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 2014 SAE InternationalAll rights reserved. No part of this publi
3、cation 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 (out
4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/AMS6490HAEROSPACE MATERIAL SPECIFICATIONAMS6490 REV. HIssued 1963-07Revised 2014-05Supersedin
5、g AMS6490GSteel Bars, Forgings, and Tubing4.0Cr - 4.2Mo - 1.0V (0.77 - 0.85C) (M-50)Premium Aircraft-Quality for Bearing ApplicationsConsumable Electrode Vacuum Melted(Composition similar to UNS T11350)RATIONALEAMS6490H results from a Five Year Review and update of this specification.1. SCOPE1.1 For
6、mThis specification covers a premium aircraft-quality, low-alloy steel in the form of bars, forgings, mechanical tubing, and forging stock.1.2 ApplicationThese products have been used typically for critical parts, such as bearings operating under heavy loads and high speeds at moderate temperatures
7、and subject to very rigid inspection standards, but usage is not limited to such applications.2. APPLICABLE DOCUMENTSThe issue of the following documents in effect on the date of the purchase order forms a part of this specification to the extent specified herein. The supplier may work to a subseque
8、nt 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 PublicationsAvailable from SAE International, 400 Commonwealth Drive,
9、 Warrendale, 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 BarsAMS2253 Tolerances, Carbon and Alloy Steel TubingAMS2259 Chemical Check Analysis Limits, Wrought Low-Alloy and Carbon SteelsAMS2300 Steel Cleanline
10、ss, Premium Aircraft-Quality, Magnetic Particle Inspection ProcedureSAE INTERNATIONAL AMS6490H Page 2 of 8AMS2370 Quality Assurance Sampling and Testing, Carbon and Low-Alloy Steel Wrought Products and Forging StockAMS2372 Quality Assurance Sampling and Testing, Carbon and Low-Alloy Steel ForgingsAM
11、S2375 Control of Forgings Requiring First Article ApprovalAMS2806 Identification, Bars, Wire, Mechanical Tubing, and Extrusions, Carbon and Alloy Steels and Corrosionand Heat-Resistant Steels and AlloysAMS2808 Identification, ForgingsAS1182 Standard Stock Removal Allowance, Aircraft-Quality and Prem
12、ium Aircraft-Quality Steel Bars and Mechanical Tubing2.2 ASTM PublicationsAvailable 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 370 Mechanical Testing of Steel ProductsASTM A 604 Macroetch Testing of Consumabl
13、e Electrode Remelted Steel Bars and BilletsASTM E 45 Determining the Inclusion Content of SteelASTM E 112 Determining Average Grain SizeASTM E 350 Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought IronASTM E 384 Knoop and Vickers Hardness of Materi
14、als3. TECHNICAL REQUIREMENTS3.1 CompositionShall 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 - COMPOSITIONElement min maxCarbon 0.77
15、 0.85Manganese - 0.35Silicon - 0.25Phosphorus - 0.015Sulfur - 0.015Chromium 3.75 4.25Molybdenum 4.00 4.50Vanadium 0.90 1.10Nickel - 0.15Cobalt - 0.25Tungsten - 0.25Copper - 0.103.1.1 Check AnalysisComposition variations shall meet the applicable requirements of AMS2259.SAE INTERNATIONAL AMS6490H Pag
16、e 3 of 83.2 Melting PracticeSteel shall be multiple melted using consumable electrode vacuum process in the remelt cycle.3.3 ConditionThe product shall be supplied in the following condition; hardness and tensile strength shall be determined in accordance with ASTM A 370:3.3.1 BarsBar shall not be c
17、ut from plate. (Also see 4.5.2).3.3.1.1 Bars 0.500 inch (12.70 mm) and Under in Nominal Diameter or Least Distance Between Parallel SidesCold finished and spheroidized annealed, having tensile strength not higher than 120.0 ksi (825 MPa), or equivalent hardness (See 8.2).3.3.1.2 Bars Over 0.500 inch
18、 (12.70 mm) in Nominal Diameter or Least Distance Between Parallel SidesHot finished and spheroidized annealed, unless otherwise ordered, having hardness not higher than 229 HB or equivalent (See 8.3). Bars ordered cold finished may have hardness as high as 248 HB, or equivalent (See 8.3).3.3.2 Forg
19、ingsAs ordered.3.3.3 Mechanical TubingCold 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 StockAs ordered by the forging ma
