1、_ 6$(7HFKQLFDO6WDQGDUGV%RDUG5XOHVSURYLGHWKDW7KLVUHSRUWLVSX EOLVKHGE6$(WRDGYDQFHWKHVWDWH 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 therefrom, LVWKHVROHUHV
2、SRQVLELOLWRIWKHXVHU 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 publication may be reproduce
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4、6-0790 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/MA1573A METRIC AEROSPACE STANDARD MA1573 REV. A Issued 1988-08 Revised 2011-10 Reaffirmed 2016-11 Superseding MA1573 Nut,
5、Self-Locking - Steel, Class 1100 MPa/235 C, MJ Thread Procurement Specification For, Metric FSC 5310 RATIONALE MA1573A has been reaffirmed to comply with the SAE five-year review policy. 1. SCOPE 1.1 Type This specification establishes the requirements for the following types of self-locking nuts: a
6、. Wrenching nuts: that is, hex, double hex, spline drive b. Anchor nuts: that is, plate nuts, gang channel nuts, shank nuts The wrenching nuts and shank nuts are made of low alloy steels, and the nut elements of plate and gang channel nuts are made of carbon steels or low alloy steels and having MJ
7、threads to ISO 5855/2. Nuts have 1100 MPa tensile strength class at room temperature. Maximum test temperature of parts at 235 C. 1.2 Application Primarily for use in aerospace propulsion systems. 2. APPLICABLE DOCUMENTS The following publications form a part of this document to the extent specified
8、 herein. The latest issue of SAE publications shall apply. The applicable issue of the 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 references cited herein, the text of this document takes precedence
9、. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. The following publications form a part of this specification to the extent specified herein. The latest issue of Aerospace Material Specifications (AMS) and Aerospace Standa
10、rds (AS maximum thread dimensions before plating for pitch diameter and minor diameter shall be within the following tolerance class before forming the self-locking feature: Tolerance Class 4G6G for sizes 1 through 5 mm Tolerance Class 4G5G for sizes 6 mm and larger 3.2.3.3 After Forming Self-Lockin
11、g Feature: The upper threaded portion shall be formed out of round in any manner which provides self-locking nuts meeting the locking torque requirements of this specification. The plated nut shall allow the GO thread plug gage to enter a minimum of three turns before engagement of the locking eleme
12、nt for nuts having overall length of threaded portion not less than 1.2 times the nominal thread diameter; nuts having shorter threaded portion shall allow GO thread plug gage to enter a minimum of three-quarters of a turn. 3.2.4 Construction: The nut shall be of the prevailing torque-type, self-con
13、tained, all metal unit, including the self-locking feature. The locking feature shall not operate by means of separate movement and shall not depend upon pressure on the bearing surface for locking action. Tool marks resulting from producing the self-locking feature shall blend smoothly without abru
14、pt change. 3.3 Heat Treatment The nuts shall be hardened and tempered as required to produce the properties in this specification and the part drawing. 3.4 Product Marking Each part shall be identification marked as specified on the part drawing. Markings shall be stamped, depressed 0.25 mm maximum,
15、 using a rounded tool form. NOTICE This document references a part which contains cadmium as a plating material. Consult local officials if you have questions concerning cadmiums use. 3.5 Plating Unless otherwise specified on the part drawing, parts shall be cadmium plated in accordance with AMS2400
16、. Nuts heat treated to 39 HRC or higher and cadmium plated shall be baked for not less than 23 h at 190 C 14 within 1 h after plating. On nuts with nominal thread sizes 6 mm and larger, the plating on the thread shall be not less than 5 m when measured on the pitch diameter. Microscopic measurement
17、of a sectioned nut shall be used as the referee method. Nuts with nominal thread sizes below 6 mm shall show complete coverage on the thread surfaces. Plating on other surfaces shall be 8 - 15 m thick, unless otherwise specified on the part drawing. AMS2400 cadmium plating shall be applied to the re
18、taining plate for floating plate nuts and channel for gang channel nuts that are made from carbon or alloy steels. 3.6 Mechanical Properties 3.6.1 Hardness: Unless otherwise specified on the part drawing, the hardness after heat treatment shall be uniform and within the range of 35 - 40 HRC or equiv
