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 2015 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/AMS6444MAEROSPACEMATERIAL SPECIFICATIONAMS6444 REV. MIssued 1960-06Revised 2015-08Superseding
5、 AMS6444LSteel, Bars, Forgings, and Tubing1.45Cr (0.93 - 1.05C) (SAE 52100) Premium Aircraft-Quality, Consumable Electrode Vacuum Remelted(Composition similar to UNS G52986)RATIONALEAMS6444M results from a Five Year Review and update of this document that revises decarburization requirements andrepo
6、rting.1. SCOPE1.1 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 parts requiring a through-hardening steel, usually with hardness of approximate
7、ly 60 HRC in section thicknesses 0.50 inch (12.7 mm) and under, 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
8、the extent specified herein. 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 Publi
9、cations Available from 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 BarsAMS2253 Tolerances, Carbon and Alloy Steel TubingAMS2259 Chemical Check Analysi
10、s Limits, Wrought Low-Alloy and Carbon SteelsSAE INTERNATIONAL AMS6444M Page 2 of 8AMS2300 Steel Cleanliness, Premium Aircraft-Quality, Magnetic Particle Inspection ProcedureAMS2370 Quality Assurance Sampling and Testing, Carbon and Low-Alloy Steel Wrought Products and Forging StockAMS2372 Quality A
11、ssurance Sampling and Testing Carbon and Low-Alloy Steel ForgingsAMS2806 Identification Bars, Wire, Mechanical Tubing, and Extrusions, Carbon and Alloy Steels and Corrosion and Heat-Resistant Steels and AlloysAMS2808 Identification ForgingsAS1182 Standard Stock Removal Allowance Aircraft-Quality and
12、 Premium Aircraft-Quality Steel Bars and Mechanical Tubing2.2 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 A370 Mechanical Testing of Steel ProductsASTM A604 Macroetch Testing of Cons
13、umable Electrode Remelted Steel Bars and BilletsASTM E45 Determining the Inclusion Content of SteelASTM E350 Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought IronASTM E384 Knoop and Vickers Hardness of Materials3. TECHNICAL REQUIREMENTS 3.1 Compos
14、ition Shall conform to the percentages by weight shown 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 - CompositionElement min maxCarbon 0.93 1.05Manganese 0.25 0.45Silicon 0.15 0
15、.35Phosphorus - 0.015Sulfur - 0.015Chromium 1.35 1.60Nickel - 0.25Molybdenum - 0.10Copper - 0.30Aluminum 0.050Oxygen 0.0015SAE INTERNATIONAL AMS6444M Page 3 of 83.1.1 Check Analysis Composition variations shall meet the applicable requirements of AMS2259.3.2 Melting Practice Steel shall be multiple
16、melted using consumable electrode vacuum practice (VAR) 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 plate (Also see 4.4.2).3.3.1.1 Bars
17、0.500 inch (12.70 mm) and Under in Nominal Diameter or Least Distance Between Parallel Sides Cold finished, with microstructure of spheroidized cementite in a ferrite matrix, having tensile strength not higher than 120 ksi (827 MPa), or equivalent hardness (see 8.2).3.3.1.2 Bars Over 0.500 inch (12.
