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 revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions. Copyright 2017 SAE International All rights reserved. No part of this
3、publication 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: +1 724-776-49
4、70 (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/AMS6431P AEROSPACE MATERIAL SPECIFICATION AMS6431 REV. P Issued 1964-06 Revised 2017-01 Supers
5、eding AMS6431N Steel, Bars, Forgings, and Tubing 1.05Cr - 0.55Ni - 1.0Mo - 0.11V (0.45 - 0.50C) (D6AC) Vacuum Consumable Electrode Remelted (Composition similar to UNS K24728) RATIONALE AMS6431P results from a Five-Year Review and update of this specification that revises decarburization testing met
6、hods (3.4.3.5), quality (3.5), and reporting (4.4). 1. SCOPE 1.1 Form This specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock. 1.2 Application These products have been used typically for ultra-high-strength structural
7、applications requiring a through-hardening weldable steel for use up to 600 F (316 C), but usage is not limited to such applications. 2. APPLICABLE DOCUMENTS The issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified he
8、rein. The supplier may work to a subsequent revision of a document unless a specific document issue is specified. When the referenced document has been cancelled and no superseding document has been specified, the last published issue of that document shall apply. 2.1 SAE Publications Available from
9、 SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or +1 724-776-4970 (outside USA), www.sae.org. AMS2251 Tolerances Low-Alloy Steel Bars AMS2253 Tolerances Carbon and Alloy Steel Tubing AMS2259 Chemical Check Analysis Limits Wrought Low-
10、Alloy and Carbon Steels AMS2300 Steel Cleanliness, Premium Aircraft-Quality Magnetic Particle Inspection Procedure SAE INTERNATIONAL AMS6431P Page 2 of 9 AMS2310 Qualification Sampling and Testing of Steels for Transverse Tensile Properties AMS2370 Quality Assurance Sampling and Testing Carbon and L
11、ow-Alloy Steel Wrought Products and Forging Stock AMS2372 Quality Assurance Sampling and Testing Carbon and Low-Alloy Steel Forgings AMS2806 Identification Bars, Wire, Mechanical Tubing, and Extrusions Carbon and Alloy Steels and Corrosion and Heat-Resistant Steels and Alloys AMS2808 Identification
12、Forgings AS1182 Standard Stock Removal Allowance Aircraft-Quality and Premium Aircraft-Quality Steel Bars and Mechanical Tubing ARP1917 Clarification of Terms Used in Aerospace Metals Specifications 2.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West C
13、onshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM A370 Mechanical Testing of Steel Products ASTM A604 Macroetch Testing of Consumable Electrode Remelted Steel Bars and Billets ASTM E112 Determining Average Grain Size ASTM E140 Hardness Conversion Tables for Metals ASTM E350 Chemical
14、Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought Iron ASTM E384 Microindentation Hardness of Materials ASTM E399 Plane-Strain Fracture Toughness of Metallic Materials 3. TECHNICAL REQUIREMENTS 3.1 Composition Shall conform to the percentages by weight show
15、n in Table 1, determined by wet chemical methods in accordance with ASTM E350, by spectrochemical methods, or by other analytical methods acceptable to purchaser. Table 1 - Composition Element Min Max Carbon Manganese Silicon Phosphorus Sulfur Chromium Nickel Molybdenum Vanadium Copper 0.45 0.60 0.1
16、5 - - 0.90 0.40 0.90 0.08 - 0.50 0.90 0.30 0.010 0.010 1.20 0.70 1.10 0.15 0.35 SAE INTERNATIONAL AMS6431P Page 3 of 9 3.1.1 Check Analysis Composition variations shall meet the applicable requirements of AMS2259 except that variations for carbon and vanadium shall apply to “Over Max” only. 3.2 Melt
17、ing Practice Steel shall be multiple melted using vacuum consumable electrode process in the remelt cycle. 3.3 Condition The product shall be supplied in the following condition; hardness and tensile strength shall be determined in accordance with ASTM A370: 3.3.1 Bars Bar shall not be cut from plat
