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 there
2、from, 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 2016 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: +1 724-776-497
4、0 (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/AMS6255F AEROSPACE MATERIAL SPECIFICATION AMS6255 REV. F Issued 1984-07 Revised 2016-11Supersed
5、ing AMS6255E Steel Bars, Forgings, and Tubing 1.1Si - 1.45Cr - 1.0Mo - 0.08Al (0.16 - 0.22C) Double Vacuum Melted (Composition similar to UNS K21940)RATIONALE AMS6255F results from a Five Year Review and update of this specification revises micro-inclusion testing (3.4.2.1), quality (3.5) and report
6、ing (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 critical carburized parts, such as bearings, gears, and shafts, requirin
7、g high minimum core hardness within a narrow range, good resistance to elevated temperature up to 600 F (316 C), and subject to rigid magnetic particle inspection standards, but usage is not limited to such applications. 2. APPLICABLE DOCUMENTS The issue of the following documents in effect on the d
8、ate of the purchase order forms a part of this specification to 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
9、 last published issue of that document shall apply. 2.1 SAE Publications 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 Bars AMS2253 Toler
10、ances Carbon and Alloy Steel Tubing AMS2259 Chemical Check Analysis Limits Wrought Low-Alloy and Carbon Steels SAE INTERNATIONAL AMS6255F Page 2 of 7 AMS2300 Steel Cleanliness, Premium Aircraft-Quality Magnetic Particle Inspection Procedure 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 ARP1917 Clarification of Terms Used in Aerospace Metals Specifications AS1182 Standard Stock Removal Allowance Aircraft-Quality and Premium Aircraft-Quality Steel Bars and Mechanical Tubing 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 A255 Determining Hardenability of Steel ASTM A370 Mechanical Testing of Steel Products ASTM A604 Macroetch Testing of Consumable Electrode Remelted Steel Bars and Billets ASTM E45 Determining the Inclusion Content of Steel ASTM E112 D
14、etermining Average Grain Size ASTM E140 Hardness Conversion Tables for Metals ASTM E350 Chemical Analysis of Carbon Steel, Low-Alloy Steel, Silicon Electrical Steel, Ingot Iron, and Wrought Iron 3. TECHNICAL REQUIREMENTS 3.1 Composition Shall conform to the percentages by weight shown in Table 1, de
15、termined 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 0.16 0.22 Manganese 0.45 0.75 Silicon 0.90 1.25 Phosphorus - 0.010 Sulfur - 0.010 Chromium 1.25 1.65 Molyb
16、denum 0.90 1.10 Aluminum 0.03 0.12 Nickel - 0.25 Copper - 0.35 SAE INTERNATIONAL AMS6255F Page 3 of 7 3.1.1 Check Analysis Composition variations shall meet the applicable requirements of AMS2259. 3.2 Melting Practice Steel shall be multiple melted using vacuum induction melting plus consumable elec
17、trode vacuum remelting. 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 0.500 Inch (12.70 mm) and Under in Nominal Diamete
18、r or Least Distance Between Parallel Sides Cold finished having tensile strength not higher than 125 ksi (862 MPa), or equivalent hardness (see 8.2). 3.3.1.2 Bars Over 0.500 Inch (12.70 mm) in Nominal Diameter or Least Distance Between Parallel Sides Hot finished and annealed unless otherwise ordere
19、d, having hardness not higher than 229 HBW, or equivalent (see 8.3). Bars ordered cold finished may have hardness as high as 248 HBW, or equivalent (see 8.3). 3.3.2 Forgings As ordered. 3.3.3 Mechanical Tubing Cold finished unless otherwise ordered, having hardness not higher than 25 HRC, or equival
20、ent (see 8.3). Tubing ordered hot finished and annealed shall have hardness not higher than 229 HBW, 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 acc
21、ordance with ASTM A370: 3.4.1 Macrostructure Rating Visual examination of transverse full cross-sections from bars, billets, tube rounds (solid, not hollow), and forging stock, etched in hot hydrochloric acid in accordance with ASTM A604, shall show no pipe or cracks. Porosity, segregation, inclusio
22、ns, and other imperfections shall be no worse than the macrographs of ASTM A604 shown in Table 2. Table 2 - Macrostructure limits Class Condition Severity 1 Freckles A 2 White Spots A 3 Radial Segregation B 4 Ring Pattern B SAE INTERNATIONAL AMS6255F Page 4 of 7 3.4.1.1 Macrostructure examination is
23、 not required for hollow tubes that are produced directly from ingots or blooms unless specified by purchaser, in which case the purchaser shall specify standards to be used. 3.4.2 Micro-Inclusion Rating of Each Heat No specimen shall exceed the limits of Table 3, determined in accordance with ASTM
24、E45, Method D: Table 3 - Micro-inclusion rating limits Type A Thin A Heavy B Thin B Heavy C Thin C Heavy D Thin D Heavy Worst Field Severity 1.5 1.0 1.5 1.0 1.5 1.0 1.5 1.0 Worst Field Frequency, maximum a 1 a 1 a 1 3 1 Total Rateable Fields, Frequency, maximum b 1 b 1 b 1 8 1 a -Combined A+B+C, not