20、nufacturer.3.4 PropertiesThe product shall conform to the following requirements; hardness testing shall be performed in accordance with ASTM A 370:3.4.1 MacrostructureVisual examination of transverse sections from bars, billets, tube rounds, and forging stock, etched in hot hydrochloric acid in acc
21、ordance with ASTM A 604, shall show no pipe or cracks. Porosity, segregation, inclusions, and other imperfections shall be no worse than the macrographs of ASTM A 604 shown in Table 2.TABLE 2 - MACROSTRUCTURE LIMITSClass Condition Severity1Freckles A2 White Spots A3 Radial Segregation B4 Ring Patter
22、n B3.4.2 Micro-Inclusion Rating of each heatNo specimen shall exceed the limits of Table 3, determined in accordance with ASTM E 45, Method D.SAE INTERNATIONAL AMS6490H Page 4 of 8TABLE 3 - MICRO-INCLUSION RATING LIMITSTypeAThinAHeavyBThinBHeavyCThinCHeavyDThinDHeavyWorst Field Severity 1.5 1.0 1.0
23、1.0 1.0 1.0 1.5 1.0Worst Field Frequency, maximum a 1 a 1 a 1 3 1Total Rateable Fields,Frequency, maximumb1 b1 b1 81a - Combined A+B+C, not more than 3 fieldsb - Combined A+B+C, not more than 8 fields3.4.2.1 A rateable field is defined as one that has a type A, B, C, or D inclusion rating of at leas
24、t No. 1.0 thin or heavy in accordance with ASTM E 45.3.4.3 Response to Heat Treatment Specimens as in 4.3.3 protected by suitable means or treated in a neutral atmosphere or neutral salt to minimize scaling and prevent either carburization or decarburization, shall have substantially uniform hardnes
25、s not lower than 60 HRC after being heated to 2025 to 2050 F (1107 to 1121 C) by any convenient means, held to equalize at temperature, and either quenched into salt bath at 1100 to 1150 F (593 to 621 C), held in salt bath for 2 minutes 0.2, and air cooled to room temperature or directly air cooled
26、to room temperature, and tempered for 2 hours 0.25 at 1000 to 1025 F (538 to 552 C).3.4.4 Average Grain Size of Bars, Forgings and TubingShall be ASTM No. 7 or finer, determined in accordance with ASTM E 112 after austenitizing and quenching as in 3.4.3.3.4.5 Decarburization3.4.5.1 Bars and tubing o
27、rdered ground, turned, or polished shall be free from decarburization on the ground, turned, or polished surfaces. Decarburization on tubing ID shall not exceed the maximum depth specified in Table 5.3.4.5.2 Allowable decarburization of bars, billets, and tube rounds ordered for redrawing or forging
28、 or to specified microstructural requirements shall be as agreed upon by purchaser and vendor.3.4.5.3 Decarburization of bars to which 3.4.5.1 or 3.4.5.2 is not applicable shall be not greater than shown in Table 4.TABLE 4A - MAXIMUM TOTAL DEPTH OF DECARBURIZATION, INCH/POUND UNITSNominal Diameter o
29、r DistanceBetween Parallel SidesInchesTotal Depth ofDecarburizationInchUp to 0.500, incl 0.015Over 0.500 to 1.000, incl 0.030Over 1.000 to 2.000, incl 0.040Over 2.000 to 3.000, incl 0.050Over 3.000 to 4.000, incl 0.065Over 4.000 to 5.000, incl 0.095SAE INTERNATIONAL AMS6490H Page 5 of 8TABLE 4B - MA
30、XIMUM TOTAL DEPTH OF DECARBURIZATION, SI UNITSNominal Diameter or DistanceBetween Parallel SidesMillimetersTotal Depth ofDecarburizationMillimetersUp to 12.50, incl 0.38Over 12.50 to 25.00, incl 0.75Over 25.00 to 50.00, incl 1.00Over 50.00 to 75.00, incl 1.25Over 75.00 to 100.00, incl 1.65Over 100.0
31、0 to 125.00, incl 2.403.4.5.4 Decarburization of all tubing to which 3.4.5.1 or 3.4.5.2 is not applicable shall be not greater than shown in Table 5.TABLE 5A - MAXIMUM TOTAL DEPTH OF DECARBURIZATION, INCH/POUND UNITSNominalOutside DiameterInchesTotal Depth ofDecarburizationInchUp to 1.000, incl 0.02
32、5Over 1.000 to 2.000, incl 0.035Over 2.000 to 3.000, incl 0.045Over 3.000 to 4.000, incl 0.055Over 4.000 to 5.000, incl 0.080TABLE 5B - MAXIMUM TOTAL DEPTH OF DECARBURIZATION, SI UNITSNominalOutside DiameterMillimetersTotal Depth ofDecarburizationMillimetersUp to 25.00, incl 0.62Over 25.00 to 50.00,
