $3lets are permitted in lieu of butt welding () tees, full penetration welds are required for the $3let to run connection. 2. hen pigging facilities are included in the design, barred tees shall be used. elding of bars shall satisf! the requirements of this MEP. <. Table #30 refers to mainline construction. 4or above ground piping (e.g., at wellsites, valve stations, pigging facilities, test facilities, compressor stations or pump stations). ;efer to 'ppendi9 ' of this Practice. . 7ic>ers indentor load shall be ≤ +/ >g. . 5ardness surve! ma! be b! an! indentation method for which there is an 'TM standard, e9cept rinell. ;efer to ection .2 of this Practice. ?. %nterpret using 'ME 2+.- and 'P% T6 ++/< or equivalent, e9cept incomplete penetration greater than +2 mm ( +A0 in), is not permitted. Co burnthroughs are permitted. -. %nterpret using 'ME E" 7%%%, 6ivision + or equivalent. . %nhibitor s!stem ma! be required. +/. P G/./0 percent, G /./+/ percentH ma9imum !ield strength shall not e9ceed / MPa (-/ >si)H macrohardness ≤ 00 5;"H microhardness ≤ 0<- 57 (//)H E; pipe ≥ CP 0 shall be sub&ected to the root guided3bend test.



<2 of /

MP 55-P-19


July 1998

#1. Cold /or'ed ends "old formed bends to be used in wet 5 0 service shall be given a stress relieving or normaliDing heat treatment if hardness after bending e9ceeds 00 5 (57 +/ 02-) or the cold strain in the outer fiber e9ceeds +. percent. (;efer to MP +3P3
##. ub Type Connectors Material for hub3t!pe connectors shall be plain carbon steel. Micro3allo! and low allo! steels are not acceptable without concurrence from the Mobil materials engineer. "ompression seal rings used with hub3t!pe connectors shall meet the requirements of C'"E M;/+?.



<< of /

%ppendi0 @ &nstru'entation 3Refer to MP $#-P-A14

#$. Tubin" Tubing e9posed to sour service or "$ 0 partial pressures in e9cess of <-.0 >Pa (? psia) shall be T!pe 2+= stainless steel. 4or services with temperatures and chlorides in the stress crac>ing region of 4igure , the tubing material shall be %ncolo! -0 or Monel.

#(. &nstru'ent 6alves and &nstru'ent &nternals %nstrument valves and internals for sour service shall be T!pe 2+= stainless steel. 4or services with temperatures and chlorides in the stress crac>ing region of 4igure , the material shall be %ncolo! -0 or a Monel allo!, if the temperature is less than +/N" (2//N4). ;upture dis>s, diaphragms and bellows shall be %ncolo! -0 or equal. hen the partial pressure of 50 e9ceeds  psia, the material shall be %nconel 0 or equal. %nstrumentation that cannot be heat treated after welding or that cannot function in the softened condition (e.g., bellows, diaphragms, ourdon tubes) shall be manufactured from materials resistant to crac>ing in the hardened or non3heat treated conditions.



< of /

%ppendi0 &@ Tana"e Tan>s designed to store sour liquids shall be fabricated in accordance with this Practice. The wetted materials shall conform to C'"E M;/+?. here 5%"3resistant carbon steel materials are not available, procurement of >illed pressure vessel carbon steels, with specified ultimate tensile strengths not to e9ceed <+,/// >Pa (/,/// psi), shall be considered. %n addition, restrictions on the use of micro3allo!ing additions and "E not to e9ceed /.<2 are recommended. The use of an appropriate organic or inorganic coating, properl! applied and inspected, shall also be considered as further protection against 5%" and $5%" crac>ing.



< of /

%ppendi0 J@ /u"itive 'issions our service facilities are t!picall! sub&ected to low3level atmospheric 5 0 contamination. $ver time, this environment can corrode sensitive electrical equipment and galvaniDed metal buildings. "aution shall be e9ercised in spacing, ventilation and material selection to ensure appropriate reliabilit! and longevit!.



%ppendi0 B@ &C Testin" of Carbon Steel Plate and Pipe

Scope hen proven resistance to 5!drogen %nduced "rac>ing (5%") is required, the 5%" test shall be conducted in accordance with C'"E TM/0-< and this appendi9, using the low p5 solution specified in C'"E TM/+??. 'll references to pipe in C'"E TM/0-< shall be applied to plate, where possible.

