1、MIL-C- 4 72 4 4A (MI) 30 October 1990 SUPERSEDING MIL-C-47244 (MI) 26 July 1974 MILITUY SPECIFICATION COATING, ABLATIVE RESISTANT This specification is approved for use by the U.S. Army Missile Command, Department of the Army, and is available for use by all Departments and Agencies of the Departmen
2、t of Defense. 1. SCOPE 1.1 Scope. This specification covers the requirements for a two- component, room temperature curing, filled, thermosetting, modified epoxy resin system that resists abrasion and erosion at extreme temperatures. 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specificat
3、ions, standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those listed in the issue of the Department of Defense Index of Specifications and Standar
4、ds (DODISS) and supplement thereto, cited in the solicitation (see 6.2). Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, U.S. Army Missile Command, ATTN: AMSMI-RD-SE-TD- ST, Redstone
5、Arsenal, AL 35898-5270 by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC N/A FSC 8030 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or net
6、working permitted without license from IHS-,-,-SPECIFICATIONS FEDERAL QQ-A-250/12 - TT-S-735 - PPP-c-2020 - MILITARY MIL-H-5606 - MIL-R-6855 - MIL-P-47215 - STANDARDS MILITARY MIL-STD-129 - (Unless otherwise indicated, r e* MIL-C-47244A 80 7799306 045b5Lb 7 M MIL-C-47244A (MI) Aluminum Alloy 7075, P
7、late and Sheet Standard Test Fluids, Hydrocarbon Chemicals, Liquid, Dry and Paste: Packaging of Hydraulic Fluid, Petroleum Base: Aircraft, Missile and Ordnance Rubber, Synthetic Sheets, Strips, Molded or Extruded Shapes, General Specification for Primer, Ablative Resistant Coating Marking for Shipme
8、nt and Storage copies of the federal and military specifications, standards, and handbooks are available from the Standardization Documents Order Desk, Bldg. 4D, 700 Robbins Ave., Philadelphia, PA 19111-5094.) 2.2 Non-Government publications. The following documents form a part of this document to t
9、he extent specified herein. Unless otherwise specified, the issues of the documents which are DoD adopted are those listed in the issue of the DODISS cited in the solicitation. Unless otherwise specified, the issues of documents not listed in the DODISS are the issues of the documents cited in the s
10、olicitation (see 6.2). AMERICAN SOCIETY FOR TESTING AND MATERIALS ASTM D 568 - Standard Test Method for Rate of Burning and/or Extent and Time of Burning of Flexible Plastics in a Vertical Position ASTM D 740 - Standard Specification for Methyl Ethyl Ketone ASTM D 792 - Standard Test Methods for Spe
11、cific Gravity (Relative Density) and Density of Plastics by Displacement ASTM D 2240 - Standard Test Method for Rubber Property - Durometer Hardness 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-47244A (MI) (Application for copies should be
12、 addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) (Non-Government standards and other publications are normally available from the organizations that prepare or distribute the documents. These documents also may be available in or through librar
13、ies or other informational services. ) 2.3 Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific ex
14、emption has been obtained. 3. REQUIREMENTS 3.1 First article sample. When required (see 6.21, a sample shall be subjected to first article inspection (see 6.3) in accordance with Section 4. 3.2 Material. The material shall be a two-component, room-temperature curing, filled, thermosetting, modified
15、epoxy resin system. The resin system is formulated by mixing a base resin and a curing agent as instructed by the manufacturer. 3.3 Physical properties. 3.3.1 Appearance. The cured resin system shall be continuous and uniform in texture. The color shall not vary from lot to lot. e 3.3.2 Specific gra
16、vity. The specific gravity of the cured resin system shall be not less than 1.2 nor more than 1.6. 3.3.3 Application time. The application time of the uncured resin system shall be not less than 60 minutes at room temperature, defined as 25O 2 3O Celsius (Cl. 3.3.4 Flow, The flow of the freshly mixe
17、d resin system shall be not more than 0.3 inch when a cylindrical section approximately 0.375 inch high and 1.50 inch in diameter is allowed to flow under its own weight on a vertical surface. In addition, the resin system shall retain a flow not more than 0.30 inch throughout the entire application
18、 time. 3.3.5 Hardness. Hardness of the cured resin system shall be as specified in table I. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-47244A (MI) Curing conditions Cond 1: Room temperature for 24 i 2 hours Cond 2: Room temperature for 7
