1、Designation: B 418 08Standard Specification forCast and Wrought Galvanic Zinc Anodes1This standard is issued under the fixed designation B 418; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in
2、parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This specification covers cast and wrought galvanic zincanodes
3、used for the cathodic protection of more noble metalsand alloys in sea water, brackish water, other saline electro-lytes, or other corrosive environments.1.2 Type I anodes are most commonly used for suchapplications. The Type I anode composition in this specifica-tion meets the chemical composition
4、requirements of MIL-A-18001J.1.3 Zinc anodes conforming to this specification may beused in other waters, electrolytes, backfills, and soils whereexperience has shown that the specified composition is efficientand reliable. Type II anodes are most commonly used for suchapplications.1.4 The values st
5、ated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its u
6、se. It is theresponsibility of the user of this standard to become familiarwith all hazards including those identified in the appropriateMaterial Safety Data Sheet (MSDS) for this product/materialas provided by the manufacturer, to establish appropriatesafety and health practices, and determine the
7、applicability ofregulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:B6 Specification for ZincB 899 Terminology Relating to Non-ferrous Metals andAlloysE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE 527 Practice for Number
8、ing Metals and Alloys in theUnified Numbering System (UNS)E 536 Test Methods for ChemicalAnalysis of Zinc and ZincAlloys2.2 Military Standard:2MIL-A-18001J Military Specification Anodes, CorrosionPreventative, Zinc, Slab Disc, and Rod Shaped2.3 ISO Standards:3ISO 3815-1 Zinc and zinc alloys Part 1:A
9、nalysis of solidsamples by optical emission spectrometryISO 3815-2 Zinc and zinc alloys Part 2: Analysis byinductively coupled plasma optical emission spectrometry3. Terminology3.1 Terms shall be defined in accordance with TerminologyB 899.3.2 Definitions of Terms Specific to This Standard:3.2.1 cat
10、hodic protection, nreduction of corrosion bymaking the protected metal the cathode in a conductingmedium by applying direct current.3.2.2 galvanic anode, na metal electrode that sacrificiallycorrodes when coupled to a more noble metal in a conductingmedium, and thereby supplies a protective electric
11、 current tothe noble electrode.3.2.3 ribbon anode, na long, continuous sacrificial anodeshape, with a diamond, square, rectangular, oval, or othercross-section, most commonly made of zinc, magnesium oraluminum, having a core wire normally made of steel, that isusually supplied in coils or reels of 1
12、00 to 3600 ft dependingupon size and cross-section.3.2.4 saline electrolyte, na solution consisting of mainlythe chlorides of the alkali metals.4. Ordering Information4.1 Orders for anodes under this specification shall includethe following information:4.1.1 ASTM designation and year of issue,4.1.2
13、Type of anode material (see Table 1),4.1.3 Quantity in pounds,1This specification is under the jurisdiction of ASTM Committee B02 onNonferrous Metals and Alloys and is the direct responsibility of SubcommitteeB02.04 on Zinc and Cadmium.Current edition approved Nov. 1, 2008. Published December 2008.
14、Originallyapproved in 1964. Last previous edition approved in 2006 as B 418 06.2Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/www.dodssp.daps.mil.3Available from American National Standards Institute (ANSI), 25 W.
15、 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.1.4 Number of anodes,4.1.5 Size of anode and whether cont
16、ains rod insert and ifso, type of insert and whether contains bolt hole and if so,whether threaded.4.1.6 Whether marking for identification is required includ-ing the marking patterns, if required, and4.1.7 Whether certification is required.5. Chemical Composition5.1 The anode shall be made from Spe
17、cial High Grade zincconforming to Specification B6, with suitable alloying addi-tions for Type I anodes. Composition of the anode alloy contentshall conform to the limits prescribed in Table 1.5.2 Evidence from laboratory tests shows that Type Icomposition may suffer intergranular corrosion. Suscept
18、ibilityto intergranular corrosion increases with increasing tempera-ture and is particularly severe above approximately 120F(50C). Intergranular corrosion can be avoided (at tempera-tures above about 120F) with Type II composition, whichmust be made from special high-grade zinc with an ironcontent w
19、ell below the 0.003 % maximum given in Specifica-tion B6.6. Methods of Chemical Analysis6.1 The chemical compositions enumerated in this specifi-cation shall, in case of disagreement, preferably be determinedby methods mutually agreed upon or the methods listed inTable 2 (note: spectrochemical metho
20、ds may includeISO 3815-1, ISO 3815-2) approved for referee purposes byASTM. Test Methods E 536 shall be used, except for Type II.7. Bolt Holes and Threads7.1 For anodes with integral inserts intended for attachmentby bolting, it is recommended that a bolt-hole spacing of 6 in.(152 mm) or even multip