19、alent, except nuts formed from carbon steel sheet shall be within the range of 35 - 44 HRC, when tested in accordance with MIL-STD-1312-6 in accordance with NASM1312-6. Sizes up to and including 10 mm nominal thread size shall be sectioned and mounted. Mounting optional for other sizes. SAE INTERNAT
20、IONAL MA1573A Page 5 of 39 3.7 Metallurgical Properties 3.7.1 Microstructure: Wrenching nuts, shank nuts, and nut elements of plate and gang channel nuts shall have microstructure of tempered martensite. 3.7.2 Surface Hardening: Parts shall have no surface hardening resulting from carburization, rec
21、arburization, or nitriding. In case of dispute over results of microscopic examination, microhardness testing shall be used as a referee method; a Vickers hardness reading within 0.08 mm of the surface more than 30 points higher than the reading in the core will be evidence of nonconformance to this
22、 requirement. 3.7.3 Decarburization: No area of total decarburization is permissible. Partial decarburization is permissible provided that the thickness over the area is less than or equal to 0.1 mm, as determined by micro-examination specified in 3.7.2; a Vickers hardness reading within 0.1 mm of t
23、he surface shall not be more than 30 points lower than the reading in the core. 3.8 Quality Parts shall be uniform in quality and condition, clean, sound, smooth, and free from burrs and foreign materials and imperfections detrimental to their performance. 3.8.1 Magnetic Particle Inspection: Parts s
24、hall be subject to magnetic particle inspection in accordance with ASTM E1444. Acceptance criteria of surface discontinuities shall be in accordance with Appendix J. 3.9 Product Performance Test Refer to Tables 7 and 8 for details of sample sizes for Acceptance Test Plan and Qualification Approval T
25、est Plan. 3.9.1 Axial Tensile Strength: Nuts shall withstand the minimum tensile load as specified in Table 1 without rupture, stripping or appearance of cracks when tested as follows: 3.9.1.1 As Received Condition at Room Temperature Nuts in as received condition tested in accordance with DOD-STD-1
26、312-108 in accordance with NAM1312-108, using alloy steel test bolts hardened and tempered to 40 HRC min or equivalent, shall withstand the axial tensile load specified in Table 1, applied at the rate specified at room temperature. 3.9.1.2 After Bake, at Room Temperature Prior to testing, the nut sh
27、all be assembled on a bolt as specified in 3.10 with at least two thread pitches protruding and baked for 6 h 0.25 at 235 C 8, and then cooled to room temperature. A new test bolt shall be used for each axial tensile test. Nuts shall be tested, after baking, at room temperature in accordance with DO
28、D-STD-1312-108 in accordance with NAM1312-108 and shall withstand the axial tensile load in Table1, applied at the rate specified. SAE INTERNATIONAL MA1573A Page 6 of 39 TABLE 1 AXIAL TENSILE LOAD d3 = max root diameter Load requirements for axial strength load is based on 1100 MPa stress. Axial ten
29、sile strength load, T = 1100 MPa x A divided by 1000 to obtain load in kN. For sizes not shown, axial tensile strength loads for nuts shall be based upon the respective companion bolt stress area and 1100 MPa stress. 3.9.1.3 Shank Nuts: Nuts with shanks designed to be flared at assembly (see Fig. 1)
30、 shall be tested as in 3.9.1 except that the bearing plate hole shall be 0.1 - 0.2 mm greater than the max shank diameter. It is not necessary to flare the shank for this test. The bearing plate hole shall be chamfered sufficiently to clear the shank nut bearing surface-to-shank max fillet. FIGURE 1
31、 - FLANGE ASSEMBLY, FLARED SHANK NUT SAE INTERNATIONAL MA1573A Page 7 of 39 3.9.2 Wrench Torque: Wrenching nuts with spline drive wrenching feature shall be tested as specified in Appendix B and shall withstand the wrench torques specified in Table 2 applied through 15 engagement cycles without any
32、permanent deformation which can interfere with the use of socket wrenches conforming to MA1586. Wrenching nuts with hexagon or double hexagon wrenching features shall be tested in the same manner and shall withstand Table 2 wrench torques in the same manner as spline drive nuts except double hexagon
33、 socket-type wrench shall be used. TABLE 2 - WRENCH TORQUE Thread Size Wrench Torque, Nm MJ5 x 0.8 13.8 MJ6 x 1 24 MJ7 x 1 40 MJ8 x 1 60 MJ10 x 1.25 115 MJ12 x 1.25 200 3.9.3 Push Out Load: Anchor nuts of the types in 3.9.3.1 (normal series and miniature series rivet hole spacing) shall be tested as
34、 specified in Appendix C and shall withstand the push-out loads for the applicable series specified in Table 3 without separating from the plate for the normal and miniature series or from the channel for the normal series. Nuts shall be serviceable after this test. 3.9.3.1 The push-out test in 3.9.
