1、. MIL-C-4724bA 0 E 777770b 0457777 7 .u INCH - POUND I I MIL-C-47246A(MI) 26 November 1990 SUPERSEDING MIL-C- 472 4 6 (MI ) 26 JULY 1974 MILITARY SPECIFICATION COATINGS, ABLATIVE, APPLICATION OF This specification is approved for use by the U.S. Army Missile Command, Department of the Army, and is a
2、vailable for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification establishes the requirements for the application of ablative coating primer and ablative coating. 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications, standards, a
3、nd 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 Standards (DODISS) and su
4、pplement 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 Arsenal, AL 35898
5、-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 networking permitted
6、 without license from IHS-,-,-* MIL-C-47246A (MI) SPECIFICATIONS MILITARY MIL-P-47215 I Primer, Ablative Resistant Coating MIL-C-47244 Coating, Ablative Resistant (Unless otherwise indicated, copies of the federal and military specifications, standards, and handbooks are available from the Naval Pub
7、lications and Forms Center, 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 the extent specified herein. Unless otherwise specified, the issues of the documents wh
8、ich 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 solicitation (see 62). AMERICAN SOCIETY FOR TESTING AND MATERIALS ASTM D 740 - Standard
9、 Specification for Methyl Ethyl Ketone ASTM D 2240 - Standard Test Mechod for Rubber Property- Durometer Hardness (Application for copies should be addressed to the American Society for Testing and Materials, 1916 Race Street, Philadelphia, PA 19103.) (Non-Government standards and other publications
10、 are normally available from the organizations that prepare or distribute the documents. documents also may be available in or through libraries or other informational services, ) These 2.3 Order of precedence. In the event of a conflict between the text of this document and the references cited her
11、ein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 Equipment. 3.1.1 Fabrication facility. The fabrication facility for application of the ablative coating sh
12、all provide the following: a. Protection of the cleaned surfaces and the coating materials from dust, dirt and water. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-t a a a MIL-C-4724bA 0 977770b 0457777 O MIL-C-47246A (MI) b. Normal ambient condi
13、tions consisting of an atmospheric pressure between 28 and 32 inches of mercury, a temperature between +15O and +35O Celsius (C), and a relative humidity not greater than 95 percent. 3.1.2 Balance. The balance shall be capable of maintaining accuracy within 1 percent over its entire range. The balan
14、ce shall be calibrated and certified to the prescribed accuracy not less than once every 90 days. 3.1.3 Heat source. Any suitable heat source such as a heat gun, oven, hot plate, or application tooling containing heating elements may be used to heat the material. 3.1.4 Miscellaneous equipment. Misce
15、llaneous equipment used in the mixing, stirring, application, or other handling of the coating materials shall be made from materials having no detrimental effect on the coating and visibly free of dust or other contamination. Use of metal spatulas, containers, and mixing equipment shall be suitable
16、, but use of porous and absorbent materials such as paper and wood shall be avoided. 3.1.5 Tooling. The tooling, such as edge and grid strips, metal masks, and form templates, shall be capable of producing finishedparts conforming to the requirements of this specification and related engineering dra
17、wings. The form templates shall be inspected for correct dimensions not less than once every 90 days. 3.2 Materials. 3.2.1 Direct. 3.2.1.1 Ablative coating. Ablative coating shall be as specified on the engineering drawing and shall conform to MIL-C-47244. 3.2.1.2 Ablative coating primer. Primer use
18、d with the ablative coating shall be as specified on the engineering drawing and sha-11 conform to MIL-P- 47215. 3.2.2 Indirect. 3.2.2.1 Abrasive paper. Abrasive paper shall be silicon carbide, garnet, or aluminum oxide, 80 to 180 grit. 3.2.2.2 Wire brushes. Wire brushes shall have bristles made fro
19、m corrosion-resistant steel. 3.2.2.3 Cheesecloth. Cheesecloth shall be clean, white and lint-free. 3.2.2.4 Masking tape. Masking tape shall be pressure-sensitive. 3.2.2.5 Mold release. The mold release shall be a nonblocking material for free release of fixtures. Silicone or other transferable mater
20、ials shall not be used. 3.2.2.6 Cleaning solvent. Cleaning solvent shall be methyl ethyl ketone conforming to ASTM D 740 or equal. 3 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- -_I_ - - -_ I- MIL-C-4724bA 80 W 9999906 0457780 7 - MIL-C-47246A(MI
21、) 3.3 Procedure. 3.3.1 Solvent-cleaning. The area to be coated (as specified on the engineering drawing) shall be solvent-cleaned as follows: a. Remove grease, oil, or other contamination by wiping with cheesecloth (see 3.2.2.3) saturated with cleaning solvent (see (3.2.2.6). b. Wipe dry with clean,
22、 dry cheesecloth. c. Allow to air-dry for not less than 15 minutes. Repeat 3.3.la and 3.3.lb until all visible evidence of grease, oil, or other contamination is removed. Warning: All safety regulations regarding the handling of flammable and toxic materials shall be observed. 3.3.2 Application of m
23、old release. A thin, uniform coat of mold release (see 3.2.2.5) shall be applied over those areas of the tooling fixtures which will be in contact with the ablative coating. 3.3.3 Masking. Areas to remain uncoated shall be masked with metal or plastic masks or tape (see 3.2.2.4) as required. 3.3.4 A
24、brasion. All surfaces to be coated shall be abraded with abrasive paper (see 3.2,2.1), wire brush (see 3.2.2.2), or non-ferrous abrasive blasting until clean, bare metal is exposed and recleaned in accordance with 3.3.1. 3.3.5 Application of coating primer. Coating primer (see 3.2.1.2) shall be appl
