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:/www.sae.org/technical/standards/AMS7725E AEROSPACE MATERIAL SPECIFICATION AMS7725 REV. E Issued 1957-01 Revised 2
5、012-03 Reaffirmed 2016-04 Superseding AMS7725D Tungsten Heavy Alloy Shapes, Sintered, High Density RATIONALE AMS7725E has been reaffirmed to comply with the SAE five-year review policy. 1. SCOPE 1.1 Form This specification covers four classes of tungsten heavy metal in the form of sintered and annea
6、led shapes. 1.2 Application This material has been used for parts, such as counterbalance weights or projectiles, for which mechanical properties are tested from the sintered and annealed shapes and that require high weight per unit volume, but usage is not limited to such applications. 1.3 Classifi
7、cation Products covered by this specification are classified as follows: Class Tungsten, Nominal % 1 90 2 92.5 3 95 4 97 Type 1 - Non-magnetic (See 8.8) Type 2 - Magnetic (See 8.8) 1.3.1 If no Class is specified Class 1 shall be supplied. If no Type is specified, Type 2 shall be supplied. 2. APPLICA
8、BLE 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 herein. The supplier may work to a subsequent revision of a document unless a specific document issue is specified. When the referenced document h
9、as 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, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA),
10、www.sae.org. AMS2750 Pyrometry 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 B 311 Density of Powder Metallurgy (PM) Materials Containing Less Than Two Percent Porosity ASTM E 8 /
11、 E 8M Tension Testing of Metallic Materials ASTM E 18 Rockwell Hardness of Metallic Materials 3. TECHNICAL REQUIREMENTS 3.1 Composition, Density and Hardness Composition, density and hardness shall be as specified in Table 1. TABLE 1 - COMPOSITION, DENSITY AND HARDNESS PROPERTIES Class Weight percen
12、t Tungsten, nominal Density g/cc Hardness HRC maximum 1 90 16.85 - 17.30 32 2 92.5 17.15 - 17.85 33 3 95 17.75 - 18.35 34 4 97 18.25 - 18.85 35 3.1.1 Type 1 Shall have a nominal tungsten percentage corresponding to the Class specified with the balance being primarily an alloy of nickel and/or copper
13、. 3.1.2 Type 2 Shall have a nominal tungsten percentage corresponding to the Class specified with the balance being primarily an alloy of nickel, iron, and other elements as required. 3.2 Condition Product shall be supplied either as-sintered, or sintered and annealed. If no condition is specified,
14、either condition may be supplied. 3.3 Properties The product shall conform to the following requirements: 3.3.1 Tensile Properties Specimens (See 4.3.1) shall conform to the requirements of Table 2 (See 8.2) determined in accordance with ASTM E 8/E 8M. SAE INTERNATIONAL AMS7725E Page 2 of 6_ TABLE 2
15、 - MINIMUM TENSILE PROPERTIES Class Type Ultimate Tensile Strength Yield Strength at 0.2% Offset ElongationA percent ksi MPa ksi MPa 1 1 94 648 75 517 2 1 2 110 758 75 517 5 2 1 94 648 75 517 2 2 2 110 758 75 517 5 3 1 94 648 75 517 1 3 2 105 724 75 517 3 4 2 100 689 75 517 2 ADetermine with a Class
16、 B2 or better extensometer. 3.3.2 Hardness Hardness as specified in Table 1 shall be determined in accordance with ASTM E 18. 3.3.3 Density Density as specified in Table 1 shall be determined in accordance with ASTM B 311. 3.3.4 Magnetic Permeability When specified (See 8.5), Type I parts shall be m
17、easured for magnetic permeability using a Severn gauge or similar equipment. Permeability shall be 1.05 Mu, maximum. 3.3.5 Microstructure Shall be a uniform and homogeneous distribution of tungsten particles in a metallic matrix, when examined at 200X magnification minimum. 3.3.6 Annealing (See 8.7)
18、 Parts shall be subjected to post sintering annealing heat treatment in accordance with the following: Vacuum or inert gas heat treat. Gas, if used, shall meet the requirements of AWS C5.10. Vacuum level shall be10-4Torr or lower. Ramp to 2192 F 25 (1200 C 6) Hold at temperature for 5 to 15 hours. F
19、orced fan cool using nitrogen*, helium, or argon gas. Parts shall be cooled to 932 F (500 C) within 5 minutes maximum. Parts shall be processed on ceramic racks/boats. Contact with carbon based fixture or rack is not permitted. Pyrometry per AMS2750 *NOTE: CRACKED AMMONIA IS NOT PERMITTED AS SOURCE
20、OF NITROGEN. 3.3.7 Alternate annealing processes are permissible when approved by the cognizant engineering organization only when demonstrated to produce equivalent physical and mechanical properties to the standard process. Composition shall meet the requirements in Table 1, 3.1.1, and 3.1.2 and s
21、hall be performed by any method agreed upon by the supplier and the purchaser. 3.4 Quality Product, as received by purchaser, shall be uniform in quality and condition, sound, and free from foreign materials and from cracks, loose particles, and other imperfections detrimental to usage of the produc
22、t. SAE INTERNATIONAL AMS7725E Page 3 of 6_ 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for Inspection The vendor of shapes 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 c
23、onfirmatory testing deemed necessary to ensure that the product conforms to specified requirements. 4.2 Classification of Tests 4.2.1 Acceptance Tests Tensile properties (3.3.1), hardness (3.3.2), density (3.3.3), microstructure (3.3.4), magnetic permeability (when specified) (3.3.4) and quality (3.