#5. Plate #5.1. Test /reuency and ocation $ne plate from each thic>ness of each heat (or ladle if a heat is refined in more than one batch) shall be tested.

#5.#. Test Coupon ;rientation and Re'oval "oupons shall be ta>en from the plate with the longitudinal a9is of the coupon parallel to the rolling direction. Test coupons shall not be heated over 0//N" (20N4) during removal, nor flattened or cold wor>ed.

#5.$. %cceptance Criteria 4or each plate, the "rac> =ength ;atio ("=;), "rac> Thic>ness ;atio ("T;) and "rac> ensitivit! ;atio (";) shall be determined and reported and include the following information:


•

%ndividual values measured on each cross3section of each specimen

•

'verage value for the three cross3sections of each coupon

•

'verage value for the three coupons (nine cross3sections) of each plate


<- of /

MP 55-P-19


July 1998

'cceptance criteria shall be based on the calculated average "=; and "T; for each coupon (i.e., the average of the three individual cross3sectional results for each coupon). These are delineated as "=;cavg and "T;cavg under the following acceptance, re&ection and retest criteria.

#5.(. Tests Test results shall be accepted when: •

"=;cavg ≤+/./ percent

•

"T;cavg ≤+. percent

$n failure to meet these acceptance criteria, retesting shall be sub&ect to negotiation between Mobil and the manufacturer.

#5.5. Reportin" of Test Results %n addition to the reporting requirements of C'"E TM/0-<, the report shall include the following: ' description of the visual appearance of each coupon (e.g., a tabulation of the number of blisters and siDe range for each coupon). •

%ndividual section ";, "=; and "T; for each of the three cross sections of each coupon. •

"oupon average ";, "=; and "T; (i.e., the average of the three cross sections for each coupon). •

Plate average ";, "=; and "T; (i.e., average of the nine cross sections e9amined from the three coupons used for each plate). •

'll ";, "=; and "T; measurements in reports shall be traceable to heat number, castAingot number and location, plate number and plate position. ;esults that do not compl! with the acceptance criteria specified in this appendi9 shall be highlighted in the report. Three copies of reports containing all relevant data and measurements as required b! C'"E TM/0-< and this appendi9 shall be submitted to Mobil.



< of /

MP 55-P-19


July 1998

#*. Pipe #*.1. ydro"en &nduced Cracin" Testin" hen sour service is specified, h!drogen induced crac>ing tests shall be made on line pipe material grades Q0 through Q. $ne pipe selected from ever! +// pipe lengths of each heat shall be tested. pecimens shall be prepared and evaluated in accordance with C'"E TM/0-<, with the test solution modified to conform with the test requirements of C'"E TM/+??. 'cceptance criteria shall be as follows: •

Co transverse crac>s

•

"rac> Thic>ness ;atio ("T;) shall be less than +. percent

•

"rac> =ength ;atio ("=;) shall be less than +/./ percent

#*.#. Retest %f an! test fails, two additional pipe lengths shall be selected at random from the +// lengths and retested. %f either of the tests fail, each pipe from the lot of +// lengths shall be tested for individual acceptance.



/ of /

%ppendi0 @ &C Resistant Plate

#. Scope This appendi9 provides guidance on the procurement of 5%" and " resistant steel plateH however, proof of resistance b! testing is not required. %f proven 5%" or " resistance is deemed necessar!, testing procedures and standards of acceptance shall be specified (refer to 'ppendi9 B for 5%" testing and C'"E TM/+?? for " testing).

#8. Steel'ain" #8.1. 6acuu' :e"assin" The plate steel shall be vacuum degassed (refer to 'ME E" %%', upplementar! ;equirement +).

#8.#. :eo0idation Practice Plate steel shall be full! >illed.

#8.$. ,rain Si=e "arbon and carbon manganese steel plate shall be made to fine grain practice.

#8.(. &nclusion S)ape Control Plate material deo9idiDed with both silicon and aluminum shall be manufactured utiliDing an inclusion shape control melting practice.



