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/AS7455BAEROSPACESTANDARDAS7455 REV. BIssued 1991-02Reaffirmed 2004-07Revised 2016-05Supersedi
5、ng AS7455ABolts and Screws, Steel, Low Alloy, Heat ResistantHardened and Tempered, Roll ThreadedFSC 5306RATIONALERevise and update sampling and inspection requirements, clarify fillet rolling requirements, and general editorial update.1. SCOPE1.1 TypeThis procurement specification covers aircraft qu
6、ality bolts and screws made from a low alloy, heat resistant steel of the type identified under the Unified Numbering System as UNS K14675. The following specification designations and their properties are covered.AS7455 140000 to 195000 psi ultimate tensile strength at room temperature.AS7455-1 140
7、000 to 195000 psi ultimate tensile strength at room temperature, nickel-cadmium plated.1.2 ApplicationPrimarily for aerospace propulsion system applications where high strength at temperatures up to approximately 900 F isrequired and the part is protected against corrosion.1.3 Safety - Hazardous Mat
8、erialsWhile the materials, methods, applications, and processes 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
9、 with the safe and proper use of any hazardous materials and to take necessary precautionary measures to ensure the health and safety of all personnel involved.SAE INTERNATIONAL AS7455BPage2of 202. REFERENCES2.1 Applicable DocumentsThe following publications form a part of this document to the exten
10、t 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 conflict between the text of this document and references cited herein, the text of this document takes pre
11、cedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained.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
12、 (outside USA), www.sae.org.AMS2416 Plating, Nickel-Cadmium, DiffusedAMS2750 PyrometryAMS6304 Low-Alloy Steel, Heat Resistant, Bars, Forgings, and Tubing 0.95Cr - 0.55Mo - 0.30V (0.40 - 0.50C)AS1132 Bolts, Screws and Nuts - External Wrenching UNJ Thread, Inch - Design StandardAS3062 Bolts, Screws, a
13、nd 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 PublicationsCopies of these documents are available online at http:/quicksearch.dla.mil
14、.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.org.ASTM E140 Standard Hardness Tables for MetalsASTM E1444/E1444M Magnetic Particle
15、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), 973-882-1170 (outside North America), www.asme.org.ASME B46.1 Surface Texture (Su
16、rface Roughness, Waviness, and Lay)SAE INTERNATIONAL AS7455BPage3of 202.1.5 AIA PublicationsAvailable from Aerospace Industries Association, 1000 Wilson Boulevard, Suite 1700, Arlington, VA 22209-3928, Tel: 703-358-1000, www.aia-aerospace.org.NASM1312-6 Fastener Test Methods, Method 6, HardnessNASM1
17、312-8 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 blanking operation.COLD ROLLING: Forming material below the recrystallization tempe
18、rature.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 requirements.DEFECTIVE: A unit of the product which contains one or more defects.DISCONTINUI
19、TY: 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 the head and the shank caused by plastic forming of the head.INCLUSION: Nonmetallic
20、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 then rolling or forging them into the surface. The allowable lap depth shall
21、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 magnification.MACHINING TEAR: A pattern of short jagged individual cracks, generally at
22、 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 of alloy, heat treated at the same time to the same specified condition, p
23、roduced as one continuous run, and submitted for manufactures 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 the metal bar, often the result of an inclusion that has been extended dur
24、ing 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 AS7455BPage4of 202.3 Unit SymbolsA ampereF degree Fahrenheit% percent (1% = 1/100)lbf pounds forcepsi pounds forc
25、e 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 the following requirements:3.2.1 DimensionsThe dimensions of finished parts, after al
26、l processing, including plating, shall conform to the part drawing. Dimensions apply after plating but before coating with solid film lubricants.3.2.2 Surface TextureSurface texture of finished parts, prior to plating or coating, shall conform to the requirements as specified on the part drawing, de
27、termined 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.3.2.3.1 Incomplete ThreadsIncomplete threads are permissible at the chamfered end and the juncture of the unthreaded portion
28、of the shank or adjacent to the head as specified in AS3062.3.2.3.2 ChamferThe entering end of the thread shall be chamfered as specified on the part drawing.3.2.4 Geometric TolerancesPart features shall be within the geometric tolerances specified on the part drawing and, where applicable, controll
29、ed in accordance with AS3063.3.3 Fabrication3.3.1 BlanksHeads shall be formed by hot forging or cold forging.3.3.2 Heat TreatmentHeaded blanks shall, before finishing the shank and the bearing surface of the head, cold working the head-to-shank fillet radius, and rolling the threads, be heat treated
30、 as follows:SAE INTERNATIONAL AS7455BPage5of 203.3.2.1 Heating EquipmentFurnaces may be any type ensuring uniform temperature throughout the parts being heated and shall be equipped with, and operated by, automatic controllers and data recorders conforming to AMS2750. The heating medium or atmospher
31、e shall cause neither surface hardening nor decarburization other than that permitted by 3.7.2.2 and 3.7.2.3.3.3.2.2 HardeningBlanks shall be uniformly heated to 1750 F 25 F, held at heat for 60 to 90 minutes, and quenched in oil or water.3.3.2.3 TemperingHardened blanks shall be tempered by heating
32、 uniformly to the temperature necessary to produce the specified hardness and microstructure but not lower than 1000 F, holding at heat for not less than 6 hours, and cooling in air.3.3.3 Oxide and Decarburization RemovalSurface oxide, oxide penetration, and decarburization except as permitted in 3.
