1、I I 23 Amil 1992 Beneficial comments (recommendations, additions, deletions) and any pertinent data which may be of use in improving this document should be addressed to: Commander, Naval Sea Systems Command, SEA 5523, Department of the Navy, Washington, DC 20362-5101 by using the self-addressed Sta
2、ndardization Document Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. SUPERSEDING . DOD-C-24689A 11 August 1989 (See 6.7) MILITARY SPECIFICATION COBALT ALLOY CASTINGS, WEAR AND CORROSION RESISTANT This specification is approved for use by all Departments and A
3、gencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers castings of cobalt-chromium-tungsten and cobalt-chromium-nickel alloys for use where corrosion and wear resistant materials are required. 1.2 Classification. Castings are of the following compositions, as specified (
4、see 6.2). (a) Composition No. 28 (UNS R30006). (b) Composition No. 21. (c) Composition No. 22 (UNS R30001). (d) Composition No. 23 (UNS R30021). 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications, standards, and handbooks. The following specifi- cations, standards, and handbooks
5、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 supplement thereto, cited in the solicitation (see 6.2). AMSC N/A AREA
6、MECA a DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NIL-C-24b89B NE W 9979906 0524048 L W MIL-C-24689B SPECIFICATIONS MILITARY MIL-C-3993 - Copper and Copper-Base Al
7、loy Mill Products; Packaging of. I STANDARDS MILITARY MIL-STD-271 - Requirements for Nondestnktive Testing Methods, MIL-STD-278 - Welding and Casting Standard. MIL-STD-792 - Identification Marking Requirements for Special Purpose Components. (Unless otherwise indicated, copies of federal and militar
8、y specifications, standards, and handbooks are available from the Standardization Documents Order Desk, BLDG. 4D, 700 Robbins Avenue, Philadelphia, PA 19111-5094.) 2.2 Non-Government Publications. The following document(s) form a part of this document to the extent specified herein. Unless otherwise
9、 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 solicitation (see 6.2). AMERICAN SOCIETY FOR
10、TESTING AND MATERIALS (ASTM) E 18 - Standard Test Methods for Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials. (DoD adopted) E 354 - Standard Methods for Chemical Analysis of High Temperature, Electrical, Magnetic, and Other Similar Iron, Nickel, and Cobalt Alloys. (Applica
11、tion for copies should be addressed to the American Society for , Testing and Materials, 1916 Race Street, Philadelphia, PA 19103-1187.) (Non-Government standards and other publications are normally available from the organizations that prepare or distribute the documents, These documents also may b
12、e available in or through libraries or other informational services.) 2.3 Order of Drecedence. 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
13、 regulations unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 First article. When specified (see 6.2), a sample shall be subjected to first article inspection (see 6.4) in accordance with 4.3, 3.2 Material. Material shall be made by an electric furnace process. Unless a specific ty
14、pe is specified (see 6.2), static, centrifugal, or investment castings may be supplied at the option of the contractor. 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-24689B 3.3 Process Prohibitions. Unspecified heat treatments, cold working
15、, straightening, OE weld repair shall not be permitted. 3.4 Descalinq. Castings shall be cleaned so that the surface is free from scale and foreign matter. If shot, grit, or vapor blasting is used, it shall be followed by machining, grinding, or pickling (provided a minimum of 0.10 inch (0.25 millim
16、eter) is removed in subsequent machining) when liquid penetrant inspection is required. 3.5 Pecovered materials. Unless otherwise specified herein, all equipment, material, and articles incorporated in the products covered by this specification shall be new and may be fabricated using materials prod
17、uced from recovered materials to the maximum extent practicable without jeopardizing the intended use. The term “recovered materials“ means materials which have been collected or recovered from solid waste and reprocessed to become a source of raw materials, as oppbsed to virgin raw materials. None
18、of the above shall be interpreted to mean that the use of used or rebuilt products is allowed under this specification unless otherwise specifically specified. 3.6 Chemical composition. The casting material shall conform to the chemical composition specified in table I. Data may be ordered to verify
19、 this requirement (see 6.3). Carbon L4angane S e Silicon Chromium Tungs ten Nickel Iron Molybdenum Others, total (Ti, As, P, S, Cu, Mo, B, Zn) Phosphorus Sulfur Boron Cobalt TABLE I. Chemical composition. Analysis (percent) JJ Composition number 20 0.90-1.4 1. O 1.5 27.0-31.0 3.5-5.5 3.0 3.0 1.5 1.0