19、 days Cond 3: Room temperature for 3 hours, followed by 66 5 1C for 3 hours, followed by room temperature for not less than 3 hours. TABLE I. Hardness requirements. Hardness value Not less than 40 Shore D Not less than 55 Shore D Not less than 55 Shore D 3.3.7 Humidity and heat resistance. The cured
20、 resin system shall withstand simultaneous exposure to a relative humidity of not less than 90 percent and temperature cycling as follows: a. A temperature of 49 f. 3C for 3 days b. Returned in not less than 3 hours to -125 3C and maintained at this temperature for not less than 30 minutes c. Uncont
21、rolled stabilization at room temperature d. Increase to 885 3C in not less than 50 minutes, and maintained at this temperature for 4 hours. No softening, sponging, blistering, checking, shrinking, or loss of adhesion shall occur. Weight of the resin system shall not increase more than 5 percent. t.h
22、an 5 percent. Thickness of the resin system shall not increase or decrease more 3.3.8 Tread resistance. The cured resin system, after continuous exposure for 72 hours (minimum) to a temperature of 882 3C, shall show no evidence of surface degradation or loss of adhesion as a result of foot traffic .
23、 3.3.9 Low temperature impact resistance. The cured resin system, when stabilized at. the temperature specified in 3.3.6, shall not shatter when impacted by a 0.5 pound steel ball dropped from heights up to 20 feet. 3.3.10 Flammability. The cured resin system shall be self extinguishing. 4 Provided
24、by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C- 472 4 4A (MI ) 3.3.11 Hydrocarbon resistance. The cured resin system shall not have any loss of adhesion or be adversely affected after exposure to hydrocarbons. The hydrocarbon-exposed resin system shall
25、 be self-extinguishing in not more than 2 seconds after ignition has been effected. 3.3.12 Blast erosion. The cured resin system shall withstand the erosive effects of a supersonic blast, with erosive loss limited to a thickness of 0.080 inch. Blast conditions shall be as follows: a. b. C. d. Temper
26、ature and pressure above the surface of the resin system shall be not less than 283OOC and not less than 330 pounds per square inch gage (psig), respectively. Direction of the blast shall be 90 5 degrees with respect to the surface of the resin system. The chemical composition (by percent weight 5 p
27、ercent) of the gas impinging on the resin system shall be : (1) Steam - 1-01. (2) Hydrogen - 3.47. (3) Carbon monoxide - 36.88. (4) Nitrogen - 7.94. (5) Hydrogen chloride - 20.47. (6) Aluminum oxide - 30.23. Duration of blast shall be not less than 90 milliseconds. 3.3.13 Shelf life. The shelf life
28、of the base resin and curing agent shall be not less than 6 months from the date of manufacture when stored in original unopened containers at a temperature not greater than 27OC. 3.3.14 Workmanship. The workmanship shall be such as to insure a high quality product which is uniform and in conformanc
29、e with this specification. 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 (examinations and tests) as specified herein. Except as otherwi
30、se specified in the contract or purchase order, the contractor may use his own or any other facilities suitable for the performance of the inspection requirements specified herein, unless disapproved by the Government. TheGovernment reserves the right to perform 5 Provided by IHSNot for ResaleNo rep
31、roduction or networking permitted without license from IHS-,-,-MIL-C-47 2 4 4A (MI ) Appearance Specific gravity Application time Flow Hardness any of the inspections set forth in this specification where such inspections are deemed necessary to ensure supplies and services conform to prescribed req
32、uirements. 3.3.1 4.6.1 3.3.2 4.6.2 3.3.3 4.6.3 3.3.4 4.6.4 3.3.5 4.6.5 4.1.1 Responsibility for compliance. All items shall meet all requirements of sections 3 and 5. The inspection set forth in this specification shall become a part of the contractors overall inspection system or quality program. T
33、he absence of any inspection requirements in the specification shall not relieve the contractor of the responsibility of ensuring that all products or supplies submitted to the Government for acceptance comply with all requirements of the contract. Sampling inspection, as part of manufacturing opera
34、tions, is an acceptable practice to ascertain conformance to requirements, however, this does not authorize submission of known defective material, either indicated or actual, nor does it commit the Government to accept defective material. 4.2 Classification of inspections. The inspection requiremen
