1、Designation: A 309 01 (Reapproved 2007)Standard Test Method forWeight and Composition of Coating on Terne Sheet by theTriple-Spot Test1This standard is issued under the fixed designation A 309; the number immediately following the designation indicates the year oforiginal adoption or, in the case of
2、 revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense. This test method replace
3、s Method 511.1 of FederalTest Method Standard No. 151b.1. Scope1.1 This test method covers the determination of the weightand composition of coating on terne sheet by the triple-spotmethod. The following three procedures are described:1.1.1 Procedure AStripping with sulfuric acid.1.1.2 Procedure DSt
4、ripping with hydrochloric acid andantimony trichloride.1.1.3 Procedure EStripping with hydrobromic acid-bromine solution.NOTE 1Procedure B (Electrolytic Stripping) and Procedure C (Strip-ping with Silver Nitrate Solution), formerly in this test method, werediscontinued because lack of usage. The des
5、ignation for Procedure D andProcedure E are retained to avoid future confusion when reference is madeonly to the procedure designation.1.2 If the percent of tin in the coating is required, strippingwith hydrobromic acid-bromine is the preferred procedure.Steel with a predeposited electrolytic nickel
6、 coating requires atwo-stage stripping method to determine total tin content. Ifboth the tin and lead percentage are required, stripping withsulfuric acid is recommended, but caution is advised since thesulfuric acid procedure has been found to produce high tinresults (see Section 11).1.3 This stand
7、ard 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. For specific hazardsstatemen
8、ts, see Section 5, Note 2, and Section 17.2. Referenced Documents2.1 ASTM Standards:2A 308/A 308M Specification for Steel Sheet, Terne (Lead-Tin Alloy) Coated by the Hot-Dip ProcessE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRelated Mat
9、erialsE57 Method for Chemical Analysis of White Metal Bear-ing Alloys3E 173 Practices for Conducting Interlaboratory Studies ofMethods for Chemical Analysis of Metals33. Significance and Use3.1 A coating of terne metal on iron or steel articles isintended to provide drawability, solderability, or co
10、rrosionresistance, or combination thereof, which can require differentamounts of coating. Specifications for terne-coated sheetsfrequently provide for these different classes (weights) ofcoating so that purchasers can select that most suitable for theirneeds. This test method provides a means of det
11、ermining theweight of coating for comparison with the material specifica-tion requirements.4. Reagents4.1 Purity of ReagentsReagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytic
12、al Reagents of the American Chemical Society,where such specifications are available.4Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.5. Hazards5.1 For precautions to be obse
13、rved in the use of certainreagents in this test method, reference shall be made toPractices E50. Particular precaution should be observed when1This is under the jurisdiction of ASTM Committee A05 on Metallic-CoatedIron and Steel Products and is the direct responsibility of Subcommittee A05.07 onMeth
14、ods of Testing.Current edition approved May 1, 2007. Published June 2007. Originallyapproved in 1947. Last previous edition approved in 2001 as A 309 - 01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM
15、Standards volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see
16、Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Stat
17、es.using the hydrobromic acid-bromine stripping solution (Proce-dure E) as described in Section 17.6. Test Specimens6.1 Test specimens for weight of coating shall be obtainedas prescribed in Specification A 308.6.2 Specimens shall be 2.25 6 0.01 in. (57.15 6 0.25 mm)square or 2.54 6 0.01 in. (64.52
18、6 0.25 mm) in diameter,except that for material narrower than 2.25 in. in width, testspecimens shall be of such a length that the area of thespecimen is equal to 5.08 in.2(3277 mm2). The weight ofcoating in grams on a specimen 5.08 in.2in area is numericallyequal to the weight of coating in ounces p
19、er square foot ofsheet. When it is not possible to secure a specimen of 5.08 in.2in area, a smaller size may be used, but it is recommended thata specimen of not less than 3 in.2(2000 mm2) be used.NOTE 2The area of 5.08 in.2is achieved by a specimen 2.25 in.square or having a diameter of 2.54 in. wi