35、3 is applicable to gang channel nuts, plate nuts (floating and non-floating except side by side, corner and side-mounted types). See Appendix A for definition of types. TABLE 3 - PUSH-OUT LOAD Thread Size Push-Out Normal Series N Push-Out Miniature Series N MJ4 x 0.7 - 360 MJ5 x 0.8 900 460 MJ6 x 1
36、950 570 MJ7 x 1 1050 - MJ8 x 1 1100 - 3.9.4 Torque Out: Anchor nuts of the types in 3.9.3.1 (normal series and miniature series rivet hole spacing) shall be tested as specified in Appendix D and shall withstand the torque out loads for the applicable series specified in Table 4 without cracking, rup
37、ture, or being deformed to a degree which will prevent normal use. This test shall be performed with no axial load on the bearing surface of the nut. SAE INTERNATIONAL MA1573A Page 8 of 39 TABLE 4 - TORQUE OUT LOAD Thread Size Torque Out Normal Series Nm Torque Out Miniature Series Nm MJ4 x 0.7 - 6
38、MJ5 x 0.8 10 9 MJ6 x 1 16 13 MJ7 x 1 22 - MJ8 x 1 33 - 3.9.5 Permanent Set: Nuts shall be tested as specified in Appendix E and shall not exceed the max permissible locking torque or be less than the min breakaway torque values specified in Table 5. The bolt or mandrel shall project thru the nut a m
39、inimum of three full thread pitches. 3.9.6 Reusability Test at Room Temperature After Bake: Nuts 5 mm nominal thread size and larger shall be tested for five consecutive cycles as specified in Appendix F, loading initially to 621 MPa in accordance with 3.9.6.3. The assembly shall be heated in a furn
40、ace to 235 C 8 and held at heat for 6 h 0.25, removed from the furnace and cooled to room temperature. 3.9.6.1 Wrenching and Reference Recording: Wrenchable nuts shall be turned relative to the fixture. The wrenchability of the tested nuts shall permit assembly of standard wrench. For non-wrenchable
41、 nuts, the bolt head shall be turned. For reference information, the assembly and breakloose torques shall be recorded for each heat cycle. 3.9.6.2 Locking Feature Torque Requirements: Nuts tested as in 3.9.6 shall conform to the minimum breakaway torque in Table 5, Column 1, for each cycle. The sel
42、f-locking torque shall be measured on installation and removal, and shall not exceed the torque in Table 5, Column 4, nor shall be less than the breakaway torque in Table 5, Column 1. 3.9.6.3 Loading by Elongation: Loading shall be determined by measurement of elongation of the bolt at room temperat
43、ure using bolts having a shank diameter equal to the thread pitch diameter. The correct loading shall be determined by using a modulus of elasticity of 203.4 GPa. Stress area for the bolt shall be based on Formula (2) area given in MA1520. The elongation shall be equal to 0.0030531L (where L = lengt
44、h of bushing) elongation of bolts using standard bushing as specified in Appendix F. 3.9.7 Reusability Test at Room Temperature, As Received Condition: Nuts shall be tested for 15 cycles as specified in Appendix G, loading to assembly torque specified in Table 5, Column 5. Wrenchable nuts shall be t
45、urned relative to the fixture. For non-wrenchable nuts, the bolt head shall be turned. Locking feature torque shall conform to the minimum breakaway torque and maximum self-locking torque in Table 5, Columns 1 and 3 respectively, for each cycle. The self-locking torque shall be measured on installat
46、ion and removal, and shall not exceed the torque in Table 5, Column 3, nor shall be less than the breakaway torque in Table 5, Column 1. After testing, the nut shall assemble freely with the fingers up to the self-locking feature. Bolt threads shall remain serviceable and permit assembly of a new nu
47、t freely with the fingers up to the self-locking feature. 3.9.8 Three Cycles at Room Temperature: Nuts shall be tested as specified in Appendix H, loading to assembly torque specified in Table 5, Column 5. Wrenchable nuts shall be turned relative to the fixture. For non-wrenchable nuts, the bolt hea
48、d shall be turned. Nuts shall conform to the minimum breakaway torque in Table 5, Column 2, for the first cycle, and Column 1 for the subsequent two cycles. The self-locking torque shall be measured on installation and removal, and shall not exceed the torque in Table 5, Column 3, nor shall be less than the breakaway torque in Table 5, Column 1. SAE INTERNATIONAL MA1573A Page 9 of 39 TABLE 5 - LOCKING FEATURE TORQUES AND ASSEMBLY TORQUE Thread Size Breakaway Torque Min. Nm Self-Locking Torque, Min. Nm Assembly Torque, Nm 1 2 3 4
