1、AEROSPACE STANDARDMA1937Issued 1985-12Reaffirmed 2006-05Nut, Hex, Free Running, ProcurementSpecification For, Metric1. SCOPE:This procurement specification covers alloy steel and corrosion and heat resistant steel free running metric nuts of the following types, styles and classes.a. Types: Hex nut
2、plain, standard heightHex nut plain, shear heightHex nut slotted, standard heightHex nut slotted, shear heightb. Styles: Washer faceDouble chamferedCastellatedc. Classes: 516 MPa axial strength, min (shear height nuts)600 MPa axial strength, min (shear height nuts)860 MPa axial strength, min1000 MPa
3、 axial strength, min1.1 Application:Primarily for fastening aerospace propulsion parts using metric fasteners where the minimum axial strengths of the classes specified in paragraph 1.c. are required. Slotted nuts are intended for use with cotterpins or other similar applicable locking devices.2. AP
4、PLICABLE DOCUMENTS:The following publications form a part of this specification to the extent specified herein. The latest issue of Aerospace Material Specifications and Aerospace Standards shall apply. The applicable issue of other documents shall be as specified in AMS 2350.SAE Technical Standards
5、 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 therefrom, is the sole respons
6、ibility of the user.” SAE reviews each technical report at least every five years at which time 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
7、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: 724-776-4970 (outside USA) Fax: 724-776-0790 Email:
8、 CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org RATIONALE This document has been reaffirmed 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
9、 MA1937 - 2 -2.1 SAE Publications:Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096.2.1.1 Aerospace Material Specifications:AMS 2350 Standards and Test MethodsAMS 2640 Magnetic Particle InspectionAMS 2645 Fluorescent Penetrant Inspection2.1.2 Aerospace Standards:AS 307 Acceptance Crit
10、eria - Magnetic Particle, Fluorescent Penetrant, and Contrast Dye Penetrant InspectionAS 1370 Metric Screw Threads - MJ ProfileMA 1566 Gaging Practice and Gage Requirements for MJ Metric Screw Threads2.2 ASTM Publications:Available from American Society for Testing and Materials, 1916 Race Street, P
11、hiladelphia, PA 19103.ASTM E8 Tension Testing of Metallic Materials2.3 ANSI Publications:Available from American National Standards Institute, 1430 Broadway, New York, NY 10018.ANSI B46.1 Surface Texture2.4 U.S. Government Publications:Available from Commanding Officer, Naval Publications and Forms
12、Center, 5801 Tabor Avenue, Philadelphia, PA 19120.2.4.1 Military Standards:MIL-STD-105 Sampling Procedures and Tables for Inspection by AttributesMIL-STD-1312 Fasteners, Test Methods3. TECHNICAL REQUIREMENTS:3.1 Material:Material shall be alloy steel or corrosion and heat resistant steel as specifie
13、d on the part drawing.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA1937 - 3 -3.2 Finished Parts:Finished parts, after all processing including plating, shall conform to the following require
14、ments:3.2.1 Dimensions: The dimensions of finished parts shall conform to the part drawing.3.2.2 Surface Texture: Surface texture of finished parts, prior to plating, shall conform to the requirements as specified on the part drawing.3.2.3 Threads: Metric screw thread MJ profile and dimensions shall
15、 be per AS 1370.3.2.3.1 Incomplete Threads: The incomplete lead threads at the entering end may be larger than the specified limits of thread size for a length not to exceed two thread pitches, including chamfer. The chamfer shall be as specified on the part drawing.3.2.4 Form and Positional Toleran
16、ces: Part features shall be within the geometric form and positional tolerances specified on the part drawing.3.3 Fabrication:3.3.1 Blanks: Nuts may be heat treated if necessary to produce the properties required as specified on the part drawing. No nuts shall be heat treated more than three times.3
17、.4 Product Marking:Each part shall, when required, be identification marked as specified by the part drawing. Unless otherwise specified, the marking may be formed by forging or stamping, raised or depressed 0.25 mm maximum, with rounded root form on depressed characters. Marking on wrenching surfac
18、es shall be depressed only. Multiple marking is permitted on hexagonal nuts.3.5 Finish:Plating shall be as specified on the part drawing. On nuts with thread sizes 6mm and larger, the plating thickness shall be not less than 5 m when measured on the thread pitch diameter. Microscopic measurement on
19、a sectioned nut shall be used as a referee method. Nuts with thread sizes 5mm and smaller shall show complete plate coverage on the threads. Plating on other surfaces shall be 8 15 m thick for alloy steel nuts. Plating is optional on other surfaces for corrosion and heat resistant steel nuts.3.6 Mec
20、hanical Properties:Parts shall conform to the requirements of 3.6.1 as applicable. Threaded members of gripping fixtures for tensile tests shall be of sufficient size and strength to develop the full strength of the part without stripping the thread. The minimum tensile test load shall be as specifi
21、ed in Table VI. Finished parts shall be tested in accordance with MIL-STD-1312, Test No. 8.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA1937 - 4 -3.6.1 Hardness: Hardness shall be uniform an
22、d within the range specified on the part drawing. Hardness shall be determined in accordance with MIL-STD-1312, Test No. 6. When hardness is not specified on the part drawing, the hardness shall be within the range of 26 32 HRC or equivalent.3.7 Quality:Parts shall be uniform in quality and conditio
23、n, clean, sound, smooth and free from burrs and foreign materials and from imperfections detrimental to their performance. Sharp edges are permissible on the slots of slotted nuts provided they are not hazardous to handling.3.7.1 Fluorescent Penetrant Inspection: Corrosion and heat resistant steel p
24、arts shall be subject to fluorescent penetrant inspection in accordance with AMS 2645 as specified on the part drawing. Acceptance criteria shall be in accordance with AS 3071 as applicable.3.7.1.1 The following conditions shall be cause for rejection of parts inspected:3.7.1.1.1 Discontinuities run
25、ning from the base of the slots on slotted nuts are not permitted.3.7.1.1.2 Nuts machined from bar: Discontinuities in a transverse direction are not permitted, except surface discontinuities in a longitudinal direction are permissible at the flats up to the maximum depth specified in Table V.3.7.1.
