1、AEROSPACE STANDARDMA1943REV.AIssued 1987-07Revised 1990-08Reaffirmed 2006-05Superseding MA1943Nuts, Self-Locking, UNS N07001730C, 1100 MPa, and 1210 MPaProcurement Specification For, MetricFSC 53101. SCOPE:This procurement specification covers aircraft quality self-locking nuts for wrenching (hex, s
2、pline) and anchor (plate, gang channel, shank) types of nuts made from a corrosion and heat resistant nickel-base alloy of the type identified under the Unified Numbering System as UNS N07001. Tension height nuts having overall length of threaded portion not less than 1.2 times the nominal thread di
3、ameter have 1210 MPa minimum tensile strength at room temperature. Shear height nuts having shorter threaded portion have 1100 MPa minimum tensile strength at room temperature. Maximum test temperature of parts is 730C1.1 Safety - Hazardous Materials:While the materials, methods, applications, and p
4、rocesses described or referenced in this specification may involve the use of hazardous materials, this specification does not address the hazards which may be involved in such use. It is the sole responsibility of the user to ensure familiarity with the safe and proper use of any hazardous material
5、s and to take necessary precautionary measures to ensure the health and safety of all personnel involved.2. REFERENCES:2.1 Applicable Documents:The following publications form a part of this specification to the extent specified herein. The latest issue of SAE publications shall apply. The applicabl
6、e issue of other documents shall be the issue in effect on the date of the purchase order.2.1.1 SAE Publications: Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical
7、 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, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which ti
8、me it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2006 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, ph
9、otocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org RATIONALE This document has been r
10、eaffirmed to comply with the SAE 5-year Review policy. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA1943 Revision A- 2 -2.1.1.1 Aerospace Material Specifications:AMS-2411 Plating, Silver, fo
11、r High Temperature ApplicationsAMS-2645 Fluorescent Penetrant InspectionAMS-5544 Sheet, Strip, and Plate, Alloy, 57Ni 19.5Cr 13.5Co 4.2Mo 3.0Ti 1.4Al 0.05Zr 0.006B, Consumable Electrode or Vacuum Induction Melted, AnnealedAMS-5706 Bars, Forgings, and Rings, Alloy, 57Ni 19.5Cr 13.5Co 4.3Mo 3.0Ti 1.4A
12、l 0.006B 0.05Zr, Consumable Electrode or Vacuum Induction Melted, 995 1040C Solution Heat TreatedAMS-5707 Bars, Forgings and Rings, Alloy, 58Ni 19.5Cr 13.5Co 4.3Mo 3.0Ti 1.4Al 0.05Zr 0.006B, Consumable Electrode or Vacuum Induction Melted, 1825 1900F (996 1038C) Solution, Stabilization and Precipita
13、tion Heat TreatedAMS-5708 Bars and Forgings, Alloy, 58Ni 19.5Cr 13.5Co 4.3Mo 3.0Ti 1.4Al, Consumable Electrode or Vacuum Induction Melted, 1975F Solution Heat TreatedAMS-5709 Bars and Forgings, Alloy, 58Ni 19.5Cr 13.5Co 4.3Mo 3.0Ti 1.4Al 0.05Zr 0.006B, Consumable Electrode or Vacuum Induction Melted
14、 1975F (1079C) Solution, Stabilization and Precipitation Heat Treated2.1.1.2 Aerospace Standards:AS1310 Fastener Torque for Threaded Applications, Definitions ofMA1370 Screw Threads - MJ Profile, MetricMA1520 Areas for Calculating Stress or Load Values for Metric MJ Externally Threaded FastenersMA1
15、566 Gaging Practice and Gage Requirements for MJ Metric Screw ThreadsMA1586 Wrench Configuration, 12 Spline Drive, MetricMA3378 Bolts 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 prevai
16、ling torque-type, self-contained, 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 b
17、lend smoothly without abrupt change.3.3 Heat Treatment:The nuts shall be solution, stabilization, and precipitation heat treated in accordance with the heat treating procedure specified in the material specification.3.4 Product Marking:Each part shall be identification marked as specified on the par
18、t drawing. Markings shall be stamped, depressed 0.25 mm maximum, using a rounded tool form.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA1943 Revision A- 5 -3.5 Plating:Unless otherwise speci
