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KUWAITSECTION
September
NEWSLETTER 2009
FOR PRIVATE CIRCULATION ONLY
INSIDE THIS ISSUE
TECHNICAL WINDOW
MEMBERS AREA
PRODUCT REVIEW
FROMSECTION PRESIDENTS DESK
I am pleased to release the September 2009 Newslof ISA- KuwaitSection.
We invite ISA Members and other AutomaProfessionals to contribute articles to be published innewsletter.
Pleasesend your feedback about your expectationsISA- KuwaitSection to
BestRegards
Ali H Al HashemiPresident
ISA- Kuwait Section
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ISA KUWAIT SECTION OFFICE
Ali H Al HashemiPresident
Ali H. AlawadhiVice President
PP MuthuSecretary
C. DakshinamurthyTreasurer
Chandra Sekhar, SMembership Chair
Kuwait National Petroleum Co
Kuwait National Petroleum Co
Rezayat Trading Co LtdOffice 24816836 Ext. 146Cell 9437119
Kuwait Oil CoOffice 23822713
Kuwait Oil Co
Weinvite interested ISAmembers towriteanythingaboutAutomation tobepublished
in thismonthlyNewsletter.
WeinviteIA&C Manufacturersandtheirrepresentatives to usethisnewsletter to
advertise their productofferings.
Invitation to Members
EditorialBoard
Shemej KumarK.K
DrajatSatriotomo
P.PMuthu
GijoKAugustine
8/13/2019 Sep 09 Issue
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SULFIDE STRESS CRACKING - NACE MR0175
History
Requirements
The NACE Standard MR0175, "SulfideStress Corrosion Cracking Resistant MetallicMaterials for Oil Field Equipment" is widelyused throughout the world. The standardspecifies the proper materials, heat treatconditions and strength levels required toprovide good service life in sour gas and oil.
environments. NACE (National Associationof Corrosion Engineers) is a worldwidetechnical organization which studies variousaspects of corrosion and the damage thatmay result in refineries, chemical plants,water systems, and other industrial systems.
MR0175 was first issued in 1975, but theorigin of the document dates to 1959 when agroup of engineers in Western Canada
pooled their experience in successfulhandling of sour gas. The group organizedas NACE committee T-1B and in 1963issued specification 1B163,"Recommendations of Materials for SourService." In 1965, NACE organized thenationwide committee T-1F-1 which issued1F166 in 1966 and MR0175 in 1975. Thespecification is revised on an annual basis.
NACE committee T-1F-1 continues to haveresponsibility for MR0175. All revisions andadditions must be unanimously approved bythe 500-plus member committee T-1,
Corrosion Control in Petroleum Production.MR0175 is intended to apply only to oil fieldequipment, flow line equipment, and oil fieldprocessing facilities where H2S is present.Only sulfide stress cracking (SSC) isaddressed. Users are advised that otherforms of failure mechanisms must beconsidered in all cases. Failure modes, such
as severe general corrosion, chloride stresscorrosion cracking, hydrogen blistering orstep-wise cracking are outside the scope ofthe document. Users must carefully considerthe process conditions when selecting
materials.While the standard is intended to be usedonly for oil field equipment, industry hastaken MR0175 and applied it to many otherareas including refineries, LNG plants,pipelines, and natural gas systems. The
judicious use of the document in theseapplications is constructive and can helpprevent SSC failures wherever H2S ispresent.
The various sections of MR0175 cover thecommonly available forms of materials andalloy systems. The requirements for heattreatment, hardness levels, conditions ofmechanical work, and post-weld heattreatment are addressed for each form ofmaterial. Fabrication techniques, bolting,platings, and coatings are also addressed.