33、7.2.3, resulting from prior heat treatment, shall be removed from the full body diameter and bearing surface of the head of the heat treated blanks prior to cold workingthe under head fillet radius and rolling the threads. The removal process shall produce no intergranular attack or corrosion of the
34、 blanks. The metal removed from the bearing surface of the head and the full body diameter of the shank shall be as little as practicable to obtain a clean, smooth surface and, in no case, shall be so great as to produce more cutting of flow lines in the head-to-shank junction than shown in Figure 1
35、B.3.3.4 Cold Working of Fillet RadiusAfter removal of oxide and decarburization as in 3.3.3, the head-to-shank fillet radius of parts having the radius complete throughout the circumference of the part shall be cold worked. The cold working shall be sufficient to remove all visual evidence of grindi
36、ng or tool marks. Distortion due to cold working shall conform to Figure 2, unless otherwise specified on the part drawing. It shall not raise metal more than 0.002 inch above the contour at “A” or depress metal more than 0.002 inch below the contour at “B” as shown in Figure 2; distorted areas shal
37、l not extend beyond “C“ as shown in Figure 2. In configurations having an undercut associated with the fillet radius, the cold working will be required only for 90 degreesof fillet arc, starting at the point of tangency of the fillet radius and the bearing surface of the head. In addition to cold wo
38、rking the head-to-shank fillet radius, shouldered bolts having an unthreaded shank diameter larger than the thread major diameter and having an undercut associated with a fillet between the threaded shank and the shoulder of the unthreaded shank, the cold working will be required only for 90 degrees
39、 of fillet arc, starting at the point of tangency of the fillet radius and the shouldered surface of the unthreaded shank. For parts with compound fillet radii between head and shank, cold work only the radius that blends with the head.3.3.5 Thread RollingThreads shall be formed on the heat treated
40、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 identification marked as specified on the part drawing. The markings may be formed by forging or stamping, raised or depressed not more than 0.010 inch maximum
41、, with rounded root form on depressed characters.3.5 PlatingWhere AS7455 is specified, any protective treatment shall be as specified on the part drawing. Where AS7455-1 is specified, parts shall be nickel-cadmium plated in accordance with AMS2416.SAE INTERNATIONAL AS7455BPage6of 203.6 Mechanical Pr
42、opertiesParts 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 have two to three full thre
43、ad 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 Strength: MIL-STD-1312-
44、8 in accordance with NASM1312-8.3.6.1 Ultimate Tensile Strength at Room Temperature3.6.1.1 Finished PartsParts having hardness within the range 42 to 46 HRC shall have an ultimate tensile load not lower than that specified in Table 3 and shall be tested to failure, first measuring and recording the
45、maximum tensile load achieved. Parts requiring minimum hardness lower than 42 HRC shall have an ultimate tensile load not lower than the product of the load specified in Table 3 and the factor listed in Note 2 of Table 3 applicable to the hardness range specified on the part drawing and shallbe test
46、ed to failure, first measuring and recording the maximum tensile load achieved. 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 shankdiameter equal to or less than the thread root diamete
47、r or having an undercut, parts shall conform to only the tensile requirements of 3.6.1.2 for the applicable minimum hardness; for such parts, the diameter of the area on which stress is based shall be the actual measured minimum diameter of the part. Tension fasteners with either standard double hex
48、agon or hexagon-type heads having a minimum metal condition in the head equal to the design parameters specified in AS1132 shall not fracture in the head-to-shank fillet radius except when this radius is associated with an undercut or with a shank diameter less than the minimum pitch diameter of the
49、 thread.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 shall be conducted in accordance with ASTM E8/E8M on specimens prepared as in 4.5. Such specimens shall meet the requirements in Table 1:Table 1 - Tensile properties of test specimensMinimum Hardnessof Specified RangeHRCUltimateTensile Strengthpsi, minimumElongationin 2 inches or 4D%, m
