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 2014 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/AMS-C-7438A AEROSPACE MATERIAL SPECIFICATION AMS-C-7438 REV. A Issued 1999-06 Rea
5、ffirmed 2006-01 Revised 2014-07 Superseding AMS-C-7438 Core Material, Aluminum, for Sandwich Construction FSC 5680 RATIONALE AMS-C-7438 and its predecessor MIL-C-7438G, Amendment 1 form the basis for all aluminum core specifications worldwide. These specifications are included by reference in most a
6、luminum core specifications, and mechanical properties are consistent throughout the industry. Revision A of AMS-C-7438 removes requirements which are deemed no longer relevant or necessary, and improves clarity of requirements which remain relevant to the industry. Grade C core materials (Alloy 202
7、4-T81) have been removed because 2024 foil is considered unavailable for the forseeable future. NOTICE The initial release of this document has been taken directly from U.S. Military Specification MIL-C-7438G, Amendment 1 and contains only minor editorial and format changes required to bring it into
8、 conformance with the publishing requirements of SAE technical standards. This document replaces MIL-C-7438G, Amendment 1. Any part numbers established by the original specification remain unchanged. The current revision of this document includes changes that were not a part of MIL-C-7438G, Amendmen
9、t 1. The original Military Specification was adopted as an SAE standard under the provisions of the SAE Technical Standards Board (TSB) Rules and Regulations (TSB 001) pertaining to accelerated adoption of government specifications and standards. TSB rules provide for (a) the publication of portions
10、 of unrevised government specifications and standards without consensus voting at the SAE Committee level, and (b) the use of the existing government specification or standard format. Under Department of Defense policies and procedures, any qualification requirements and associated qualified product
11、s lists are mandatory for DOD contracts. Any requirement relating to qualified products lists (QPLs) has not been adopted by SAE and is not part of this SAE technical document. SAE INTERNATIONAL AMS-C-7438A Page 2 of 26 1. SCOPE 1.1 Scope This specification covers treated aluminum core material for
12、structural sandwich construction. 1.2 Classification 1.2.1 Aluminum core material for sandwich construction shall be furnished in the following grades, as specified (See 6.3.1 and 6.5): Grade Description B For exposure up to 350 F (See 3.2.1.1). 1.2.2 Aluminum core material for sandwich construction
13、 shall be furnished in the following classes, as specified (See 6.3.1 and 6.5): Class Description 1 High corrosion resistance (See 3.2.2). 2 Standard corrosion resistance (See 3.2.2). 1.2.3 Aluminum core material for sandwich construction shall be furnished in the following types, as specified (See
14、6.3.1 and 6.5): Type Description N Non-perforated (See 3.3.2). P Perforated (See 3.3.2). HP Highly Perforated (See 3.3.2). 2. REFERENCES 2.1 Applicable 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 specifie
15、d 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. 2.1.1 SAE Publications Availabl
16、e from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. AMS-A-81596 Aluminum Foil for Sandwich Construction AMS-STD-401 Sandwich Construction and Core Materials, General Test Methods AMS-QQ-A-2
17、50/4 Aluminum Alloy 2024, Plate and Sheet AMS-QQ-A-250/5 Aluminum Alloy Alclad 2024, Plate and Sheet 2.1.2 ASQ Publications Available from American Society for Quality, 600 North Plankinton Avenue, Milwaukee, WI 53203, Tel: 800-248-1946 (United States or Canada), 001-800-514-1564 (Mexico), or +1-414
18、-272-8575 (all other locations), www.asq.org. ANSI/ASQ Z1.4 Sampling Procedures and Tables for Inspection by Attributes SAE INTERNATIONAL AMS-C-7438A Page 3 of 26 2.1.3 ASTM Publications Available from ASTM International, 100 Barr Harbor Drive, P.O Box C700, West Conshohocken, PA 19428-2959, Tel: 61
19、0-832-9585, www.astm.org. ASTM B 117 Salt Spray (Fog) Testing ASTM C 366 Measurement of Thickness of Sandwich Cores ASTM D 3951 Commercial Packaging, Practice for ASTM D 1974 Standard Practice for Method of Closing, Sealing, and Reinforcing Fiberboard Shipping Containers ASTM D 5118 Standard Practic
20、e for Fabrication of Fiberboard Shipping Boxes ASTM D 5168 Standard Practice for Fabrication and Closure of Triple Wall Corrugated Fiberboard Containers ASTM D 6251 Standard Specification for Natural Wood-Cleated Panelboard Shipping Boxes 2.1.4 U.S. Government Publications Available from DLA Documen