18、70 mm) in Nominal Diameter or Least Distance Between Parallel Sides Hot finished and annealed, unless otherwise ordered, with microstructure of spheroidized cementite in a ferrite matrix, having hardness not higher than 207 HB, or equivalent (see 8.3). Bars ordered cold finished may have hardness as
19、 high as 248 HB, or equivalent (see 8.3).3.3.2 Forgings As ordered.3.3.3 Mechanical Tubing Cold finished, unless otherwise ordered, with microstructure of spheroidized cementite in a ferrite matrix, having hardness not higher than 24 HRC, or equivalent (see 8.3). Tubing ordered hot finished and anne
20、aled shall have hardness not higher than 95 HRB, or equivalent (see 8.3).3.3.4 Forging Stock As ordered by the forging manufacturer.3.4 Properties The product shall conform to the following requirements; hardness testing shall be performed in accordance with ASTM A370:3.4.1 MacrostructureVisual exam
21、ination of transverse full cross-sections from bars, billets, tube rounds or 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
22、 in Table 2.SAE INTERNATIONAL AMS6444M Page 4 of 8Table 2 - Macrostructure limitsClass Condition Severity1 Freckles A2 White Spots B3 Radial Segregation B4 Ring Pattern B3.4.2 Micro-Inclusion RatingNo specimen shall exceed the limits shown in Table 3, determined in accordance with ASTM E45, Method D
23、.Table 3 - Micro-inclusion rating limitsLimitsAThinAHeavyBThinBHeavyCThinCHeavyDThinDHeavyWorst Field Severity 2.0 1.0 1.5 1.0 1.5 1.0 1.5 1.0Worst Field Frequency,maximum a 1 a 1 a 1 5 3Total Rateable FieldsFrequency, maximum b 1 b 1 b 1 c 3a - Combined A+B+C, not more than 3 fieldsb - Combined A+B
24、+C, not more than 8 fieldsc - Any number of lower rateable D-type thin field per specimen is permissible.3.4.2.1 Thickness of D-type heavy shall not exceed 0.0005 inch (12.7 m).3.4.2.2 A rateable field is defined as one that has a type A, B, C, or D inclusion rating of at least 1.0 thin or heavy ina
25、ccordance with ASTM E45.3.4.3 Response to Heat Treatment of Bars, Forgings, and TubingSpecimens 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 hardne
26、ss not lower than 63 HRC at any point below any permissible decarburization after being placed in a furnace that is at 1525 F 10 F (829 C 6 C), allowed to heat to 1525 F 10 F (829 C 6 C), held at heat for 20 minutes 2 minutes, and quenched in commercial paraffin oil (90 to 110 SUS at 100 F (38 C) at
27、 room temperature.3.4.4 Decarburization 3.4.4.1 Bars and tubing ordered 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 4.3.4.4.2 Allowable decarburization o
28、f bars, billets, and tube rounds ordered for redrawing or forging or to specified microstructural requirements other than spheroidized cementite in a ferrite matrix shall be as agreed upon by purchaser and producer.3.4.4.3 Decarburization of bars that 3.4.4.1 or 3.4.4.2 is not applicable shall be no
29、t greater than shown in Table 4.3.4.4.4 Decarburization on the ID and OD of tubes that 3.4.4.1 or 3.4.4.2 is not applicable shall be not greater than that shown in Table 4.SAE INTERNATIONAL AMS6444M Page 5 of 8Table 4A - Maximum total depth of decarburization limits, inch/pound unitsNominal Diameter
30、or DistanceBetween Parallel SidesInchesTotal Depth ofDecarburizationBarsHot FinishedInchTotal Depth ofDecarburizationBarsAnnealedInchTotal Depth ofDecarburizationBarsCold FinishedInchTotal Depth ofDecarburizationTubesAnnealedInchTotal Depth ofDecarburizationTubesCold FinishedInchUp to 0.250, incl 0.
