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/AS7470CAEROSPACESTANDARDAS7470 REV. C Issued 1991-02 Revised 2008-10 Reaffirmed 2012
5、-11 Superseding AS7470B Bolts and Screws, Steel, Corrosion and Moderate Heat Resistant Heat Treated, Roll Threaded RATIONALEAS7470C has been reaffirmed to comply with the SAE five-year review policy. SAE AS7470C Page 2 of 23 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth D
6、rive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AMS2750 AMS5616 AS1132 AS3062 AS3063 AS8879 Pyrometry Steel, Corrosion and Heat Resistant, Bars, Wire, Forgings, Tubing, and Rings 13Cr 2.0Ni 3.0W Annealed Bolts, Screws and Nuts- E
7、xternal Wrenching UNJ Thread, Inch- Design Standard Bolts, Screws and Studs- Screw Threads Requirements Bolts, Screws and Studs- Geometric Control Requirements Screw Threads- UNJ Profile, Inch Controlled Radius Root with Increased Minor Diameter 2.1. 2 ASTM Publications Available from ASTM Internati
8、onal, 100 Barr Harbor Drive, P 0. 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 D 3951 Commercial Packaging ASTM E 1444 Magnetic Particle Examination 2.1.3 ASME Publicati
9、on Available from American Society of Mechanical Engineers, 22 Law Drive, P 0 Box 2900, Fairfield, NJ 07007-2900, Tel: 973-882-1170, www.asme.org. ASME B46.1 Surface Texture (Surface Roughness, Waviness, and Lay) 2.1.4 AlA Publications Available from Aerospace Industries Association, 1000 Wilson Bou
10、levard, Suite 1700, Arlington, VA 22209-3928, Tel: 703-358-1000, www.aia-aerospace.org. NASM1312-6 Fastener Test Methods, Method 6, Hardness NASM1312-8 Fastener Test Methods, Method 8, Tensile strength NASM1312-12 Fastener Test Methods, Plating Thickness SAE AS7470C Page 3 of 23 2.2 Definitions BURR
11、: A rough edge or ridge left on the metal due to a cutting, grinding, piercing or 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 chara
12、cter. DEFECT: Any nonconformance of the unit of product with specified requirements. 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 s
13、tringer. 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 then rolling or forging them into the surfac
14、e. 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 in when viewed at X200 magnification. MACHINING TEAR: A pattern of short, jagge
15、d 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 of alloy, heat treated at the same time to th
16、e 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 impurity in the metal bar, often the result of inclusions th
17、at 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. 2.3 Unit Symbols A -ampere oc - degree Celsius OF - degree Fahrenheit g -gram (mass) cm3 -cubic cen
18、timeter h -hour in -inch SAE AS7470C Page 4 of 23 in2 - square inch min - minute of time % -percent (1% = 1/100) lbf - pounds force psi - pounds force per square inch sp gr -specific gravity 3. TECHNICAL REQUIREMENTS 3.1 Material Shall be AMS5616 steel, unless otherwise specified on the part drawing
19、. 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 part drawing. Dimensions apply after plating but before coating with solid film lubrican
20、ts. 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 846.1. 3.2.3 Threads Screw thread UNJ profile and dimensions shall be in accordance with AS8879, unless oth
21、erwise specified on the part drawing. 3.2.3.1 Incomplete Threads Incomplete threads are permissible at the chamfered end at 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 specifi
22、ed 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. SAE AS7470C Page 5 of 23 3.3 Fabrication 3.3.1 Blanks Heads shall be formed by hot or cold forging or m
23、achining. 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 dimension to exceed the specified limits. 3.3.2 Heat Treatment Headed and machined blanks shall, before finishing the s
24、hank and the bearing surface of the head, cold working the head-to-shank fillet radius when specified, and rolling the threads, be heat treated as follows: 3.3.2.1 Heating Equipment Furnaces may be any type ensuring uniform temperature throughout the parts being heated and shall be equipped with, an
25、d operated by, automatic temperature controllers and data recorders conforming to AMS2750. The heating medi um or atmosphere shall cause no surface hardening by carburizing or nitriding. 3.3.2.2 Hardening Blanks of AMS5616 shall be uniformly heated to 1750 oF 25 F, held at heat for 15 to 20 min, and
26、 suitably quenched. For other steels, the temperature, time, and quenching medium shall be as agreed by purchaser and vendor. 3.3.2.3 Tempering Hardened blanks shall be tempered by heating uniformly to a temperature necessary to produce the specified hardness and microstructure but not within the ra
27、nge of 700 to 1000 F, holding at heat for not less than 1 h, and cooling. 3.3.3 Oxide Removal Surface oxide, and oxide penetration caused by 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 working the under h
28、ead fillet radius when specified 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 and
29、 smooth surface and, in no case, shall be so great as to produce more cutting of flow lines in the head-to-shank junction of forged headed parts than shown in Figure 1. 3.3.4 Cold Working of Fillet Radius After removal of oxide as in 3.3.3, the head-to-shank fillet radius of parts having the radius
