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MSS SP-55-2006

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

forEvaluatiOn of Surface Irregularities

Standard PracticeDeveloped and Approved by theManufacturers Standardization Society o theValve and Fittings Industry Inc.127 Park Street NEVIenna Virginia 22180Phone: 703) 281-6613F a x : 7 0 3 ) 2 8 1 ~ 7 1E-mail: info@mss-hq.org

C v t M S SPrcMdod IHS u n d o l l c wM MSSNo roproduction or nolworlclng ponnlho wlhout from IHS

www.mss-hq.org

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Capyridlt MSS

MSS STANDARD PR CTICE SP-55

This MSS Standard Practice was developed under the consensus of the MSS Technical Committee 304 andthe MSS Coordinating Committee. The content of this Standard Practice is the result of the efforts ofcompetent and concerned volunteers to provide an effective, clear, and nonexclusive specification thatwill benefit the industry a whole. This MSS Standard Practice is intended as a basis for commonpractice by the manufacturer, the user, and the general public. The existence of an MSS Standard Practicedoes not in itself preclude the manufacture, sale, or use of products not confonning to the StandardPractice. Mandatory conformance is established only by reference in a code, specification, sales contract, orpublic law, as applicable.

Unless otherwise specifically noted in this MSS SP, any standard referred to herein is identified by the dateof issue that was applicable to the referenced standard(s) at the date of issue of this 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_halJ beconsidered for reference only .

In this Standard Practice all notes, annexes, tables, and figures are construed to be essential to theunderstanding of the message of the standard, and are considered part of the text unless noted assupplemental . All appendices appearing in this document are construed as supplemental .Supplemental'' information does not include 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 should read Extractedfrom MSS SP-55, 2006 withpermission of the publisher, the Manufacturers Standardization Society. Reproduction prohibi ted undercopyright convention unless written pennission is granted by the Manufacturers Standardization Society ofthe Valve and Fittings Industry Inc.

Originally Approved April, 1961

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

Prollidod by IHS unclor lic. oa wilh SSNo rwproducllon or n orlclng willux t .. . orn IHS

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MSS ST ND RD PR CTICE

FOREWORThe MSS SP-55 Quality Standard for Steel Castings for Valves Flanges Fittings and Other PipingComponents- Visual Method for Evaluation of Surface Irregularities was originally adopted in 1961. It wasdeveloped for the purpose of providing the industry with a uniform means for identifying various types ofcasting surface irregularities.A set of 60 reference photographs illustrating these casting surface irregularities is included in this StandardPractice to permit a visual comparison of an actual casting surface with the reference photographs for thepurpose of the establishing acceptable/unacceptable casting surface irregularities.The format of this Standard Practice was revised in 1996 to be consistent with other MSS Standard Practices.

.. - :_c o:_This 2006 revis ed edition includes :updatefin t1w referenced standards Annex A to .reflect current applicabledates and the updated addresses of the referenced publications organizations.

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MSS STANDARD PRACTICE SP-SS

T BLE OF CONTENTS

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

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

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

PHOTOGRAPHS .................................................................................................................Type I through XII

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

COMPONENTS - VISUAL METHOD FOR EVALUATION OF SURFACE IRREGULARITIESI.: scOPE.1.1 This Standard Practice is intended tosupplement the requirements of ASTMSpecifications A 216/A 216M, A 217/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 photographs typical of thevarious surface irregularities common to steelpressure castings and illustrations of generallyacceptable and generally r e j ~ t a b l e quality. Table 1of Section 5 is provided to show MSS interpretation

- ' ~ . ........ as to the relationsh ip.-ween this Standardhacticeand the le:vels...oLsurface . quality illustrate.d by thecomparators- and the photOgraphs of the SteelCasting Research and Trade Association (SCRAT A)Comparators for the Definition of Surface Quality ofSteel Castings.

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1.2 For additional nondestructive examinationsdefining quality of steel castings, this StandardPractice may be supplemented by the followingStandard Practices: SP-53 "Magnetic ParticleExamination Method", SP-54 "RadiographicExamination Method", SP-93 "Liquid PenetrantExamination 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 the collection with fiveexamples being included of each type. The twoexamples in each case shown to the left illustrateacceptable degrees of the particular type ofirregularity. The three examples to the right arecharacterized as containing unacceptable defects.2.2 It is recognized that problems may beencountered in evaluating surfaces of castings over awide range of size and section thickness using thesame set of standards. This guide attempts to.minimize the size effect and is intended forgeneral use ror any 4 ln. x 5 in. (100mm x125mm) area.

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1

3. REFERENCE PHOTOGRAPHS3.1 A set of 60 reference photographs illustratingvarious casting surface irregularities, which can beobserved by visual inspection, is included herewith.These photographs are actual-size examples ofgradations in acceptable and non-acceptableirregularities. It is intended that irregularities lesspronounced than those shown as non-acceptableshall be accepted under this guide.3.2 Photographs included are of actual castingsand may exhibitft fface irregularities other than thetype c h ~ a c t e r i z e d - _ i n . _ h ~ h e ~ i n g ~ h type ofsurface irregularity shallDe judged only against theseries of photographs identified with the type.

