1、Designation: D7667 10Standard Test Method forDetermination of Corrosiveness to Silver by AutomotiveSpark-Ignition Engine FuelThin Silver Strip Method1This standard is issued under the fixed designation D7667; the number immediately following the designation indicates the year oforiginal adoption or,
2、 in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the corro-siveness to silver by aut
3、omotive spark-ignition engine fuel (forexample, gasoline), as defined by Specification D4814 orsimilar specifications in other jurisdictions, having a vaporpressure no greater than 124 kPa (18 psi) at 37.8C (100F) byone of two procedures.1.1.1 Procedure AInvolves the use of a pressure vessel.1.1.2 P
4、rocedure BInvolves the use of a vented test tube.1.2 The values stated in SI units are to be regarded as thestandard. The values in parentheses are for information only.1.3 WARNINGMercury has been designated by manyregulatory agencies as a hazardous material that can causecentral nervous system, kid
5、ney and liver damage. Mercury, orits vapor, may be hazardous to health and corrosive tomaterials. Caution should be taken when handling mercury andmercury containing products. See the applicable product Ma-terial Safety Data Sheet (MSDS) for details and EPAswebsitehttp:/www.epa.gov/mercury/faq.htmfo
6、r addi-tional information. Users should be aware that selling mercuryand/or mercury containing products into your state or countrymay be prohibited by law.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of
7、this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D130 Test Method for Corrosiveness to Copper from Pe-troleum Products by Copper Strip TestD3241 Test Method for Therm
8、al Oxidation Stability ofAviation Turbine FuelsD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum ProductsD4814 Specification for Automotive Spark-Ignition EngineFuelE1 Specification for ASTM Liquid-in-Glass Thermomete
9、rs2.2 Energy Institute Standards:3IP 227 Determination of Corrosiveness to Silver of AviationTurbine Fuels - Silver Strip Method2.3 ASTM Adjuncts:4Color standard for tube deposit rating (5 aluminum strips)3. Terminology3.1 Abbreviations:PTFE = polytetrafluoroethylenePV = pressure vesselPVP = pressur
10、e vessel procedureSSCD = silver strip centering deviceTSMD = temperature sensing and monitoring deviceVTTP = vented test tube procedure4. Summary of Test Method4.1 A polished, thin silver strip is immersed in 30 mL of thesample being tested, and heated at 50C (122F) for 2 h. At theend of the heating
11、 period, the silver strip is removed, washed,and the color and tarnish level assessed against the Silver StripClassifications in Table 1.5. Significance and Use5.1 Crude petroleum contains sulfur compounds, most ofwhich are removed during refining. However, of the sulfurcompounds remaining in the pe
12、troleum product or introducedinto the fuel during storage and distribution, some can have acorroding action on various metals and this corrosivity is notnecessarily related directly to the total sulfur content. Theeffect can vary according to the chemical types of sulfur1This test method is under th
13、e jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.05.0C on Color and Reactivity.Current edition approved Oct. 1, 2010. Published December 2010. DOI:10.1520/D766710.2For referenced ASTM standards, visit the ASTM website, www.a
14、stm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,U.K., http:/www.energyinst.org.uk.4Available from
15、ASTM International Headquarters. Order Adjunct No.ADJD3241. Original adjunct produced in 1986.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United Spounds present. The silver strip corrosion test is designedto assess the relative degree of corro
16、sivity of a petroleumproduct towards silver and silver alloys.5.2 Under some circumstances, reactive sulfur compoundspresent in automotive spark-ignition engine fuels can tarnish oreven corrode silver alloy fuel gauge in-tank sender units orsilver-plated bearings (in 2-stroke cycle engines). To mini
17、mizeor prevent the failure of silver alloy in-tank sender units bytarnish or corrosion, Specification D4814 requires that fuelsshall pass a silver strip corrosion test.6. Apparatus6.1 Silver Strip Corrosion Pressure Vessel (Procedure A),constructed from stainless steel according to dimensions giveni
18、n Fig. 1, as described in Test Method D130. The vessel shallbe capable of withstanding a test pressure of 700 kPa (100 psi).Alternative designs for the vessels cap and synthetic rubbergasket may be used provided that the internal dimensions of thevessel are the same as shown in Fig. 1, which allow a
