1、Designation: B418 16aStandard Specification forCast and Wrought Galvanic Zinc Anodes1This standard is issued under the fixed designation B418; 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 p
2、arentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This specification covers cast and wrought galvanic zincanodes used for the cathodic protection of more noble metalsand alloys in sea water, brac
3、kish water, other salineelectrolytes, 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 requirements of MIL-A-18001K.1.3 Zinc anodes conforming to this specification may be
4、used 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 stated in inch-pound units are to be regardedas standard. The values given in parenthe
5、ses 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 use. It is theresponsibility of the user of this standard to become familiarwith all
6、hazards including those identified in the appropriateSafety Data Sheet (SDS) for this product/material as providedby the manufacturer, to establish appropriate safety and healthpractices, and determine the applicability of regulatory limi-tations prior to use.2. Referenced Documents2.1 ASTM Standard
7、s:2B6 Specification for ZincB899 Terminology Relating to Non-ferrous Metals and Al-loysB949 Specification for General Requirements for Zinc andZinc Alloy ProductsE29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE527 Practice for Numbering Metals and A
8、lloys in theUnified Numbering System (UNS)E536 Test Methods for Chemical Analysis of Zinc and ZincAlloys2.2 Military Standard:3MIL-A-18001K w/INT. AMENDMENT 3, 24 October2007 Military Specification Anodes Sacrificial Zinc Alloy2.3 ISO Standards:4ISO 3815-1 Zinc and zinc alloys Part 1: Analysis of so
9、lidsamples 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 TerminologyB899.3.2 Definitions of Terms Specific to This Standard:3.2.1 cathodic protecti
10、on, 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 current tothe
11、 noble electrode.3.2.3 saline electrolyte, na solution consisting of mainlythe chlorides of the alkali metals.4. Ordering Information4.1 Orders for zinc anodes under this specification shallinclude information as specified in Specification B949.4.2 Additional ordering information specific to this st
12、andardis as follows:4.2.1 Type of anode material (see Table 1),4.2.2 Number of anodes,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 Oct. 1, 2016. P
13、ublished November 2016. Originallyapproved in 1964. Last previous edition approved in 2016 as B418 16. DOI:10.1520/B0418-16a.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
14、refer to the standards Document Summary page onthe ASTM website.3Available from DLA Document Services, Building 4/D, 700 Robbins Ave.,Philadelphia, PA 19111-5094, http:/quicksearch.dla.mil.4Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, htt
15、p:/www.ansi.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.2.3 Size of anode and whether contains rod insert and ifso, type of insert and whether contains bolt ho
16、le and if so,whether threaded.5. Chemical Requirements5.1 The anode shall be made from Special 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
17、 laboratory tests shows that Type Icomposition may suffer intergranular corrosion. Susceptibilityto 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
18、 Type II composition, whichmust be made from special high-grade zinc with an ironcontent well below the 0.003 % maximum given in Specifica-tion B6.5.3 Chemical requirement procedures shall be in compli-ance with the provisions of Specification B949.6. Sampling for Chemical Analysis6.1 The sample for
19、 chemical analysis shall be taken asfollows:6.1.1 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 20 000 lb (9070 kg) of zincanodes cast from a single melt or not more than 5000 lb (2268kg) of anodes ca
20、st in a single 24-h period from more than onemelt. The minimum number of anodes to be sampled shall beas specified in Table 2.6.1.2 Taking Sample for Chemical AnalysisEach selectedanode shall be sampled by drilling or machining with anonferrous tool. The use of a drill with a tungsten carbide tipis
21、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 50 g total.6.1.3 Other sampling procedures shall be in compliancewith the provisions of Specification
22、 B949.7. Methods of Chemical Analysis7.1 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 3 (note: spectrochemical methods may includeISO 3815-1, ISO 3815-2) approved for
23、referee purposes byASTM. Test Methods E536 shall be used, except for Type II.NOTE 1Test Methods E536 is directly applicable, in an unmodifiedform, only to alloys 3, 5, and 7. ISO 3815-1 and ISO 3815-2 are genericmethods applied to zinc and zinc alloys. Each of the methods may bemodified and formatte
24、d for the alloy to be assayed. An experiencedchemist, using suitable and/or traceable standards along with valid qualityassurance techniques, will be able to perform and validate the methodsand demonstrate acceptable precision and accuracy.8. Bolt Holes and Threads8.1 For anodes with integral insert
25、s intended for attachmentby bolting, it is recommended that a bolt-hole spacing of 6 in.(152 mm) or even multiples thereof be used.8.2 Anodes with projecting rod inserts threaded for attach-ment by means of a bolted connection shall have UnifiedNational Coarse threads.9. Workmanship, Finish, and App
26、earance9.1 The zinc anodes shall be free of flash, burrs, cracks,blow holes, and surface slag, consistent with 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 d
27、iagonallyacross opposite edges of the anode. Drill holes and saw cuts forsampling shall not be cause for rejection unless they are severeenough to cause premature failure of the anode.10. Rejection and Rehearing10.1 Claims to be considered in accordance with the provi-sions of Specification B949.11.
28、 Investigation of Claim11.1 Claims shall be investigated in accordance with theprovisions of Specification B949.TABLE 1 Chemical RequirementsAType (UNS)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
29、(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 conformance with this specification, the observed value or calculated value obtainedfrom analysis shall be rounded off to the nearest unit in the last
30、right hand place of figures used in expressing the specified limit, in accordance with the rounding methodof Practice E29.BUNS designations were established in accordance with Practice E527.CDetermined arithmetically by difference.TABLE 2 Minimum Number of Anodes in SampleNumber of Anodes in LotMini
31、mum Number ofAnodes in Sample1to500 2500 to 1000 3Each additional 1000 or part thereof 1TABLE 3 Methods of AnalysisMethodASTMDesignationSpectrochemical AnalysisChemical AnalysisChemical Analysis Test Methods E536B418 16a212. Settlement of Claims12.1 Claims shall be settled in accordance with the pro
32、vi-sions of Specification B949.13. Product Identification Marking and Packaging13.1 Each slab, block, jumbo or ingot shall be marked foridentification in accordance with the provisions of Specifica-tion B949.14. Keywords14.1 cathodic protection; galvanic anodes; zinc; zinc anodesSUMMARY OF CHANGESCo
33、mmittee B02 has identified the location of selected changes to this standard since the last issue (B41816)that may impact the use of this standard. (Approved October 1, 2016.)(1) The definition for the term ribbon anode was removed as itis now defined in Terminology B899 because it was previouslyals
34、o defined in Specification B69.Committee B02 has identified the location of selected changes to this standard since the last issue (B41812)that may impact the use of this standard. (Approved May 1, 2016.)(1) The references to specific sections in Specification B949were removed.ASTM International tak
35、es no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own re
36、sponsibility.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 standardsand should be addres
37、sed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at th
38、e 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). Permission rights to photocopy the standard may also be secured from the Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 16a3