25、 more than 3 fields b - Combined A+B+C, not more than 8 fields 3.4.2.1 A rateable field is defined as one that has a Type A, B, C, or D inclusion rating of at least No. 1.0 thin or heavy in accordance with ASTM E45. 3.4.3 Average Grain Size of Bars, Forgings and Tubing Shall be ASTM No. 4 or finer,
26、determined in accordance with ASTM E112. 3.4.4 Hardenability of Each Heat Shall be J1/16 inch (1.6 mm) = 47 HRC maximum and J6/16 inch (9.5 mm) = 30 HRC minimum, determined on the standard end-quench specimen in accordance with ASTM A255 except that the steel shall be normalized at 1700 F 10 F (927
27、C 6 C) and the specimen austenitized at 1650 F 10 F (899 C 6 C). 3.5 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. 3.5.1 Steel shall be premium aircraft-qual
28、ity conforming to AMS2300. 3.5.2 Bars and 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 which contain flash-line end grain, shall follow the genera
29、l 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 Mechanical Tubing In accordance with AMS2253. SAE INTERNATIONAL AMS6255F Page 5 of 7 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The producer of th
30、e 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 confirmatory testing deemed necessary to ensure that the product conforms to specified requirements. 4.2 Classification
31、 of Tests 4.2.1 Acceptance Tests Composition (3.1), condition (3.3), macrostructure (3.4.1), micro-inclusion rating (3.4.2), average grain size (3.4.3), hardenability (3.4.4), quality (3.5), and tolerances (3.6) are acceptance tests and shall be performed on each heat or lot as applicable. 4.2.2 Per
32、iodic Tests Frequency-severity cleanliness 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 testing is specified by purchaser. 4.3 Sampling and Testing 4.3.1 Bars, Mechanical Tubing, and Forgin
33、g Stock In accordance with AMS2370. 4.3.2 Forgings In accordance with AMS2372. 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 m
34、ultiple melting operations), the results of tests for composition, macrostructure, micro-inclusion rating and hardenability of each heat and for average grain size of each lot, and stating that the product conforms to the other technical requirements. This report shall include the purchase order num
35、ber, heat and lot numbers, AMS6255F, 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 If the ship size/shape is cut from a larger cross section, report the nomi
36、nal metallurgically worked size (also see 3.3.1). 4.4.3 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 melting operations), the results of tests for
37、 composition, macrostructure, micro-inclusion rating and hardenability of each heat and the results of any additional property requirements imposed by 8.6. This report shall include the purchase order number, heat number, AMS6255F, size and quantity. 4.5 Resampling and Retesting 4.5.1 Bars, Mechanic
38、al Tubing, and Forging Stock In accordance with AMS2370. 4.5.2 Forgings In accordance with AMS2372. SAE INTERNATIONAL AMS6255F Page 6 of 7 5. PREPARATION FOR DELIVERY 5.1 Sizes Except when exact lengths or multiples of exact lengths are ordered, straight bars and tubing will be acceptable in mill le
39、ngths of 6 to 20 feet (1.8 to 6.1 m), but not more than 10% of any shipment shall be supplied in lengths shorter than 10 feet (3 m). 5.2 Identification 5.2.1 Bars and Mechanical Tubing In accordance with AMS2806. 5.2.2 Forgings In accordance with AMS2808. 5.2.3 Forging Stock As agreed upon by purcha
40、ser and producer. 5.3 Protective Treatment Bars and mechanical tubing ordered cold drawn, cold rolled, ground, turned, or polished shall be protected from corrosion prior to shipment. 5.4 Packaging The product shall be prepared for shipment in accordance with commercial practice and in compliance wi
41、th applicable rules and regulations pertaining to the handling, packaging, and transportation of the product to ensure carrier acceptance and safe delivery. 6. ACKNOWLEDGMENT A producer shall include this specification number and its revision letter in all quotations and when acknowledging purchase
42、orders. 7. REJECTIONS Product not conforming to this specification, or to modifications authorized by purchaser, will be subject to rejection. 8. NOTES 8.1 Revision Indicator A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, n
43、ot editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editoria
44、l changes only. 8.2 Tensile strength to hardness conversions are presented in ASTM A370. 8.3 Hardness conversion tables for metals are presented in ASTM E140. 8.4 Terms used in AMS are clarified in ARP1917. 8.5 Dimensions and properties in inch/pound units and the Fahrenheit temperatures are primary
45、; dimensions and properties in SI units and the Celsius temperatures are shown as the approximate equivalents of the primary units and are presented only for information. SAE INTERNATIONAL AMS6255F Page 7 of 7 8.6 Purchase documents should specify not less than the following: AMS6255F Product form and size (and/or part number) of product desired Quantity of product desired If forging stock, specify any additional property requirements beyond those reported in 4.4.3 and provide details of how to obtain the desired samples. PREPARED BY AMS COMMITTEE “E”
