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 2016 SAE InternationalAll rights reserved. No part of this publi
3、cation 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 (out
4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/AS7458BAEROSPACESTANDARDAS7458 REV. BIssued 1991-02Reaffirmed 2006-06Revised 2016-01Supersedi
5、ng AS7458AStuds, Steel, Low Alloy, Heat ResistantNormalized and Tempered, Roll Threaded135000 psi Tensile StrengthRATIONALERevise and update sampling and inspection requirements and general editorial update.1. SCOPE1.1 TypeThis procurement specification covers aircraft quality studs made from a low
6、alloy, heat resistant steel of the type identified under the Unified Numbering System as UNS K14675.AS7458 135 000 psi ultimate tensile strength at room temperature.AS7458-1 135 000 psi ultimate tensile strength at room temperature, nickel-cadmium plated.1.2 ApplicationPrimarily for aerospace propul
7、sion system applications where good strength at temperatures up to approximately 900 F is required and the part is protected against corrosion.1.3 Safety - Hazardous MaterialsWhile the materials, methods, applications, and processes described or referenced in this specification may involve the use o
8、f 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 materials and to take necessary precautionary measures to ensure the health and safe
9、ty of all personnel involved.SAE INTERNATIONAL AS7458BPage2of 192. REFERENCES2.1 Applicable DocumentsThe 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
10、 in effect on the date of the purchase order. In theevent of conflict 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
11、.2.1.1 SAE PublicationsAvailable from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org.AMS2416 Plating, Nickel-Cadmium, DiffusedAMS2750 PyrometryAMS6304 Low-Alloy Steel, Heat Resistant, Bars,
12、 Forgings, and Tubing 0.95Cr - 0.55Mo - 0.30V (0.40 - 0.50C)AS3062 Bolts, Screws, and Studs, Screw Thread RequirementsAS3063 Bolts, Screws, and Studs, Geometric Control RequirementsAS8879 Screw Threads - UNJ Profile, Inch Controlled Radius Root with Increased Minor Diameter2.1.2 U.S. Government Publ
13、icationsCopies of these documents are available online at http:/quicksearch.dla.mil.MIL-STD-2073-1 Military Packaging, Standard Practice for2.1.3 ASTM PublicationsAvailable from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.or
14、g.ASTM E140 Standard Hardness Tables for MetalsASTM E1444/E1444M Magnetic Particle ExaminationASTM E8/E8M Tension Testing of Metallic Materials2.1.4 ASME PublicationsAvailable from ASME, P.O. Box 2900, 22 Law Drive, Fairfield, NJ 07007-2900, Tel: 800-843-2763 (U.S./Canada), 001-800-843-2763 (Mexico)
15、, 973-882-1170 (outside North America), www.asme.org.ASME B46.1 Surface Texture (Surface Roughness, Waviness, and Lay)SAE INTERNATIONAL AS7458BPage3of 192.1.5 AIA PublicationsAvailable from Aerospace Industries Association, 1000 Wilson Boulevard, Suite 1700, Arlington, VA 22209-3928, Tel: 703-358-10
16、00, www.aia-aerospace.org.NASM1312-6 Fastener Test Methods, Method 6, HardnessNASM1312-8 Fastener Test Methods, Method 8, Tensile TestingNASM1312-12 Fastener Test Methods, Method 12, Plating Thickness2.2 DefinitionsBURR: A rough edge or ridge left on the metal due to cutting, grinding, piercing, or
17、blanking operation.COLD ROLLING: Forming material below the recrystallization temperature.CRACK: Rupture in the material which may extend in any direction and which may be intercrystalline or transcrystalline in character.DEFECT: Any nonconformance of the unit or the product with specified requireme
18、nts.DEFECTIVE: A unit of the product which contains one or more defects.DISCONTINUITY: An interruption in the normal physical structure or configuration of a part; such as a lap, seam, inclusion, crack, machining tear, or stringer.HEAT PATTERN: A discernible difference in etched appearance between t
19、he head and the shank caused by forming of the head.INCLUSION: Nonmetallic particles originating from the material making process. They may exist as discrete particles or strings of particles extending longitudinally.LAP: Surface imperfection caused by folding over metal fins or sharp corners and th
20、en rolling or forging them into the surface. The allowable lap depth shall not exceed the limit specified herein. The minimum condition that shall be rated as a lap is a fold having its length equal to or greater than three times its width with a depth of 0.0005 inch when viewed at 200X magnificatio