20、 “ “ “ Remainder 21 1.8-2.2 0.50 0.80-1.5 23.0-25.0 11.0-13.0 3.0 2.0 1.0 1.0 “ “ “ Remainder 22 2.0-2.6 1.0 1.5 29.0-33.0 11.0-14.0 3.0 3.0 1.0 1.0 “ -“- “ Remainder 23 0.20-0.30 1.0 1.0 25.0-29.0 “ 1.75-3.75 3.0 5.0-6.0 - -“ 0.04 0.04 O. 007 Remainder a u Maximum unless a range is shown. 3 Provide
21、d by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-24b89B HE W 999990b 0524050 T m P 4, MIL-C-24689B TABLE II. Hardness (Rockwell “Ctt), Static and centrifugal Investment Alloy castings lJ castings lJ Composition 20 40 37 Composition 21 50 48 Composition
22、 22 50 48 Composition 23 23- 34 23-34 1/ All values minimum except where a range is shown. 3.8 Heat treatment. Composition 23 castings shall not be stress relieved. Composition 20, 21, 22 castings shall be stress relieved at 1650 f 25 degrees Fahrenheit (F) (900 * 14 degrees Celsius (“C) for 1 hour
23、per inch of cross section with 2 hours minimum total time at iemperature. Castings shall be cooled in the furnace at 250F (120C) per hour maximum to 500F (260C). Below 500F (260C) the castings may be cooled in still air to ambient temperature. Cooling may be done in steps provided the specified cool
24、ing rate is maintained. 3.9 Soundness. Castings shall be of uniform quality and condition, free of cracks, burrs, sand, tears, shrinkage, cold shuts, excessive scale, fins, porosity, and segregation to the extent they meet the visual and nondestructive inspection requirements. 3.10 Removal of surfac
25、e defects. Surface defects may be ground out provided the ground out area is radiused and does not reduce the castings dimensions below the minimum dimensions of the casting drawing. The bottom radius of the ground out area shall be at least three times its depth, 3.11 Weld repair, Weld repair is no
26、t permitted without specific approval from the command or agency concerned. When weld repair is approved, the welding procedure will be approved as directed by the repair approval authority. 3.12 Dimensions. Castings shall be so that they can be laid out and machined to the finished dimensions of th
27、e casting drawing, within the specified tolerances. Sufficient stock shall be allowed for finishing. 3.13 Identification. Each castingshall be permanently marked as specified in 3.13.1 through 3.13.3. 3.13.1 Information reauired. Individual castings shall be marked with the following: (a) Foundrys n
28、ame or trademark. (b) Specification and composition number. (c) Pattern or piece number. (d) Heat number and heat treat lot number. 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-3.13.2 Methods and location of marking. The methods of marking shall
29、 be permanent marking and in accordance with MIL-STD-792. The location of marking be removed by machining. shall be at a low stress area as shown on the drawing or on an area that will not, 3.13.3 Small castings. Where individual castings cannot be marked as specified in 3.13.1 and 3.13.2, they may
30、be bundled or boxed and each bundle or box marked with a metal tag containing the specified information. 3.14 Allov identity. Prior to shipment, all castings shall be verified to be cobalt-chromium-molybdenum-nickel alloy. 4. QUALITY ASSURANCE PROVISIONS 4.1 Responsibilitv for InsDection. Unless oth
31、erwise 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 otherwise specified in the contract or purchase order, the contractor may use his own or any other facilities s
32、uitable for the Performance of the inspection requirements specified herein, unless disapproved by the Government. The Government reserves the right to perform any of the inspections set forth in this specification where such inspections are deemed necessary to ensure supplies and services conform t
33、o prescribed requirements. 4.1.1 ResDonsibilitv 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. The absence of any inspection requirements i
34、n 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 the manufacturing operations, is an acceptable practice to asc
35、ertain 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 requirements specified herein are classified as f
36、ollows: (a) First article inspection (see 4.3). (b) Quality conformance inspection (see 4.4). 4.3 First article inspection. First article inspection shall consist of the test as specified in 4.3.2.- 4.3.1 Sampling for first article inspection. The first castings submitted for inspection shall be the
37、 first article sample. 4.3.2 Radiographic inspection. The first article casting shall be radio- graphically inspected in accordance with MIL-STD-271 to the acceptance criteria in accordance with MIL-STD-278 of the criticality level specified, or to another - standard, as specified (see 6.2). 5 Provi
38、ded by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-24689B 4.4 Qualitv conformance insuectioq. Qualfty conformance inspection shall consist of the examinations and tests as specified in 4.5 and 4.6. 4.4.1 Lot definition, Lots shall be as defined in 4.4.
