MSS SP 55 2006 Scaned - [PDF Document] (2024)

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MSS SP-55-2006

Quality Standard for Steel Castingsfor Valves ; . ~ a n g e sFittings andOther Piping ComponentsVisual Method

forEvaluatiOn of Surface Irregularities

Standard PracticeDeveloped and Approved by theManufacturersStandardization Society o theValve and Fittings Industry Inc.127Park Street NEVIenna Virginia 22180Phone: 703) 281-6613F a x : 7 03 ) 2 8 1 ~ 7 1E-mail: [emailprotected]

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www.mss-hq.org

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MSS STANDARD PR CTICE SP-55

This MSS Standard Practice was developed under the consensus ofthe MSS Technical Committee 304 andthe MSS Coordinating Committee.The content of this Standard Practice is the result of the effortsofcompetent and concerned volunteers to provide an effective,clear, and nonexclusive specification thatwill benefit the industrya whole. This MSS Standard Practice is intended as a basis forcommonpractice by the manufacturer, the user, and the generalpublic. The existence of an MSS Standard Practicedoes not in itselfpreclude the manufacture, sale, or use of products not confonningto the StandardPractice. Mandatory conformance is established onlyby reference in a code, specification, sales contract, orpubliclaw, as applicable.

Unless otherwise specifically noted in this MSS SP, any standardreferred to herein is identified by the dateof issue that wasapplicable to the referenced standard(s) at the date of issue ofthis MSS SP. (See AnnexA.)

Non-toleranced dimensions i n ~ t a n d a r d Practice are.nominal, and _ unless o t h e r w ~ _ J P e c i f i e d s_halJbeconsidered for reference only .

In this Standard Practice all notes, annexes, tables, andfigures are construed to be essential to theunderstanding of themessage of the standard, and are considered part of the text unlessnoted assupplemental . All appendices appearing in this documentare construed as supplemental .Supplemental'' information does notinclude mandatory requirements.

U.S. customary units in this SPare the standard; the metric (SI)units are for reference only.

Any part of this standard may be quoted. Credit lines shouldread Extractedfrom MSS SP-55, 2006 withpermission of the publisher,the Manufacturers Standardization Society. Reproduction prohibi tedundercopyright convention unless written pennission is granted bythe Manufacturers Standardization Society ofthe Valve and FittingsIndustry Inc.

Originally Approved April, 1961

Copyright 1985 byManufacturers Standardization SocietyoftheValve and Fittings Industry, Inc.Printed in U.S.A.

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MSS ST ND RD PR CTICE

FOREWORThe MSS SP-55 Quality Standard for Steel Castings forValves Flanges Fittings and Other PipingComponents- Visual Methodfor Evaluation of Surface Irregularities was originally adopted in1961. It wasdeveloped for the purpose of providing the industrywith a uniform means for identifying various types ofcastingsurface irregularities.A set of 60 reference photographsillustrating these casting surface irregularities is included inthis StandardPractice to permit a visual comparison of an actualcasting surface with the reference photographs for thepurpose ofthe establishing acceptable/unacceptable casting surfaceirregularities.The format of this Standard Practice was revised in1996 to be consistent with other MSS Standard Practices.

.. - :_c o:_This 2006 revis ed edition includes :updatefin t1wreferenced standards Annex A to .reflect current applicabledatesand the updated addresses of the referenced publicationsorganizations.

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MSS STANDARD PRACTICE SP-SS

T BLE OF CONTENTS

SECTION1 SCOPE.................................................................................................................................................12 DEFINITION OF SURFACE QUALITY BY VISUAL INSPECTION............................................. 13 REFERENCEPHOTOGRAPHS ........................................................................................................ 14 -lERMINOLOGY FOR REFERENCE PHOTOGRABHS..................................................................1. COMPARISON OEMSS S P ~ 5 S ACCEPTANCE CRITERIA WITH SCRATASTANDARD... : c O V E R I N G ~ S U R F A C ETE:XTURlfQUALITYSTAFIDAimS: .... ~ ~ ~ : : . : . ~ . : : . ~ . : .: : ~ ~ : ~ : : : ~ : : : r .