+ of /

MP 55-P-19


July 1998

#9. C)e'ical %nalysis #9.1. eat %nd Product %nalysis oth heat and product anal!sis for carbon and carbon3manganese steels shall satisf! the requirements of the following: Material

Ma?imum +imit in Percent

"arbon

/.+

Manganese

+.0/

Phosphorus

/./+

ulfur

/.//2

ilicon

/.2

Total $ther Elements

+./

"arbon Equivalent (%%)

/.<2

#9.#. nspecified le'ents The quantit! of unspecified elements shall be within the limits stated in 'ME E" %%', Table + and in the above table.

$A. eat Treat'ent Material shall be normaliDed at +2N" R +2N" (+?N4 R 0N4) for one hour per 0 mm (+ in) of thic>ness. 4or steel less than 0 mm (+ in), the minimum hold time shall be one hour.

$1. Mec)anical Properties =ow strength steel plate, such as 'TM '+A'+M #rade  or /, is preferred.



0 of /

MP 55-P-19


July 1998

$#. +on-:estructive 0a'ination 3T a'ination C)ec4 Plate shall be sub&ect to straight3beam ultrasonic e9amination according to 'TM '?-A'?-M and the appropriate inspection levels indicated in the table below. upplementar! requirements +.+ (+// percent surface scan) and 0.0 (alternate acceptance level) shall be applied when indicated b! the table. ;egarding the alternate acceptance level, the plate shall be re&ected when an! area with one or more discontinuities, producing a continuous total loss of bac> reflection, cannot be encompassed within the specified circle diameter. 4or each inspection level, the recording of indications shall appl! to all plate thic>nesses. ;ecordable indications shall be reported in a s>etch that mirrors the geometr! of the plate and dimensions the location and depth (from the test surface) of the recordable indications. (;efer to MP +03P3/+.) +evel 1

+evel #

+evel $

Plate Thic>ness

t ≤+/ mm (t ≤2A- in)

t ≤/ mm (t ≤0 in)

t ≥/ mm (t ≥0in)

5%" Test

Cot ;equired

Cot ;equired

;equired

canning =evel

Per 'TM '?-A'?-M

Per 'TM '?-A'?-M +.+ (+// percent)

Per 'TM '?-A'?-M +.+ (+// percent)

"ircle iDe

Per 'TM '?-A'?-M, =evel %%

0 mm (+ in)

 mm (+A< in)

$$. &C Testin" %n critical service, 5%" tests shall be performed b! suppliers to prove that their steel possesses sufficient 5%" resistance. 5%" testing procedures based on C'"E TM/0-<, with a C'"E TM/+?? low p5 solution, are provided in 'ppendi9 B of this Practice. 4or acceptance, the "T; (crac> thic>ness ratio) and "=; (crac> length ratio) shall not e9ceed +. percent and +/./ percent, respectivel!. 6etailed information on acceptance and retest criteria are provided in 'ppendi9 B.



2 of /

%ppendi0 M@ Carbon Steel Castin"s for Severe Service

$(. Scope This appendi9 provides guidance on the procurement of carbon steel castings for valves, flanges, fittings or other pressure containing parts for severe service. Proof of resistance to sulfide stress crac>ing (") is not requiredH however, if proven resistance to " is desired, testing procedures and standards of acceptance shall be specified on the purchasing documents.

$5. C)e'ical %nalysis "hemical anal!sis shall satisf! the requirements of 'TM '0+A'0+M or 'TM '20A'20M, for carbon steels and carbon3manganese steels, as applicable. Total unspecified elements shall not e9ceed /.+/ percent. The carbon equivalent of butt welding castings shall not e9ceed /.<2.

$*. eat Treat'ent "astings shall be heat treated to ensure hardness below 0// 5 throughout. The method of heat treatment and the timeAtemperature thermal c!cle shall be shown on the mill certificate.

$. ardness Testin" The surface of each casting shall be hardness tested using an indentation method recogniDed b! an 'TM standard. 5ardness shall not e9ceed 0// 5 or equivalent, as determined b! conversion tables in 'TM '2?/ ;E7 ' or 'TM E+


< of /

MP 55-P-19


July 1998

$8. +on-:estructive 0a'ination $8.1. 0a'ination %ccordin" to MP A$-P-A# "astings shall be e9amined to the Jualit! %l requirements of MP /23P3/0.