26、1.3 Nuts cold forged: Discontinuities in a transverse direction are not permitted, except surface discontinuities due to forging are permissible within the limits specified in Table V as follows;On the top and bottom face, provided there are no more than two extending across the full width, and no d
27、iscontinuity extends into the thread chamfer.At the intersection of the top or bottom face with the hex flat.3.7.2 Magnetic Particle Inspection: Alloy steel parts shall be subject to magnetic particle inspection in accordance with AMS 2640. Acceptance criteria shall be in accordance with AS 3071 as
28、applicable. The nuts shall be magnetized in a circular direction only. The magnetizing field shall be normal to the longitudinal axis of the nut. Amperage shall be 1.2 1.6 A/mm2of contact area. Resolution of disputed rejections shall be based on wet, residual, black oxide suspension method.3.7.2.1 T
29、he following conditions shall be cause for rejection of parts inspected:3.7.2.1.1 Discontinuities running from the base of the slots on slotted nuts are not permitted.3.7.2.1.2 Nuts machined from bar: As specified in 3.7.1.1.2.3.7.2.1.3 Nuts cold forged: As specified in 3.7.1.1.3.Copyright SAE Inter
30、national Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA1937 - 5 -4. QUALITY ASSURANCE PROVISIONS:4.1 Responsibility for Inspection:The vendor of parts shall supply all samples for vendors tests and shall be responsible
31、for performing all required tests. Results of such tests shall be reported to the purchaser as required by 4.4. The purchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that the parts conform to the requirements of this specification.4.2 Classific
32、ation of Tests:The inspection and testing of parts are classified as follows:a. Acceptance tests as in 4.3.1 which are to be performed on each production inspection lot.b. Periodic tests which to be performed periodically on production lots at the discretion of the vendor or purchaser. None required
33、 in this specification.4.3 Production Inspection Lot:A 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 run, and submitted for inspection at the s
34、ame time.4.3.1 Acceptance Tests: The acceptance tests shall be performed on each production inspection lot. The acceptance tests consist of all the tests specified in Table I.4.3.1.1 Non-Destructive Test - Visual and Dimensional: A random sample shall be selected from each production lot. The size o
35、f the sample shall be as specified in Table III. The classification of defects for parts shall be as specified in Table II. Detects not classified in Table II shall be classified as minor B defects. All dimensional characteristics are considered defective when out of part drawing tolerance.4.3.1.2 H
36、ardness Test (See 3.6.1): A random sample shall be selected from each production inspection lot. The size of the sample shall be as specified in Table IV, column A. The sample units may be selected from those that have been subjected to and passed the visual and dimensional inspection, with the addi
37、tional units selected at random from the production inspection lot as necessary.4.3.1.3 Non-Destructive Inspection: Parts shall be subject to fluorescent penetrant inspection or magnetic particle inspection as specified on the part drawing.4.3.1.4 Destructive Tests: A random sample shall be selected
38、 from each production inspection lot. The size of the sample shall be as specified in Table IV, column B. The sample units may be selected from those that have been subjected to and passed the non-destructive tests.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo re
39、production or networking permitted without license from IHS-,-,-SAE MA1937 - 6 -4.3.1.5 Product Performance: The nuts shall develop the minimum axial tensile strength as specified in Table VI. The nut shall be assembled on a test bolt or mandrel as shown in Figure 1, and subjected to the axial load
40、specified in Table VI, relevant to the nut strength. The nut shall support this load without rupture. Bolt or mandrel tension failure below the rated axial strength of the nut is not cause for rejection. Nuts used for this test shall not be included with deliverable nuts.4.3.2 Acceptance Quality: Th
41、e acceptance quality level and acceptance number of defectives for the acceptance tests shall be as specified in Table III and IV.4.4 Reports:The vendor of parts shall furnish with each shipment a report stating that the chemical composition of the parts conforms to the applicable material specifica
42、tion, showing the results of tests to determine conformance to the hardness and tensile strength requirements, and stating that the parts conform to all other technical requirements of this specification. This report shall include the purchase order number, MA 1937, contractor or other direct suppli
43、er of material, part number, nominal size, and quantity.4.5 Resampling and Retesting:If any part used in the above tests fails to meet the specified requirements for mechanical properties and quality as in 3.6 and 3.7, disposition of the parts may be based on the results of testing three additional
44、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 Identific
45、ation:5.1.1 Parts having different part numbers shall be packaged in separate containers.5.1.2 Each container of parts shall be marked to show the following information:METRIC FASTENERSMA 1937PART NUMBER _PURCHASE ORDER NUMBER _QUANTITY _MANUFACTURERS IDENTIFICATION _5.1.3 Containers of parts shall
46、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 product to ensure carrier acceptance and safe delivery. Packaging shall conform to carrier rules and regulations ap
47、plicable to the mode of transportation.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-,-SAE MA1937 - 7 -5.1.4 For direct U.S. Military procurement, packaging shall be as specified in the request for p
48、rocurement.6. ACKNOWLEDGMENT:A vendor shall mention this specification number in all quotations and when acknowledging purchase orders.7. REJECTIONS:Parts not conforming to this specification 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:Title, number, and date of this specificationPart number or size of parts desiredQuantity of parts desiredApplicable
