1、 ANSI/MSS SP-55-2011 Quality Standard for Steel Castings for Valves, Flanges, Fittings, and Other Piping Components Visual Method for Evaluation of Surface Irregularities Standard Practice Developed and Approved by the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. 12
2、7 Park Street, NE Vienna, Virginia 22180-4602 Phone: (703) 281-6613 Fax: (703) 281-6671 E-mail: infomss-hq.org MSS www.mss-hq.org ANSI/MSS STANDARD PRACTICE SP-55i This MSS Standard Practice was developed under the consensus of the MSS Technical Committee 304 and the MSS Coordinating Committee. In a
3、ddition, this Standard Practice was approved by an ANSI/MSS Consensus Committee and by ANSI as an American National Standard. The content of this Standard Practice is the resulting efforts of competent and experienced volunteers to provide an effective, clear, and non-exclusive standard that will be
4、nefit the industry as a whole. This MSS Standard Practice describes minimal requirements and is intended as a basis for common practice by the manufacturer, the user, and the general public. The existence of an MSS Standard Practice does not in itself preclude the manufacture, sale, or use of produc
5、ts not conforming to the Standard Practice. Mandatory conformance to this Standard Practice is established only by reference in other documents such as a code, specification, sales contract, or public law, as applicable. MSS has no power, nor does it undertake, to enforce or certify compliance with
6、this document. Any certification or other statement of compliance with the requirements of this Standard Practice shall not be attributable to MSS and is solely the responsibility of the certifier or maker of the statement. “Unless indicated otherwise within this MSS Standard Practice, other standar
7、ds documents referenced to herein are identified by the date of issue that was applicable to this Standard Practice at the date of approval of this MSS Standard Practice (see Annex A). This Standard Practice shall remain silent on the validity of those other standards of prior or subsequent dates of
8、 issue even though applicable provisions may not have changed.” By publication of this Standard Practice, no position is taken with respect to the validity of any potential claim(s) or of any patent rights in connection therewith. MSS shall not be held responsible for identifying any patent rights.
9、Users are expressly advised that determination of patent rights and the risk of infringement of such rights are entirely their responsibility. In this Standard Practice, all text, notes, annexes, tables, figures, and references are construed to be essential to the understanding of the message of the
10、 standard, and are considered normative unless indicated as “supplemental”. All appendices, if included, that appear in this document are construed as “supplemental”. Note that supplemental information does not include mandatory requirements. Substantive changes in this 2011 edition are “flagged” by
11、 parallel bars as shown on the margins of this paragraph. The specific detail of the change may be determined by comparing the material flagged with that in the previous edition. U.S. customary units in this Standard Practice are the standard; (SI) metric units are for reference only. Non-toleranced
12、 dimensions in this Standard Practice are nominal, and, unless otherwise specified, shall be considered “for reference only”. Excerpts of this Standard Practice may be quoted. Credit lines should read Extracted from ANSI/MSS SP-55-2011 with permission of the publisher, Manufacturers Standardization
13、Society of the Valve and Fittings Industry, Inc. Reproduction and/or electronic transmission or dissemination is prohibited under copyright convention unless written permission is granted by the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. All rights reserved. Origi
14、nally Published: April 1961 Current Edition Approved by MSS: September 2010 Current Edition Approved by ANSI/MSS Consensus Committee: August 2011 Current ANSI/MSS Edition Published: October 2011 MSS is a trademark of the Manufacturers Standardization Society of the Valve and Fittings Industry, Inc.