35、ts specified herein are classified as follows: a. First article inspection (see 4.3). b. Quality conformance inspection (see 4.4). 4.3 First article inspection. First article inspection shall be conducted only on the first article sample and shall consist of all the examinations and tests specified
36、herein. 4.4 Quality conformance inspection. Quality conformance inspection for acceptance of the resin system shall consist of the examinations and tests shown in table II. TABLE II. Quality conformance inspection. Examination and tests Requirement paragraph Test paragraph 4.4.1 Lot size. Lot size s
37、hall consist of all the resin system submitted for acceptance at the same time which has been prepared by the same company without a change in materials or processes in one continuous period of operation. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS
38、-,-,-MIL-C-47244A (MI) 4.4.2 Samplinq. Unless otherwise specified (see 6.2), 1 pint of resin and 1 pint of curing agent from one unit representative of each lot shall be selected at random for quality conformance testing. Each container of resin and curing agent shall be considered as a unit of prod
39、uct. Failure of sample to meet the quality conformance requirements shall be cause for lot rejection. 4.5 Test methods. 4.5.1 Test conditions. Unless otherwise specified in the applicable test, all tests shall be performed at room temperature and at relative humidity between 40 and 60 percent. 4.5.2
40、 Test panels. Unless otherwise specified in the applicable test, test panels shall consist of 9.50 inch squares of 0.50 inch thick aluminum conforming to QQ-h-250/12, with the resin system applied to centered 5 inch squares on each aluminum square. 4.5.2.1 Precleaning. Prior to application of the re
41、sin system, the aluminum squares shall be cleaned by abrading the surface with 180 to 200 grit sandpaper, washed with methyl ethyl ketone (MEK) solvent conforming to ASTM D 740 and allowed to dry for 20 minutes, minimum. 4.5.2.2 Primer. A primer conforming to MIL-P-47215 shall be brush- coated on th
42、e cleaned aluminum squares and allowed to air-dry for not less than 30 minutes. 4.5.2.3 Application of resin system. The quantity of resin system required for testing, not less than 90 grams (9) of base resin, shall be mixed thoroughly in the proportion specified in 3.2 in not lonoer than 5 minutes,
43、 preferably by a standardized mechanical mixing method. Unless otherwise specified, the test panels shall have the resin system troweled on the aluminum squares to a thickness of not less than 0.165 inch nor more than 0.205 inch and cured at room temperature for 7 days. Except for the nardness tests
44、 (see 4.5.51, the resin system shall be tested within 3 days after cure. 4.6 Physical property tests. 4.6.1 Appearance. The appearance of tile resin system shall be checked visually and shall be as specified in 3.3.1. 4.6.2 Specific gravity. The specific gravity of the resin system shall be etermine
45、d in accordance with ASTM D 792 and shall be as specified in 3.3.2. 4.6.3 Application time. With the base resin, curing agent, and compound application gun stabilized at the conditions specified in 4.5.1 for not less than 8 hours, 90 grams or more of base resin shall be mixed thoroughly with the cur
46、ing agent in the proportion specified in 3.2. The mixed resin system shall be promptly used to fill a standard 603 Senco Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-47244A 0 m 7779906 0456522 2 W c k MIL-C-47244A (MI) compound gun cartridge
47、, or equivalent, having a Semco 254 nozzle with an orifice diameter of not less than 0.120 inch nor greater than 0.130 inch. The gun and resin system shall be maintained at standard conditions throughout the test. not less than 85 psig nor more than 95 psig. From two to three inches of the resin sys
48、tem shall be extruded inikially to clear trapped air. At the end of 60 minutes, measured fromthe time mixing was begun, the resin system shall be extruded onto a suitable receptacle for 1 minute. The amount of resin system extruded during the 1-minute period shall be weighed and shall be not less th
49、an 20 g. The gun shall be attached to a constant supply of air or inert gas at 4.6.4 Flow. The flow test shall include initial flow and flow at the end of the application time and shall be conducted with a test jig as shown in figure 1. The flow test jig shall be placed on a table with the front face upward and with the plunger depressed to the limit of its travel. The application gun shall be filled and attached to the pressure source
