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 theref
2、rom, 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 2013 SAE International All rights reserved. No part of this pub
3、lication 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: +1 724-776-4970
4、(outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AS4958AAEROSPACESTANDARDAS4958 REV. AIssued 1997-10 Reaffirmed 2001-10 Revised 2013-
5、10 Superseding AS4958 Performance, Nut, Self-Locking, Castellated, Prevailing Torque, UNJ 16 Pitch Thread Form RATIONALEAs a result of a five year review the documents has been updated to include the correct thread spec, changes and additions to referenced specifications. 1. SCOPE 1.1 Type This docu
6、ment covers all metal, castellated, self-locking nuts made from alloy steel of the types identified under the Unified Numbering System as UNS G41300 and UNS G43400. 1.2 Application Where self-locking nuts with UNJ 16 pitch thread form are required for use with standard AS8879 external threads. 2. RE
7、FERENCES 2.1 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 order. In the event of confl
8、ict 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. 2.1.1 SAE Publications Available from SAE International, 400 Com
9、monwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.AMS2411 Plating, Silver for High Temperature Applications AMS6370 Steel, Bars, Forgings, and Rings, 0.95Cr - 0.20Mo (0.28 - 0.33C) (SAE 4130) SAE INTERNATIONAL AS4958A Pag
10、e 2 of 8 AMS6371 Steel, Mechanical Tubing, 0.95Cr - 0.20Mo (0.28 - 0.33C) (SAE 4130) AMS6414 Steel, Bars, Forgings, and Tubing, 0.80Cr - 1.8Ni - 0.25Mo (0.38 - 0.43C) (SAE 4340) Vacuum Consumable Electrode Remelted AMS 6415 Steel, Bars, Forgings, and Tubing, 0.80Cr - 1.8Ni - 0.25Mo (0.38 - 0.43C) (S
11、AE 4340) AMS-H-6875 Heat Treatment of Steel Raw MaterialsAS478 Identification Marking Methods AS1310 Fastener Torque for Threaded Applications, Definitions of AS3071 Acceptance Criteria - Magnetic Particle, Fluorescent Penetrant, and Contrast Dye Penetrant Inspection AS8879 Screw Threads - UNJ Profi
12、le, Inch, Controlled Radius Root with Increased Minor Diameter 2.1.2 U.S. Government Publications Available from DLA Document Services, Building 4/D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, Tel: 215-697-6396, http:/quicksearch.dla.mil/.MIL-PRF-7808 Lubricating Oil, Aircraft Turbine Engine,
13、Synthetic Base MIL-PRF-23699 Lubricating Oil, Aircraft Turbine Engine, Synthetic Base, Nato Code Number 0-156 2.1.3 ASME Publications Available from ASME, 22 Law Drive, P.O. Box 2900, Fairfield, NJ 07007-2900, Tel: 800-843-2763 (U.S./Canada), 001-800-843-2763 (Mexico), 973-882-1170 (outside North Am
14、erica), www.asme.org.ASME B46.1 Surface Texture (Surface Roughness, Waviness, and Lay) 2.1.4 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org.ASTM E18 Standard Test Methods for Rockwell Hardne
15、ss of Metallic Materials ASTM D3951 Standard Practice for Commercial Packaging 2.2 Definitions PRODUCTION INSPECTION LOT: Shall be all finished parts of the same part number, made from a single heat of alloy, heat treated at the same time to the same specified condition, produced as one continuous r
16、un, and submitted for suppliers inspection at the same time. ROOM TEMPERATURE: Ambient temperature (68 F approximately). Refer to AS1310 for definitions related to fastener torque. SAE INTERNATIONAL AS4958A Page 3 of 8 2.3 Unit Symbols F degree, Fahrenheit lbf-in pound-force inch, torque HRC hardnes
17、s, Rockwell C scale 3. TECHNICAL REQUIREMENTS 3.1 Material Shall be alloy steel 4130 per AMS6370 or AMS6371, or alloy steel 4340 per AMS6414 or AMS6415 as specified on purchase order, unless otherwise specified on part drawing. 3.2 Construction Each nut shall be a self-contained unit including the s
18、elf-locking device. The locking device shall not operate by means of separate movement from the installation and shall not depend on pressure from the bearing surface for the locking action. The locking area shall be set to meet the locking torque requirements of Table 1, when used with UNJ 16 pitch