15、Copyright , 2011 by Manufacturers Standardization Society of the Valve and Fittings Industry, Inc. Printed in U.S.A. ANSI/MSS STANDARD PRACTICE SP-55ii FOREWORD The MSS SP-55, Quality Standard for Steel Castings for Valves, Flanges, Fittings, and Other Piping Components Visual Method for Evaluation
16、of Surface Irregularities, was originally adopted in 1961. It was developed for the purpose of providing the industry with a uniform means for identifying various types of casting surface irregularities. A set of 60 reference photographs illustrating these casting surface irregularities is included
17、in this Standard Practice to permit a visual comparison of an actual casting surface with the reference photographs for the purpose of the establishing acceptable/unacceptable casting surface irregularities. The format of this Standard Practice was revised in 1996 to be consistent with other MSS Sta
18、ndard Practices. The 2006 revised edition included updates in the referenced standards, Annex A, to reflect current applicable dates and the updated addresses of the referenced publications organizations. This 2011 revised American National Standard edition includes updates to the applicable organiz
19、ations and referenced standards, indicating current dates, names, and addresses of the referenced publications or organizations within this Standard Practice. In addition, an Annex B has been introduced that contains the pre-existing set of 60 reference photographs, along with various editorial corr
20、ections that include Section 5. IMPORTANT NOTICE: Due to variations in viewing environments, the printed version published by MSS shall be the “official” rendering of this Standard Practice for inspection, code, or any other purpose. ANSI/MSS STANDARD PRACTICE SP-55iii TABLE OF CONTENTS SECTION PAGE
21、 1 SCOPE 1 2 DEFINITION OF SURFACE QUALITY BY VISUAL INSPECTION 1 3 REFERENCE PHOTOGRAPHS 1 4 TERMINOLOGY FOR REFERENCE PHOTOGRAPHS . 1 5 COMPARISON OF MSS SP-55 ACCEPTANCE CRITERIA WITH CTI COMPARATORS COVERING SURFACE TEXTURE QUALITY STANDARDS 2 TABLE 1 Acceptance Levels in the CTI Comparators Con
22、sidered Equivalent to the Acceptance Criteria of MSS SP-55 . 3 ANNEX A Referenced Standards and Applicable Dates 4 B Type I through XII Acceptable and Unacceptable Reference Photographs . 6 ANSI/MSS STANDARD PRACTICE SP-551 1. SCOPE 1.1 This Standard Practice is intended to supplement the requiremen
23、ts of ASTM Standard Specifications A216/A216M, A217/A217M, A351/A351M, A352/A352M, A389/A389M, A487/A487M, and A744/A744M, and to provide a series of reference photographs typical of the various surface irregularities common to steel pressure castings and illustrations of generally acceptable and ge
24、nerally rejectable quality. Table 1 of Section 5 is provided to show MSS interpretation as to the relationship between this Standard Practice and the levels of surface quality illustrated by the comparators and the associated photographs of the Castings Technology International (CTI), “Comparators f
25、or the Definition of Surface Quality of Steel Castings”. 1.2 For additional nondestructive examinations defining quality of steel castings, this Standard Practice may be supplemented by the following MSS Standard Practices: SP-53, “Magnetic Particle Examination Method”; SP-54, “Radiographic Examinat
26、ion Method”; SP-93, “Liquid Penetrant Examination Method”; SP-94, “Ultrasonic Examination Method”; and SP-112, “Visual and Tactile Method”. 2. DEFINITION OF SURFACE QUALITY BY VISUAL INSPECTION 2.1 Twelve general types of surface irregularities are characterized in the collection (see Section 3) wit
27、h five examples being included for each type. The two examples in each case shown to the left illustrate acceptable degrees of the particular type of irregularity. The three examples to the right are characterized as containing unacceptable defects. 2.2 It is recognized that problems may be encounte
28、red in evaluating surfaces of castings over a wide range of size and section thickness using the same set of standards. This guide attempts to minimize the size effect and is intended for general use for any 4 in. x 5 in. (100mm x 125mm) area. 3. REFERENCE PHOTOGRAPHS 3.1 A set of 60 reference photo
29、graphs illustrating various casting surface irregularities, which can be observed by visual inspection, is included herewith (see Annex B). These photographs are actual size examples of gradations involving acceptable and non-acceptable irregularities. It is intended that irregularities less pronoun
30、ced than those shown as non-acceptable shall be accepted under this guide. 3.2 Photographs included are of actual castings and may exhibit surface irregularities other than the type characterized in the heading. Each type of surface irregularity shall be judged only against the series of photographs
31、 identified with the type. 4. TERMINOLOGY FOR REFERENCE PHOTOGRAPHS 4.1 It should be noted that all definitions and discussions of terminologies apply only to surface irregularities and not to internal defects. The types of surface irregularities illustrated in the reference photographs are as follo
32、ws: a) Type I Hot Tears and Cracks Linear surface discontinuities or fractures caused by either internal or external stresses or a combination of both acting on the casting. They may QUALITY STANDARD FOR STEEL CASTINGS FOR VALVES, FLANGES, FITTINGS, AND OTHER PIPING COMPONENTS VISUAL METHOD FOR EVAL
