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 ther
2、efrom, 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, stabilized or cancelled. SAE invites your written comments and suggestions. Copyright 2012 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: 724-776-4970 (
4、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:/www.sae.org/technical/standards/MA3374C METRIC AEROSPACE STANDARD MA3374 REV. C Issued 1986-02 Reaffirmed 2006-05 Re
5、vised 2012-08 Superseding MA3374B Bolts and Screws, UNS S66286, Corrosion and Heat Resistant Steel, Procurement Specification, Metric FSC 5306 RATIONALE Correct paragraph number references for FPI machined heads are not permitted, except lightening holes may be produced by any suitable method. Wrenc
6、hing recesses may be forged or machined. Flash or chip clearance in machined recesses shall not cause recess dimensions to exceed the specified limits. Heading stock to be hot forged shall not be heated to a temperature higher than 1150 C. 3.3.2 Heat Treatment Shall conform to the technical requirem
7、ents and other provisions specified in AMS2759/3 for A-286, 980 C solution treatment and 720 C aging treatment. SAE MA3374C Page 5 of 22 3.3.2.1 Solution Heat Treatment Headed blanks of AMS5731 shall, before finishing the shank and the bearing surface of the head, cold rolling the head-to-shank fill
8、et radius, and rolling the threads, be solution heat treated as in 3.3.2. 3.3.2.2 Ageing Treatment After solution heat treatment as in 3.3.2.1, blanks shall be heat treated by ageing as in 3.3.2. 3.3.3 Oxide Removal Surface oxide and oxide penetration resulting from prior heat treatment shall be rem
9、oved from the full body diameter and bearing surface of the head of the solution and aged heat treated blanks prior to cold rolling the 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 bearin
10、g 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 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 circumf
11、erence of the part, shall be cold rolled. The cold rolling shall be sufficient to remove all visual evidence of grinding or tool marks. Distortion due to cold rolling shall conform to Figure 2, unless otherwise specified on the part drawing. No raised metal (excrescence) is permitted on the head bea
12、ring surface (face) or depressed metal more than 0.025 mm below the fillet radius contour as shown in Figure 2; the unthreaded shank at the position shown in Figure 2, inclusive of distortion, shall not exceed the unthreaded shank diameter by an amount more than that specified in Figure 2. In config
13、urations having an undercut connected with the fillet radius, 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 bearing surface of the head. For shouldered bolts, having an unthreaded shank diameter larger than the thr
14、ead 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 degrees of fillet arc, starting at the point of tangency of the fillet radius and the shouldered surface of the unthrea
15、ded shank. 3.3.5 Thread Rolling Threads shall be formed on the heat treated and finished blanks 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 passivation treatment and copper sulfa
16、te test in accordance with ASTM A967. 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 0.25 mm maximum, with rounded root form on depressed characters. 3.5 Mechanical Properties Where
17、 MA3374 is specified, parts shall conform to the requirements of 3.5.1, 3.5.2, and 3.5.4. Where MA3374-1 is specified, parts shall conform to the requirements of 3.5.1, 3.5.2, and 3.5.3. Threaded members of gripping fixtures for tensile and stress-rupture tests shall be of sufficient size and streng
18、th to develop the full strength of the part without stripping the thread. The loaded portion of the shank shall have two to three full thread turns from the thread runout exposed beween the loading fixtures during the tensile and stress-rupture tests. SAE MA3374C Page 6 of 22 MA3374 finished parts s
19、hall be tested in accordance with the following test methods: a. Hardness: MIL-STD-1312-6 in accordance with NASM 1312. b. Ultimate Tensile Strength at Room Temperature: MIL-STD-1312-108 in accordance with NASM 1312. c. Stress-Rupture Strength at 650 C MIL-STD-1312-10 in accordance with NASM 1312. M