4. TEJMJNOLOGY FOR REFEBENCEPHOTOGRAPHS4.1 It should be noted that all definitions anddiscussions of terminologies apply only to surfaceirregularities and not to internal defectc;. The typesof surface irregularities illustrated in the referencephotographs are as follows:

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

b ype ShrinkageA void left in cast metai as a result ofsolidification shrinkage and the progressivefreezing of metal, which is exposed uponcutting off risers and gates.c) Type III Sand InclusionsSand that becomes entrapped in the moltenmetal and shows on 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 entrapment ofgas during solidification.

e) Type V VeiningFeatures on the surface of castingsappearing as a ridge and associated withmovement or cracking of sand.f Type VI Rat TailsFeatures on the surface of castings

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

Surface irregularities caused by incompletefusing or by folding of molten metalsurfaces.h Type VIII Cutting Markslqegularities in casting surfaces resultingfrom burning or mechanical mean51 used in

the cleaning of castings.i) Type X Scabs

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

Evidence of chaplets on surface of castingdisclosing incomplete fusion, whichlikewise can apply to internal chills.k Type XI Weld RepairAreas

Evidence of improper surface preparationafter welding.

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

PrOYi- by HS under lie . . . with MSSNo ,.11'-' ' or n-or111ng pormltl8d without li from IHS2

5. COMPARISON OF SP-55 ACCEPTANCECRITERIA Wim SCRATA STANDARDCOVERING TEXTURE QUALITYSTANDARDS

5.1 MSS and other societies have publishedstandards illustrating various levels of surfacetexture and irregularities classified by type. TheSCRATA standard discussed in this section does notidentity specific levels as being acceptable. leavingthe issue to the product specification or contract.5.2 Table 1 has been included for the purpose ofshowing MSS interpretation as to the levels ofdiscontinuity by type. which would be met bycastings cotifotltnngto P = 5 ~ . -- .... : v ~ . ... .-..:...:.- .-, - -. =5.3 The SCRATA comparators are plastic replicasof actual casting surfaces, each of which is alsorepresented by photograph. The standard suggests. designating acceptance criteria on drawings.5.4 SP 55 acceptance criteria have been reviewedagainst the SCRATA standard to designate the.acceptance criteria of each type. which areequivalent to SP-55 acceptance criteria.Comparisons published in Table 1 represent theMSS interpretation. They are intended to be ofassistance to those interpreting the SCRAT Astandard.

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MSS

- . . . . ~

STANDARD PRACTICE

T BLEAcceptance Levels in the SCRATA Comparators Considered Equivalent to theAcceptance Criteria of SP-SSSP-55 SCRATA COMPARATORSCLASSIFICATION 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 or betterTYPEV NO EXAMPLESVeining Use MSS SP-55TYPE VI NO EXAMPLESRat Tails Use MSS SP-55TYPE VII D2Wrinkles, Laps, Folds, and Cold Shuts or betterTYPEVIIT G2 or betterCutting Marks H4 or betterTYPE IX El

Scabs or betterTYPE X F2Chaplets or betterTYPE XI J3

Weld Repair Areas or betterTYPE.Xll A3Surface Roughness or better

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SP-SS

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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 is placed after the main text for convenience.Standard Name or Description

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

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

SCR T

Standard Specification for:Steel Castings, Carbon, Suitable for Fusion Welding for High Temperature ServiceSteel Castings, Martensitic Stainless and Alloy for Pressure Contain ing Parts,Suitable for High Temperature ServiceSteel Castings, Austenitic, Austenitic-Ferritic Duplex), for Pressure-Containing PartsSteel Castings, Ferri ic and Martensitic, for Pressure Containing Parts,Suitable for Low-Temperature ServiceSteetCastings, Alloy, Specially Heat Treated, for Pressure Containing Parts,Suitable for High Temperature ServiceSteel Castings, Suitable for 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 Particle Examination MethodQuality Standard for Steel Castings for Valves, Flanges and Fittings and OtherPiping Components -Radiographic Examination MethodQuality Standard for Steel Castings and Forgings for Valves, Flanges and Fittings andOther Piping Components - Liquid Penetrant Examination MethodQuality Standard for Ferri ic and Martensitic Steel Castings for Valves. Flanges andFittings and Other Piping Components - Ultrasonic Examination MethodQuality Standard for Evaluation of Cast Surface Finishes - Visual and Tactile Method

Comparators for the Defmition of Surface Quality of Steel Castings

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NOTE: The two acceptable uampl of thistype do not show hot tears or crad sNo irregularities of this Type areacceptable der this standGrd

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