NAVY MIL-DTL-24779 C-2013 ANODES SACRIFICIAL ALUMINUM ALLOY.pdf

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1、Comments, suggestions, or questions on this document should be addressed to: Commander, Naval Sea Systems Command, ATTN: SEA 05S, 1333 Isaac Hull Avenue, SE, Stop 5160, Washington Navy Yard DC 20376-5160 or emailed to CommandStandardsnavy.mil, with the subject line “Document Comment”. Since contact

2、information can change, you may want to verify the currency of this address information using the ASSIST Online database at https:/assist.dla.mil. AMSC N/A FSC 3426 INCH-POUND MIL-DTL-24779C(SH) 8 January 2013 SUPERSEDING MIL-DTL-24779B(SH) 23 July 2009 DETAIL SPECIFICATION ANODES, SACRIFICIAL, ALUM

3、INUM ALLOY This specification is approved for use by the Naval Sea Systems Command, Department of the Navy, and is available for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers conventional and low voltage aluminum alloy sacrificial ano

4、des for U.S. Navy ships, submarines, and marine structures. 1.2 Classification. Anodes are of the following types and styles, as specified (see 6.2). Anodes that require a higher degree of tolerance in either machining or casting are designated by “-CT”. 1.2.1 Conventional aluminum types. a. Type AH

5、S Aluminum, hull slab (steel strap core) (see figures A-1 to A-3) b. Type ASS Aluminum, submarine slab (steel strap core) (see figures A-5, A-7, and A-9) c. Type ATS Aluminum, teardrop shape (steel strap core) (see figure A-10) d. Type AHC Aluminum, hull slab (steel core) (see figures A-11, A-12, A-

6、15, and A-16) e. Type AEP Aluminum, fairwater slab (pipe core or pipe bushing core) (see figures A-19 to A-31) (1) Style A Square slab (see figures A-19 and A-20) (2) Style B Circular slab (see figures A-21 to A-30) (3) Style C Semi-circular slab (see figure A-31) f. Type ABP Aluminum, bar (pipe cor

7、e) (see figure A-32) g. Type APN Aluminum, plate (no core) (see figures A-33 to A-34) 1.2.2 Low voltage aluminum types. a. Type LHS Low Voltage Aluminum, hull slab (steel strap core) (see figures A-1 to A-4) b. Type LSS Low Voltage Aluminum, submarine slab (steel strap core) (see figures A-5 to A-9)

8、 c. Type LTS Low Voltage Aluminum, teardrop shape (steel strap core) (see figure A-10) d. Type LHC Low Voltage Aluminum, hull slab (steel core) (see figures A-11 to A-18) e. Type LEP Low Voltage Aluminum, fairwater slab (pipe core or pipe bushing core) (see figures A-19 to A-31) (1) Style A Square s

9、lab (see figures A-19 and A-20) (2) Style B Circular slab (see figures A-21 to A-30) (3) Style C Semi-circular slab (see figure A-31) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24779C(SH) 2 f. Type LBP Low Voltage Aluminum, bar (pipe cor

10、e) (see figure A-32) g. Type LPN Low Voltage Aluminum, plate (no core) (see figures A-33 and A-34) h. Type LES Low Voltage Aluminum, anode (I-beam with welded bushing core) (see figures A-36 and A-37) (1) Style A Chamfered rectangular slab (see figure A-36) (2) Style B Square slab (see figure A-37)

11、1.2.3 Close tolerance low voltage aluminum types. a. Type LEP-B-CT Low Voltage Aluminum, Close Tolerance, fairwater slab (pipe core or pipe bushing core) (see figure A-35) b. Type LSS-CT Low Voltage Aluminum, Close Tolerance, submarine slab (steel strap core) (see figure A-38) 1.2.4 Other anode geom

12、etries. Other geometries are acceptable as approved by NAVSEA. a. Type LRN Low Voltage Aluminum, rod shape (no core) (see figure A-39) b. Type LDM Low Voltage Aluminum, segmented disk (see figures A-40 to A-43) c. Type LMP Low Voltage Aluminum, mooring chain (pipe core) (see figure A-44) 2. APPLICAB

13、LE DOCUMENTS 2.1 General. The documents listed in this section are specified in sections 3, 4, or 5 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made

14、to ensure the completeness of this list, document users are cautioned that they must meet all specified requirements of documents cited in sections 3, 4, or 5 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The followin

15、g 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 cited in the solicitation or contract. DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-A-18001 - Anodes, Sacrificial Zinc Alloy (Copies

16、 of this document are available online at https:/assist.dla.mil/quicksearch/ or https:/assist.dla.mil.) 2.2.2 Other Government documents, drawings, and publications. The following other Government documents, drawings, and publications form a part of this document to the extent specified herein. Unle

17、ss otherwise specified, the issues of these documents are those cited in the solicitation or contract. CODE OF FEDERAL REGULATIONS (CFR) 29 CFR 1910 - Occupational Safety and Health Standards 29 CFR 1915 - Occupational Safety and Health Standards for Shipyard Employment (Copies of these documents ar

18、e available from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20401 or online at www.gpoaccess.gov/index.html.) Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24779C(SH) 3 2.3 Non-Government publications.