39、1.1 through 4.4.1.2. 4.4.1.1.1 Master melt used. When a master melt is used, a lot shall consist of all material cast from the same master melt, by the same process, and presented for inspection at the same time. 4.4.1.1.2 Master melt not used. When a master melt is not used, a lot shall consist of
40、all the castings cast from the same heat, by the same process, and presented for inspection at the same time. 4.4.1.1.3 Carbon additions, When carbon additions are made during pouring of castings and for the purpose of carbon analysis only, a lot shall be further defined as the castings poured betwe
41、en carbon additions. 4.4.1.2 Visual and dimensional examination, and mechanical property tests. A lot shall consist of all the castings from a lot as defined in 4.4.1.1.1 or 4.4.1.1.2 that have the same maximum cross-section and which have been heat treated together. 4.4.2 Samplinq. Sampling for qua
42、lity conformance inspection shall be as specified in 4.4.2.1 through 4.4.2.4. 4.4.2.1 Sampling for visual and dimensional examination. Each casting shall be examined visually and dimensionally. 4.4.2.2 Samplinacal analysis. Two samples shall be selected at random from each lot. Samples may be taken
43、from the ladle or from casting blanks. When taken from the ladle, the samples shall be poured at the same time the castings are poured. When carbon additions are made to the melt during pouring of the castings, samples shall be taken for carbon analysis as follows: one immediately before each additi
44、on and one after each addition, following an appropriate hold time for homogenization, 4.4.2.3 Sampling for hardness tests. Two castings shall be tested from each lot. 4.4.2.4 SamDling - for nondestructive inspection. Each casting shall be inspected. 4.5 Visual and dimensional examination. Castings
45、shall be examined for conformance to 3.4, 3.9, 3.12, 3.13 and the criteria below. Any casting which fails to meet the dimensional requirement of the casting drawing shall be rejected. The criteria for acceptance of visual surface porosity shall be as follows: Critical machined surfaces, as specified
46、 (see 6.2) shall be free of porosity. For all other surfaces, porosity with a maximum opening of 3/32 inch or less is acceptable provided that the internal surfaces are visible, the depth does 6 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-C-2
47、4689B not exceed 1/8 inch, and the minimum wall thickness (determined from drawing dimensions) is not violated. Surface porosity with greater than 3/32 inch opening, or deeper than 1/8 inch, or having internal surfaces that are not visible, shall be explored by grinding (see 3.10) or the casting sha
48、ll be rejected, 4.6 Test methods. 4.6.1 Chemical analvsis. Chemical analysis shall be performed by wet or spectrochemical methods as determined by the contractor. In case of dispute, the wet method as specified in ASTM E 354 shall govern. Chemical composition shall be as specified in 3.6. 4.6.2 Hard
49、ness test, Hardness tests shall be performed in accordance with ASTM E 18. Hardness shall be as specified in 3.7. 4.6.3 Nondestructive testinq. When specified on the casting drawing, castings shall be liquid penetrant inspected or radiographed to the extent specified. Test method shall be in accordance with MIL-STD-271. Acceptance criteria shall be as specified on the casting drawing or in the contract or purchase order. Data may be ordered to