TABLE. Acceptance Levels in the Scrata Comparators ConsideredEquivalent tothe Acceptance Criteria of MSS SP-55................................................................................................3

ANNEXA Referenced Standards and Applicab1e Dates....................................................................................4

PHOTOGRAPHS.................................................................................................................TypeI through XII

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MSS STANDARDPRACTICE I SP-55QUALITY STANDARDFOR STEEL CASTINGSFOR VALVES, FLANGES, FlmNGS AND OTHER PIPING

COMPONENTS - VISUAL METHOD FOR EVALUATION OF SURFACEIRREGULARITIESI.: scOPE.1.1 This Standard Practice is intendedtosupplement the requirements of ASTMSpecifications A 216/A 216M, A217/A 217M, A351/A 351M, A 3S'lJA 352M, A 389/A 389M, A487/A 487M,and A 744/A 144M and to provide aseries of reference photographstypical of thevarious surface irregularities common tosteelpressure castings and illustrations of generallyacceptable andgenerally r e j ~ t a b l e quality. Table 1of Section 5 isprovided to show MSS interpretation

- ' ~ . ........ as to the relationsh ip.-ween thisStandardhacticeand the le:vels...oLsurface . quality illustrate.dby thecomparators- and the photOgraphs of the SteelCasting Researchand Trade Association (SCRAT A)Comparators for the Definition ofSurface Quality ofSteel Castings.

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1.2 For additional nondestructive examinationsdefining qualityof steel castings, this StandardPractice may be supplemented by thefollowingStandard Practices: SP-53 "Magnetic ParticleExaminationMethod", SP-54 "RadiographicExamination Method", SP-93 "LiquidPenetrantExamination Method", SP-94 "UltrasonicExamination Method"and SP-112 "Visual andTactile Method".

2. DEFINITION OF SURFACE QUALITY BYVISUAL INSPECI'ION2.1 Twelve.general types of surface irregularitiesare characterized in thecollection with fiveexamples being included of each type. Thetwoexamples in each case shown to the left illustrateacceptabledegrees of the particular type ofirregularity. The three examplesto the right arecharacterized as containing unacceptabledefects.2.2 It is recognized that problems may beencountered inevaluating surfaces of castings over awide range of size andsection thickness using thesame set of standards. This guideattempts to.minimize the size effect and is intended forgeneral useror any 4 ln. x 5 in. (100mm x125mm) area.

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3. REFERENCE PHOTOGRAPHS3.1 A set of 60 reference photographsillustratingvarious casting surface irregularities, which canbeobserved by visual inspection, is included herewith.Thesephotographs are actual-size examples ofgradations in acceptable andnon-acceptableirregularities. It is intended that irregularitieslesspronounced than those shown as non-acceptableshall be acceptedunder this guide.3.2 Photographs included are of actual castingsandmay exhibitft fface irregularities other than thetype c h ~ a c t er i z e d - _ i n . _ h ~ h e ~ i n g ~ h type ofsurfaceirregularity shallDe judged only against theseries of photographsidentified with the type.

4. TEJMJNOLOGY FOR REFEBENCEPHOTOGRAPHS4.1 It should be notedthat all definitions anddiscussions of terminologies apply only tosurfaceirregularities and not to internal defectc;. The typesofsurface irregularities illustrated in the referencephotographs areas follows:

a ype Hot Tears and racksLinear surface discontinuities orfracturescaused by either internal or external stressesor acombination of both acting on thecasting. They may occur during,orsubsequent to, solidification. In general,visible surface cracksor hot tears, or both,are not acceptable.

b ype ShrinkageA void left in cast metai as a resultofsolidification shrinkage and the progressivefreezing of metal,which is exposed uponcutting off risers and gates.c) Type III SandInclusionsSand that becomes entrapped in the moltenmetal and showson the surface of thecasting.

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MSS STANDARD PRACTICE SP-55

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d) Type V Gas PorosityVoids in cast metal caused by entrapmentofgas during solidification.

e) Type V VeiningFeatures on the surface of castingsappearing asa ridge and associated withmovement or cracking of sand.f Type VIRat TailsFeatures on the surface of castings

appearing as a depression resulting fromfaulting or buckling ofthe mold surfaces.g) Type VII Wrinkles Laps - F-olds and Cold.. :.:-Siriits_ -_ - .-

Surface irregularities caused by incompletefusing or by foldingof molten metalsurfaces.h Type VIII Cutting Markslqegularities incasting surfaces resultingfrom burning or mechanical mean51 usedin

the cleaning of castings.i) Type X Scabs

S l i ~ h t l y raised surface blemishes that reusually sandcrusted over by a thin porouslayer of metal.j) Type Chaplets

Evidence of chaplets on surface of castingdisclosing incompletefusion, whichlikewise can apply to internal chills.k Type XI WeldRepairAreas

Evidence of improper surface preparationafter welding.

l) Type XII Surface RoughnessSurface texture due to design.pattern,gating, and sand conditions.

