1、_ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising there
2、from, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2014 SAE International All rights reserved. No part of this p
3、ublication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AIR4779CAEROSPACEINFORMATION REPORT AIR4779 REV. CIssued 1994-06 Revised 2014-01
5、Superseding AIR4779B Users Guide to AMS Specifications RATIONALE AIR4779C results from a Five Year Review and update of this information report. FOREWORD SAE has been the source of Aerospace Material Specifications since 1939 when the SAE Aircraft Materials Division issued the original 101 specifica
6、tions. Aeronautical Material Specifications, as AMS were originally known, were created in response to a recognized need for industry-generated, industry-oriented specifications that would eliminate, or markedly reduce the number of individual company specifications covering the same materials or pr
7、ocesses. AMS specifications continue to be developed by the Aerospace Materials Division (AMD) under the direction of the SAE Aerospace Council. Commodity committees, with members from aerospace companies, material producers, processors, independents, and government organizations, meet at least twic
8、e each year to review and issue new or revised documents. There are now more than 2400 AMD documents used throughout the world to define, procure, and produce aerospace materials. An AMS specification is designed to be an enforceable procurement document defining a product or a service, part of the
9、contract between a purchaser and a vendor of products or services. It is necessary that it be complete, precise, unambiguous, and reasonable. Although AMS specifications are said to be “users specifications“, they are the result of considerable discussion and negotiation between users and producers.
10、 An AMS specification has to be a compromise between the needs of the user and the capability of the producer to economically and reliably provide the product. The Editorial Style Manual for Preparation of Aerospace Material Specifications (AMS) - Metals and Processes is to be used when drafting AMS
11、 documents for metals and related processes. Special guidelines for nonmetals are included in the Nonmetallic Materials Appendix. 1. SCOPE The reader of specifications sometimes needs some help understanding the format of an AMS and reasoning behind certain usage of terms. The scope of this AIR is t
12、o explain the functions of the various sections of the specifications, why some of the terms in AMS specifications are used, and how the specification system works. After the introduction (Section 3 of this document), the topics are presented in the order they usually appear in specifications. SAE I
13、NTERNATIONAL AIR4779C Page 2 of 8 2. APPLICABLE DOCUMENTS The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publications shall be the issue in effect on the date of the purchase orde
14、r. In the event of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. SAE Publications 2.1Available from SAE I
15、nternational, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.ARP1917 Clarification of Terms Used in Aerospace Metals Specifications 3. INTRODUCTORY MATERIAL Metal Product Specifications 3.1The underlying philoso
16、phy behind most of the metal product specifications is: If (1) we define the material composition limits, the basic methods of melting and alloying, the methods of working and shaping, and the heat treatment of the product, and if (2) we measure and meet selected requirements for certain properties
17、of the product such as: tensile strength and ductility, hardness, grain size, microstructure, surface characteristics, or other properties pertinent to the specific product, then (3) we can be confident that the product is controlled and can be relied upon to have the other important engineering pro
18、perties within statistically established limits. Not included are other properties which will be inherent in the product if the specified requirements are met, or which may be of interest to some users, but are not needed to define and control the product. The details of the requirements differ cons
19、iderably among the various alloy systems and product forms. The tests designated to measure the selected characteristics are those judged most likely to verify the overall performance of each alloy and product. Nonmetallic Product Specifications 3.2Most nonmetallic product specifications depend on d
20、efinition and measurement of end item performance characteristics, rather than control of the ingredients and methods used to make the product. Otherwise, nonmetallic product specifications are similar to metal specifications. Nonmetallic product specifications define uncured and cured raw materials
21、, as well as finished parts. Included are plastics and rubber, sealants, coatings, fluids, fabrics, ceramics, reference materials, and a variety of other materials not otherwise categorized. Process Specifications 3.3These specifications generally define the basic materials, facilities, preparation
22、methods, critical processing steps, control requirements, and end item performance requirements of a process. The specification normally does not provide all of the step by step “how to“ details of a process because there are often numerous acceptable ways to meet the requirements of a process. The
23、specification format for process specifications is somewhat different from the AMS material specification format to address the unique needs of each process. Converted Government Specifications 3.4Another category indicates AMS Specifications that have been adopted from government specifications. Th
24、ese AMS carry a document identification number that relates to the original government specification (e.g., “AMS-QQ-A-200“ is based on Federal Standard “QQ-A-200“, AMS-H-6875 is based on MIL-H-6875, etc.). The initial publication of such a “converted government specification“ contained technical req
25、uirements and text that was virtually identical to the original government specification. Subsequent revision, cancellation, supersession or stabilization of converted government specifications is under the cognizance of the designated AMS Committee. For these reasons, the format and styling of a co
26、nverted government spec can differ radically from other AMS specifications. SAE INTERNATIONAL AIR4779C Page 3 of 8 4. DOCUMENT IDENTIFIERS AMS Number, Revision Letter, Date 4.1The four digit specification number for a new AMS is established by SAE when the specification is ready for initial publicat
27、ion. The number is selected to place the new specification near similar materials and products or processes in the various indexes. The classification system is best illustrated by examining the “SAE AMS INDEX“. Specification revisions are identified by the original number with the letter “A“ added
