1、AEROSPACE MATERIAL SPECIFICATION AMS6427 REV. M Issued 1952-02 Revised 2014-08 Superseding AMS6427L Steel Bars, Forgings, and Tubing 0.88Cr - 1.8Ni - 0.42Mo - 0.08V (0.28 - 0.33C) (4330 Mod) (Composition similar to UNS K23080) RATIONALE AMS6427M results from a Five Year Review and update of this spe
2、cification that corrects the composition in the title and revises decarburization and reporting requirements. 1. SCOPE 1.1 Form This specification covers an aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock. 1.2 Application These products have been
3、 used typically for parts requiring a combination of high tensile strength and good ductility with relatively high impact strength and hardness, but usage is not limited to such applications. Certain design and processing procedures may cause these products to become susceptible to stress-corrosion
4、cracking after heat treatment. ARP1110 recommends practices to minimize such conditions. 2. APPLICABLE DOCUMENTS The issue of the following documents in effect on the date of the purchase order forms a part of this document to the extent specified herein. The supplier may work to a subsequent revisi
5、on 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 SAE International, 400 Commonwealth Drive, Warren
6、dale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 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-Alloy and Carbon Steels AMS2301 Steel Cleanliness,
7、 Aircraft Quality, Magnetic Particle Inspection Procedure _ 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 parti
8、cular use, including any patent infringement arising therefrom, 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 201
9、4 SAE International All rights reserved. No part of this 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
10、: 877-606-7323 (inside USA and Canada) Tel: +1 724-776-4970 (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/AMS6427M SAE INTERNATIO
11、NAL AMS6427M Page 2 of 8 AMS2370 Quality Assurance Sampling and Testing, Carbon and Low-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
12、 Alloy Steels and Corrosion and Heat-Resistant Steels and Alloys AMS2808 Identification, Forgings AS1182 Standard Stock Removal Allowance, Aircraft-Quality and Premium Aircraft Quality Steel Bars and Mechanical Tubing ARP1110 Minimizing Stress Corrosion Cracking in Wrought Forms of Steels and Corros
13、ion-Resistant Steels and Alloys 2.2 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9585, www.astm.org. ASTM A 255 Hardenability of Steel ASTM A 370 Mechanical Testing of Steel Products ASTM E 23 Notched Bar Im
14、pact Testing of Metallic Materials ASTM E 112 Determining Average Grain Size ASTM E 350 Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought Iron ASTM E 381 Macroetch Testing Steel Bars, Billets, Blooms, and Forgings ASTM E 384 Knoop and Vickers Hardn
15、ess of Materials 3. TECHNICAL REQUIREMENTS 3.1 Composition Shall conform to the percentages by weight shown in Table 1, determined by wet chemical methods in accordance with ASTM E 350, by spectrochemical methods, or by other analytical methods acceptable to purchaser. TABLE 1 - COMPOSITION Element
16、min max Carbon Manganese Silicon Phosphorus Sulfur Chromium Nickel Molybdenum Vanadium Copper 0.28 0.75 0.15 - - 0.75 1.65 0.35 0.05 - 0.33 1.00 0.35 0.025 0.025 1.00 2.00 0.50 0.10 0.35 3.1.1 Check Analysis Composition variations shall meet the applicable requirements of AMS2259. SAE INTERNATIONAL
17、AMS6427M Page 3 of 8 3.2 Condition The product shall be supplied in the following condition; hardness and tensile strength shall be determined in accordance with ASTM A 370: 3.2.1 Bars 3.2.1.1 Bars 0.500 Inch (12.70 mm) and Under in Nominal Diameter or Least Distance Between Parallel Sides Cold fini
