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 2012 SAE International All rights reserved. No part of this pub
3、lication 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
4、(outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/AS7468BAEROSPACESTANDARDAS7468 REV. B Issued 1991-01 Revised 2000-08 Reaffirmed 2012
5、-11 Superseding AS7468A Bolts, Cobalt-Chromium-Nickel Alloy UNS R30035, Tensile Strength 260 ksi, Procurement Specification FSC 5306 RATIONALEAS7468B has been reaffirmed to comply with the SAE five-year review policy. SAE AS7468B Page 2 of 26 I 2. REFERENCES: 2.1 Applicable Documents: The following
6、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 in effect on the date of the purchase order. In the event of conflict between the text of this document and refere
7、nces 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. 2.1.1 SAE Publications: Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. AMS 2750 Pyrometr
8、y AMS 5844 Alloy, Corrosion Resistant, Bars, 20Cr 35Ni 35Co 1 OMo, Vacuum Induction Plus Vacuum Consumable Electrode Melted, Solution Heat Treated and Work Strengthened AS3062 AS3063 AS8879 Bolts, Screws and Studs, Screw Thread Requirements Bolts, Screws and Studs, Geometric Control Requirements Scr
9、ew Threads - UNJ Profile, Inch 2.1.2 U.S. Government Publications: Available from DODSSP, Subscription Services Desk, Building 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094. MS21296 Bolt, Tension, Steel, 260 ksi Ftu, 450 F, External Wrenching, Spline Drive, Flanged Head 2.1.3 ASTM Publications
10、: Available from ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959. ASTM E 8 Tension Testing of Metallic Materials ASTM E 112 Determining Average Grain Size 1 ASTM E 140 Standard Hardness Conversion Tables for Metals ASTM E 1417 Liquid Penetrant Examination ASTM D 3951 Commercial Packagi
11、ng SAE AS7468B Page 3 of 26 2.1.4 AIA/NAS Publications: Available from Aerospace Industries Association of America, Inc. (AlA), 1250 Eye Street NW, Suite 1100, Washington, DC 20005-3924. NASM 1312-6 NASM 1312-8 NASM 1312-11 NASM 1312-13 Fastener Test Methods, Method 6, Hardness Fastener Test Methods
12、, Method 8, Tensile Strength Fastener Test Methods, Method 11, Tension Fatigue Fastener Test Methods, Method 13, Double Shear Test 2.1.5 ASME Publications: Available from ASME, 22 Law Drive, Box 2900, Fairfield, NJ 07007-2900. ASME B46.1 Surface Texture (Surface Roughness, Waviness, and Lay) 2.2 Def
13、initions: BURR: A rough edge or ridge left on the metal due to a cutting, grinding, piercing or blanking operation. 1 COLD WORKING: Forming material below the recrystallation temperature. CRACK: Rupture in the material which may extend in any direction and which may be intercrystalline or transcryst
14、alline in character. 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 the etched appearance between the head and shank caused by the plastic formin
15、g of the head. INCLUSION: Nonmetallic particles originating from the material making process. They may exist as discrete particles or strings of particles extending longitudinally. 1 INSPECTION LOT: Shall consist of parts from a single production lot, of the same part number. I LAP: Surface imperfec
16、tion caused by folding over metal fins or sharp corners 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 widt
17、h with a depth of 0.0005 inch when viewed at 200X magnification. MACHI Nl NG 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. NON-CONFORMANCE: A departure from a
18、specified requirement for any characteristic. NON-CONFORMING UNIT: A unit of the product that has one or more non-conformances. SAE AS7468B Page 4 of 26 2.2 (Continued): PRODUCTION INSPECTION LOT: Shall be all finished parts of the same part number, made from a single heat of alloy, heat treated at
19、the same time to the same specified condition, produced as one continuous run, and submitted for vendors inspection at the same time. 1 ROOM TEMPERATURE: Ambient temperature (68 oF approximately). SEAM: Longitudinal surface imperfection in the form of an unwelded, open fold in the material. STRINGER
20、: A solid nonmetallic impurity in the metal or 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 the part without any loose ends and is within the dimensional limits of the part. 12.3 Unit Symb
21、ols: 0 OF % lbf ksi sp gr HRC -degree, angle -degree Fahrenheit - percent (1% = 1/1 00) - pounds force - kips (1000 pounds) per square inch - specific gravity - hardness Rockwell C scale 3. TECHNICAL REQUIREMENTS: 3.1 Material: Shall be AMS 5844 alloy heading stock. 3.2 Design: Finished (completely
22、manufactured) parts shall conform to the following requirements: Dimensions: The dimensions of finished parts, after all processing, including plating, shall conform to the part drawing. Dimensions apply after plating but before coating with solid film lubricants. 3.2.2 Surface Texture: Surface text
23、ure of finished parts, prior to plating or coating, shall conform to the requirements as specified on the part drawing, determined in accordance with ASME 846.1. 13.2.3 Threads: Screw thread UNJ profile and dimensions shall be in accordance with AS8879, unless otherwise specified on the part drawing
24、. SAE AS7468B Page 5 of 26 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 AS3062. 3.2.3.2 Chamfer: The entering end of the thread shall be chamfered as
25、specified on the part drawing. 13.2.4 Geometric Tolerances: Part features shall be within the geometric tolerances specified on the part drawing and, where applicable, in accordance with AS3063. 3.3 Fabrication: 3.3.1 Blanks: Heads shall be formed by hot or cold forging; machined heads are not permi
26、tted, except lightening holes may be produced by any suitable method. Wrenching recesses may be forged or machined. Flash or chip clearance in machined recesses shall not cause recess dimensions to exceed the specified limits. 13.3.2 Heat Treatment: Before finishing the shank and bearing surface of
27、the head, cold working the head-to-shank fillet radius, and rolling the threads, headed blanks shall be aged as follows: 3.3.2 .1 Heating Equipment: Furnaces may be any type ensuring uniform tern perature throughout the parts being heated and shall be equipped with, and operated by, automatic temper
28、ature controllers and data recorders conforming to AMS 2750. 3.3.2.2 Aging Heat Treatment: Headed blanks shall be aged by heating to a temperature within the range 1000 to 1200 F, holding at the selected temperature within 25 oF for 4 to 4.5 hours, and cooling at a rate equivalent to air cooling. 3.