21、t Services, Building 4/D, 700 Robbins Avenue, Philadelphia, PA 19111-5094, Tel: 215-697-6396, http:/quicksearch.dla.mil/. MIL-STD-2073-1 Standard Practice for Military Packaging A-A-203 Paper, Kraft, Untreated MIL-DTL-17667 Paper, Wrapping, Chemically Neutral (Non-Corrosive) 2.1.5 Order of precedenc
22、e In the event of a conflict between the text of this specification and the references cited herein, the text of this specification shall take precedence. 2.2 Definitions The following definitions apply to terms that are uncommon or have special meaning as used in this specification: 2.2.1 BLOCK: A
23、volume of honeycomb material that is created during node adhesive bonding. This term may be used for material that has or has not been expanded to its nominal cell size and density. Slices of various thicknesses are cut from blocks. 2.2.2 BUCKLED CELL WALLS: Permanent buckling or crushing in the thi
24、ckness direction of greater than 0.010 inch. Also called columnar buckling or columnar failure. 2.2.3 DOUBLE FOILS: A stacking misalignment defect that can occur for honeycomb that is manufactured using a corrugation process or an expansion process. See Figure 1 for a depiction of this defect. This
25、defect is comprised of two or more adjacent ribbons of foil. 2.2.4 FLAKES: Excess metal attached to foil edges which do not interfere with core thickness measurement. Also called foil edge burrs. 2.2.5 LOOSE METAL: Loose pieces of honeycomb or foil. SAE INTERNATIONAL AMS-C-7438A Page 4 of 26 2.2.6 M
26、ISMATCHED NODES: A stacking misalignment defect that can occur for honeycomb that is manufactured using a corrugation process, rather than an expansion process. See Figure 1 for a depiction of this defect. 2.2.7 NOTCH: Removed material from part of a cell wall that has a depth (in the T direction) o
27、f at least 0.020 inches. This does not include intended features that are part of the engineering drawing/definition. Notches are also called gouged cell walls. 2.2.8 ROLLED METAL: Cell walls that are bent over at the top or bottom surface of the core. When viewed in the T direction, this causes an
28、increase in the apparent foil thickness. 2.2.9 SLICE: A constant thickness volume of honeycomb material that is sliced or removed from a block of greater thickness. This term may be used for material that has or has not been expanded to its nominal cell size and density. 2.2.10 SPLIT CELL WALLS: Tea
29、rs in the cell wall that extend greater than 0.03 inch below the surface. 2.2.11 UNBONDED NODES: Separation across the full width of a node bond, for greater than 50% of the core thickness. 3. REQUIREMENTS 3.1 First article When specified, samples shall be subjected to first article inspection (See
30、4.5 and 6.4). 3.2 Materials The materials comprising the core shall conform to the applicable specifications and as specified herein. 3.2.1 Metal The core shall be fabricated from aluminum alloy foil conforming to AMS-A-81596. 3.2.1.1 Grade B Grade B core shall be of Alloy 5052 or Alloy 5056 foil, a
31、s specified (See 3.2.4 and 6.3.1). After foil is processed into Grade B core, the temper shall be optional. 3.2.2 Metal Finish The core shall be formed from chemically treated or coated foil for protection against corrosion (See 3.7). The chemical treatment or coating shall be applied to the foil, p
32、rior to application of bonding material (See 3.2.3). 3.2.3 Bonding material The adhesive used to bond the aluminum foil to form the cells of the core shall be of such quality that the resultant core will meet the requirements specified herein. SAE INTERNATIONAL AMS-C-7438A Page 5 of 26 3.2.4 Trade n
33、ame and code number The manufacturer shall designate each core material combination by a trade name and code number which shall be used to identify the core (See 6.3.1). The code number shall consist of the following: a. Designated density. b. Cell size in fractions of an inch. c. Nominal foil thick
34、ness in ten-thousandths of an inch. d. “P” for perforation, if so specified (See 3.3.2). For non-perforation, no coding required. “N” for Type N, “P” for Type P, or “HP” for Type HP. e. Alloy (standard designation). If applicable, temper required (See 3.2.1.2). f. For hexagonal core cell walls, “C”
35、for corrugated if so specified. For expanded, no coding required. g. “S” for special core cell configurations, if other than hexagonal. h. “CL1” for Class 1, “CL2” for Class 2. Example: Grade B material with a density of 4.5 pounds per cubic foot, fabricated with a 1/8-inch cell size, and 0.0010 inc