18、shed having tensile strength not higher than 130 ksi (896 MPa), or equivalent hardness (See 8.2). 3.2.1.2 Bars Over 0.500 Inch (12.70 mm) in Nominal Diameter or Least Distance Between Parallel Sides Hot finished and annealed if necessary, unless otherwise ordered, having hardness not higher than 241
19、 HB, or equivalent (See 8.3). Bars ordered cold finished may have hardness as high as 248 HB, or equivalent (See 8.3). 3.2.1.3 Bars shall not be cut from plate. (Also see 4.4.2.) 3.2.2 Forgings Normalized and tempered having hardness not higher than 269 HB, or equivalent (See 8.3). 3.2.3 Mechanical
20、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). 3.2.4 Forging Stock As ordered by the forging manufacturer. 3.3 Properties The
21、 product shall conform to the following requirements; hardness shall be performed in accordance with ASTM A 370: 3.3.1 Macrostructure Visual examination of transverse full cross sections from bars, billets, tube rounds (solid, not hollow), and forging stock, etched in hot hydrochloric acid in accord
22、ance with ASTM E 381, shall show no pipe or cracks. Porosity, segregation, inclusions, and other imperfections shall be no worse than the macrographs of ASTM E 381 shown in Table 2. TABLE 2 - MACROSTRUCTURE LIMITS Section Size Cross-Sectional Area Square Inches Section Size Cross-Sectional Area Squa
23、re Centimeters Macrographs Up to 36, incl Up to 232, incl S2 - R1 - C2 Over 36 to 133, incl Over 232 to 858, incl S2 - R2 - C3 Over 133 Over 858 Note 1 Note 1 Limits for larger sizes shall be agreed upon by purchaser and vendor. The purchaser shall have written approval from the cognizant engineerin
24、g organization. 3.3.1.1 If tubes are produced directly from ingots or large blooms, transverse sections may be taken from the tubes rather than tube rounds. Macroetch standards for such tubes shall be as agreed upon by purchaser and vendor. 3.3.2 Average Grain Size of Bar, Forgings and Tubing Shall
25、be ASTM No. 5 or finer, determined in accordance with ASTM E 112. SAE INTERNATIONAL AMS6427M Page 4 of 8 3.3.3 Hardenability of Each Heat Shall be J 14/16 inch (22 mm) = 49 HRC minimum and J 24/16 inch (38 mm) = 45 HRC minimum, determined on the standard end-quench test specimen in accordance with A
26、STM A 255 except that the steel shall be normalized at 1700 F 10 (927 C 6) and the test specimen austenitized at 1550 F 10 (843 C 6). 3.3.4 Decarburization 3.3.4.1 Bars and tubing ordered ground, turned, or polished shall be free from decarburization on the ground, turned, or polished surfaces. Deca
27、rburization on tubing ID shall not exceed the maximum depth specified in 3.3.4.4. 3.3.4.2 Allowable decarburization of bars, billets, and tube rounds or tubing ordered for redrawing or forging or to specified microstructural requirements shall be as agreed upon by purchaser and vendor. 3.3.4.3 Decar
28、burization of bars when 3.3.4.1 or 3.3.4.2 is not applicable shall be not greater than shown in Table 3. TABLE 3A - MAXIMUM TOTAL DEPTH OF DECARBURIZATION, BARS, INCH/POUND UNITS Nominal Diameter or Distance Between Parallel Sides Inches Total Depth of Decarburization Inch Up to 0.375, incl 0.015 Ov
29、er 0.375 to 0.500, incl 0.017 Over 0.500 to 0.625, incl 0.019 Over 0.625 to 1.000, incl 0.022 Over 1.000 to 1.500, incl 0.025 Over 1.500 to 2.000, incl 0.030 Over 2.000 to 2.500, incl 0.035 Over 2.500 to 3.000, incl 0.040 Over 3.000 to 5.000, incl 0.045 TABLE 3B - MAXIMUM TOTAL DEPTH OF DECARBURIZAT
30、ION, BARS, SI UNITS Nominal Diameter or Distance Between Parallel Sides Millimeters Total Depth of Decarburization Millimeters Up to 9.52, incl 0.38 Over 9.52 to 12.70, incl 0.43 Over 12.70 to 15.88, incl 0.48 Over 15.88 to 25.40, incl 0.56 Over 25.40 to 38.10, incl 0.64 Over 38.10 to 50.80, incl 0.