33、UATION OF SURFACE IRREGULARITIES ANSI/MSS STANDARD PRACTICE SP-552 occur during, or subsequent to, solidification. In general, visible surface cracks or hot tears, or both, are not acceptable. b) Type II Shrinkage A void left in cast metal as a result of solidification shrinkage and the progressive
34、freezing of metal, which is exposed upon cutting off risers and gates. c) Type III Sand Inclusions Sand that becomes entrapped in the molten metal and shows on the surface of the casting. d) Type IV Gas Porosity Voids in cast metal caused by entrapment of gas during solidification. e) Type V Veining
35、 Features on the surface of castings appearing as a ridge and associated with movement or cracking of sand. f) Type VI Rat Tails Features on the surface of castings appearing as a depression resulting from faulting or buckling of the mold surfaces. g) Type VII Wrinkles, Laps, Folds and Cold Shuts Su
36、rface irregularities caused by incomplete fusing or by folding of molten metal surfaces. h) Type VIII Cutting Marks Irregularities in casting surfaces resulting from burning or mechanical means used in the cleaning of castings. i) Type IX Scabs Slightly raised surface blemishes that are usually sand
37、 crusted over by a thin porous layer of metal. j) Type X Chaplets Evidence of chaplets on surface of casting disclosing incomplete fusion, which likewise can apply to internal chills. k) Type XI Weld Repair Areas Evidence of improper surface preparation after welding. l) Type XII Surface Roughness S
38、urface texture due to design, pattern, gating, and sand conditions. 5. COMPARISON OF MSS SP-55 ACCEPTANCE CRITERIA WITH CTI COMPARATORS COVERING SURFACE TEXTURE QUALITY STANDARDS 5.1 MSS and other societies have published standards illustrating various levels of surface texture and irregularities cl
39、assified by type. 5.2 Table 1 has been included for the purpose of showing MSS interpretation as to the levels of discontinuity by type, which would be met by castings conforming to MSS SP-55. 5.3 The CTI Comparators are plastic replicas of actual casting surfaces, each of which is also represented
40、by a photograph of the replica. 5.4 MSS SP-55 acceptance criteria have been reviewed against the CTI Comparators to designate the acceptance criteria of each type, which are equivalent to MSS SP-55 acceptance criteria. Comparisons published in Table 1 represent the MSS interpretation. They are inten
41、ded to be of assistance to those interpreting the CTI Comparators (1). (1) The CTI surface comparators for steel castings discussed in Section 5 do not identify specific levels as being acceptable. Such issues are left to the product specification or contract. ANSI/MSS STANDARD PRACTICE SP-553 TABLE
42、 1 Acceptance Levels in the CTI Comparators Considered Equivalent to the Acceptance Criteria of MSS SP-55 MSS SP-55 CLASSIFICATION CTI COMPARATORS EQUIVALENT TYPE I Hot tears and cracks (None acceptable) None Acceptable TYPE II Shrinkage NO EXAMPLES Use MSS SP-55 TYPE III Sand Inclusions B2 or bette
43、r TYPE IV Gas Porosity C2 or better TYPE V Veining NO EXAMPLES Use MSS SP-55 TYPE VI Rat Tails NO EXAMPLES Use MSS SP-55 TYPE VII Wrinkles, Laps, Folds, and Cold Shuts D2 or better TYPE VIII Cutting Marks G2 or better H4 or better TYPE IX Scabs E1 or better TYPE X Chaplets F2 or better TYPE XI Weld
44、Repair Areas J3 or better TYPE XII Surface Roughness A3 or better ANSI/MSS STANDARD PRACTICE SP-554 ANNEX A Referenced Standards and Applicable Dates This Annex is an integral part of this Standard Practice and is placed after the main text and before Annex B (Photographs) for convenience. Standard
45、Name Description ASTM; ANSI/ASTM Standard Specification for: A216/A216M-08 Steel Castings, Carbon, Suitable for Fusion Welding, for High-Temperature Service A217/A217M-10 Steel Castings, Martensitic Stainless and Alloy, for Pressure-Containing Parts, Suitable for High-Temperature Service A351/A351M-
46、10 Castings, Austenitic, for Pressure-Containing Parts A352/A352M-06 Steel Castings, Ferritic and Martensitic, for Pressure-Containing Parts, Suitable for Low-Temperature Service A389/A389M-10 Steel Castings, Alloy, Specially Heat-Treated, for Pressure-Containing Parts, Suitable for High-Temperature
47、 Service A487/A487M-93(2007) Steel Castings Suitable for Pressure Service A744/A744M-10 Castings, Iron-Chromium-Nickel, Corrosion Resistant, for Severe Service MSS SP-53-1999 (R 2007) Quality Standard for Steel Castings and Forgings for Valves, Flanges, and Fittings and Other Piping Components Magne
48、tic Particle Examination Method SP-54-1999 (R 2007) Quality Standard for Steel Castings for Valves, Flanges and Fittings and Other Piping Components Radiographic Examination Method SP-93-2008 Quality Standard for Steel Castings and Forgings for Valves, Flanges, Fittings, and Other Piping Components
49、Liquid Penetrant Examination Method SP-94-2008 Quality Standard for Ferritic and Martensitic Steel Castings for Valves, Flanges, Fittings, and Other Piping Components Ultrasonic Examination Method SP-112-2010 Quality Standard for Evaluation of Cast Surface Finishes Visual and Tactile Method CTI Comparators for the Definition of Surface Quality of Steel Castings (Relevant to ICS Number Code 77.140.80 - Iron and Steel Castings) ANSI/MSS STANDARD PRACTICE SP-555 ANNEX A (Continued) Referenced Standards and Applicable Dates Publications of the following o
