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 2016 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:/standards.sae.org/AS7241A AEROSPACE STANDARD AS7241 REV. AIssued 2006-11 Revised 2011-10Reaffirmed 2016-11 Supers
5、eding AS7241 Washers, Spring Lock, Corrosion Resistant Steel 18Cr - 9NI (UNS S30200), Procurement Specification for RATIONALE AS7241A has been reaffirmed to comply with the SAE five-year review policy. 1. SCOPE 1.1 Type This procurement specification covers plain helical lock washers made of corrosi
6、on-resistant steel.of the type identified under the Unified Numbering System as UNS S30200. 1.2 Application Primarily for use with corrosion-resistant steel threaded fasteners; not recommended for use at temperatures higher than 700 F (370 C). 2. REFERENCES 2.1 Applicable Documents The following pub
7、lications 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 order. In the event of conflict between the text of this document and reference
8、s 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. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 87
9、7-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AMS2248 Chemical Check Analysis Limits, Wrought Corrosion and Heat Resistant Steels and Alloys, Maraging and Other Highly-Alloyed Steels, and Iron Alloys AMS2371 Quality Assurance Sampling of Corrosion and Heat Resistant
10、Steels and Alloys, Wrought Products Except Forgings and Forging Stock 2.1.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM E 18 Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materia
11、ls ASTM E 353 Chemical Analysis of Stainless, Heat-Resisting, Maraging, and Other Similar Chromium-Nickel-Iron Alloys 2.1.3 ANSI Publications Available from ANSI, 25 West 43rd Street, New York, NY 10036-8002, Tel: 212-642-4900, www.ansi.org. ANSI/ASQC Z1.9 Sampling Procedures and Tables for Inspecti
12、on by Variables for Percent Nonconforming 2.1.4 U.S. Government Publications Available from the Document Automation and Production Service (DAPS), Building 4/D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, Tel: 215-697-6257, http:/assist.daps.dla.mil/quicksearch/. MIL-STD-2073-1 Standard Practic
13、e for Military Packaging 2.2 Unit Symbols F - degree, Fahrenheit C - degree, Celsius % - percent (1% = 1/100) mm - millimeter in - inch 3. TECHNICAL REQUIREMENTS 3.1 Material 3.1.1 Chemical Composition Shall conform to the following percentages by weight, determined by wet chemical methods in accord
14、ance with ASTM E 353 or by spectrochemical or other analytical methods approved by purchaser: TABLE 1 CHEMICAL COMPOSITION min max Carbon - 0.15 Manganese - 2.00 Silicon - 1.00 Phosphorus - 0.040Sulfur - 0.030Nickel 8.00 10.00Chromium 17.00 19.00Molybdenum - 0.75 Copper - 0.75 SAE INTERNATIONAL AS72
15、41A 2 of 5_ 3.1.1.1 Check Analysis Composition variations shall meet the applicable requirements of AMS2248. 3.1.2 Condition Cold worked. 3.2 Fabrication 3.2.1 Helix Washers shall be coiled so that the free height is approximately twice the thickness of the washer section. Gap and relationship of th
16、e severed ends shall be such as to prevent the washers tangling. 3.3 Properties Parts shall conform to the following requirements: 3.3.1 Hardness Shall be 35 - 43 HRC, determined in accordance with ASTM E 18. 3.3.2 Temper After the first compression to flat, the free height of a washer shall be not
17、less than 0.66 times the original free height. Subsequent compressions to flat shall not further reduce this free height by more than 0.005 in (0.13 mm) but the free height after ten compressions to flat shall be not less than 0.66 times the original free height. 3.3.3 Toughness A portion of washer
18、shall be firmly gripped in vise jaws having sharp edges. Ends of washer shall be free and an axis passing through the slot shall be parallel to top of vise. An equal portion of washer shall be gripped in wrench jaws. Edges of wrench jaws shall be sharp and in a plane parallel to top of vise. Free po
19、rtion of washer, between the grip of vise and wrench, shall be approximately 25% of washer diameter. Movement of wrench in the direction that increases the free height of the washer shall twist the lock washer through 90 without evidence of fracture. When a washer fractures because of twist, the str
20、ucture at the point of fracture shall show a fine grain; the washers shall deliver, at the instant of fracture, a tough, springy, reactive shear. 3.4 Quality The flat faces and the inner and outer periphery of the washers shall be smooth and free from knurling, serration, die marks, and deep scratch
21、es; however, slight feed marks are permissible. The ends at the gap shall not have cutting edges at the contact surfaces. Washers shall have rounded edges and shall be free from internal and external imperfections detrimental to their performance. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility f
22、or Inspection The vendor of parts shall supply all samples for vendors test and shall be responsible for performing all required tests. Results of such tests shall be reported to the purchaser as required by 4.4. Purchaser reserves the right to sample and to perform any confirmatory testing deemed n
23、ecessary to ensure that the parts conform to the requirements of this specification. SAE INTERNATIONAL AS7241A 3 of 5_ 4.2 Classification of Tests Tests to determine conformance to all technical requirements of this specification are classified as acceptance tests and shall be performed on each lot.
24、 4.3 Sampling Shall be in accordance with the following; a lot shall be all parts of the same part number presented for vendors inspection at one time: 4.3.1 Composition One sample per lot. 4.3.2 Other Requirements In accordance with ANSI/ASQC Z1.9 to an AQL of 3.5%. 4.4 Reports The vendor of parts
25、shall furnish with each shipment a report stating that the parts conform to the technical requirements of this specification. This report shall include the purchase order number, this specification number and its revision letter, contractor or other direct supplier of the material, part number, nomi
26、nal size, and quantity. 4.5 Resampling and Retesting If any specimen used in the above tests fails to meet the specified requirements, disposition of the parts may be based on the results of testing three additional specimens for each original nonconforming specimen. Failure of any retest specimen t
27、o meet the specified requirements shall be cause for rejection of the parts represented and no additional testing shall be permitted. Results of all tests shall be reported. 5. PREPARATION FOR DELIVERY 5.1 Identification and Packaging 5.1.1 Parts having different part number shall be packaged in sep
28、arate containers. 5.1.2 Each container shall be marked to show not less than the following information: a. Washers, Corrosion Resistant Steel b. AS7241 c. Part number d. Lot number e. Purchase order number f. Quantity g. Manufacturers identification SAE INTERNATIONAL AS7241A 4 of 5_ 5.1.3 Containers
29、 of parts shall be prepared for shipment in accordance with commercial practice and in compliance with applicable rules and regulations pertaining to the handling, packaging, and transportation of the parts to ensure carrier acceptance and safe delivery. 5.1.4 For direct U.S. Military procurement, p
30、ackaging shall be in accordance with MIL-STD-2073-1 industrial packaging, unless Level A is specified in the request for procurement. 6. ACKNOWLEDGMENT A vendor shall mention this specification in all quotations and when acknowledging purchase orders. 7. REJECTIONS Parts not conforming to this speci
31、fication or to modifications authorized by purchaser will be subject to rejection. 8. NOTES 8.1 For direct U.S. Military procurement, purchase documents should specify not less than the following: a. Title, number, and date of this specification b. Part number of parts desired c. Quantity of parts d
32、esired d. Level A packaging, if required 8.2 Revision Indicator A change bar (|) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the d
33、ocument title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only. PREPARED BY SAE E-25, GENERAL STANDARDS FOR AEROSPACE AND PROPULSION SYSTEMS SAE INTERNATIONAL AS7241A 5 of 5_