21、n.MACHINING TEAR: A pattern of short jagged individual cracks, generally at right angles to the direction of machining, frequently the result of improperly set cutting tools, or dull cutting tools.PRODUCTION INSPECTION LOT: Shall be all finished parts of the same part number, made from a single heat
22、 of alloy,heat treated at the same time to the same specified condition, produced as one continuous run, and submitted formanufacturers inspection at the same time.SEAM: Longitudinal surface imperfection in the form of an unwelded, open fold in the material.STRINGER: A solid nonmetallic impurity in
23、the metal bar, often the result of an inclusion that has been extended during the rolling process.TIGHT BURR: A burr closely compacted and binding in the periphery of a part without loose ends and is within the dimensional limits of the part.SAE INTERNATIONAL AS7458BPage4of 192.3 Unit SymbolsA - amp
24、ereF - degree Fahrenheit% - percent (1% = 1/100)lbf - pounds forcepsi - pounds force per square inchsp gr - specific gravity3. TECHNICAL REQUIREMENTS3.1 MaterialShall be AMS6304 steel, unless otherwise specified on the part drawing.3.2 DesignFinished (completely manufactured) parts shall conform to
25、the following requirements:3.2.1 DimensionsThe dimensions of finished parts, after all processing, including plating, shall conform to the part drawing. Dimensions applyafter plating but before coating with solid film lubricants.3.2.2 Surface TextureSurface texture of finished parts, prior to platin
26、g or coating, shall conform to the requirements as specified on the part drawing, determined in accordance with ASME B46.1.3.2.3 ThreadsScrew thread UNJ profile and dimensions shall be in accordance with AS8879, unless otherwise specified on the part drawing. Tolerances for pitch diameter of stud en
27、d threads shall be as specified on the part drawing. The special stud end thread requirements shall be in accordance with AS3062 for the following requirements:a. Lead and half-angle variationsb. Taperc. Out-of-roundnessd. Stud lead threadse. Stud thread runout3.2.3.1 The requirements for thread cre
28、st variations, locking holes in the nut end thread, incomplete lead thread, and thread runout on nut end thread shall be as specified in AS3062.3.2.3.2 ChamferThe entering end of the thread (both ends) shall be chamfered as specified on the part drawing.3.2.4 Geometric TolerancesPart features shall
29、be within the geometric tolerances specified on the part drawing and, where applicable, controlled in accordance with AS3063.SAE INTERNATIONAL AS7458BPage5of 193.3 Fabrication3.3.1 BlanksBlanks shall be machined sufficiently to remove surface defects and decarburization except as noted in 3.7.2.3. B
30、lanks may be produced by machining, upsetting, extruding, or by a combination of these methods.3.3.1.1 When a shoulder or shoulders are produced by upsetting, the metal removed from the bearing surface shall be as little as practicable to provide a clean, smooth surface.3.3.2 Heat TreatmentBlanks, u
31、nless machined from heat treated stock, shall, before finishing the shank and rolling the threads, be heat treated as follows:3.3.2.1 Heating EquipmentFurnaces may be any type ensuring uniform temperature throughout the parts being heated and shall be equipped with, and operated by, automatic contro
32、llers and data recorders conforming to AMS2750. The heating medium or atmosphere shall cause no surface hardening by carburizing or nitriding nor decarburization other than that permitted by 3.7.2.2 and 3.7.2.3.3.3.2.2 NormalizingBlanks of AMS6304 shall be uniformly heated to 1750 F 25 F, held at he
33、at for 60 to 90 minutes, and cooled in still air or in a cooling chamber or the furnace.3.3.2.3 TemperingNormalized blanks of AMS6304 shall be tempered by heating uniformly to the temperature necessary to produce the specified hardness and microstructure but not lower than 1100 F, holding at heat fo
34、r not less than 6 hours, and cooling in air.3.3.2.4 For steels other than AMS6304, heat treatment shall be as agreed upon by purchaser and manufacture.3.3.3 Oxide and Decarburization RemovalSurface oxide, oxide penetration, and decarburization except as permitted in 3.7.2.3, resulting from prior hea
35、t treatment, shall be removed from the full body diameter and the bearing surfaces, as applicable, of the heat treated blanks prior to rolling the threads. The removal process shall produce no intergranular attack or corrosion of the blanks.3.3.4 Thread RollingThreads shall be formed on the heat tre