20、thin the tolerances of theprocedure.6.3 The specimens shall be clean; if necessary, they shall bewashed with solvent naphtha or other suitable solvent, thenwith alcohol, and dried thoroughly.PROCEDURE ASTRIPPING WITHSULFURIC ACID7. Reagents and Materials7.1 Hydrochloric Acid (sp gr 1.12)Mix 500 mL o
21、f HCl(sp gr 1.19) with 400 mL of distilled water.7.2 Mercuric Chloride SolutionPrepare a saturated solu-tion of mercuric chloride (HgCl2) in water.7.3 Potassium Dichromate, Standard Solution (0.1 N,1mL= 0.00559 g Fe)Prepare and standardize as prescribed forReagent 10 in Practices E50.7.4 Potassium I
22、odate, Standard Solution (0.05 N,1mL=0.003 g Sn)Prepare and standardize as prescribed for Re-agent 12 in Practices E50, making suitable adjustments in thequantities of reagents and water used so that the solution willbe 0.05 N.7.5 Sodium Bicarbonate Solution (saturated)Saturatefreshly boiled distill
23、ed water with NaHCO3.7.6 Sodium Bicarbonate Solution (dilute)Dissolve about10 g of NaHCO3in 1 L of freshly boiled distilled water.7.7 Sodium Diphenylamine Sulfonate Indicator SolutionDissolve 0.20 g of sodium diphenylamine sulfonate in 100 mLof water. Store in a dark-colored bottle.7.8 Stannous Chlo
24、ride, Reducing SolutionDissolve 100 gof SnCl22H2O in 500 mL of HCl (sp gr 1.19), dilute to 1 L,and mix. Preserve in a dark-colored bottle containing a smallamount of granular or mossy tin metal.7.9 Starch SolutionPrepare solution as prescribed forReagent 110 in Practices E50.7.10 Sulfuric Acid (sp g
25、r 1.84).7.11 Sulfuric-Phosphoric Acid Mixture Pour 150 mL ofconcentrated sulfuric acid (H2SO4, sp gr 1.84) into 300 mL ofwater while stirring. Cool, add 150 mL of concentratedphosphoric acid (H3PO4, sp gr 1.69), dilute to 1 L with water,and mix.8. Procedures for Stripping8.1 After cleaning as descri
26、bed in 6.3, weigh each testspecimen separately to the nearest 0.001 g. Wrap a stiffplatinum or nickel wire about each specimen in such a mannerthat it may be held firmly in an acid solution in a horizontalposition. Using a 600-mL beaker, heat 60 mL of H2SO4(sp gr1.84) to 250C (Warningsee Note 3.). I
27、mmerse each speci-men for about 112 min (see Note 4) in the hot acid; thenremove and momentarily immerse in 50 mL of distilled watercontained in a 600-mL beaker. Rub the surface of the specimenwith a policeman while washing with about 50 mL of distilledwater from a wash bottle. Dry the specimen. If
28、the coating hasnot been completely removed, again immerse in the acid andrepeat the procedure. Thoroughly dry and reweigh the speci-men. The loss in weight represents the weight of coatingtogether with iron dissolved from the steel sheet.NOTE 3A suitable face shield should be worn in order to protec
29、t theoperator from accidental splashing or popping of hot sulfuric acid.NOTE 4The stripping must be conducted in a manner to ensure thatthe temperature of the stripping solution is maintained at a minimum of250C for at least 112 min after immersing the test panel. Successivestrippings (at 250C) may
30、be necessary to remove all of the coatingcompletely.9. Chemical Analysis9.1 Cool the H2SO4solution in which the specimen wasstripped and combine with the washings obtained in the600-mL beaker while stripping the specimen. Pour the solutioninto a 500-mL volumetric flask, and rinse the beaker with HCl
31、(sp gr 1.12). Add the rinsings to the flask and dilute to the500-mL mark with HCl (sp gr 1.12), again diluting to the markafter cooling, if necessary. (In the case of lead-coated sheets itmay be necessary to dilute to 1 L with HCl (sp gr 1.12) toensure complete solution of lead, in which case approp
32、riatechanges shall be made in the aliquot portions taken for thesubsequent tests described in 9.2, 9.3, and 9.4.) The solutionmust now be analyzed for iron and, if desired, lead and tin.9.2 Determination of IronTransfer a 100-mL aliquot ofthe solution in the 500-mL volumetric flask (see 9.1)toa400-m
33、L beaker. Heat to boiling, rinse the cover and the sides ofthe beaker with water, and immediately reduce the iron by thedropwise addition of the SnCl2reducing solution. Add 3 dropsin excess after the disappearance of the ferric iron color. Cooland dilute to about 175 mL with water. Add to the soluti
34、on, allat once, 10 mL of the saturated HgCl2solution. Mix gently bystirring the solution. Let stand for 3 to 5 min.Add 20 mL of thesulfuric-phosphoric acid mixture and 5 to 6 drops of thesodium diphenylamine sulfonate indicator solution. Titratewith the standard K2Cr2O7solution to a purple end point
35、.Calculate the grams of iron in the stripping solution as follows:Iron, g 5 5 ABwhere:A = millilitres of K2Cr2O7standard solution required totitrate to a purple end point andB = iron equivalent of the K2Cr2O7solution, kg/L.9.3 Determination of TinTransfer a 200-mL aliquot of thesolution in the 500-m