31、76 Over 50.80 to 63.50, incl 0.89 Over 63.50 to 76.20, incl 1.02 Over 76.20 to 127.00, incl 1.14 3.3.4.3.1 Limits for depth of decarburization of bars over 5.000 inches (127.00 mm) in nominal diameter or distance between parallel sides shall be as agreed upon by purchaser and vendor. 3.3.4.4 Decarbu
32、rization of tubing when 3.3.4.1 or 3.3.4.2 is not applicable shall be not greater than shown in Table 4. SAE INTERNATIONAL AMS6427M Page 5 of 8 TABLE 4A - MAXIMUM TOTAL DEPTH OFDECARBURIZATION, TUBING, INCH/POUND UNITS Nominal Wall Thickness Inches Total Depth of Decarburization Inch ID Total Depth
33、of Decarburization Inch OD Up to 0.109, incl 0.008 0.015 Over 0.109 to 0.203, incl 0.010 0.020 Over 0.203 to 0.400, incl 0.012 0.025 Over 0.400 to 0.600, incl 0.015 0.030 Over 0.600 to 1.000, incl 0.017 0.035 Over 1.000 0.020 0.040 TABLE 4B - MAXIMUM TOTAL DEPTH OF DECARBURIZATION, TUBING, SI UNITS
34、Nominal Wall Thickness Millimeters Total Depth of Decarburization Millimeters ID Total Depth of Decarburization Millimeters OD Up to 2.77, incl 0.20 0.38 Over 2.77 to 5.16, incl 0.25 0.51 Over 5.16 to 10.16, incl 0.30 0.64 Over 10.16 to 15.24, incl 0.38 0.76 Over 15.24 to 25.40, incl 0.43 0.89 Over
35、25.40 0.51 1.02 3.3.4.5 Decarburization shall be measured by the metallographic method or by a traverse method using microhardness testing in accordance with ASTM E 384. The microhardness method shall be conducted on a hardened but untempered specimen protected during heat treatment to prevent chang
36、es in surface carbon content. Depth of decarburization, when measured by the microhardness method, is defined as the perpendicular distance from the surface to the depth under that surface where there is no further increase in hardness. Such measurements shall be far enough away from any adjacent su
37、rface to be uninfluenced by any decarburization on the adjacent surface. In case of dispute, the depth of decarburization determined using the microhardness traverse method shall govern. 3.3.4.5.1 When determining the depth of decarburization, it is permissible to disregard local areas provided the
38、decarburization of such areas does not exceed the above limits by more than 0.005 inch (0.13 mm) and the width is 0.065 inch (1.65 mm) or less. 3.3.5 Impact Strength The Izod impact value shall be not less than 15 foot-pounds (20 Nm) at room temperature, determined in accordance with ASTM E 23 using
39、 a V-notched specimen. Specimens, before test, shall have hardness not lower than 45 HRC after being quenched in oil from 1550 F 10 (843 C 6) and tempered at 600 F 10 (316 C 6). Before heat treatment, specimens shall be to size or approximately to size except for the notch. 3.4 Quality The product,
40、as received by purchaser, shall be uniform in quality and condition, sound, and free from foreign materials and from imperfections detrimental to usage of the product. 3.4.1 Steel shall be aircraft quality conforming to AMS2301. 3.4.2 Bars and tubing ordered hot rolled or cold drawn, or ground, turn
41、ed, or polished shall, after removal of the standard stock removal allowance in accordance with AS1182, be free from seams, laps, tears, and cracks open to the machined, ground, turned, or polished surface. 3.4.3 Grain flow of die forgings, except in areas that contain flash-line end grain, shall fo
42、llow the general contour of the forgings, showing no evidence of reentrant grain flow. SAE INTERNATIONAL AMS6427M Page 6 of 8 3.5 Tolerances 3.5.1 Bars In accordance with AMS2251. 3.5.2 Mechanical Tubing In accordance with AMS2253. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection Th
43、e vendor of the product shall supply all samples for vendors tests and shall be responsible for the performance of all required tests. Purchaser reserves the right to sample and to perform any confirmatory testing deemed necessary to ensure that the product conforms to specified requirements. 4.2 Cl
44、assification of Tests 4.2.1 Acceptance Tests Composition (3.1), condition (3.2), macrostructure (3.3.1), average grain size (3.3.2), hardenability (3.3.3), decarburization (3.3.4), frequency-severity cleanliness rating (3.4.1), and tolerances (3.5) are acceptance tests and shall be performed on each
45、 heat or lot as applicable. 4.2.2 Periodic Tests Grain flow of die forgings (3.4.3) and impact strength (3.3.5) are periodic tests and shall be performed at a frequency selected by the vendor unless frequency of testing is specified by purchaser. 4.3 Sampling and Testing 4.3.1 Bars, Mechanical Tubin
46、g, and Forging Stock In accordance with AMS2370 except as specified in 4.3.3. 4.3.2 Forgings In accordance with AMS2372 4.3.3 Specimens for impact testing shall be taken longitudinally from sections rolled or forged from full cross-section to not over 2.0 inches (51 mm) round or square. SAE INTERNAT
47、IONAL AMS6427M Page 7 of 8 4.4 Reports 4.4.1 The producer of bars, forgings and tubing shall furnish with each shipment a report showing the producer identity, country where the metal was melted (e. g., final melt in the case of metal processed by multiple melting operations), the results of composi
48、tion, macrostructure, hardenability and frequency-severity cleanliness rating for each heat and for condition (hardness or tensile) and average grain size of each lot and stating that the product conforms to the other technical requirements. This report shall include the purchase order number, heat
49、and lot numbers, AMS6427M, product form and size (and/or part number, if applicable) and quantity. If forgings are supplied, the size and melt source of stock used to make the forgings shall also be included. 4.4.2 Report the nominal metallurgically worked cross sectional size and the cut size, if different (Also see 3.2.1.3). 4.4.3 The producer of forging stock shall furnish with each shipment a