$8.#. 0a'ination of
$9. Repair by
(A. Certification "astings shall be supplied with certification equivalent to the requirements of 'TM '?/2A'?/2M ;E7 '.



 of /

%ppendi0 +@ Sea'
Scope This appendi9 provides guidance on the procurement of 5%" and " resistant carbon steel pipe for severe sour service. The process conditions shall be stated on the purchasing documents. hen proof of 5%" or " resistance is necessar!, detailed testing procedures and standards of acceptance shall be specified b! the Mobil Materials pecialist.

(1. Steel'ain" (1.1. :eo0idation teel shall be full! >illed.

(1.#. &nclusion S)ape Control teel deo9idiDed with both silicon and aluminum shall be inclusion shape controlled.

(#. C)e'ical %nalysis oth heat and product anal!sis of carbon and carbon3manganese steels shall satisf! the requirements of the material standard or the following table, whichever is more stringent. Material


"arbon

/.+

Manganese

+.0/

Phosphorus

/./+

ulfur

/.//2



 of /

MP 55-P-19


Material


ilicon

/.2


+./

"arbon Equivalent

/.
July 1998

($. Metallur"ical Condition of R< Sea' ness, as a result of a normaliDing treatment.

((. Mec)anical Properties The actual ultimate tensile strength of procured pipe shall be restricted to a ma9imum number of /,/// >Pa (-/,/// psi). ;epresentative cross3section samples of the seam weld shall be metallurgicall! e9amined and hardness tested. The metallurgical e9amination shall be proof of the microstructure of the weld. ' hardness surve! ta>en across the weldment from parent metal to parent metal using the 7ic>ers +/ >g load shall not result in a hardness e9ceeding 0<- 5v +/.

(5. &C Testin" "onsideration shall be given to 5%" testing of pipe according to C'"E TM/0-<, using the low p5 solution defined in C'"E TM/+??. "T; (crac> thic>ness ratio) and "=; (crac> length ratio) shall not e9ceed +. percent and +/./ percent respectivel!. %f necessar!, a s!stem for retesting ma! be developed from information contained in 'ppendi9 B.

(*. Certification Mill certification shall reflect the fact that 5%" testing has been performed and was satisfactor! (if required).



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%ppendi0 ;@ Carbon Steel
Scope This appendi9 provides guidance on the procurement of 5%" and " resistant wrought carbon steel fittings for severe sour service. hen proof of 5%" or " resistance is considered necessar!, testing procedures and standards of acceptance shall be specified b! the Mobil materials engineer. 4ittings shall meet the requirements of a recogniDed fitting material standard such as 'TM '02
(. Steel'ain" (.1. :eo0idation teel shall be full! >illed.

(.#. Steel ,rain Si=e teel shall be made to a fine grain practice.

(.$. &nclusion S)ape Control teel deo9idiDed with both silicon and aluminum shall be inclusion shape controlled.

(.(. C)e'ical %nalysis oth heat and product anal!sis shall satisf! the requirements of the material standard or the following Ma9imum =imit data, whichever is more stringent. 7anadium used for grain refinement or deo9idiDation shall not e9ceed /./- percent (;efer to 'TM '?--, 0.+).



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MP 55-P-19


Material


"arbon

/.+

Manganese

+.0/

Phosphorus

/./+

ulfur

/.//2

ilicon

/.2


+./

"arbon Equivalent

/.
July 1998

(8. /ittin" Manufacture 4or welded fittings, the control of welding, P5T and C6E are necessar!. Manufacture b! cold wor> shall not be permitted without subsequent thermal stress relief adequate to reduce hardness below 0// 5.

(9. Mec)anical Properties The actual ultimate tensile strength of procured fittings shall be a ma9imum of /,/// >Pa (-/,/// psi). The surface of each fitting shall be hardness tested using an indentation method recogniDed b! an 'TM standard. 5ardness shall not e9ceed the lesser of that required b! the material standard, 0// 5 or equivalent as determined b! conversion tables in 'TM '2?/ ;E7 ' or 'TM E+
5A.


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Materials and Corrosion for Sour Service

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