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Figure 1
Figure 2
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Figures 1 and 2 taken from MR0175 definethe sour systems where SSC may occur.Low concentrations of H2S at low pressuresare considered outside the scope of thedocument. The low stress levels at lowpressures or the inhibitive effects of oil maygive satisfactory performance with standardcommercial equipment. Many users,however, have elected to take aconservative approach and specify NACEcompliance any time a measurable amount
of H2S is present. The decision to followMR0175 must be made by the user basedon economic impact, the safety aspectsshould a failure occur, and past fieldexperience. Legislation can impact thedecision as well. MR0175 must now befollowed by law for sour applications underseveral jurisdictions; Texas (RailroadCommission), off-shore (under U.S. MineralsManagement Service), and Alberta, Canada(Energy Conservation Board).
Figure 3
Figure 4
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The Basics of Sulfide StressCracking
Carbon Steel
Cast Iron
Stainless Steel
SSC develops in aqueous solutions ascorrosion forms on a material. Hydrogenions are a product of many corrosionprocesses (Figure 3). These ions pick up
electrons from the base material producinghydrogen atoms. At that point, two hydrogenatoms may combine to form a hydrogenmolecule. Most molecules will eventuallycollect, form hydrogen bubbles, and floataway harmlessly. Some percentage of thehydrogen atoms will diffuse into the basemetal and embrittle the crystalline structure.When the concentration of hydrogenbecomes critical and the tensile stressexceeds the threshold level, SSC occurs.H2S does not actively participate in the SSCreaction; sulfides promote the entry of the
hydrogen atoms into the base material.In many instances, particularly amongcarbon and low alloy steels, the cracking willinitiate and propagate along the grainboundaries. This is called intergranularstress cracking. In other alloy systems orunder specific conditions, the cracking willpropagate through the grains. This is calledtransgranular stress corrosion cracking.Sulfide stress cracking is most severe atambient temperature, 20 to 120F (-7 to49C). Below 20F (-7C) the diffusion rateof the hydrogen is so slow that the critical
concentration is never reached. Above120F (49C) the diffusion rate is so fast thatthe hydrogen passes through the material insuch a rapid manner that the criticalconcentration is not reached. Theoccurrence of stress corrosion crackingabove 120F (49C) is still likely and mustbe carefully considered when selectingmaterial. In most cases, the stress corrosioncracking will not be SSC but some otherform. Chloride stress corrosion cracking islikely in deep sour wells as most exceed300F (149C) and contain significant
chloride levels.The susceptibility of a material to SSC isdirectly related to its strength or hardnesslevel. This is true for carbon steels, stainlesssteels, and nickel based alloys. Whencarbon or alloy steel is heat treated toprogressively higher hardness levels, thetime to failure decreases rapidly for a givenstress level (Figure 4). Years of field
experience have shown that good SSCresistance is obtained below 22 HRC for thecarbon and low alloy steels. SSC can stilloccur below 22 HRC, but the likelihood offailure is greatly reduced.
Carbon and low alloy steels have acceptableresistance to SSC provided their processingis carefully monitored. The hardness mustbe less than 22 HRC. If welding orsignificant cold working is done, stress reliefis required. Even though the base metalhardness of a carbon or alloy steel is lessthan 22 HRC, areas of the heat effectedzone will be harder. Post-weld heattreatment will eliminate these excessivelyhard areas.
ASME SA216 grades WCB and WCC arethe most commonly used body castingmaterials. It is Fishers policy to stressrelieve all WCB and WCC castings toMR0175 whether they have been welded ornot. This eliminates the chance of a weldrepair going undetected and not beingstress-relieved.
ASME SA352 grades LCB and LCC are verysimilar to WCB and WCC. They are impacttested at -50F (-46C) to ensure goodtoughness in low temperature service. LCBand LCC are used in the northern U.S.,
Alaska, and Canada where temperaturescommonly drop below the -20F (-32C)permitted for WCB. All LCB and LCCcastings to MR0175 are also stress-relieved.
Gray, austenitic, and white cast irons cannotbe used for any pressure retaining parts,due to low ductility. Ferritic ductile iron to
ASTM A395 is acceptable when permittedby ANSI, API, or industry standards.