36、L volumetric flask (see 9.1) to a 300-mLA 309 01 (2007)2Erlenmeyer flask. Add3gofiron in the form of fine wire orthin sheet and1gofpowdered antimony. Fit the flask with aone-hole rubber stopper containing a glass tube bent twice atright angles, with the end of the short bend projecting throughthe st
37、opper, the other end being long enough to reach almost tothe bottom of a beaker placed on a level with the flask. Pourabout 300 mL of a dilute solution of NaHCO3into this beaker.Place the flask on a hot plate, with the glass tube extending intothe beaker containing the dilute solution of NaHCO3. Aft
38、erboiling the solution in the flask for about 5 min, remove thebeaker containing the dilute NaHCO3solution and substituteanother containing about 50 mL of a saturated solution ofNaHCO3. Move both the beaker and the flask to a cool place.This will cause a small amount of the saturated solution ofNaHC
39、O3to enter the flask and exclude the air. Finally cool thesolution to about 10C. Add 5 mL of starch solution and titratewith KIO3solution. It is desirable to run a duplicate analysisfor tin, adding the KIO3solution quickly to a point slightly lessthan the end point found in the previous determinatio
40、n, thenfinishing the titration more slowly. This duplicate analysis maybe run using one of the other triple-spot test specimens.Calculate the grams of tin stripped from the test specimen fromthe number of millilitres of KIO3solution used for the titration,as follows:Tin, g 5 5AB/2where:A = KIO3solut
41、ion required to titrate the samples, mL andB = tin equivalent of the KIO3solution, kg/L.9.4 Determination of LeadAfter ascertaining that all thePbCl2is in solution, remove a 100-mL aliquot from the500-mL volumetric flask (see 9.1) and place in a 400-mLbeaker. Add 10 mL of H2SO4(sp gr 1.84), cover, a
42、nd evaporateto fumes of SO3. Cool and dilute to 200 mL with water. Allowto settle and then filter on a weighed Gooch crucible, washingwith H2SO4(1 + 19). Dry and ignite at a dull red heat. Cool andreweigh. Calculate the grams of lead stripped from the testspecimen, as follows:Lead, g 5 5A 2 B! 3 0.6
43、831where:A = weight of Gooch crucible and ignited precipitate, andB = weight of Gooch crucible.10. Calculation10.1 Weight of CoatingCalculate the weight of coating inounces per square foot as follows:Weight of coating 5 A 2 Bwhere:A = loss in weight of specimen, g (see Section 8), andB = iron stripp
44、ed from the test specimen (see 9.2), when aspecimen of 5.08 in.2(3277 mm2) in area is used, g.For specimens of other sizes, a suitable correctionfactor must be applied.10.2 Percent of Tin in CoatingCalculate the percent of tinin the coating as follows:Tin, % 5 T/ T 1 L!# 3 100where:T = tin stripped
45、from the test specimen (see 9.3), g andL = lead stripped from the test specimen (see 9.4), g.10.3 Percent of Lead in CoatingCalculate the percent oflead in the coating by subtracting the percentage of tin from100 %.11. Precision and Bias11.1 Due to the limited number of laboratories participatingin
46、the cooperative testing of this procedure, a precisionstatement conforming to the requirements of Practices E 173cannot be furnished. Comparison of the percent tin found bythe three cooperating laboratories (Table 1) with the known tinvalue in the samples indicates that the sulfuric acid procedure(P
47、rocedureA) yields high tin results. It is therefore advised thatcaution be exercised when reporting percent tin values ob-tained using the sulfuric acid method. The weight of coatingresults (Table 2) generally agreed to within 0.01 oz/ft2betweenreplicate samples and between different laboratories.PR
48、OCEDURE DSTRIPPING WITHHYDROCHLORIC ACID AND ANTIMONYTRICHLORIDE12. Reagent12.1 Antimony Trichloride-Hydrochloric Acid SolutionDissolve approximately 40 g of SbCl3in HCl (sp gr 1.19) anddilute to 1 L with the HCl.13. Procedure for Stripping13.1 After cleaning as described in 6.3, weigh each testspec
49、imen separately to the nearest 0.001 g. Immerse in the coldSbCl3-HCl solution until the coating is removed and all actionceases. The reaction will leave the specimen coated withantimony. Wash thoroughly to remove the loosely adherentantimony, dry, and reweigh. The loss in weight in grams is theweight of coating in ounces per square foot of sheet when aspecimen of 5.08 in.2(3277 mm2) in area is used. For speci-mens of other sizes a suitable correction factor must be applied.TABLE 1 Tin DeterminationSampleAssumed TinValueASulfuric Acid Method (Proced
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