19、 nominal25 by 150 mm (1 by 6 in.) test tube (see 6.2) and the SSCD (see6.4) to be placed inside the pressure vessel.6.2 Test Tubes, of borosilicate glass of nominal 25 by150 mm (1 by 6 in.) dimensions, preferably graduated at 30 mLvolume.5,6The internal dimensions shall be checked as accept-able by
20、use of a silver strip (see 7.4). When 30 mL of sampleis added to the test tube with the silver strip in it, a minimumof 5 mm of liquid shall be above the top surface of the strip.6.3 Test Bath, General, whether liquid or solid, the test bathshall be able to maintain the test temperature to within 61
21、C(2F) of the required test temperature. It is recommended thatbaths be placed inside a fume-hood.6.3.1 Bath, shall be fitted with suitable supports to hold eachtest tube (see 6.2) in a vertical position to a depth of about 100mm (4 in.) as measured from the bottom of the test tube to thebath surface
22、.6.3.2 Bath Medium, as a liquid bath medium, both water andoil have been found to be satisfactory and controllable at thespecified test temperature and duration required by the testprocedure.5The sole source of supply of the apparatus known to the committee at this timeis Quark Enterprises, Inc., 32
23、0 Morton Ave., Rosenhayn, NJ 08352.6If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.TABLE 1 Silver Strip Classific
24、ationsNOTEAcknowledgementThis table has been reproduced from Standard IP 227.Classification Designation Description0 No Tarnish Identical to a freshly-polished strip but may have some very slightloss of luster1 Slight Tarnish Faint brown or white discoloration of strip (see 12.2)2 Moderate Tarnish P
25、eacock colors such as blue or mauve or medium/dark straw orbrown coloration (see 12.2)3 Slight blackening Spots and patches of black or gray on surface or uniform thin film ofblack deposit4 Blackening Uniform heavy blackening with or without scalingFIG. 1 Pressure Vessel for Silver Strip Corrosion T
26、est Procedure AD7667 1026.3.3 Solid Block Bath, made of aluminum, shall meet thetest temperature control, test duration, and immersion condi-tions required by the test procedure, and shall be verified, atleast annually, for temperature measurement (heat transfer) byrunning tests on tubes filled with
27、 30 mL of product plus a thinsilver strip of the given nominal dimensions, plus a tempera-ture sensor.6.3.3.1 Wells provided in the solid block bath to accommo-date pressure vessels (see Fig. 1) shall be of the followingdimensions: 54 mm (218 in.) diameter from top, up to a depthof 70 mm (234 in.) c
28、ontinuing with an opening of 38 mm(112 in.) diameter up to a depth of 140 mm (512 in.). Anopening of 8 mm (516 in.) diameter by 210 mm (814 in.)depth shall be provided in the center of the block for immersionof a metal temperature sensor (connected to a suitable 50 61C (122 6 2F) temperature control
29、ler), or thermometer (see6.5).6.3.3.2 Wells provided in the solid block bath to accommo-date test tubes shall be of the following dimensions: 20 mm(1116 in.) diameter by 140 mm (512 in.) deep. An opening of8 mm (516 in.) diameter by 210 mm (814 in.) depth shall beprovided in the center of the block
30、for immersion of a metaltemperature sensor (connected to a suitable 50 6 1C (122 62F) temperature controller), or thermometer (see 6.5).6.3.3.3 Provide insulation made of 25.4 mm (1.0 in.) thickfiberglass with aluminum backing (or, similar insulation) tocover all the four sides of the solid block ba
31、th.6.4 Silver Strip Centering Device (SSCD),6,7made of ma-terial which is gasoline-compatible at 50C (122F) for theduration of the test, such as Acetal Resin, White Nylon 6/6, orPTFE. See details in A1.1(Assembly View) and A1.2 (Indi-vidual Parts View). Length of SSCD inside the test tube is suchtha
32、t the lower edge of the assembled silver strip is about 22 mm(78 in.) from the bottom of the test tube.6.5 Temperature Sensing and Monitoring Device (TSMD),capable of sensing and monitoring the desired test temperaturein the bath to within an accuracy of 61C (2F). The ASTM12C (12F) (see Specificatio
33、n E1) or IP 64C (64F) totalimmersion thermometer has been found suitable for use in thetest. If used, no more than 10 mm (0.4 in.) of the mercury shallextend above the surface of the bath at the test temperature.6.6 Timing Device, electronic or manual, capable of accu-rately measuring the test durat