19、 external thread form per AS8879. TABLE 1 - LOCKING TORQUES NominalThread Size Class 3B MaximumPrevailingTorque lbf-in MinimumBreakaway Torque lbf-in1.5625-16 630 85 1.7500-16 690 100 2.0000-16 765 110 2.2500-16 825 120 2.5000-16 890 135 2.7500-16 950 145 3.0000-16 1000 155 3.2500-16 1015 165 3.5000
20、-16 1100 175 3.7500-16 1150 185 4.0000-16 1200 195 4.2500-16 1225 205 3.3 Threads Shall conform to AS8879 except in the thread locking area of the finished part. 3.3.1 Thread Perpendicularity Prior to thread locking development, the bearing surface shall be perpendicular to the thread pitch cylinder
21、 axis within the limits specified on the part drawing. Perpendicularity shall be determined by a method agreed upon by the purchaser and the vendor. The perpendicularity requirement shall apply to the bearing surface of the nut. The nuts to be inspected shall permit at least two turns of free engage
22、ment on the thread arbor. SAE INTERNATIONAL AS4958A Page 4 of 8 3.3.2 Plating Nuts shall be plated on the threads and bearing surface, other surfaces optional in accordance with AMS2411, unless otherwise specified on the part drawing. The plating thickness shall not be less than 0.0002 inch when mea
23、sured on the thread pitch diameter. 3.3.3 Plating Allowance Internal thread plating allowance shall be as specified in AS8879, unless otherwise specified on the part drawing. 3.4 Heat Treatment Nuts shall be heat treated in accordance with AMS-H-6875 so as to achieve a hardness as in 3.4.1. 3.4.1 Ha
24、rdness Hardness testing per ASTM E18. Unless otherwise specified on the part drawing, the hardness after heat treatment as in 3.4 shall be within the range of 28 to 38 HRC. 3.5 Nondestructive Testing As specified on part drawing or purchase order. Acceptance criteria per AS3071. 3.6 Performance Unle
25、ss otherwise specified on the part drawing or purchase order, nuts shall conform to the performance requirements in 3.6.1, 3.6.2, and 3.6.3. 3.6.1 Locking Feature Torque The locking feature torque shall be tested on sample quantity as in 4.3.1.3 of nuts selected at random from the lot. All tests sha
26、ll be conducted at room temperature on representative nuts assembled on externally threaded mandrels with no axial stress and having thread limits as in 3.7. Mandrels to be marked accordingly as MAX and MIN. Mandrels to be of any convenient length so as to pass through the nut a minimum of three thr
27、ead pitches. Nut must assemble freely, with the fingers, up to the self-locking area. The test shall be run in such a manner that a dependable measure of torque will be obtained. An increase in temperature of the nut during testing shall not be more than 74 F. Sample quantity of nuts shall meet reus
28、ability requirements as in 3.6.2. 3.6.2 Reusability Unless otherwise specified on purchase order or part drawing, the maximum prevailing or installation torque, and the minimum breakaway torque (see AS1310) shall be within torque limits of Table 1, after 12 cycle reusability. 3.6.2.1 Reusability Tes
29、t Procedure a. Of the representative sample nuts chosen at random in 3.6.1, one half of the sample quantity is to be tested on the maximum test mandrel, and the other half of the sample quantity is to be tested on the minimum test mandrel. Identify each nut with a tag as numbered 1, 2, 3, etc. b. Nu
30、t and mandrel to be lubricated with oil as in 3.8 prior to torque testing. c. Assemble selected nut on appropriate test mandrel. The end of the test mandrel shall extend into the bearing side of the nut 1.5 to 3 thread turns at the start of the test. d. Perform a single cycle torque test. Installati
31、on and breakaway torque shall be measured and recorded for each nut tested. Check for damage to the threads of the mandrel and the nut, such as galling or cracking. Recorded single cycle installation and breakaway torque must be within the limits of Table 1. SAE INTERNATIONAL AS4958A Page 5 of 8 e.