19、The following documents form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract. ASTM INTERNATIONAL ASTM A36/A36M - Standard Specification for Carbon Structural Steel ASTM A108 - Standard S

20、pecification for Steel Bar, Carbon and Alloy, Cold-Finished ASTM A524 - Standard Specification for Seamless Carbon Steel Pipe for Atmospheric and Lower Temperatures ASTM E34 - Standard Test Methods for Chemical Analysis of Aluminum and Aluminum-Base Alloys ASTM E290 - Standard Test Methods for Bend

21、Testing of Material for Ductility ASTM E1251 - Standard Test Method for Analysis of Aluminum and Aluminum Alloys by Spark Atomic Emission Spectrometry (Copies of these documents are available from ASTM International, 100 Barr Harbor Dr., P.O. Box C700, West Conshohocken, PA 19428-2959 or online at w

22、ww.astm.org.) EUROPEAN COMMITTEE FOR STANDARDIZATION BS EN 10025-1 - Hot Rolled Products of Structural Steel. General Technical Delivery Conditions BS EN 10305-1 - Steel Tubes for Precision Applications (Copies of these documents are available online from BSI at http:/ NACE INTERNATIONAL (NACE) NACE

23、 TM0190 - Impressed Current Laboratory Testing of Aluminum Alloy Anodes (Copies of this document are available from NACE International, 1440 South Creek Drive, Houston, TX 77084-4906 or online at www.nace.org.) THE SOCIETY FOR PROTECTIVE COATINGS (SSPC) SSPC SP-10 - Near-White Blast Cleaning (Copies

24、 of this document are available from SSPC Publication Sales, 40 24th Street, 6th floor, Pittsburgh, PA 15222-4656 or online at www.sspc.org.) 2.4 Order of precedence. Unless otherwise noted herein or in the contract, in the event of a conflict between the text of this document and the references cit

25、ed herein, 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 Qualification. Anodes furnished under this specification shall be products that are authorized by th

26、e qualifying activity for listing on the applicable qualified products list before contract award (see 4.2 and 6.3). 3.2 Material. The material described by this specification contains elements for which the Occupational Safety and Health Administration (OSHA) has set standards for exposure limits.

27、Handling and application of aluminum anode material shall be in accordance with 29 CFR 1910 and 29 CFR 1915 and any other safety/health regulations (local or otherwise) that may apply. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24779C(SH

28、) 4 3.2.1 Chemical composition. The chemical composition shall be within the ranges listed in table I (see 4.6.3.1 through 4.6.3.4). Any changes in formulation, ingredients, manufacturing processes, or manufacturing locations (specifically in indium, gallium, zinc, or silicon) outside of the origina

29、lly qualified range shall be approved by NAVSEA. TABLE I. Chemical composition. Element Conventional aluminum Low voltage aluminum Weight (percent) Weight (percent) Indium 1/ 0.014 0.020 0.005 Gallium 1/ 0.02 0.092 0.110 Zinc 1/ 4.0 6.5 0.15 Silicon 0.08 0.20 0.10 Copper 0.005 Iron 0.08 Mercury 0.00

30、01 Tin 0.001 Nickel 0.005 Magnesium 0.010 Manganese 0.010 Bismuth 0.002 Cadmium 0.002 Titanium 0.002 Lead 0.002 Boron 0.001 Aluminum 1/ Remainder Remainder NOTE: 1/ Indium, gallium, zinc, and aluminum raw material purity shall be a minimum 99.8 percent by weight. 3.2.2 Recycled, recovered, or enviro

31、nmentally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum extent possible, provided that the material meets or exceeds the operational and maintenance requirements, and promotes economically advantageous life cycle costs. 3.2.3 Storage

32、. The aluminum anode shall be stored under cover and both top and bottom of each strap and threaded insert shall get a coating of a light grease or corrosion inhibitor to minimize atmospheric corrosion of the straps during storage (see 4.5.2). 3.3 Service performance. The aluminum alloy anodes cover

33、ed by this specification shall remain electrochemically active and provide continuous in-service cathodic protection until the anodes are consumed. Anode properties shall meet the requirements specified in 3, given the range of operating conditions normally encountered during extended marine service

34、 (for example, transition from sea to brackish water, or varying seawater temperatures, and salinity). Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24779C(SH) 5 3.3.1 Conventional aluminum anode qualification. 3.3.1.1 Long-term seawater im