21、les thereof be used.7.2 Anodes with projecting rod inserts threaded for attach-ment by means of a bolted connection shall have UnifiedNational Coarse threads.8. Workmanship, Finish, and Appearance8.1 The zinc anodes shall be free of flash, burrs, cracks,blow holes, and surface slag, consistent with
22、good commercialpractice. Cast anodes shall not have shrinkage cavities exceed-ing14 the depth of the anode or 1 in. (25.4 mm), whichever issmaller when measured from a straightedge placed diagonallyacross opposite edges of the anode. Drill holes and saw cuts forsampling shall not be cause for reject
23、ion unless they are severeenough to cause premature failure of the anode.9. Sampling9.1 The sample for chemical analysis shall be taken asfollows:9.1.1 Selection of PortionA number of anodes shall beselected at random to give a representative sample of the lot. Alot shall consist of not more than 20
24、 000 lb (9070 kg) of zincanodes cast from a single melt or not more than 5000 lb (2268kg) of anodes cast in a single 24-h period from more than onemelt. The minimum number of anodes to be sampled shall beas specified in Table 3.9.1.2 Taking Sample for Chemical AnalysisEach selectedanode shall be sam
25、pled by drilling or machining with anonferrous tool. The use of a drill with a tungsten carbide tipis recommended. The tool bit or drill shall not penetrate intothe core material or a cored anode. The cuttings from all anodesin a lot shall be thoroughly mixed to form a uniform sample ofnot less than
26、 50 g total.10. Claims10.1 Claims to be considered shall be made in writing to themanufacturer within 30 days of receipt of anodes at thepurchasers plant and the results of the purchasers tests shallbe given. The manufacturer shall be given one week from dateof receipt of such claim to investigate h
27、is records and then shallagree either to satisfy the claim or send a representative to theplant of the purchaser.11. Investigation of Claims11.1 The inspector representing the manufacturer shall ex-amine all pieces where physical defects are claimed. If agree-ment is not reached, the question of fac
28、t shall be submitted toa mutually agreeable umpire, whose decision shall be final.11.2 On a question of chemical analysis, a sample shall betaken by the representatives of both the manufacturer and thepurchaser as described in Section 4. The properly mixed andTABLE 1 Chemical RequirementsAType (UNS)
29、BAluminum, % Cadmium, %Iron,max,%Lead,max,%Copper,max,%Others,Total,%ZincC,%Type I (Z32120) 0.10.5 0.0250.07 0.005 0.006 0.005 0.1 remainderType II (Z13000) 0.005 max 0.003 max 0.0014 0.003 0.002 . remainderAThe following applies to all specified limits in this table: For purposes of determining con
30、formance with this specification, the observed value or calculated valueobtained from analysis shall be rounded off to the nearest unit in the last right hand place of figures used in expressing the specified limit, in accordance with the roundingmethod of Practice E29.BUNS designations were establi
31、shed in accordance with Practice E 527.CDetermined arithmetically by difference.TABLE 2 Methods of AnalysisMethodASTMDesignationSpectrochemical AnalysisChemical AnalysisChemical Analysis Test Methods E 536TABLE 3 Minimum Number of Anodes in SampleNumber of Anodes in LotMinimum Number ofAnodes in Sam
32、ple1to500 2500 to 1000 3Each additional 1000 or part thereof 1B418082quartered sample shall be separated into three parts, each ofwhich shall be placed in a sealed envelope, one for themanufacturer, one for the purchaser, and one for the umpire ifnecessary. The manufacturer and the purchaser shall e
33、ach makean analysis, and if the results do not establish or dismiss theclaim to the satisfaction of both parties, the third sample shallbe submitted to a mutually agreeable umpire, who shalldetermine the question of quality, and whose determinationshall be final.12. Rejection and Rehearing12.1 The e
34、xpenses of the manufacturers representative andof the umpire shall be paid by the loser or divided in proportionto the concession in case of compromise. In case of rejectionbeing established, damages shall be limited to the payment bythe manufacturer of freight both ways for replacement of thereject
35、ed anodes with anodes conforming to this specification.13. Product Marking13.1 A manufacturers identifying brand shall be cast,stamped, or displayed on at least one surface of each anode orpackage of anodes.14. Keywords14.1 cathodic protection; galvanic anodes; zinc; zinc anodesSUMMARY OF CHANGESCom
36、mittee B02 has identified the location of selected changes to this standard since the last issue (B 418 - 06)that may impact the use of this standard. (Approved November 1, 2008.)(1) Revisions have been made to Sections 2.3 and 6.1 to addanalytical spectrochemical methods ISO 3815-1 andISO 3815-2.AS
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38、ntirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standards
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40、 on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).B418083
