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 reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright 2011 SAE International All rights reserved. No part of this publication ma
3、y 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 (outside US
4、A) 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/AS7474CAEROSPACESTANDARDAS7474 REV. C Issued 1991-02 Reaffirmed 2006-05 Revised 2011-10 Superse
5、ding AS7474B Bolts and Screws, Steel, Corrosion Resistant, UNS S17400 Tensile Strength 140 ksi Procurement Specification FSC 5306RATIONALETo revise paragraph 3.6 by adding “two to” three threads in agreement with NASM1312 test methodology and general updating of specifications and SAE formatting req
6、uirements also tables 1 to 7 have been redrawn. 1. SCOPE 1.1 Type This specification covers bolts and screws made from a corrosion and heat resistant, martensitic iron base alloy of the type identified under the Unified Numbering System as UNS S17400. The following specification designations and the
7、ir properties are covered: AS7474 140 ksi minimum ultimate tensile strength at room temperature 100 ksi stress corrosion test 72 ksi to 7.2 ksi tension-tension fatigue AS7474-1 140 ksi minimum ultimate tensile strength at room temperature 100 ksi stress corrosion test 88 ksi minimum ultimate shear s
8、trength at room temperature 1.2 Application Primarily for aerospace propulsion system applications where corrosion resistance and high strength in tension is required in temperatures not to exceed 600 F. 1.3 Safety - Hazardous Materials While the materials, methods, applications, and processes descr
9、ibed 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 with the safe and proper use of any hazardous materials and to take
10、necessary precautionary measures to ensure the health and safety of all personnel involved. SAE AS7474C Page 2 of 22 2. REFERENCES 2.1 Applicable Documents The following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The ap
11、plicable 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. Nothing in this document, however, supersedes applicable laws and r
12、egulations 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 724-776-4970 (outside USA), www.sae.org.AMS2700 Passivation of Corrosion Resistant Steels
13、 AMS2759/3 Heat Treatment Precipitation-Hardening Corrosion-Resistant and Maraging Steel Parts AMS5643 Steel, Corrosion-Resistant, Bars, Wire, Forgings, Tubing, and Rings 16Cr 4.0Ni 0.30Cb 4.0Cu Solution Heat Treated, Precipitation Hardenable AS1132 Bolts, Screws and Nuts - External Wrenching UNJ Th
14、read, 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 Minor Diameter 2.1.2 AIA Publications AIA Publications: Available fr
15、om Aerospace Industries Association, 1000 Wilson Boulevard, Suite 1700, Arlington,VA 22209-3928, Tel: 703-358-1000, www.aia-aerospace.org. NASM 1312-6 Fastener Test Methods, Method 6, Hardness NASM 1312-8 Fastener Test Methods, Method 8, Tensile Strength NASM 1312-9 Fastener Test Methods, Method 9,
16、Stress Corrosion NASM 1312-11 Fastener Test Methods, Method 11, Tension Fatigue NASM 1312-12 Fastener Test Methods, Method 12, Thickness of Metallic Coatings NASM 1312-13 Fastener Test Methods, Method 13, Double Shear Test SAE AS7474C Page 3 of 22 2.1.3 ASTM Publications Available from ASTM Internat
17、ional, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM E 8 Tension Testing of Metallic Materials ASTM E 140 Standard Hardness Tables for Metals ASTM E 1417 Liquid Penetrant Examination ASTM D 3951 Commercial Packaging 2.1.4 ASME Publicati
18、ons Available from American Society of Mechanical Engineers, 22 Law Drive, P.O.Box Box 2900, Fairfield, NJ 07007-2900 Tel 973-882-1170, www.asme.orgASME B46.1 Surface Texture (Surface Roughness, Waviness, and Lay) 2.2 Definitions BURR: A rough edge or ridge left on the metal due to a cutting, grindi
19、ng, piercing or blanking operation. DEFECTIVE: A unit of product which contains one or more defects. 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 contin
20、uous run, and submitted for vendors inspection at the same time. 2.3 Unit Symbols C degree Celsius F degree Fahrenheit cm3cubic centimeter g gram (mass) HRC hardness, Rockwell C scale % percent (1% = 1/100) h hour lbf pound-force ksi kips (1000 pounds) per square inch sp gr specific gravity SAE AS74
21、74C Page 4 of 22 3. TECHNICAL REQUIREMENTS 3.1 Material Shall be AMS5643 steel heading stock. 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 or coating, shall
22、conform to the requirements as specified on the part drawing. Dimensions shall 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, de
23、termined in accordance with ASME B46.1. 3.2.3 Threads Screw thread UNJ profile and dimensions shall be in accordance with AS8879, unless otherwise specified on the part drawing.3.2.3.1 Incomplete Threads Incomplete threads are permissible at the chamfered end and the juncture of the unthreaded porti
24、on 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 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, co
25、ntrolled in accordance with AS3063. 3.3 Fabrication 3.3.1 Blanks Heads shall be formed by hot or cold forging; machined heads are not permitted, except lightening holes may be produced by any suitable method. Wrenching recesses may be forged or machined. 3.3.2 Heat Treatment Shall conform to the tec
26、hnical requirements and other provisions specified in AMS2759/3 for 17-4PH, condition H 1100 treatment.3.3.2.1 Solution Heat Treatment Blanks shall be solution heat treated as in 3.3.2. SAE AS7474C Page 5 of 22 3.3.2.2 Aging Heat Treatment Solution treated blanks shall be heat treated by aging as in