18、e (also see 4.4.2). 3.3.1.1 Bars 0.500 inch (12.70 mm) and Under in Nominal Diameter or Least Distance Between Parallel Sides Cold finished having tensile strength not higher than 145 ksi (1000 MPa) or equivalent hardness (see 8.2). 3.3.1.2 Bars Over 0.500 inch (12.70 mm) in Nominal Diameter or Leas
19、t Distance Between Parallel Sides Hot finished and annealed, unless otherwise ordered, having hardness not higher than 265 HB, or equivalent (see 8.3). Bars ordered cold finished may have hardness as high as 285 HB, or equivalent (see 8.3). 3.3.2 Forgings Normalized and tempered having hardness not
20、higher than 285 HB, or equivalent (see 8.3). 3.3.3 Mechanical Tubing Cold finished, unless otherwise ordered, having hardness not higher than 25 HRC, or equivalent (see 8.3). Tubing ordered hot finished and annealed shall have hardness not higher than 99 HRB, or equivalent (see 8.3). 3.3.4 Forging S
21、tock As ordered by the forging manufacturer. 3.4 Properties The product shall conform to the following requirements; hardness and tensile testing shall be performed in accordance with ASTM A370: 3.4.1 Macrostructure Visual examination of transverse full cross-sections from bars, billets, tube rounds
22、 (solid, not hollow), and forging stock, etched in hot hydrochloric acid in accordance with ASTM A604, shall show no pipe or cracks. Porosity, segregation, inclusions, and other imperfections shall be no worse than the macrographs of ASTM A604 shown in Table 2. Table 2 - Macrostructure limits Class
23、Condition Severity 1 2 3 4 Freckles White Spots Radial Segregation Ring Pattern A A B B SAE INTERNATIONAL AMS6431P Page 4 of 9 3.4.1.1 Macrostructure examination is not required for hollow tubes that are produced directly from ingots or blooms unless specified by purchaser, in which case the purchas
24、er shall specify standards to be used. 3.4.2 Average Grain Size of Bars, Forgings, and Tubing Shall be ASTM No. 5 or finer, determined in accordance with ASTM E112. 3.4.3 Decarburization 3.4.3.1 Bars and tubing ordered ground, turned, or polished shall be free from decarburization on the ground, tur
25、ned, or polished surfaces. Decarburization on tubing ID shall not exceed the maximum total depth specified in Table 4. 3.4.3.2 Allowable decarburization of bars, billets, and tube rounds ordered for redrawing or forging or to specified microstructural requirements shall be as agreed upon by purchase
26、r and producer. 3.4.3.3 Decarburization of bars that 3.4.3.1 or 3.4.3.2 is not applicable shall be not greater than shown in Table 3. Table 3 Table 3A - Maximum total depth of decarburization, inch/pound units Nominal Diameter or Distance Between Parallel Sides Inches Total Depth of Decarburization
27、Inch Up to 0.375, incl Over 0.375 to 0.500, incl Over 0.500 to 0.625, incl Over 0.625 to 1.000, incl Over 1.000 to 1.500, incl Over 1.500 to 2.000, incl Over 2.000 to 2.500, incl Over 2.500 to 3.000, incl Over 3.000 to 5.000, incl 0.015 0.017 0.019 0.022 0.025 0.030 0.035 0.040 0.045 Table 3B - Mini
28、mum total depth of decarburization, SI units Nominal Diameter or Distance Between Parallel Sides Millimeters Total Depth of Decarburization Millimeters Up to 9.52, incl Over 9.52 to 12.70, incl Over 12.70 to 15.88, incl Over 15.88 to 25.40, incl Over 25.40 to 38.10, incl Over 38.10 to 50.80, incl Ov
29、er 50.80 to 63.50, incl Over 63.50 to 76.20, incl Over 76.20 to 127.00, incl 0.38 0.43 0.48 0.56 0.64 0.76 0.89 1.02 1.14 SAE INTERNATIONAL AMS6431P Page 5 of 9 3.4.3.4 Decarburization of tubing that 3.4.3.1 or 3.4.3.2 is not applicable shall be not greater than shown in Table 4. Table 4 Table 4A -
30、Maximum total depth of decarburization, inch/pound units Nominal Wall Thickness Inches Total Depth of Decarburization Inch ID Total Depth of Decarburization Inch OD Up to 0.109, incl Over 0.109 to 0.203, incl Over 0.203 to 0.400, incl Over 0.400 to 0.600, incl Over 0.600 to 1.000, incl Over 1.000 0.