32、If torque values conform, select the nut with the lowest breakaway torque value. This nut is to be reassembled on the minimum test mandrel and installation and breakaway torque measured and recorded for an additional 11 cycles. Allow the mandrel to cool to room temperature after each cycle. The addi
33、tional recorded values shall be within the limits of Table 1. f. For sample quantities greater than two pieces, the sample nut tested on the maximum test mandrel with the lowest breakaway torque value shall be reassembled on the minimum test mandrel and installation and breakaway torque measured and
34、 recorded for an additional 11 cycles as previously described. g. If additional recorded torque values conform, the remaining single cycled nuts are deemed acceptable and can be returned to the lot. h. All nuts subjected to 12 cycle testing shall be scrapped. 3.6.3 Permanent Set At least three nuts
35、shall be assembled on a maximum mandrel lubricated with oil as in 3.8 so that the mandrel protrudes through the nut not less than three thread turns. Nuts shall then be removed from the maximum mandrel and reassembled on a minimum mandrel in the same manner. Test shall be conducted at room temperatu
36、re with no axial stress. Installation and breakaway torque shall be measured and recorded. The nuts shall not exceed the maximum installation torque value as in Table 1, and shall not be lower than the minimum breakaway torque value as in Table 1, during installation and removal on the minimum mandr
37、el. 3.7 Test Mandrel Thread Limits Dimensional limits for maximum and minimum test mandrels shall be as follows. Mandrel major diameter to be within 0.0005 and pitch diameter to be within 0.0010 of the maximum and the minimum dimensional limit as specified for applicable thread size in AS8879 for cl
38、ass 3A threads. Thread minor diameter to have the full limit of AS8879 thread specification. See example Tables 2 and 3. TABLE 2 - MAXIMUM MANDREL EXAMPLE ThreadSize Major Dia +0.0000-0.0005Pitch Dia +0.0000-0.0010 Minor Dia 2.5000-16 2.5000 2.4594 2.4199-2.4278 TABLE 3 - MINIMUM MANDREL EXAMPLE Thr
39、eadSize Major Dia +0.0005-0.0000Pitch Dia +0.0010-0.0000 Minor Dia 2.5000-16 2.4906 2.4553 2.4199-2.4278 a. Material of mandrels to be steel having a hardness of 42 to 47 HRC. b. Surface roughness to be 32 microinch Ra per ASME B46.1. c. Mandrel to have 45 degrees lead-in chamfer. d. Use of a bolt o
40、r stud meeting the previous requirements is optional. SAE INTERNATIONAL AS4958A Page 6 of 8 3.8 Test Lubrication Sample test nuts and test mandrel threads shall be lubricated with oil per MIL-PRF-7808 or MIL-PRF-23699. 3.9 Quality Parts shall be uniform in quality and condition, clean, sound, smooth
41、, and free from burrs and foreign materials, and from imperfections detrimental to their performance. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection and Compliance The supplier of parts shall supply all parts for tests and shall be responsible for performing all required tests. Pu
42、rchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that parts conform to the requirements of this document. 4.2 Classification of Tests 4.2.1 Acceptance Tests Tests for material (3.1), threads (3.3), locking feature torque (3.6.1), and dimensions
43、per part drawing are classified as acceptance tests and shall be performed on each production inspection lot. 4.2.2 Preproduction Tests Tests for all technical requirements of this document are classified as preproduction tests and shall be performed prior to or on the first-article shipment of a ty
44、pe and size of part desired by purchaser, and also, when purchaser deems confirmatory preproduction testing to be required. 4.3 Sampling Shall be as follows: 4.3.1 For Acceptance Tests 4.3.1.1 Material Per material specification. 4.3.1.2 Threads and Dimensions All parts selected for locking feature
45、torque reusability test shall be subjected to and have passed dimensional and thread inspection prior to torque testing. 4.3.1.3 Reusability Test Parts selected at random from production inspection lot as described in Table 4. SAE INTERNATIONAL AS4958A Page 7 of 8 TABLE 4 Lot Size Sample Size Under
46、9 2 9 - 24 4 25 - 89 6 90 - 279 8 Over 280 10 4.3.2 For Preproduction Tests As specified herein or as agreed upon by purchaser and supplier. 4.4 Reports 4.4.1 The vendor shall furnish with, or prior to, the first shipment of parts of each part number a report of test data showing that the parts conf
47、orm to all technical requirements of this document and the part drawing. 4.4.2 The supplier of part shall furnish with each production inspection lot shipment a report stating that the chemical composition of the parts conform to the applicable material specification, and showing the results of test
48、s to determine conformance to the acceptance tests. This report shall include the purchase order number, production lot number, AS4958A, contractor or direct supplier of material, part number, nominal size, and quantity. 4.5 Resampling and Retesting If any part used in the tests fails to meet the sp
49、ecified requirements, disposition of the parts may be based on the results of testing three additional parts for each original nonconforming part. Failure of any retest part to 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 Packaging and Identification per ASTM D3