27、 3.3.2. In no case shall material be re-aged between 700 F and 1050 F. 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 and aged heat treated blanks prior to cold r
28、olling the under head fillet radius and rolling the 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,
29、 smooth surface. 3.3.4 Cold Rolling of 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 rolled sufficiently to remove all visual evidence of grinding or tool marks. Dist
30、ortion due to cold rolling 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 shall not extend beyond “C
31、” as shown in Figure 2. In configurations having an undercut connected with the fillet radius, the cold rolling will be required only for 90 degrees of fillet arc, starting at thepoint of tangency of the fillet radius and the bearing surface of the head. For shouldered bolts, having an unthreaded sh
32、ank 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 rolling will be required only for 90 degrees of fillet arc, starting at the point of tangency of the fillet radius and the s
33、houldered surface of the unthreaded shank. 3.3.5 Thread Rolling Thread shall be formed on the heat treated and finished blank by a single cold rolling process after removal of oxide as in 3.3.3.3.3.6 Passivation Treatment Parts, after finishing, shall be degreased and then subjected to the passivati
34、on treatment and copper sulfate test in accordance with AMS2700. 3.4 Product Marking Each part shall be identification marked as specified by the part drawing. Unless otherwise specified on the part drawing, the markings may be formed by forging or stamping, raised or depressed 0.010 inch maximum, w
35、ith rounded root form on depressed characters. 3.5 Plating Where required, surfaces shall be plated as specified on the part drawing. Thickness determined in accordance with MIL-STD-1312-12 in accordance with NASM1312-12. 3.6 Mechanical Properties Where AS7474 is specified, parts shall conform to th
36、e requirements of 3.6.1, 3.6.2, 3.6.3, and 3.6.4. Where AS7474-1 is specified, parts shall conform to the requirements of 3.6.1, 3.6.2, 3.6.4, and 3.6.5. Threaded members of gripping fixtures for tensile, fatigue, and stress corrosion tests shall be of sufficient size and strength to develop the ful
37、l strength of the partwithout stripping the thread. The loaded portion of the shank shall have a minimum of two to three full thread turns from the thread runout exposed between the loading fixtures during tensile, fatigue, and stress corrosion tests. SAE AS7474C Page 6 of 22 AS7474 finished parts s
38、hall be tested in accordance with the following test methods: a. Hardness: MIL-STD-1312-6 in accordance with NASM1312-6. b. Ultimate Tensile Strength at Room Temperature: MIL-STD-1312-8 in accordance with NASM1312-8. c. Stress Corrosion at Room Temperature: MIL-STD-1312-9 in accordance with NASM1312
39、-9. d. Fatigue Strength at Room Temperature: MIL-STD-1312-11 in accordance with NASM1312-11. AS7474-1 finished parts shall be tested in accordance with the following test methods: e. Hardness: MIL-STD-1312-6 in accordance with NASM1312-6. f. Ultimate Tensile Strength at Room Temperature: MIL-STD-131
40、2-8 in accordance with NASM1312-8. g. Stress Corrosion at Room Temperature: MIL-STD-1312-9 in accordance with NASM1312-9. h. 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 sha
41、ll have an ultimate tensile load not lower than that specified in Table 1 and shall be tested to failure in order to observe fracture location, 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 sect
42、ion 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 have an ultimate tensile strength not lower than 140 ksi; for such parts, the diameter of the area on which stress is based shall be
43、the actual measured minimum diameter of the part. Tension fasteners with either standard double hexagon 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
44、is connected with an undercut or with a shank diameter less than the minimum pitch diameter of the thread. 3.6.1.2 Machined Test Specimens If 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 E 8 on specimen
45、s prepared as in 4.4.7. Specimens may be required by the purchaser to perform confirmatory tests. Such specimens shall meet the following requirements: a. Ultimate Tensile Strength, minimum: 140 ksi b. Yield Strength at 0.2% Offset, minimum: 120 ksi c. Elongation in 2 inch or 4D, minimum: 14% d. Red
46、uction of Area, minimum: 45% 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 Hardness Shall be uniform and within the range 32 to 38 HRC (see 8.1), but hardness of the threaded section and of the head-to-shan
47、k fillet area may be higher as a result of the cold rolling operations. SAE AS7474C Page 7 of 22 3.6.3 Fatigue Strength Finished parts tested in tension-tension fatigue at room temperature, with maximum load as specified in Table 1 and minimum load equal to 10% of maximum load, shall have average li
48、fe of not less than 65 000 cycles with no part having life less than 45 000 cycles. Tests need not be run beyond 130 000 cycles. Life of parts which do not fail in less than 130 000 cycles shall be taken as 130 000 cycles for purposes of computing average life. If the shank diameter of the part is l
49、ess than the minimum pitch diameter of the thread, parts shall withstand fatigue testing as above using loads sufficient to produce a maximum stress of 72 ksi and a minimum stress of 7.2 ksi. The above requirements apply only to parts 0.138 inch and larger in nominal thread size with round, square, hexagonal, or double hexagonal heads designed for tension applications and not having an undercut and having a head-to-sh