UNS S41000 stainless steel (410 stainlesssteel) and other martensitic grades must bedouble tempered to a maximum allowablehardness level of 25 HRC. Post-weld heattreatment is also required. S41600 stainlesssteel is similar to S41000 with the exceptionof a sulfur addition to produce freemachining characteristics. Use of free
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machining steels is not permitted byMR0175.
CA6NM is a modified version of the castS41000 stainless steel. MR0175 allows itsuse, but specifies the exact heat treatmentrequired. Generally, the carbon content must
be restricted to 0.3 percent maximum tomeet the 23 HRC maximum hardness. Post-weld heat treatment is required for CA6NM.
The austenitic stainless steels haveexceptional resistance to SSC in theannealed condition. The standard specifiesthat these materials must be 22 HRCmaximum and free of cold work to preventSSC. The cast and wrought equivalents of302, 304, 304L, 305, 308, 309, 310, 316,316L, 317, 321, and 347 are all acceptableper MR0175.
Post-weld heat treatment of the 300 Seriesstainless steels is not required. Thecorrosion resistance may be effected bywelding. However, this can be controlled byusing the low carbon grades, or low heatinput levels and low interpass temperatures.
Wrought S17400 (17-4PH) stainless steel isallowed, but must be carefully processed toprevent SSC. The standard now gives twodifferent acceptable heat treatments forS17400. One treatment is the double H1150heat treatment which requires exposing thematerial at 1150F (621C) for four hours
followed by air cooling and then exposing foranother four hours at 1150F (621C). Amaximum hardness level of 33 HRC isspecified. The second heat treatment is theH1150M treatment. First, the material isexposed for two hours at 1400F (760C),then air cooled and exposed for four hoursat 1150F (621C). The maximum hardnesslevel is the same for this condition.
CB7Cu-1 (Cast 17-4PH) is not approved perMR0175. However, many users havesuccessfully applied it for trim parts in pastyears in the same double heat treated
conditions as the wrought form.
Two high strength stainless steel grades areacceptable for MR0175. The first is S66286(grade 660 or A286) which is a precipitationhardening alloy with excellent resistance toSSC and general corrosion. The maximumhardness level permitted is 35 HRC.
The second material is S20910 (XM-19)which is commonly called Nitronic 50R. Thishigh strength stainless steel has excellentresistance to SSC and corrosion resistancesuperior to S31600 or S31700. Themaximum allowable hardness is 35 HRC.The "high strength" condition, whichapproaches 35 HRC, can only be producedby hot working methods. Cold drawnS20910 is also acceptable for shafts, stems,and pins. It is our experience that the SSCresistance of S20910 is far superior toS17400 or other austenitic stainless steelsat similar hardness levels. The only othermaterials with similar stress crackingresistance at these strength levels are thenickel-based alloys which are, of course,much more expensive. A few duplexstainless steels are now acceptable perMR0175. Wrought S31803 (2205) and
S32550 (Ferralium 255) are acceptable to28 HRC. Wrought S32404 (Uranus 50) isacceptable to 20 HRC. Only one cast duplexstainless steel is acceptable, alloy Z6CNDU20.08M, NF A 320-55 FrenchNational Standard.
The final category in MR0175 is thenonferrous materials section. In general, thenickel-based alloys are acceptable to amaximum hardness level of 35 HRC. All
have excellent resistance to SSC.Commonly used acceptable materialsinclude nickel-copper alloys N04400 (alloy400) and N04405 (alloy 405) and theprecipitation hardening alloy N05500 (K500).The nickel-iron-chromium alloys includealloys N06600 (alloy 600) and N07750 (alloyX750). The acceptable nickel-chromium-molybdenum alloys include alloys N06625(alloy 625), and N10276 (alloy C276). Theprecipitation hardening grade N07718 (alloy718) is also acceptable to 40 HRC. Wherehigh strength levels are required along withgood machinability, Emerson ProcessManagement Regulator Technologies usesN05500, N07718, N07750, or N09925 (alloy925). They can be drilled or turned, then agehardened. Several cobalt based materialsare acceptable, including R30035 (alloyMP35N), R30003 (Elgiloy), and R30605(Haynes 25 or L605).