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5. COMPARISON OF SP-55 ACCEPTANCECRITERIA Wim SCRATASTANDARDCOVERING TEXTURE QUALITYSTANDARDS

5.1 MSS and other societies have publishedstandards illustratingvarious levels of surfacetexture and irregularities classified bytype. TheSCRATA standard discussed in this section does notidentityspecific levels as being acceptable. leavingthe issue to theproduct specification or contract.5.2 Table 1 has been included forthe purpose ofshowing MSS interpretation as to the levelsofdiscontinuity by type. which would be met bycastingscotifotltnngto P = 5 ~ . -- .... : v ~ . ... .-..:...:.- .-, - -.=5.3 The SCRATA comparators are plastic replicasof actual castingsurfaces, each of which is alsorepresented by photograph. Thestandard suggests. designating acceptance criteria on drawings.5.4SP 55 acceptance criteria have been reviewedagainst the SCRATAstandard to designate the.acceptance criteria of each type. whichareequivalent to SP-55 acceptance criteria.Comparisons published inTable 1 represent theMSS interpretation. They are intended to beofassistance to those interpreting the SCRAT Astandard.

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MSS

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STANDARD PRACTICE

T BLEAcceptance Levels in the SCRATA Comparators ConsideredEquivalent to theAcceptance Criteria of SP-SSSP-55 SCRATACOMPARATORSCLASSIFICATION EQUIVALENT

TYPE IHot tears and cracks None Acceptable(None acceptable)

TYPE IT NO EXAMPLESShrinkage Use MSS SP-55

t . , < .. ~ . _ .. ...-l YFEUI . ___ - - ... ------ B2 _ _---Sand Inclusions . or better - - .. - TYPE IV C2Gas Porosity orbetterTYPEV NO EXAMPLESVeining Use MSS SP-55TYPE VI NO EXAMPLESRatTails Use MSS SP-55TYPE VII D2Wrinkles, Laps, Folds, and Cold Shutsor betterTYPEVIIT G2 or betterCutting Marks H4 or betterTYPE IXEl

Scabs or betterTYPE X F2Chaplets or betterTYPE XI J3

Weld Repair Areas or betterTYPE.Xll A3Surface Roughness orbetter

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MSS STANDARD PRACTICE SP-55

NNEXReferenced Standards and Applicable Dates

This Annex is an integral part of this Standard Practice and isplaced after the main text for convenience.Standard Name orDescription

ASTMA 216/A 216M- 2004A 217/A 217M- 2004A 351/A 351M- 2006A352/A 352M - 2006A 389/A 389M ;; 2003 ,A 487/A 487M- l993 R03)A744/A 744M- 2000 R06)

MSSSP-53-1999 R 2002)SP-54-1999 R 2002)SP-93-1999 R2004)SP-94-1999 R 2004)SP-112-1999 R 2004)

SCR T

Standard Specification for:Steel Castings, Carbon, Suitable forFusion Welding for High Temperature ServiceSteel Castings,Martensitic Stainless and Alloy for Pressure Contain ingParts,Suitable for High Temperature ServiceSteel Castings,Austenitic, Austenitic-Ferritic Duplex), for Pressure-ContainingPartsSteel Castings, Ferri ic and Martensitic, for PressureContaining Parts,Suitable for Low-Temperature ServiceSteetCastings,Alloy, Specially Heat Treated, for Pressure ContainingParts,Suitable for High Temperature ServiceSteel Castings, Suitablefor Pressure Service

C a ~ t i n g s Iron-Chromium-Nickel Base, Corrosion Resistant,for Severe Service

Quality Standard for Steel Castings and Forgings for Valves,Flanges and Fittingsand Other Piping Components - Magnetic ParticleExamination MethodQuality Standard for Steel Castings for Valves,Flanges and Fittings and OtherPiping Components -RadiographicExamination MethodQuality Standard for Steel Castings and Forgingsfor Valves, Flanges and Fittings andOther Piping Components -Liquid Penetrant Examination MethodQuality Standard for Ferri icand Martensitic Steel Castings for Valves. Flanges andFittings andOther Piping Components - Ultrasonic Examination MethodQualityStandard for Evaluation of Cast Surface Finishes - Visual andTactile Method

Comparators for the Defmition of Surface Quality of SteelCastings

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NOTE: The two acceptable uampl of thistype do not show hot tearsor crad sNo irregularities of this Type areacceptable der thisstandGrd

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