28、to indicate the first revision since firstrelease, “B“ for the second revision, etc. The date of the initial issue and of the most recent revision are shown below the specification number on the first page. When parallel specifications, AMS _ (for the inch-pound system) and MAM _ (metric system), ar
29、e issued for the same product, both will have the same specification number but need not have the same revision letter. For metal product specifications, most if not all MAM (metric system) documents have been cancelled and superseded by the AMS specification to which metric equivalent values have b
30、een added. Title Block 4.2The first line in the title block is the title of the specification. It provides a brief identification of the principal product or process covered. If a specification covers too many product forms for all to be in the title, the most important forms (as identified by the c
31、ommittee responsible for the specification) are shown in the title and the “less important“ forms are mentioned in the scope paragraph. The second and third lines are subtitles which provide enough information to distinguish the specification from others which have similar titles. Usually, the secon
32、d line identifies the alloy and the third line indicates the condition of the product. A fourth line in specifications for metal products shows the UNS (Unified Numbering System) number most similar to the composition of the alloy. However this number should be considered a reference and not a part
33、of the contractual requirements of the specification. (See 12.3.) Scope (Section 1 of an AMS) 4.3This section (1) includes paragraphs identifying forms of product covered, typical applications, classes, grades, or types covered and, if necessary, may include precautions to be observed in handling, p
34、rocessing, or usage of the product. 4.3.1 Form This paragraph identifies all of the product forms covered by the specification, including those not in the title, and repeating those that are in the title. Examples of product forms include: bar, plate, castings, forging stock, forgings, brazing fille
35、r, etc. 4.3.2 Application This paragraph informs the user of typical applications for the product or process and may include important properties intended to help determine if the product or process might be considered for the proposed application. Although the paragraph offers examples of applicati
36、ons of the product or process, it does not require that users should avoid other applications which may not be similar to the examples. 4.3.3 Classification If the specification covers more than one product form or process type, surface condition, processing method, etc., a classification paragraph
37、may be used to define such variations and their designation by type, grade, or class of the product or process. SAE INTERNATIONAL AIR4779C Page 4 of 8 4.3.4 Precautions A standard general paragraph is included, when appropriate, to notify that some materials, applications, and/or processes covered o
38、r referenced in a specification are considered hazardous and that the user must assume responsibility for identifying and implementing suitable precautions. A more specific warning may be expressed for some materials or processes when deemed appropriate by the committee. 5. APPLICABLE DOCUMENTS (Sec
39、tion 2 of an AMS) This section (2) lists other specifications, standards, recommended practices, and publications that are included by reference in Sections 1, 3, 4, and 5. Documents referenced in other than these sections are not requirements and, therefore, are not listed in Section 2. Each docume
40、nt applies only to the extent referenced in the AMS. This paragraph also provides the general policy 5.1for determining which revision or issue to be used for any referenced document. If a certain revision is to be used, this is stated. Any contrary instructions (i.e., specified by customer, drawing
41、, purchase order, etc.) take precedence. 6. TECHNICAL REQUIREMENTS (Section 3 of an AMS) This section (3) defines the required manufacturing methods and the properties which must be measured and met to assure that the product or process will be satisfactory for the intended usage. Other properties w
42、hich are inherent in the product if the specified requirements are met, or which may be of interest to some users but are not needed to define and control the product or process, are not included. In most specifications, this section (3) also defines the test procedures to be used to verify complian
43、ce with the requirements. Special Terminology 6.1Certain terms or phrases that need explanations can appear anywhere in the technical section. These will be covered in the following paragraphs. Those peculiar to certain paragraphs in the section will be covered later in the discussion of that paragr
44、aph. Other terms used in AMS may be clarified in ARP1917. 6.1.1 “Unless Otherwise Specified“ These words advise the purchaser, the producer, and others (such as auditors, customers of the user, and accreditors or surveyors) that the purchaser is specifically authorized to, and may routinely, specify
45、 an alternative to this requirement. Some users may not require this language, based on the position that the purchaser is always at liberty to change any requirement in the specification if the supplier will comply. However, other users find that auditors and prime contractors may question complian
46、ce with the specification if such changes are made. Producers may also be at some liability risk if their product labeled AMS1234 has not met or been tested for all specified requirements in the specification. Documentation between purchasers and suppliers is commonly used to clarify such requiremen
47、ts. 6.1.2 “When Approved By Purchaser“ This phrase allows a variation to be made in the specification requirements. For example, a rough, oxygen-rich, or decarburized surface may be allowed if the purchaser knows that the discrepant layer will be removed by machining during fabrication of the part.
48、However, written approval is required. 6.1.3 “Acceptable to Purchaser“ The phrase “acceptable to purchaser“ is used to avoid a presumed requirement that the producer must have formal written approval by the user of any alternative (i.e., procedure, method, technique, etc.). This phrase does not requ
49、ire that the purchaser issue a specific approval of an alternative method used by the producer, but permits the purchaser to disapprove the alternative if the method has been determined to be unsatisfactory to purchasers requirements. SAE INTERNATIONAL AIR4779C Page 5 of 8 Composition 6.2Metal specifications have a composition paragraph with a table showing the alloying elements and the required limits. The order of listing of the el