36、ated and finished blanks by a single rolling process after removal of oxide and decarburization as in 3.3.3.3.4 Product MarkingEach part shall be marked for oversize on stud end thread and for material code on the nut end as specified on the part drawing. The markings may be formed by stamping, depr
37、essed 0.010 inch maximum, with rounded root form on depressed characters.3.5 PlatingWhere AS7458 is specified, any protective treatment shall be as specified on the part drawing. Where AS7458-1 is specified, parts shall be nickel-cadmium plated in accordance with AMS2416.SAE INTERNATIONAL AS7458BPag
38、e6of 193.6 Mechanical PropertiesParts shall conform to the requirements of 3.6.1 and 3.6.2. Threaded members of gripping fixtures for tensile test shall be of sufficient size and strength to develop the full strength of the part without stripping the thread. The loaded portion of the shank shall hav
39、e two to three full thread turns from the thread runout exposed between the loading fixtures during the tensile test. Finished parts shall be tested in accordance with the following applicable test methods:a. Hardness: MIL-STD-1312-6 in accordance with NASM1312-6.b. Room Temperature Ultimate Tensile
40、 Strength: MIL-STD-1312-8 in accordance with NASM1312-8.3.6.1 Ultimate Tensile Strength at Room Temperature3.6.1.1 Finished PartsParts shall have an ultimate tensile load not lower than that specified in Table 2 and shall be tested to failure, first measuring and recording the maximum tensile load a
41、chieved. If the size or shape of the part is such that failure would occur outside the threaded section but the part can be tested satisfactorily, such as parts having a shank diameter equal to or less than the thread root diameter or having an undercut, parts shall conform to only the ultimate tens
42、ile strength requirements of 3.6.1.2; for such parts, the diameter of the area on which stress is based shall be the actual measured minimum diameter of the part.3.6.1.2 Machined Test SpecimensIf the size or shape of the part is such that a tensile test cannot be made on the part, tensile tests shal
43、l be conducted in accordance with ASTM E8/E8M on specimens prepared as in 4.5. Such specimens shall meet the following requirements:a. Ultimate Tensile Strength, minimum: 135000 psib. Yield Strength at 0.2% Offset, minimum: 115000 psic. Elongation in 2 in or 4D, minimum: 15%d. Reduction of Area, min
44、imum: 40%3.6.1.2.1 When permitted by purchaser, hardness tests on the end of parts may be substituted for tensile tests of machined specimens.3.6.2 HardnessShall be uniform and within the range 30 to 38 HRC, but hardness of the threaded sections may be higher as a result of the cold working operatio
45、ns.3.7 QualityParts shall be uniform in quality and condition, clean, sound, smooth, and free from burrs and foreign materials, and from imperfections detrimental to usage of the parts.3.7.1 Macroscopic ExaminationParts or sections of parts, as applicable, shall be etched in a solution consisting of
46、 approximately 50% hydrochloric acid (sp gr 1.19), and 50% water for sufficient time to reveal flow lines but not longer than 15 minutes, and then be examined at a magnification of approximately 20X to determine conformance to the requirements of 3.7.1.1, 3.7.1.2, and 3.7.1.3, except that examinatio
47、n for the thread imperfections as specified in 3.7.1.3 should be made by microscopic examination of specimens polished and etched as in 3.7.2.SAE INTERNATIONAL AS7458BPage7of 193.7.1.1 Flow LinesFlow lines in threads shall be continuous, shall follow the general thread contour, and shall be of maxim
48、um density at the root of the thread (see Figure 1). Below the thread roots, flow lines not affected by forming shall be parallel to the axis except that on the nut end of studs formed by extruding, the flow lines may be oblique to the axis for a distance from the end of the larger diameter to the s
49、maller diameter equal to 1.5 times the “B“ dimension of Table 2 of AS3062.3.7.1.2 Internal DefectsExamination of longitudinal sections of parts shall reveal no cracks, laps, or porosity except laps in threads as permitted in 3.7.1.3.3 and 3.7.1.3.4.3.7.1.3 Threads3.7.1.3.1 Root defects such as laps, seams, notches, slivers, folds, roughness, and oxide scale are not permissible (see Figure 2).3.7.1.3.2 Multiple laps on the