20、A3374-1 finished parts shall be tested in accordance with the following test methods: a. Hardness: MIL-STD-1312-6 in accordance with NASM 1312-6. b. Ultimate Tensile Strength at Room Temperature: MIL-STD-1312-108 in accordance with NASM 1312. c. Room Temperature Ultimate Shear Strength: MIL-STD-1312
21、-13 in accordance with NASM 1312. 3.5.1 Ultimate Tensile Strength at Room Temperature 3.5.1.1 Finished Parts Tension bolts shall 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
22、the maximum tensile load achieved. Screws, such as 100 degree flush head, pan head, and fillister head, shall have an ultimate tensile load not lower than that specified in Table 1; screws need not be tested to failure, however, the maximum tensile load achieved shall be measured and recorded. If th
23、e 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 shank diameter equal to or less than the thread root diameter or having an undercut, parts shall conform to only the ultimate tensile strength r
24、equirements of 3.5.1.2; 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 hexagon, double hexagon or spline drive heads having a minimum metal condition in the head equal to the design parameters specif
25、ied in MA1518, shall 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. 3.5.1.2 Machined Test Specimens If the size or shape of the part is such that a tensile test cannot
26、be made on the part, tensile tests shall be conducted in accordance with ASTM E8/E8M on specimens 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: 900 MPa b. Yi
27、eld Strength at 0.2% Offset, minimum: 590 MPa c. Elongation in 5D, minimum: 15% d. Reduction of Area, minimum: 20% 3.5.1.2.1 When permitted by purchaser, hardness tests on the end of parts may be substituted for tensile tests of machined specimens. 3.5.2 Hardness Shall be uniform and within the rang
28、e 24 to 36 HRC (see 8.1), but hardness of the threaded section and of the head-to-shank fillet area may be higher as a result of the cold rolling operations. Parts shall not be rejected on the basis of hardness if the tensile strength properties specified in 3.5.1 are met. SAE MA3374C Page 7 of 22 3
29、.5.3 Ultimate Shear Strength Finished bolts having a close toleranced full shank as in MA1518 shall have an ultimate double shear load not lower than that specified in Table 1. The double shear test may be discontinued without a complete shear failure after the ultimate double shear load has been re
30、ached, first measuring and recording the maximum dobule shear load achieved. Shear bolts having special shank diameters shall have the minimum ultimate double shear load based on 590 MPa minimum shear strength. Shear tests are not required for screws, such as 100 degree flush head, having a grip les
31、s than 2.5 times the nominal diameter or protruding head screws, such as pan head and fillister head, having a grip less than 2 times the nominal diameter. Shear test is not required for the following conditions: a. Bolts or screws threaded to head. b. Protruding head bolts or screws having a coarse
32、 toleranced full shank. c. Protruding head bolts or screws having a PD or relieved shank. 3.5.4 Stress-Rupture Strength at 650 C 3.5.4.1 Finished Parts Finished tension bolts, maintained at 650 C 2 C while the tensile load specified in Table 1 is applied continuously, shall not rupture in less than
33、23 h. If the shank diameter of the part is less than the maximum root diameter of the thread but the part can be tested satisfactorily, parts shall conform to the requirements of 3.5.4.1.1. Screws, such as 100 degree flush head, pan head, and fillister head, are not required to be tested for stress-
34、rupture strength at 650 C. 3.5.4.1.1 Parts having a shank diameter less than the maximum root diameter of the thread shall be tested as in 3.5.4.1 except that the load shall be as specified in 3.5.4.2. The diameter of the area on which stress is based shall be the actual measured minimum diameter of
35、 the part. 3.5.4.2 Machined Test Specimens If the size or shape of the part is such that a stress-rupture test cannot be made on the part, a test specimen prepared as in 4.4.7, maintained at 650 C 2 C while a load sufficient to produce an initial axial stress of 480 MPa is applied continuously, shal
