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 there
2、from, 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 2017 SAE International All rights reserved. No part of this p
3、ublication 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: +1 724-776-497
4、0 (outside USA) Fax: 724-776-0790 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/AS7478D AEROSPACE STANDARD AS7478 REV. D Issued 1991-01 Reaffirmed 2006-05 Revised 2017-03 Supe
5、rseding AS7478C Bolts and Screws, Steel, UNS S66286 Classification: 130 ksi/1200 F 1800 F Solution Heat Treated, Aged After Roll Threaded Procurement Specification for FSC 5306 RATIONALE Paragraph 3.7.2 altered to require 200X magnification for metallurgical examination and to exclude 200X magnifica
6、tion inspection for surface hardness and grain size. 1. SCOPE This procurement specification covers bolts and screws made from a corrosion and heat resistant, age hardenable iron base alloy of the type identified under the Unified Numbering System as UNS S66286. 1.1 Type The following specification
7、designations and their properties are covered: AS7478: 130 ksi minimum ultimate tensile strength at room temperature 65 ksi stress-rupture strength at 1200 F AS7478-2: 130 ksi minimum ultimate tensile strength at room temperature 78 ksi minimum ultimate shear strength at room temperature 1.1.1 Class
8、ification 130 ksi minimum tensile strength at room temperature 1200 F maximum test temperature of parts 1.2 Application Primarily for aerospace propulsion system applications where stress-rupture strength and creep resistance are required at elevated temperature. SAE INTERNATIONAL AS7478D Page 2 of
9、19 1.3 Safety - Hazardous Materials While the materials, 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
10、to ensure familiarity 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. 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this document to the extent specified
11、 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 precedence. No
12、thing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside
13、 USA), www.sae.org. AMS2759/3 Heat Treatment Precipitation-Hardening Corrosion-Resistant and Maraging Steel Parts AMS5731 Steel, Corrosion and Heat-Resistant, Bars, Wire, Forgings, Tubing, and Rings 15Cr - 25.5Ni - 1.2Mo - 2.1Ti - 0.006B - 0.30V Consumable Electrode Melted, 1800 F (982 C) Solution H
14、eat Treated AS1132 Bolts, Screws and Nuts - External Wrenching UNJ Thread, Inch - Design Standard AS3062 Bolts, Screws and Studs, Screw Thread Requirements AS3063 Bolts, Screws, and Studs, Geometric Control Requirements AS8879 Screw Threads - UNJ Profile, Inch Controlled Radius Root with Increased M
15、inor Diameter 2.1.2 ASME Publications Available 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 (Surface Roughness, Waviness, and Lay) 2.1.3 AS
16、TM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM D3951 Commercial Packaging ASTM E8/E8M Tension Testing of Metallic Materials ASTM E112 Determining Average Grain Size ASTM E139 Conducting
17、Creep, Creep-Rupture, and Stress-Rupture Test of Metallic Materials ASTM E140 Standard Hardness Tables for Metals ASTM E1417/E1417M Liquid Penetrant Examination SAE INTERNATIONAL AS7478D Page 3 of 19 2.2 Definitions BURR: A rough edge or ridge left on the metal due to a cutting, grinding, piercing,
18、or blanking operation. COLD ROLLING: Forming material below the recrystallation 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 of product with specified requireme
19、nts. DEFECTIVE: A unit of 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: The discernible difference in etched appearance between
20、the head and shank caused by the plastic 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 cor
21、ners and then 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 m
22、agnification. 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
23、 a single heat of alloy, heat treated at the same time to the same specified condition, produced as one continuous run, and submitted for vendors inspection at the same time. SEAM: Longitudinal surface imperfection in the form of an unwelded, open fold in the material. STRINGER: A solid nonmetallic
24、impurity in the metal bar, often the result of inclusions that have been extended during the rolling process. TIGHT BURR: A burr closely compacted and binding in the periphery of a part without any loose ends and is within the dimensional limits of the part. 2.3 Unit Symbols - degree, angle C - degr
25、ee Celsius F - degree Fahrenheit % - percent (1% = 1/100) lbf - pound-force ksi - kips (1000 pounds) per square inch sp gr - specific gravity HRC - hardness, Rockwell C scale SAE INTERNATIONAL AS7478D Page 4 of 19 3. TECHNICAL REQUIREMENTS 3.1 Material Shall be AMS5731 steel heading stock, unless ot
26、herwise specified on part drawing. 3.2 Design Finished (completely manufactured) parts shall conform to the following requirements: 3.2.1 Dimensions The dimensions of finished parts, after all processing including plating, shall conform to the requirements as specified on the part drawing. Dimension
27、s apply after plating but before coating with dry film lubricants. 3.2.2 Surface Texture Surface texture of finished parts, prior to plating or coating, shall conform to the requirements as specified on the part drawing, determined in accordance with ASME B46.1. 3.2.3 Threads Screw thread UNJ profil
28、e and dimensions shall be in accordance with AS8879, unless otherwise specified on the part drawing. 3.2.3.1 Incomplete Lead and Runout Threads Incomplete threads are permissible at the entering end and the juncture of the unthreaded portion of the shank or adjacent to the head as specified in AS306
29、2. 3.2.3.2 Chamfer The entering end of the thread shall be chamfered as specified on the part drawing. 3.2.4 Geometric Tolerances Part features shall be within the geometric tolerances specified on the part drawing and, where applicable, controlled in accordance with AS3063. 3.3 Fabrication 3.3.1 Bl
30、anks Heads shall be formed by hot forging, cold forging; or machining. Heading stock to be hot forged shall be heated to a temperature not higher than 2100 F. Lightening holes may be produced by any suitable method. Wrenching recesses may be forged or machined. Flash or chip clearance in machined re
31、cesses shall not cause dimensions to exceed the specified limits. 3.3.2 Heat Treatment Shall conform to the technical requirements and other provisions specified in AMS2759/3 for A-286, 1800 F solution heat treatment and 1325 F aging treatment. SAE INTERNATIONAL AS7478D Page 5 of 19 3.3.2.1 Solution
32、 Heat Treatment Headed and machined blanks of AMS5731, unless machined from solution heat treated stock, shall, before finishing the shank and the bearing surface of the head, cold rolling the head-to-shank fillet radius when specified, and rolling the threads, be solution heat treated as in 3.3.2.