36、h nominal thickness, nonperforated and using corrugated Class 2 Alloy 5052 shall be coded as follows: Trade name - 4.5 -1/8-10(5052N)C-CL2 If the core cell configuration is other than hexagonal, such as reinforced hexagonal, double corrugated, or staggered hexagonal, then the core shall be coded as
37、follows: Trade name - 8.1 -3/16-30(5056HP)S-CL1 3.3 Fabrication 3.3.1 Configuration The core material shall consist of ribbons of aluminum foil bonded together to form cells approximately of uniform shapes, usually hexagonal in shape. The cores shall be made either by assembling corrugated ribbons o
38、r by strip-bonding flat ribbons and then expanding the core cells to proper shape. If the core material is purchased in the unexpanded condition, it shall be capable of meeting the requirements of this specification after proper expansion to the full cell configuration and proper density. 3.3.2 Perf
39、oration Unless otherwise specified (See 6.3.1), the aluminum foil shall be non-perforated. When perforation Type P or HP is specified, the perforations shall be of such size and location that all cells are vented at least every 1/4 inch in thickness dimension. When Type HP is specified, there shall
40、be no fewer than 6000 perforations per square foot of foil, uniformly spaced and staggered. 3.3.3 Form The core shall be furnished as pieces, unexpanded blocks or slices, or expanded slices as specified by purchaser. The dimensions and tolerances for the pieces, blocks, or slices shall be as specifi
41、ed by purchaser. 3.4 Physical properties Physical properties and tolerances shall be in accordance with Table 1. SAE INTERNATIONAL AMS-C-7438A Page 6 of 26 3.4.1 Foil thickness The core foil thickness shall be within the limits of designated value specified in Table 2. 3.5 Compressive and shear stre
42、ngth properties of hexagonal configuration core Core flatwise compressive strength and shear strength (associated with shear distortion in the LT and WT planes, see Figure 2) for the nominal density of the core shall conform to the requirements listed in Table 3 as applicable for the basis metal and
43、 test conditions. Compressive strength and shear strength of any specimen shall be not less than the value specified in the applicable tables (See Tables 4 to 7) when tested in accordance with the applicable test procedure (See 4.7.5 to 4.7.8). When shear strength is determined by using the beam fle
44、xural shear test, the facings of the core sandwich shall be Alloy 2024-T3 or 2024-T81 bare, conforming to AMS-QQ-A-250/4, or clad, conforming to AMS-QQ-A-250/5. 3.6 Delamination strength The core shall have a delamination strength or node bond strength capable of withstanding not less than the ultim
45、ate tensile load specified in Table 8 when tested in accordance with the applicable test procedure (See 4.7.9). 3.7 Corrosion resistance properties The material shall be treated so as to be capable of protecting the base metal when subjected to the salt spray test specified in 4.7.10. At the end of
46、30 days exposure, Class 1 core shall not show a loss of weight greater than 20 milligrams per square foot of exposed foil area. At the end of 30 days exposure, Class 2 core shall not show a loss of weight greater than 125 milligrams per square foot of exposed foil area. 3.8 Mechanical properties of
47、special core configuration The mechanical properties of special core configuration or hexagonal configuration material not specified herein, shall be specified in the contract or purchase order, or covered by applicable drawings (See 6.3.1). 3.9 Workmanship Clean, lint-free gloves shall be worn when
48、 handling core material. The core material shall be clean and free from grease, oil, lotion, release agent, silicone, tape residue, moisture, or dirt. 3.9.1 Visual imperfections Visual imperfections shall not exceed the values specified in Table 9 for the specified cell size (See 4.6.2.1.1). 3.9.2 M
49、ismatched nodes The c/d ratio (See Figure 1) of mismatched nodes for corrugated core shall not exceed 0.25 (See 4.6.2.1.1). 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibility for inspection Unless otherwise specified in the contract or purchase order, the contractor is responsible for the performance of all inspection requirements as specified herein. Except as otherwise specified in the contract or purchase order, the contractor may use his