19、fied on the part drawing, parts shall be silver plated in accordance with AMS-2411. 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 of a sectioned nut shall be used as the referee met
20、hod. Nuts with nominal thread size below 6 mm shall show complete coverage on the thread surfaces. Plating on other surfaces shall be 8 to 15 m thick, unless otherwise specified on the part drawing. No plating shall be applied to the retaining plate for plate nuts and channel for channel nuts, unles
21、s otherwise specified on the part drawing.3.6 Mechanical Properties:3.6.1 Hardness: Unless otherwise specified on the part drawing, the hardness after heat treatment as in 3.3 shall be uniform and within the range of 32 to 42 HRC, 301 to 390 HB, or 318 to 412 HV when tested in accordance with MIL-ST
22、D-1312-6. Sizes up to and including 10 mm nominal thread size shall be sectioned and mounted. Mounting is optional for other sizes.3.7 Metallurgical Properties:3.7.1 Microstructure: Wrenching nuts, shank nuts, and nut elements of plate and gang channel nuts shall have a microstructure of completely
23、recrystallized material.3.7.2 Grain Size: Shall be predominantly two to six with no grains finer than seven or coarser than one as determined by comparison of a polished and etched specimen with the chart in ASTM E 112. In the case of disagreement on the grain size by the comparison method, then int
24、ercept (Heyn) procedure shall be used.3.8 Quality:Parts shall be uniform in quality and condition, clean, sound, smooth, and free from burrs and foreign materials and from imperfections detrimental to their performance.3.8.1 Fluorescent Penetrant Inspection: Parts shall be subject to fluorescent pen
25、etrant inspection in accordance with AMS-2645. Acceptance criteria of surface discontinuities shall be in accordance with Appendix J.3.9 Product Performance Tests:Refer to Tables 7 and 8 for details of sample sizes for Acceptance Test Plan and Qualification Test Plan.3.9.1 Axial Tensile Strength: Nu
26、ts shall withstand the minimum tensile load as specified in Table 1 without rupture, stripping, or appearance of cracks when tested as follows:Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA19
27、43 Revision A- 6 -3.9.1.1 As Received Condition at Room Temperature: Nuts in as received condition tested in accordance with DOD-STD-1312-108, using alloy steel test bolts hardened and tempered to 40 HRC minimum, 371 HB minimum or 392 HV minimum, shall withstand the axial tensile load specified in T
28、able 1, applied at the rate specified at room temperature.3.9.1.2 After 730C Bake at Room Temperature: Prior to testing, the nut shall 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 730C 8 and cooled to room temperature. A new test b
29、olt shall be used for each axial tensile test. Nuts shall be tested, after baking, at room temperature in accordance with DOD-STD-1312-108 and shall withstand the axial tensile load specified in Table 1, applied at the rate specified.Copyright SAE International Provided by IHS under license with SAE
30、Not for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA1943 Revision A- 7 -TABLE 1 - Axial Tensile Load and Tensile AreaCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,
31、SAE MA1943 Revision A- 8 -3.9.1.3 Shank Nuts: Nuts with shanks designed to be flared at assembly (see Figure 1) shall be tested as in 3.9.1 except that the bearing plate hole shall be 0.1 to 0.2 mm greater than the maximum shank diameter. It is not necessary to flare the shank for this test. The
32、bearing plate hole shall be chamfered sufficiently to clear the shank nut bearing surface-to-shank maximum fillet.FIGURE 1 - Flange Assembly, Flared Shank Nut3.9.2 Wrench Torque: Wrenching nuts with a spline drive wrenching feature shall be tested as specified in Appendix B and shall withstand the w
33、rench torques specified in Table 2 applied through 15 engagement cycles without any permanent deformation which can interfere with the use of socket wrenches conforming to MA1586. Wrenching nuts with hexagon wrenching features shall be tested in the same manner and shall withstand Table 2 wrench tor