36、l not rupture in less than 23 h. Tests shall be conducted in accordance with ASTM E139. 3.6 Quality Parts shall be uniform in quality and condition, free from burrs (tight burrs may be acceptable if part performance is not affected), foreign materials, and free from imperfections detrimental to the
37、usage of the parts. 3.6.1 Macroscopic Examination Specimens cut from headed blanks and from finished parts shall be etched in a suitable etchant and examined at a magnification of approximately 10X to determine conformance to the requirements of 3.6.1.1 and 3.6.1.2. The head and shank section shall
38、extend not less than D/2 from the bearing surface of the head and the threaded shank section shall extend not less than D/2 beyond the thread runout where “D” is the nominal diameter of the shank after heading. If the two sections would overlap, the entire length of the part shall be sectioned and e
39、xamined as a whole. 3.6.1.1 Flow Lines 3.6.1.1.1 Head-To-Shank, Headed Blanks After heading and prior to heat treatment, examination of an etched section taken longitudinally through the blank shall show flow lines in the shank, head- to-shank fillet, and bearing surface which follow the contour of
40、the blank as shown in Figure 1. Flow lines in headed blanks having special heads, such as Dee- or Tee-shaped heads or thinner than MA1518 standard heads, shall be as agreed upon by purchaser and vendor. SAE MA3374C Page 8 of 22 3.6.1.1.2 Head-To-Shank, Finished Part Examination of a longitudinal sec
41、tion through the part shall show evidence that the head was formed by forging (see Figure 1A). 3.6.1.1.3 Threads Examination of a longitudinal section through the threaded portion of the shank shall show evidence that the threads were rolled. This evidence shall include traces of flow lines as shown
42、 in Figure 3. 3.6.1.2 Internal Defects Examination of longitudinal sections of the head and shank shall reveal no cracks, laps, or porosity. Thread imperfections as in 3.6.2.4 shall be examined in accordance with 3.6.2. 3.6.2 Microscopic Examination Specimens cut from parts shall be polished, etched
43、 in Kallings reagent 100 cm3of absolute ethyl alcohol, 100 cm3of hydrochloric acid (sp gr 1.19), and 5 g of cupric chloride, Marbles reagent 20 cm3of hydrochloric acid (sp gr 1.19), 20 cm3of water, and 4 g of cupric sulfate pentahydrate, or other suitable etchant, and examined at a magnification not
44、 lower than 100X to determine conformance to the requirements of 3.6.2.1, 3.6.2.2, 3.6.2.3, and 3.6.2.4. 3.6.2.1 Microstructure Parts shall have microstructure of completely recrystallized material except in the area of the threads and the head-to-shank fillet radius. 3.6.2.2 Grain Size Shall be AST
45、M No. 5 or finer as determined by the comparison method of ASTM E112. Up to 25% of the areas examined may exhibit a grain size as large as ASTM No. 2. Such areas shall be separated by at least 0.65 mm. Bands of fine or coarse grains are not permitted. In case of dispute, the intercept (Heyn) method
46、shall be used. 3.6.2.3 Surface Hardening Parts shall have no change in hardness from core to surface except as produced during cold rolling of the head-to-shank fillet radius and rolling of threads. There shall be no evidence of carburization or nitriding. In case of dispute over results of the micr
47、oscopic examination, microhardness testing shall be used as a referee method; a Vickers hardness reading of an unrolled surface which exceeds the reading in the core by more than 30 points shall be evidence of nonconformance to this requirement. 3.6.2.4 Threads 3.6.2.4.1 Root defects such as laps, s
48、eams, notches, slivers, folds, roughness, and oxide scale are not permissible (see Figure 4). 3.6.2.4.2 Multiple laps on the flanks of threads are not permissible regardless of location. SAE MA3374C Page 9 of 22 3.6.2.4.3 Single Lap on Thread Profile Shall conform to the following: a. Rateable Lap:
49、Shall have its length equal to or greater than three times its width. The minimum interpretable lap size is 0.013 mm in length or depth when viewed at 200X magnification. b. Thread Flank Above the Pitch Diameter: A slight lap is permissible along the flank of the thread above the pitch diameter on either the pressure or nonpressure flank (one lap at any cross-section through the thread) provided it extends towards the