33、 incl 0.88Over 50.00 to 75.00, incl 1.12Over 75.00 to 100.00, incl 1.40Over 100.00 to 125.00, incl 2.003.4.5.5 Decarburization shall be measured by the metallographic method or by the microhardness traverse method using microhardness testing in accordance with ASTM E 384. The microhardness method sh
34、all be conducted on a hardened but untempered specimen protected during heat treatment to prevent changes 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 th
35、ere is no further increase in hardness. Such measurements shall be far enough away from any adjacent surface to be uninfluenced by decarburization on the adjacent surface. In case of dispute, the depth of decarburization determined using the microhardness traverse method shall govern.3.4.5.5.1 When
36、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 0.065 inch (1.65 mm) or less.3.5 QualityThe product, as received by purchaser, shall be
37、uniform in quality and condition, sound, and free from foreign materials and from imperfections detrimental to usage of the product.3.5.1 Steel shall be premium aircraft-quality conforming to AMS2300.SAE INTERNATIONAL AMS6490H Page 6 of 83.5.2 Bars and mechanical tubing ordered hot rolled or cold dr
38、awn, or ground, turned, 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.3.5.3 Grain flow of die forgings, except in areas that contain flash-line
39、end grain, shall follow the general contour of the forgings showing no evidence of reentrant grain flow.3.6 Tolerances3.6.1 BarsIn accordance with AMS2251.3.6.2 Mechanical TubingIn accordance with AMS2253.4. QUALITY ASSURANCE PROVISIONS4.1 Responsibility for InspectionThe vendor of the product shall
40、 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 Classification of Tests4.2.1 Acc
41、eptance TestsComposition (3.1), condition (3.3), macrostructure (3.4.1), micro-inclusion rating (3.4.2), response to heat treatment(3.4.3), average grain size (3.4.4), decarburization (3.4.5), and tolerance (3.6) are acceptance tests and shall be performed on each heat or lot as applicable.4.2.2 Per
42、iodic TestsFrequency-severity rating (3.5.1) and grain flow of die forgings (3.5.3) 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 Testing4.3.1 Bars, Forging Stock, and Mechanical TubingIn accorda
43、nce with AMS2370.4.3.2 ForgingsIn accordance with AMS2372.4.3.3 Specimens for response to heat treatment (3.4.3) shall be taken midway between surface and center of samples representing the top and bottom of each remelted ingot involved in the lot obtained from semi-finished or finishedproduct. The
44、surface to be tested shall be ground sufficiently to remove any surface condition, scale, carburization, or decarburization that might affect readings.4.3.3.1 Alternately, the specimen may be obtained from the finished lot.4.4 ApprovalWhen specified, approval and control of forgings shall be in acco
45、rdance with AMS2375.SAE INTERNATIONAL AMS6490H Page 7 of 84.5 Reports4.5.1 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 opera
46、tions) and results of tests for composition, macrostructure, micro-inclusion rating for each heat, and for response to heat treatment for each heat (or lot See 4.3.3.1), and for condition (hardness or tensile strength)and average grain size of each lot, and stating that the product conforms to the o
47、ther technical requirements. This report shall include the purchase order number, heat and lot numbers, AMS6490H, product form and size or part number, and quantity. If forgings are supplied, the size and melt source of stock used to make the forgings shall also be included.4.5.2 Report the nominal
48、metallurgically worked cross sectional size and the cut size, if different (Also see 3.3.1).4.5.3 The producer of forging stock 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 me
49、lting operations) and the results of tests for composition, macrostructure, micro-inclusion rating for each heat and response to heat treatment for each heat (or lot See 4.3.3.1). This report shall include the purchase order number, heat number, AMS6490H, size and quantity. 4.6 Resampling and Retesting4.6.1 Bars, Forging Stock, and Mechanical TubingIn accordance with AMS2370.4.6.2 ForgingsIn accordance with