31、005 0.015 0.003 0.012 0.010Over 0.250 to 0.500, incl 0.006 0.015 0.004 0.012 0.010Over 0.500 to 0.750, incl 0.008 0.015 0.006 0.012 0.010Over 0.750 to 1.000, incl 0.010 0.015 0.008 0.012 0.010Over 1.000 to 2.000, incl 0.017 0.022 0.015 0.020 0.014Over 2.000 to 3.000, incl 0.025 0.030 0.025 0.030 0.0
32、19Over 3.000 to 4.000, incl 0.035 0.045 0.035 0.035 0.024Over 4.000 to 5.000, incl 0.055 0.065 0.055 0.040 0.028Table 4B - Maximum total depth of decarburization limits, SI unitsNominal Diameteror DistanceBetween Parallel SidesMillimetersTotal Depth ofDecarburizationBarsHot FinishedMillimeterTotal D
33、epth ofDecarburizationBarsAnnealedMillimeterTotal Depth ofDecarburizationBarsCold FinishedMillimeterTotal Depth ofDecarburizationTubesAnnealedMillimeterTotal Depth ofDecarburizationTubesCold FinishedMillimeterUp to 6.35, incl 0.13 0.38 0.08 0.30 0.25Over 6.35 to 12.70, incl 0.15 0.38 0.10 0.30 0.25O
34、ver 12.70 to 19.05, incl 0.20 0.38 0.15 0.30 0.25Over 19.05 to 25.40, incl 0.25 0.38 0.20 0.30 0.25Over 25.40 to 50.80, incl 0.43 0.56 0.38 0.51 0.36Over 50.80 to 76.20, incl 0.64 0.76 0.64 0.76 0.48Over 76.20 to 101.60, incl 0.89 1.14 0.89 0.89 0.61Over101.60 to 127.00, incl 1.40 1.65 1.40 1.02 0.7
35、13.4.4.5 Decarburization shall be evaluated by one of the methods of 3.3.4.6 or 3.3.4.7.3.4.4.6 Metallographic MethodA cross section taken perpendicular to the surface shall be prepared, etched, and visually examined metallographically at a magnification not to exceed 100X. The product shall not sho
36、w a layer of complete (ferrite) or partial decarburization exceeding the limits of Table 4.3.4.4.7 Hardness Traverse MethodThe total depth of decarburization shall be determined by a traverse method using microhardness testing in accordance with ASTM E384, at a magnification not exceeding 100X, cond
37、ucted on a hardened but untempered specimen protected during heat treatment to prevent changes in surface carbon content. Tempering is generally not recommended, but if tempered, the tempering temperature shall be not higher than 300 F (149 C). Depth of decarburization is defined as the perpendicula
38、r 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 on the adjacent surface. Acceptance shall be as listed in Table 4.3.4.4.8 When d
39、etermining 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.3.4.4.9 In the case of dispute, the total depth of decarburi
40、zation determined using the microhardness traverse method shall govern.SAE INTERNATIONAL AMS6444M Page 6 of 83.5 Quality The product, 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
41、.3.5.1 Steel shall be premium aircraft-quality conforming to AMS2300.3.5.2 Bars and mechanical tubing ordered hot rolled or cold drawn, 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
42、 to the machined, ground, turned, or polished surface.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 evidence of reentrant grain flow.3.6 Tolerances 3.6.1 Bars In accordance with AMS2251.3.6.2 Mechanica
43、l 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 for the performance of all required tests. Purchaser reserves the right to sample and to perform any
44、 confirmatory testing deemed necessary to ensure that the product conforms to specified requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests Composition (3.1), condition (3.3), macrostructure (3.4.1), micro-inclusion rating (3.4.2), response to heat treatment (3.4.3), decarburization (3.
45、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 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 producer unless frequency of
46、 testing is specified by purchaser.4.3 Sampling and Testing 4.3.1 Bars, Mechanical Tubing, and Forging Stock In accordance with AMS2370.4.3.2 Forgings In accordance with AMS2372.SAE INTERNATIONAL AMS6444M Page 7 of 84.3.3 Samples for response to heat treatment (see 3.4.3) shall be as follows: 4.3.3.
47、1 Specimens from bars shall be full cross-sections of the bar, except length and width need not exceed 1.5 inches (38 mm) respectively, ground on both faces normal to the axis so that the length is 0.50 inch 0.010 inch(12.7 mm 0.25 mm).4.3.3.2 Specimens from mechanical tubing shall be full cross-sec
48、tions of the tubing, shall have wall thickness not over 0.625 inch (15.88 mm) with wall thicknesses over 0.625 inch (15.88 mm) being turned to 0.625 inch 0.010 inch(15.88 mm 0.25 mm), and shall be ground on both faces so that the length is 0.50 inch 0.010 inch (12.7 mm 0.25 mm).4.4 Reports 4.4.1 The
49、 producer of bar, forgings and tubing shall furnish with each shipment a report showing 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 tests for composition, macrostructure, and micro-inclusion rating of each heat, and for condition and response to heat treatment of each lot, and stating that t