33、Blanks of other materials shall be solution heat treated in accordance with the applicable material specification. If blanks are machined from solution heat treated stock, only the aging treatment as in 3.3.2.2 is necessary. 3.3.2.2 Aging Treatment After cold rolling the fillet radius as in 3.3.4 wh
34、en specified and rolling the threads as in 3.3.5, parts of AMS5731 shall be heat treated by aging as in 3.3.2. Parts of other materials shall be heat treated by aging after cold rolling the fillet radius as in 3.3.4 when specified and rolling the threads as in 3.3.5, in accordance with the applicabl
35、e material specification. 3.3.3 Oxide Removal Surface oxide and oxide penetration resulting from prior heat treatment shall be removed from the full body diameter and bearing surface of the head of the solution heat treated blanks prior to cold rolling the fillet radius when specified and rolling th
36、e threads. The oxide removal process shall produce no intergranular attack or corrosion of the 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. 3.3.4 Cold Rolling of Fillet Radi
37、us After removal of oxide as in 3.3.3, the head-to-shank fillet radius of headed parts having the radius complete throughout the circumference of the part when specified shall be cold rolled sufficiently to remove all visual evidence of grinding or tool marks. If there is no visual evidence of grind
38、ing or tool marks prior to cold working, the fillet shall still be cold worked. Distortion due to cold rolling shall conform to Figure 1, 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
39、 the contour at “B” as shown in Figure 1; distorted areas shall not extend beyond “C” as shown in Figure 1. In configurations having an undercut connected with the fillet radius, the cold rolling will be required only for 90 of fillet arc, starting at the point of tangency of the fillet radius and t
40、he bearing surface of the head. For shouldered bolts having an unthreaded shank diameter larger than the thread major diameter and having an undercut connected with a fillet between the threaded shank and the shoulder of the unthreaded shank, the cold working will be required only for 90 of fillet a
41、rc, starting at the point of tangency of the fillet radius and the shouldered surface of the unthreaded shank. The shank diameter on full shank close tolerance bolts shall not exceed its maximum diameter limit after cold rolling the head to shank fillet radius. 3.3.5 Thread Rolling Threads shall be
42、formed on the finished blanks by a single cold rolling process after removal of oxide as in 3.3.3. 3.3.6 Cleaning Parts, after finishing, shall be degreased and immersed in one of the following solutions for the time and temperature shown: a. One volume of nitric acid (sp gr 1.42) and 9 volumes of w
43、ater for not less than 20 minutes at room temperature. b. One volume of nitric acid (sp gr 1.42) and 4 volumes of water for 30 to 40 minutes at room temperature. c. One volume of nitric acid (sp gr 1.42) and 4 volumes of water for 10 to 15 minutes at 140 to 160 F. 3.3.6.1 Immediately after removal f
44、rom the cleaning solution, parts shall be thoroughly rinsed in clean water at 70 to 200 F. SAE INTERNATIONAL AS7478D Page 6 of 19 3.4 Product Marking Each part shall be identification marked as specified by the part drawing. The markings may be formed by forging or stamping, raised or depressed 0.01
45、0 inch maximum, with rounded root form on depressed characters. 3.5 Plating or Coating Where required, surfaces shall be plated as specified by the part drawing. Where coating with dry film lubricants is required, the under-head bearing surface, unthreaded shank, and threads shall be coated as speci
46、fied on the part drawing; other surfaces are optional to coat, unless otherwise specified. Plating thickness determined in accordance with plating specification. 3.6 Mechanical Properties Where AS7478 is specified, parts shall conform to the requirements of 3.6.1, 3.6.2, and 3.6.4. Where AS7478-2 is
47、 specified, parts shall conform to the requirements of 3.6.1, 3.6.2, and 3.6.3. Threaded members of gripping fixtures for tensile and stress-rupture tests shall be of sufficient size and strength to develop the full strength of the part without stripping the thread. AS7478 finished parts shall be te
48、sted in accordance with the following test methods: a. Hardness: MIL-STD-1312-6 in accordance with NASM1312-6 b. Room Temperature Ultimate Tensile Strength: MIL-STD-1312-8 in accordance with NASM1312-8 c. Stress-Rupture Strength at 1200 F: MIL-STD-1312-10 in accordance with NASM1312-10 AS7478-2 fini
49、shed parts shall be tested in accordance with the following test methods: a. Hardness: MIL-STD-1312-6 in accordance with NASM1312-6 b. Room Temperature Ultimate Tensile Strength: MIL-STD-1312-8 in accordance with NASM1312-8 c. Ultimate Double Shear at Room Temperature: MIL-STD-1312-13 in accordance with NASM1312-13 3.6.1 Ultimate Tensile Strength at Room Temperature 3.6.1.1 Finished Parts Parts shall have an ultimate te