31、008 0.010 0.012 0.015 0.017 0.020 0.015 0.020 0.025 0.030 0.035 0.040 Table 4B - Maximum total depth of decarburization, SI units Nominal Wall Thickness Millimeters Total Depth of Decarburization Millimeter ID Total Depth of Decarburization Millimeters OD Up to 2.77, incl Over 2.77 to 5.16, incl Ove
32、r 5.16 to 10.16, incl Over 10.16 to 15.24, incl Over 15.24 to 25.40, incl Over 25.40 0.20 0.25 0.30 0.38 0.43 0.51 0.38 0.51 0.64 0.76 0.89 1.02 3.4.3.5 Decarburization shall be evaluated by one of the two methods of 3.4.3.5.1 or 3.4.3.5.2. 3.4.3.5.1 Metallographic Method A cross section taken perpe
33、ndicular to the surface shall be prepared, etched, and visually examined metallographically at a magnification not to exceed 100X. Optical indications of decarburiztion shall not show a layer of complete (ferrite) or partial decarburization exceeding the limits of Tables 3 or 4. 3.4.3.5.2 Hardness T
34、raverse Method The total depth of decarburization shall be determined by a traverse method using microindentation hardness testing in accordance with ASTM E384, at a magnification not exceeding 100X, conducted on a hardened but untempered specimen protected during heat treatment to prevent changes i
35、n surface carbon content. Depth of decarburization is defined as the perpendicular distance from the surface to the depth under that surface where there is not further increase in hardness. Such measurements shall be far enough away from any adjacent surface to be uninfluenced by any decarburization
36、 on the adjacent surface. Acceptance shall be as listed in Tables 3 or 4. 3.4.3.5.3 When determining the depth of decarburization, it is permissible to disregard local areas provided the decarburization of such areas does not exceed the above limits by more than 0.005 inch (0.13 mm) and the width is
37、 0.065 inch (1.65 mm) or less. 3.4.3.5.4 In case of dispute, the total depth of decarburization determined using the microindentation hardness traverse method shall govern. SAE INTERNATIONAL AMS6431P Page 6 of 9 3.4.4 Response to Heat Treatment of Bars, Forgings, Tubing, and Forging Stock Tensile sp
38、ecimens, from product 10.0 inches (254 mm) and under in nominal diameter or least distance between parallel sides, shall conform to the following requirements after being hardened by heating in a protective atmosphere to a temperature within the range 1650 to 1700 F (899 to 927 C), holding at the se
39、lected temperature for 40 minutes per inch (25 mm) of section thickness or nominal diameter but not less than 60 minutes, and quenching in oil, and tempered by heating to a temperature within the range 1025 to 1050 F (552 to 566 C), holding at the selected temperature for 2 hours per inch (25 mm) of
40、 section thickness or nominal diameter but not less than 4 hours, and cooling in air to room temperature. 3.4.4.1 Longitudinal Tensile Properties Shall be as shown in Table 5; testing in the longitudinal direction need not be performed on product tested in the transverse direction. Table 5 - Longitu
41、dinal tensile properties Property Value Tensile Strength Yield Strength at 0.2% Offset, minimum Elongation in 4D, minimum Reduction of Area, minimum 220 to 250 ksi (1517 to 1724 MPa) 190 ksi (1310 MPa) 12% 35% 3.4.4.2 Transverse Tensile Properties Shall be as shown in Table 6, determined on specimen
42、s selected and prepared in accordance with AMS2310; transverse tensile property requirements apply only to product that tensile specimens not less than 2.50 inches (63.5 mm) in length can be taken. Table 6 - Transverse tensile properties Property Value Tensile Strength Yield Strength at 0.2% Offset,
43、 minimum Elongation in 4D, minimum Reduction of Area, minimum Average of all tests Any one test 220 to 250 ksi (1517 to 1724 MPa) 190 ksi (1310 MPa) 9% 30% 25% 3.4.4.3 Hardness Shall not be lower than 46 HRC, or equivalent (see 8.3). 3.4.4.4 Fracture Toughness When specified, the product shall be su
44、bjected to fracture toughness testing in accordance with ASTM E399, and shall meet a minimum KICproperty value of 67 ksi inch (73.6 MPa m ) for LT (or LS) orientation. 3.5 Quality The product, as received by purchaser, shall be uniform in quality and condition, sound, and free from foreign materials
45、 and from imperfections detrimental to usage of the product. 3.5.1 Steel shall be premium aircraft-quality conforming to AMS2300 except that a maximum average frequency (F) rating of 0.10 and maximum average severity (S) rating of 0.20 shall apply. SAE INTERNATIONAL AMS6431P Page 7 of 9 3.5.2 Bars a
46、nd mechanical tubing shall be free from seams, laps, tears, and cracks after removal of the standard stock removal allowance in accordance with AS1182. 3.5.3 Grain flow of die forgings, except in areas that contain flash-line end grain, shall follow the general contour of the forgings showing no evi
47、dence of reentrant grain flow. 3.6 Tolerances 3.6.1 Bars In accordance with AMS2251. 3.6.2 Mechanical Tubing In accordance with AMS2253. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The producer of the product shall supply all samples for producers tests and shall be responsible
48、 for the performance of all required tests. Purchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that product conforms to specified requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests Composition (3.1), condition (3.3), macrostructure
49、 (3.4.1), average grain size (3.4.2), decarburization (3.4.3), tensile properties (3.4.4), hardness (3.4.4.3), fracture toughness when specified (3.4.4.4), and tolerances (3.6) are acceptance tests and shall be performed on each heat or lot as applicable. 4.2.2 Periodic Tests Frequency-severity cleanliness rating (3.5.1) and grain flow of die forgings (3.5.2) are periodic tests and shall be performed at a frequen