25、ied in a single coat by brushing, spraying, or wiping. The coating primer shall be allowed to dry for not less than 30 minutes prior to application of the ablative coating, 3.3.6 Application of ablative coatinq. The ablative coating (see 3.2.1.1) shall be applied as follows: a. depth, using double-b
26、acked adhesive tape or clamps. Install edge and grid strips as necessary to control the coating b. The two-component coating material (see MIL-C-47244) shall be mixed in accordance with the manufacturers instructions. NOTE: specified by the manufacturer. If the temperature is lowered, the applicatio
27、n life will be lengthened. The application life of the mixed coating is.as c. applicable engineering drawing, by troweling. Work the coating into small areas, exercising care to prevent voids and air pockets and to maintain the coating thickness compatible with the depth control strips installed and
28、 the form templates used. Apply the coating over the primed areas, as specified on the Heat may be applied to the 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-472qbA 80 9799906 0457783 9 = MIL-C-47246A (MI) coating material or tooling (see
29、 3.1.3) to facilitate material flow and improve finish smoothness but care shall be taken to avoid excessive reduction of material application life (see 6.1). Open any existing air pockets and fill voids with additional coating material. d. At temperatures ranging from +16O to +38OC, expose the coat
30、ing for not less than 8 hours of curing. e. Upon completion of the curing cycle, remove all edge and grid strips and miscellaneous tooling. The uncoated areas exposed by the removal of the grid strips shall then be processed in accordance with 3.3.1 through 3.3.5, 3.3.6c, and 3.3.6d. 3.3.7 Rework. a
31、pplying additional primer and coating as required. reworked as follows: Defective areas may be reworked by cleaning the area and Eroded areas may be a. brush and solvent-clean as specified in 3.3.1. Remove any charred ablative coating with abrasive paper or wire b. Apply additional coating (see 3.2.
32、1.1) as required. c. Cure as specified in 3.3.6d. Note: Use coating primer (see 3.2.1.2) whenever the erosion extends to the metal structure. 3.3.8 Coating hardness. The hardness of the coating after curing as specified in 3.3.6d, shall be not less than 45 Shore D. 3.4 Workmanship. The coating shall
33、 conform to the requirements of the engineering drawing. The coating shall be continuous, uniform, free from foreign material, and free of excessive pits or blisters. Due to coating material viscosity, the entrapment of small air bubbles during application cannot be avoided, but pits or bubbles with
34、 a dimension in excess of 0.19 inch shall be reworked as specified in 3.3.7. 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
35、 and tests) as specified herein. Except as otherwise 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. The Government reserves the rig
36、ht to perform any of the inspections set forth in this specification where such inspections are deemed necessary to ensure supplies and services conform to prescribed requirements. 4.1.1 Responsibility for compliance. All items shall meet all requirements of sections 3 and 5. The inspection set fort
37、h in this specification shall become a part of the contractors overall inspection 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-47246A 80 a 9774906 0457782 O = MIL-C-47246A (MI) . system or quality program. The absence of any inspection req
38、uirements 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 operations, is an acceptable practice
39、 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 Inspection records. Suitable inspection records substantiating that requirements of 3.1,
40、 3.2, 3.3, and 3.4 have been complied with shall be maintained and shall be available to the procuring activity. 4.3 Acceptance testing. Each coated part shall be subjected to the visual inspection and coating hardness test specified herein. the test requirements shall be cause for part rejection. F
41、ailure to meet 4.3.1 Visual inspection. Unless otherwise specified by the procuring activity, each coated part shall be visually inspected 100 percent and shall conform to the requirements of 3.4. The thicknessof coating may be verified by demonstrating compatibility with the depth control establish
42、ed by grid and edge strips and form templates used in the application techniques of 3.3.6. 4.3.2 Coatinq hardness test. The coating hardness shall be determined in accordance with ASTM D 2240, and shall be as specified in 3.3.8. 5. PACKAGING. I This section is not applicable to this specification. 6
43、. NOTES (This section contains information of a general or explanatory nature that may be helpful, but is not mandatory.) 6.1 Intended use. This specification is intended to be used to establish the requirements for the application of ablative coating primer and ablative coating. 6.2 Acquisition req
44、uirements. Acquisition documents must specify the following: a. Title, number, and date of the specification b. Issue of DODISS to be cited in the solicitation, and if required, the specific issue of individual documents referenced (see 2.1.1). 6.3 Metrication. Metric equivalents in accordance with
45、FED-STD-376 are acceptable for use in this specification. 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-C-4724bA 80 W 779990b 0457783 i E MIL-C-47246A (MI) 6.4 Subject term (keyword) listing. Covering, protective Primer Shielding material 6.
46、5 Application life reduction. Curing of the ablative coating material is rapidly accelerated by heat, with full cure occurring in approximately 30 minutes at +66OC. Therefore, the use of heat in processing should be conditioned by the detrimental effects of reduced application life of the heated mat
47、erial. 6.6 Changes from previous issue. Marginal notations are not used in . this revision to identify changes with respect to the previous issue due to the extensiveness of the changes. Custodian: Amy-MI Civilian Coordinating Activity: GSA-FSS 7 Preparing Activity: AKRIY-MI Project 8030-A130 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-