29、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, work-strengthened, and aged blanks prior to cold working the fillet radius and rolling the threads. Th
30、e 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. SAE AS7468B Page 6 of 26 3.3.4 Cold Working of
31、 Fillet Radius: 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 shall be cold worked sufficiently to remove all visual evidence of grinding or tool marks. Distortion due to cold working shall conf
32、orm 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 shall not extend beyond “C“ shown in Figure 2. In configuration
33、s having an undercut connected with the fillet radius, the cold working will be required only for goo of fillet arc, starting at the point of tangency of the fillet radius and the bearing surface of the head. For shouldered bolts, having an unthreaded shank diameter larger than the thread major diam
34、eter 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 goo of the fillet arc, starting at the point of tangency of the fillet radius and the shouldered surface of the unthreaded shank. The sh
35、ank diameter on close tolerance full shank bolts shall not exceed its maximum diameter limit after cold working the head-to-shank fillet radius. 3.3.5 Thread Rolling: Thread shall be formed on the finished blanks by a single cold rolling process after removal of oxide as in 3.3.3. 3.3.6 Cleaning: Pa
36、rts, after finishing, shall be degreased and submerged in one of the following solutions for the time and temperature shown: r.3.6.1 a. One volume of nitric acid (sp gr 1.42) and g volumes of water for not less than 20 minutes at room temperature. b. One volume of nitric acid (sp gr 1 .42) and 4 vol
37、umes 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 oF. Water Rinse: Immediately after removal from the cleaning solution, parts shall be thoroughly rinsed in clean water at 70 to 200 oF. 3.4 Prod
38、uct Marking: Each part shall be identification marked as specified on the part drawing. The markings may be formed by forging or stamping, raised or depressed 0.010 inch maximum, with rounded root form on depressed characters. 3.5 Plating or Coating: Where required, surfaces shall be plated or coate
39、d as specified by the part drawing. Where coating with solid film lubricants is required, the under head bearing surface, the unthreaded shank, and the threads shall be coated as specified on the part drawing; other surfaces are optional to coat, unless otherwise specified. Plating thickness shall b
40、e determined in accordance with the requirements in the applicable plating specification. SAE AS7468B Page 7 of 26 I I 3.6 Mechanical Properties: 3.6.1 Where AS7468 is specified, parts shall conform to the requirements of 3.6.1, 3.6.2 and 3.6.3. Where AS7468-1 is specified, parts shall conform to th
41、e requirements of 3.6.1, 3.6.2, and 3.6.4. Threaded members of gripping fixtures for tensile tests, and fatigue tests 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 a minimum of three full thr
42、eads from the thread runout exposed between the loading fixtures during tensile test. AS7468 finished parts shall be tested in accordance with the following test methods: a. Hardness: b. Ultimate Tensile Strength at Room Temperature: c. Fatigue Strength at Room Temperature: NASM 1312-6 NASM 1312-8 N
43、ASM 1312-11 AS7468-1 finished parts shall be tested in accordance with the following test methods: a. Hardness: b. Ultimate Tensile Strength at Room Temperature: c. Ultimate Double Shear at Room Temperature: Ultimate Tensile Strength at Room Temperature: NASM 1312-6 NASM 1312-8 NASM 1312-13 3.6.1.1
44、Finished Parts: Tension bolts, such as double hexagon and spline drive heads, shall have an ultimate tensile load not lower than that specified in Table 2 and shall be tested to failure in order to observe fracture location, first measuring and recording the maximum tensile load achieved. If size an
45、d shape of the part is such that failure would occur outside the threaded section but 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 have an ultimate tensile strength not lower than 260 ksi; f
46、or 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 hexagon or spline drive heads having a minimum metal condition in the head equal to the design parameters specified in MS21296, sh
47、all not fracture in the head-to-shank fillet radius except when this radius is connected with an undercut or with a shank diameter less than the minimum pitch diameter of the thread. r612 Machined Test Specimens: If the size and the shape of the part is such that a tensile test cannot be made on the
48、 part, tensile tests shall be conducted in accordance with ASTM E 8 on specimens prepared as in 4.5. 7. Specimens may be required by the purchaser to perform confirmatory tests. Such specimens shall meet the following room temperature requirements: a. Ultimate Tensile Strength, minimum: b. Yield Str
49、ength at 0.2% Offset, minimum: c. Elongation in 40, minimum: d. Reduction of Area, minimum: 260 ksi 230 ksi 8% 35% SAE AS7468B Page 8 of 26 3.6.1.2.1 When permitted by the purchaser, hardness tests on the end of parts may be substituted for tensile tests of machined specimens. r62 3.6.3 3.6.4 Hardness: Shall be uniform and not lower than 44 HRC (see 8.1), but hardness of the threaded section and of the head-to-shank fillet area may be highe