34、ion within the allowable toler-ance.6.7 Forceps, with inert tips, stainless steel or polytetrafluo-roethylene (PTFE) tips, have been found suitable for use inhandling the silver strips.6.8 Polishing Board,150by100by3mm(6by4by18 in.)solid plastic piece having a smooth surface, for placement ofsilver
35、strip during polishing.6.9 Optional Equipment:6.9.1 Refrigerator, for cooling samples below 5C (41F)during storage.7. Reagents and Materials7.1 Wash Solvent, 2,2,4-trimethylpentane (iso-octane) ofminimum 99.75% purity. (WarningExtremely flammable,see 8.1.)7.2 Surface Preparation/Polishing Material,
36、Scouring-pad,approximately 400-grit, made of polyester material that is freeof detergents or spongy material, containing aluminum oxideas a scouring-aid.6,8NOTE 1Some 400-grit pads are commercially available in the form of229 by 152 by 9.5 mm (9 by 6 by38 in.) thick pads. For ease of handlingand pol
37、ishing, it is recommended that the pads be cut so that thedimensions of the scouring-pads are about 114 by 38 by 9.5 mm ( 412 by112 by38 in.).7.3 Waterproof Aluminum Oxide Cloth Sanding Sheets orRolls,6,9150-grit.7.4 Silver Strips, Use strips 36.0 to 40.0 mm (1716 to 1916in.) long, 6.25 to 6.35 mm (
38、1564 to14 in.) wide and 0.526 to0.541 mm ( 13564 in.) thick, assaying at 99.9% (m/m) Agminimum.6,10When necessary, cut, straight and smooth, usinga sharp tin-snip or any other metal-cutting device, (such as aheavy-duty 152 mm (6 in.) shear6,11) approximately 38.0 mm(112 in.) long strips from the lon
39、ger strips supplied. Strips maybe used repeatedly, but should be discarded when the originalshape becomes deformed, or surface shows pitting, scratches ortarnish that cannot be removed by the specified polishingprocedure.7.5 Ashless Filter Paper or Disposable Gloves or Finger-Tip Protectors, for use
40、 in protecting the silver strip fromcoming in contact with the individual during polishing.8. Hazards8.1 Wash Solvent.(Warning iso-octane: Harmful if in-haled. Vapors may cause flash fire. Keep away from heat,sparks and open flames, and container closed. Use withadequate ventilation. Avoid build-up
41、of vapors and eliminateall sources of ignition, especially non-explosion-proof electri-cal apparatus and heaters. Avoid prolonged breathing of vaporor spray mist.)8.2 Gasoline, (Unleaded or Leaded).(WarningKeepaway from heat, sparks and open flames, and container closed.Use with adequate ventilation
42、. Avoid build-up of vapors andeliminate all sources of ignition, especially non-explosion-proof electrical apparatus and heaters. Avoid prolonged breath-ing of vapor or spray mist. Avoid prolonged or repeated skincontact.)8.3 Pressure Vessel, heat and pressure will be built-up in thepressure vessel
43、during the test. After the test, cool anddepressurize pressure vessel carefully and fully before openingit for inspection of the silver strip.7The sole source of supply of the apparatus known to the committee at this timeisK the test Procedure, A or B; test duration, minutes; andtest temperature, de
44、grees Celsius, in the following format:Corrosion, silver strip, by D7667, Procedure A or B, X at Y: Z (1)where:X = test duration, in minutes,Y = test temperature, C, andZ = classification category (that is 0, 1, 2, 3 or 4).14. Precision and Bias14.1 PrecisionThe precision of this test method has not
45、been determined.NOTE 5In the case of results which consist of a rating on a non-linearscale, no generally accepted method for determining precision or bias iscurrently available.14.2 BiasThe procedure in this test method has no biasbecause the results of silver corrosion are defined only in termsof
46、this test method.15. Keywords15.1 automotive gasoline; corrosiveness to silver; silvercorrosion; silver stripANNEX(Mandatory Information)A1. SILVER STRIP CENTERING DEVICE (SSCD)A1.1 Assembly ViewA1.1.1 See Fig. A1.1.A1.2 Individual Parts ViewA1.2.1 See Fig. A1.2.D7667 105NOTEMATERIAL: ALL PARTS - GA
47、SOLINE COMPATIBLE AT 50C (122F) for 2-3 H/TEST SUCH AS ACETAL RESIN, WHITE NYLON 6/6OR PTFE.FIG. A1.1 Assembly ViewD7667 106NOTEMATERIAL: ALL PARTS - GASOLINE COMPATIBLE AT 50C (122F) for 2-3 H/TEST SUCH AS ACETAL RESIN, WHITE NYLON 6/6OR PTFE.All dimensions are in millimetres.FIG. A1.2 Individual P
48、arts ViewD7667 107ASTM International takes 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 o
49、f such rights, are entirely 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 standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may at