Nonferrous Alloys
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Aluminum based and copper alloys may beused for sour service, but the user iscautioned that severe corrosion attack mayoccur on these materials. They are seldomused in direct contact with H2S.
Several wrought titanium grades are now
included in MR0175. The only commonindustrial alloy is R50400 (grade 2).
Springs in compliance with NACE representa difficult problem. To function properly,springs must have very high strength(hardness) levels. Normal steel andstainless steel springs would be verysusceptible to SSC and fail to meet MR0175.
In general, very soft, low strength materialsmust be used. Of course, these materials
produce poor springs. The two exceptionsallowed are the cobalt based alloys, such asR30003, which may be cold worked andhardened to a maximum hardness of 60HRC and alloy N07750 which is permitted to50 HRC.
Coatings, platings, and overlays may beused provided the base metal is in acondition which is acceptable per MR0175.The coatings may not be used to protect a
base material which is susceptible to SSC.Coatings commonly used in sour service arechromium plating, electroless nickel (ENC)and ion nitriding. Overlays and castingscommonly used include CoCr-A (StelliteR oralloy 6), R30006 (alloy 6B), and NiCr-C(ColmonoyR 6) nickel-chromium-boronalloys. Tungsten carbide alloys areacceptable in the cast, cemented, orthermally sprayed conditions. Ceramiccoatings such as plasma sprayed chromiumoxide are also acceptable.
ENC is often used by Emerson Process
Management Regulator Technologies as awear-resistant coating. As required byMR0175, it is applied only to acceptablebase metals. ENC has excellent corrosionresistance in sour, salt containingenvironments.
Many people have the misunderstandingthat stress relieving following machining isrequired by MR0175. Provided goodmachining practices are followed usingsharp tools and proper lubrication, theamount of cold work produced is negligible.SSC resistance will not be affected. MR0175actually permits the cold rolling of threads,provided the component will meet the heattreat conditions and hardness requirementsspecified for the given parent material. Colddeformation processes such as burnishingare also acceptable.
Bolting materials must meet therequirements of MR0175 when bolting isdirectly exposed to a sour environment.Standard ASTM A193 grade B7 bolts or
A194 grade 2H nuts can be used perMR0175 provided they are outside of thesour environment. If the bolting will bedeprived atmospheric contact by burial,insulation, or flange protectors, then gradesof bolting such as B7 and 2H areunacceptable. The most commonly usedfasteners for "exposed" applications are
ASTM A193 grade B7M bolts and A194grade 2M nuts. They are tempered andhardness tested versions of the B7 and 2Hgrades. HRC 22 is the maximum allowablehardness.
Many customers use only B7M bolting forbonnet, packing box, and flange joints. Thisreduces the likelihood of SSC if a leakdevelops and goes undetected orunrepaired for an extended time. It must beremembered, however, that use of lowerstrength bolting materials such as B7M oftenrequires pressure vessel derating.
MR0175 does not address elastomer andpolymer materials. However, the importance
of these materials in critical sealing functionscannot be overlooked. User experience hasbeen successful with elastomers such asnitrile, neoprene, fluoroelastomer (FKM),and perfluoroelastomer (FFKM). In general,fluoropolymers such as teflon (TFE) can beapplied without reservation within theirnormal temperature range.
Springs
Coatings
Stress Relieving
Bolting
Composition Materials
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Codes and Standards
The Commercial Application of NACE
Applicable ASTM, ANSI, ASME, and APIstandards are used along with MR0175 asthey would normally be used for otherapplications. The MR0175 requires that allweld procedures be qualified to these same
standards. Welders must be familiar with theprocedures and capable of making weldswhich comply.
Special documentation of materials toMR0175 is not required by the standard andNACE itself does not issue any type of acertification. It is the producer'sresponsibility to properly monitor thematerials and processes as required byMR0175.