35、mersion performance. The anode current capacity calculated shall be at least 1150 ampere-hours per pound (2535 ampere-hours per kilogram) for each anode, when tested in accordance with 4.2.1. In addition, the free corrosion potential of each anode tested at the end of the long-term seawater immersio

36、n test shall be between -1.05 and -1.15 volts versus saturated silver/silver chloride in seawater. 3.3.1.2 Short-term electrochemical performance. Short-term electrochemical tests shall be conducted in accordance with 4.2.2. Required anode current capacity shall be at least 1150 ampere-hours per pou

37、nd (2535 ampere-hours per kilogram) for each anode and the anode operating potential of each anode shall be between -1.05 and -1.15 volts versus saturated silver/silver chloride in seawater. 3.3.2 Low voltage aluminum anode qualification. 3.3.2.1 Long-term seawater immersion performance. The anode c

38、urrent capacity shall be at least 750 ampere-hours per pound (1656 ampere-hours per kilogram) for each anode, when tested in accordance with 4.2.1. In addition, the free corrosion potential of each anode tested at the end of the long-term seawater immersion test shall be between -0.800 and -0.900 vo

39、lt versus saturated silver/silver chloride in seawater. 3.3.2.2 Short-term electrochemical performance. Short-term electrochemical tests shall be conducted in accordance with 4.2.2. Required anode current capacity of each anode shall be a minimum of 816 ampere-hours per pound (1800 ampere-hours per

40、kilogram) and the anode operating potential of each anode shall be between -0.780 and -0.830 volt versus saturated silver/silver chloride in seawater. 3.4 Construction. 3.4.1 Steel straps/cores. Type AHS/LHS, ASS/LSS, ATS/LTS, and AHC/LHC anodes shall have strap cores of a steel material in accordan

41、ce with ASTM A36/A36M or BS EN 10025-1. 3.4.2 Pipe cores. Type ABP/LBP, AEP/LEP, LDM, and LMP anodes shall have core inserts from mild steel pipe or pipe couplings in accordance with ASTM A524 or BS EN 10305-1. 3.4.3 I-beam with welded bushing core. Type LES shall have an I-beam welded to threaded b

42、ushing as shown on figures A-36 and A-37. Steel material shall be in accordance with ASTM A36/A36M and ASTM A108 or BS EN 10025-1 or BS EN10305-1. 3.4.4 Steel core surface preparation. Steel core material shall be free of surface oxides such as rust, or other coatings including galvanizing, cadmium,

43、 or tin. The steel core shall be abrasive blasted to a near white finish in accordance with SSPC SP-10 and cast within the aluminum anode within 4 hours after blasting to ensure minimal buildup of surface oxides. 3.4.5 Type LRN anodes (no core). The anodes shall pass the tests demonstrating mechanic

44、al properties (see 3.8) and other requirements covered by this specification. 3.4.6 Weight. Minimum weight requirements are specified on figures A-1 through A-44. The total weight of the specified type of anode received divided by the total number of anodes of that type shall be equal to or greater

45、than the minimum weight of anode type specified (see 4.5). 3.4.7 Dimensions. Anode dimensions shall be as specified on figures A-1 through A-44 (see 4.5). Table II provides additional information regarding dimensions, tolerances, and the mounting of anodes. 3.4.7.1 Stud hole elongation of ASS/LSS ty

46、pe anodes. When specified (see 6.2), ASS/LSS straps may be modified as shown on figure A-9. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-DTL-24779C(SH) 6 TABLE II. Dimension, tolerance, and mounting notes. Conventional anode type Figures (conv

47、entional anode type) Low voltage anode type Figures (LVA type) Comments AEP A-21 to A-30 LEP A-21 to A-30 The diameter of Type AEP/LEP Style B anodes shall not vary by more than 0.12 inch (3 millimeters) from the specified diameter. AHS A-1 to A-3 LHS A-1 to A-4 Cores and straps for anode Types AHS/

48、LHS, ASS/LSS, and AHC/LHC shall be positioned so they are embedded 0.25 inch (6.5 millimeters) -0.06 inch (1.5 millimeters) +0.13 inch (3.0 millimeters), as shown on figures A-1 to A-9 and A-11 to A-18, which may be measured from either surface, as applicable. ASS A-5, A-7, A-9 LSS A-5 to A-9 AHC A-

49、11, A-12, A-15, A-16 LHC A-11 to A-18 ATS A-10 LTS A-10 Cores and straps for anode Type ATS/LTS shall be positioned so they are embedded 0.25 inch (6.5 millimeters) 0.13 inch (3.0 millimeters), as shown on figure A-10, which may be measured from either surface, as applicable. AHC A-12 A-16 LHC A-12 A-14 A-16 A-18 The Type AHC/LHC anodes shown on figures A-12, A-1