34、ques in the same manner as spline drive nuts except a double hexagon socket-type wrench shall be used.TABLE 2 - Wrench TorqueCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA1943 Revision A- 9 -
35、3.9.3 Push Out Load: Anchor nuts of the types in 3.9.3.1 shall be tested as specified in Appendix C and shall withstand the push out loads specified in Table 3 without separating from the plate or channel. Nuts shall be serviceable after this test.TABLE 3 - Push Out Load3.9.3.1 The push out test in
36、3.9.3 is applicable to gang channel nuts, plate nuts (floating and nonfloating nuts except side by side, corner and side mounted types). See Appendix A for definition of types.3.9.4 Torque Out: Anchor nuts of the types in 3.9.3.1 shall be tested as specified in Appendix D and shall withstand the tor
37、que out loads specified in Table 4 without cracking, rupture, 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 retainer plate.TABLE 4 - Torque Out Load3.9.5 Permanent Set: Nuts shall be tested as specified
38、in Appendix E and shall not exceed the maximum permissible locking torque or be less than the minimum breakaway torque values specified in Table 5. The bolt or mandrel shall project through the nut a minimum of three thread pitches.Copyright SAE International Provided by IHS under license with SAENo
39、t for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA1943 Revision A- 10 -3.9.6 Reusability Test at Room Temperature After 730C Bake: Nuts 5 mm nominal thread size and larger shall be tested for five consecutive cycles as specified in Appendix F, loading initially t
40、o 590 MPa in accordance with 3.9.6.3 for tension height nuts; and for shear height nuts, the initial load shall be 517 MPa in accordance with 3.9.6.3. The assembly shall be heated in a furnace to 730C 8 and held for 6 h 0.25, removed from the furnace and cooled to room temperature.3.9.6.1 Wrenching
41、and Reference Recordings: Wrench type nuts shall be turned relative to the fixture. The wrenchability of the tested nuts shall permit assembly of standard wrench. For nonwrenchable nuts, the bolt head shall be turned. For reference information, the assembly and breakloose torques shall be recorded f
42、or 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 self-locking torque shall be measured on installation and removal, and shall not exceed the torque in Table 5, Column 4, nor
43、 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 bolt elongation at room temperature using bolts having a shank diameter equal to the thread pitch diameter. The correct loading shall be determined by using a mo
44、dulus of elasticity of 213.7 GPa. Stress area for the bolt shall be based on Formula (2) areas given in MA1520. For tension height nuts, the elongation shall be equal to 0.002761L (where L = length of bushing) elongation of bolts using standard bushing as specified in Appendix F; similarly, for shea
45、r height nuts, the bolt elongation shall be equal to 0.002419L.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 for shear height nuts, and Column 6 for tension h
46、eight nuts. Wrenching type nuts shall be turned relative to the fixture. For nonwrenchable nuts, the bolt head shall be turned. The locking feature torque shall conform to the minimum breakaway and maximum self-locking torque in Table 5, Column 1 and 3, respectively, for each cycle. The self-locking
47、 torque shall be measured on installation and removal, and shall not exceed the torque in Table 5, Column 3, nor 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
48、 and permit assembly of a new nut freely with the fingers up to the self-locking feature.3.9.8 Three-Cycle Test at Room Temperature: Nuts shall be tested as specified in Appendix H, loading to assembly torque specified in Table 5, Column 5, for shear height nuts, and Column 6 for tension height nuts
49、 Wrenching type nuts shall be turned relative to the fixture. For nonwrenchable nuts, the bolt head shall be turned. Nuts shall conform to the minimum breakaway torque in Table 5, Column 2a for the first cycle, and Column 2b for the subsequent two cycles. The self-locking torque shall be measured on installation and removal, and s