24、4) are acceptance tests and shall be performed on each lot. 4.2.2 Periodic Tests Composition (3.1) is a periodic test. 4.3 Sampling Shall be in accordance with the following. A lot shall be all sintered shapes formed from one blend of powder and thermally processed in a single batch or a single cont
25、inuous sinter run. 4.3.1 Tensile properties, hardness, density and microstructure shall be taken from one part per lot. One tensile specimen minimum shall be extracted from the centerline of the thickest portion of the part and tested to show conformance to the requirements of 3.3.1. Where the part
26、is of such a size or shape as to prevent extraction of a tensile specimen, a test block with a nominal thickness of the maximum section thickness of the actual production part, formed from the same blend of powder and thermally processed with the lot may be used and the tensile specimen shall be ext
27、racted from that block. 4.3.2 Composition shall be determined from a suitable sized sample of the blended powder used to manufacture the lot of sintered parts. 4.4 Approval 4.4.1 Sample sintered shapes from new or reworked master patterns shall be approved by purchaser before shapes for production u
28、se are supplied, unless such approval is waived by purchaser. 4.4.2 Vendor shall use ingredients, processing techniques, and methods of inspection on production sintered shapes which are essentially the same as those used on the approved sample shapes. If necessary to make any change in ingredients,
29、 processing techniques, or methods of inspection, vendor shall submit for reapproval a statement of the proposed changes in materials, processing, or both and, when requested, sample shapes. Production shapes made by the revised procedure shall not be shipped prior to receipt of reapproval. 4.5 Repo
30、rts The vendor of shapes shall furnish with each shipment a report showing the results of tests on each lot in the shipment to determine conformance to the acceptance test requirements and stating that the material conforms to the other technical requirements. This report shall include the purchase
31、order number, AMS7725E, lot number, Class, Type (1 or 2), form, size or part number, and quantity. SAE INTERNATIONAL AMS7725E Page 4 of 6_ 4.6 Resampling and Retesting If any specimen used in the above tests fails to meet the specified requirements, disposition of the shapes may be based on the resu
32、lts of testing three additional specimens for each original nonconforming specimen. Failure of any retest specimen to meet the specified requirements shall be cause for rejection of the shapes represented. Results of all tests shall be reported. 5. PREPARATION FOR DELIVERY 5.1 Identification Individ
33、ual pieces shall have attached a durable tag marked with the purchase order number, AMS7725E, class, type, and nominal size or part number or shall be boxed and the box marked with the same information. 5.2 Packaging The product shall be prepared for shipment in accordance with commercial practice a
34、nd in compliance with applicable rules and regulations pertaining to the handling, packaging, and transportation of the product to ensure carrier acceptance and safe delivery. 6. ACKNOWLEDGMENT A vendor shall include this specification number and its revision letter in all quotations and when acknow
35、ledging purchase orders. 7. REJECTIONS Product not conforming to this specification, or to modifications authorized by purchaser, will be subject to rejection. 8. NOTES 8.1 A change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revisions, not
36、 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 editorial
37、changes only. 8.2 The minimum property requirements listed in Table 1 have not been substantiated by AMS procedures. 8.3 Terms used in AMS are clarified in ARP1917. 8.4 Dimensions and properties in inch/pound units and the Fahrenheit temperatures are primary; dimensions and properties in SI units an
38、d the Celsius temperatures are shown as the approximate equivalents of the primary units and are presented only for information. 8.5 Purchase documents should specify not less than the following: AMS7725E Material Class (if to be specified) Material type (if to be specified) Condition (if to be spec
39、ified) Whether magnetic permeability testing is required Form and size or part number of product desired Quantity of shapes desired. SAE INTERNATIONAL AMS7725E Page 5 of 6_ 8.6 Type 1 materials are generally more corrosion-resistant than Type 2 materials. However, both Types may require additional c
40、orrosion resistant coatings for corrosion protection. 8.7 Annealing is performed to improve mechanical properties, especially % elongation, in thick parts by removing residual hydrogen from sintered forms and to reduce the embrittling effects of residual elements that can accumulate along the tungst
41、en/matrix interface during cooling from sintering. 8.8 Common magnetic alloy contain tungsten with transition metals such as nickel, iron or other elements. Common non-magnetic alloys contain tungsten and transition metals such as nickel, copper or other. 8.9 Similar Specifications AMS-T-21014 and A
42、STM B 777 are listed as similar specifications; however they are typically not used for structural applications. They are listed here for information only and shall not be construed as an acceptable alternate unless all requirements of this AMS are met. PREPARED BY AMS COMMITTEE “G” SAE INTERNATIONAL AMS7725E Page 6 of 6_