30、complete throughout the circumference of the part shall, when specified, be cold rolled sufficiently to remove all visual evidence of grinding or tool marks. Distortion due to cold working shall co nform to Figure 2, unless otherwise specified on the part drawing. It shall not rai se metal more than
31、 0.002 in above the contour at “A“ or depress metal more than 0.002 in below the contour at “B“ as shown in Figure 2; distorted areas shall 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 9
32、0 degrees of fillet arc, starting at the point of tangency of the fillet radius and the bearing surface of the head. In addition to cold working the head-to-shank fillet radius, shouldered bolts having an unthreaded shank diameter larger than the thread major diameter and having an undercut associat
33、ed with a fillet between the threaded shank and the shoulder of the unthreaded shank, the cold working will be required only for 90 degrees 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 b
34、etween head and shank, cold work only the radius that blends with the head. SAE AS7470C Page 6 of 23 3.3.5 Thread Rolling Threads shall be formed on the heat treated and finished blanks by a single rolling process after removal of oxide as in 3.3.3. 3.3.6 Cleaning Parts, after finishing, shall be de
35、greased 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 water for not less than 20 min at room temperature. b. One volume of nitric acid (sp gr 1.42) and 4 volumes of water for 30 to 40 min at room temperat
36、ure. c. One volume of nitric acid (sp gr 1.42) and 4 volumes of water for 10 to 15 min at 140 to 160 oF. d. Citric acid solution containing 4 to 10 weight percent of citric acid, for a minimum of 20 min at a temperature in the range of 70 to 120 F. 3.4 Product Marking Each part shall be identificati
37、on marked as specified by the part drawing. The markings may be formed by forging or stamping, raised or depressed not more than 0.010 in maximum, with rounded root form or depressed characters. 3.5 Plating Where required, any protective treatment shall be as specified by the part drawing. 3.6 Mecha
38、nical Properties I Parts 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 thre
39、e 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 Strength:
40、MIL-STD-1312-8 in accordance with NASM1 312-8. 3.6.1 Ultimate Tensile Strength at Room Temperature 3.6.1.1 Finished Parts Parts having hardness not lower than 30 HRC shall have an ultimate tensile load not lower than that specified in Table 3 and shall be tested to failure, first measuring and recor
41、ding the maximum tensile load achieved. Parts requiri ng minimum hardness not lower than 35 HRC shall have an ultimate tensile load not lower than the minimum ultimate tensile load specified in Table 3 multiplied by 1.08. If the size or shape of the part is such that failure would occur outside the
42、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 tensile strength requirements of 3.6.1.2; for such parts, the diameter of the area on which
43、 stress is based shall be actual measured minimum diameter of the part. Tension fasteners with either standard double hexagon or hexagon type head 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 exc
44、ept when this radius is associated with an undercut or with a shank diameter less than the minimum pitch diameter of the thread, or where cold working of the fillet radius is not required and the heads are machined. SAE AS7470C Page 7 of 23 3.6.1.2 Machined Test Specimens If the size or shape of the
45、 part is such that a tensile test can not be made on the part, tensile tests shall be conducted in accordance with ASTM E 8 on specimens prepared as in 4.4. Such specimens shall meet the requirements in Table 1: TABLE 1-TENSILE PROPERTIES OF TEST SPECIMENS Minimum Hardness of Ultimate Tensile Elonga
46、tion in 2 in or Specified Range, Strength, 40, Reduction of Area, HRC psi minimum %minimum %minimum 30 140 000 17 40 35 152 000 13 35 3.6.1.2.1 When permitted by purchaser, hardness test on the end of the parts may be substituted for tensile test of machined specimens. 3.6.2 Hardness Unless otherwis
47、e specified on the part drawing, hardness shall be uniform and within the range 30 to 38 HRC, but hardness of the threaded section and of the head-to-shank fillet area when cold working of this area is specified, may be higher as a result of the cold working operations. 3.7 Quality Parts shall be un
48、iform in quality and condition, clean, sound, smooth and free from burrs and foreign materials, and from imperfections detrimental to their performance. 3. 7.1 Macroscopic Examination Parts or sections of parts, as applicable, shall be etched in a solution consisting of approximately 50% hydrochlori
49、c acid (sp gr 1.1 9), 50% water, or other suitable etchant for sufficient time to reveal flow lines but not longer than 15 min, and then examined at a magnification of approximately 20X to determine conformance to the requirements of 3. 7.1.1 and 3. 7.1.2, and 3. 7.1.3, except that examination for 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. 3. 7.1.1