It is not uncommon for manufacturers to"upgrade" standard manufacturedcomponents to MR0175 by hardness testing.This produces a product which complieswith MR0175, but which may not provide thebest solution for the long-term. If theconstruction was not thoroughly recorded atthe outset, it may be difficult to getreplacement parts in the proper materials.The testing necessary to establish that eachpart complies is quite expensive. And, dueto the "local" nature of a hardness test, thereis also some risk that "upgraded" parts do
not fully comply.With proper in-house systems, it is quitesimple to confidently produce a constructionwhich can be certified to MR0175 withoutthe necessity of after manufacture testing.This eliminates many costly extras andadditionally provides a complete record ofthe construction for future parts procurement.
An order entry, procurement, andmanufacturing system which is integratedand highly structured is required in order toconfidently and automatically provideequipment which complies.
Due to its hierarchical nature and its use byall company functions, Emerson ProcessManagement Regulator Technologiessystem is ideal for items such as MR0175which requires a moderate degree of controlwithout undue cost. In order to illustrate thesystem used by Emerson ProcessManagement Regulator Technologies, anexample will be used.
Most products produced by EmersonProcess Management RegulatorTechnologies (including products to MR0175)will be specified by a Fisher Standard (FS)number. These numbers (e.g. FSED-542)completely specify a standardizedconstruction including size, materials, andother characteristics. The FS number is ashort notation which represents a series ofpart groups (modules) describing theconstruction. One module may represent a3-inch WCB valve body with ANSI Class 300flanges, another may specify a certain valveplug and seat ring. The part numbers whichmake up these modules are composed of adrawing number and a material/finishidentifier. The drawing describes thedimensions and methods used to make thepart, while the material/finish referenceconsiders material chemistry, form, heat
treatment, and a variety of other variables.The part number definition also includes avery specific "material reference number"which is used to identify a materialspecification for purchase of materials. Thematerial specification includes the ASMEdesignation as well as additional qualifiers,as necessary, to ensure compliance withspecifications such as NACE MR0175.
For NACE compliant products, an FSnumber and a NACE option are generallyspecified. The FS number establishes thestandard construction variation. The optionmodifies the construction and materials tocomply totally with MR0175 requirements.The option eliminates certain standardmodules and replaces them with NACEsuitable modules. Each part in a NACEsuitable module has been checked to assurethat it complies to the specification in formand manufacturing method and that it isproduced from an appropriate material.
It is due to this top-to-bottom systemintegrity that Emerson Process ManagementRegulator Technologies can be confident of
MR0175 compliance without the need forextensive test work. At each level of thesystem documentation, there are specificreferences to and requirements forcompliance to MR0175. Further, since theconstruction is permanently documented atall levels of detail, it is possible to confidentlyand simply procure replacement parts at anyfuture date.
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Test documentation is available in a varietyof forms, including certificates of compliance,hardness test data, chemical and physicaltest reports, and heat treat reports. Sincethese items will have some cost associatedwith them, it is important to examine theneed for documentation in light of thevendor's credibility and manufacturingcontrol systems. Emerson ProcessManagement Regulator Technologies'snormal manufacturing processes andprocedures assure that all NACE specifiedproducts will comply without the need foradditional test expense.
Emerson Process Management RegulatorTechnologies has been producingequipment for a variety of sour conditionsand specifications since the mid-1950's andhas thousands of devices in service.MR0175 has been shown to be an excellenttechnical reference for solving the complexapplication problems found in the handlingof sour fluids. As more sour hydrocarbonsare produced, it grows in importance andapplicability.
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MEMBER AREA
New international achievement for KNPC: Specialist Ali Alawadhi has
achieved and became a permanent member in the international standard
IEC 61511.
Engineer Ali Alawadhi, Specialist Instrument Design of MAB refinery, was invited to
join as a permanent member the technical committee of the international standard IEC
61511 and was invited to attend the committee semi-annual meeting that was conductedbetween 12-14 May 2009 in The Hague, Netherlands.
The three days meetings included members representing United State of America,
United Kingdom, Netherlands, Norway, Finland, France, China, and Germany. Mr.
Alawadhi who is the fi rst certified Functional Safety Expert from Kuwait b y the C FSEorganization, is the first member to join the committee Middle East region.
As the opening meeting start ed, the chairman asked the new members of b oth Kuwait andFinland to introduce themselves. Mr. Alawadhi briefed the members of his technical
background and experience. He also demonstrated the strategic role Kuwait is p laying in
the oil sector and how Kuwait National Petroleum Company is continuously improvingthe integrity and availability of its refineries with the latest technology in line with the
vision and the values committed by KNPC top management to achieve high Performance,
building best people and always adopt best practices.
During the meetings, Mr. Alawadhi was selected to join two task teams working on thenew revision of international standard, the hardware Fault Tolerance team and the Safety
Manual task team. He is in the process of registering the s tate of Kuwait to have the full
membership of IEC (International Electrotechnical Commission) in order to participate inthe IEC voting process.
Asking Mr. Alawadhi for his experience of the event, he Sayed: The most interesting,
intensive and informative ev ent I h ave ever experienced. He added it was very excitingto work with experts from all around the world and to h ear some referring to KNPC
experience during the meetings from the p oints and issues I have raised and consideringour feedback and requirements as end-users in the new revision of the international
standards.
Up Coming Event
ISA Kuwait Section in association with EMERSON PROCESS
MANAGEMENT will be arranging a technical session on Smart Wireless
Solutions Engineering for Processon Wednesday October 07, 2009.The venue and time will be intimated to all members in the course of time.
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ScopeCorder Captures and Analyzes Real Time Electro-Mechanical Signals.
Todays engineers depend increasingly upon versatile test equipment with a wide variety ofmeasurements. is just such a capable instrument, which
enables simultaneous measurement & Analysis of various Electro-Mechanical parameters.
ScopeCorder is a new measurement tool combining the fu of an forcapturing instantaneous phenomena and of a data for monitoring long-term-trend.
The DL750 allows inputs from physical sensors such as thermocouples, strain gages or
acceleration sensors. As such it has become popular instrument among engineers working
in different areas like Research, Development, Production, Quality and Maintenance across
the industries like Electrical & Electronics, Power, Process, Automotive, Aerospace, and
electromechanical etc.
The DL750 packs a large display on the front, a hard drive inside, and a printer on top. The
unit's left side panel is populated with three USB ports, an Ethernet port, a SCSI port, a
video port, a GPIB port, 16 bit digital input Connectors, and a ZIP drive/ floppy drive, or PC
Card drive with a space for the power plug. On the right side, the DL750 has a room for 8
two-channel input modules.
In between the inputs and
communications ports, the
10-kg DL750 has up to 1
GW of memory. You can
allocate the memory to any
channel or combination of
channels. The instrumentoffers a wide range of user-
selectable Input Modules
(such as logic, temperature,
strain, acceleration, rotational analysis, frequency, d voltage) that covers almost every
measurement need. It packs speeds of up to 10 MS/sec with 12-bit resolution and 1 MS/s at
16-bit resolution. Most modules provide 1000 V of signal isolation.
DL750 ScopeCorder can capture and analyze data in real time with functions usually
reserved for digital oscilloscopes. Functions include channel math (such as sine, cosine, log,
and integrals), digital filtering, spectral analysis, and go/no-go limit testing. With all of its
capabilities, the DL750 ScopeCorder, is going to be a Must Have Instrument in everyrelated industry & plant.
In recognition of the instrument's reliability and versatility, the editors of
have named it the . The
annual Test of Time award honors a product that continues to provide state-of-the- art
performance for at least five years after its introduction.
The from packs up to 16 analog inputs,16 logic channels, and almost every I/O port imaginable into a portable,lar e-screen instrument.
Yokogawa DL750 ScopeCorder
oscilloscoperecorder
winner of the 2008 Test of Time award
DL750 ScopeCorder Yokogawa
Wide Range of Plug-in Modules
For Detailed information please contact [email protected]
Test &
Measurem ent World
