1、Designation: D1275 15315/98Standard Test Method forCorrosive Sulfur in Electrical Insulating Liquids1This standard is issued under the fixed designation D1275; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi
2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been adopted for use by government agencies to replace Method 5328-2 of Federal Test Method Standard No. 791b.This standard
3、 was adopted as an ASTM-IP Standard.This standard has been approved for use by agencies of the U.S. Department of Defense.INTRODUCTIONPrior to 2006, this test method existed as a singular method in which the main aging parameters ofthe test specimen were 19 h at 140C. In 2006, it was determined that
4、 those parameters wereinadequate (not sensitive enough to detect all levels of corrosive sulfur) and Method B was institutedin which the main aging parameters were 48 h at 150C. The old parameters were kept as Method Ato avoid any confusion. The current edition of this test method for the copper cor
5、rosion procedurereverts back to a singular method in which the main aging parameters are the same as the previousMethod B (2006-2014). Results from the current test method cannot be compared or correlated to themethod prior to 2006 and only to Method B from 2006 to 2014.1. Scope1.1 This test method
6、describes the detection of corrosivesulfur compounds (both inorganic and organic) in electricalinsulating liquids.1.2 New and in-service insulating liquids may containelemental sulfur or sulfur compounds, or both, that causecorrosion under certain conditions of use. This test method isdesigned to de
7、tect the presence of, or the propensity to form,free (elemental) sulfur and corrosive sulfur compounds bysubjecting copper or silver to contact with an insulating liquidunder prescribed conditions.1.3 The values stated in SI units are to be regarded as thestandard. Inch-pound units are included for
8、informationalpurposes.1.4 This standard does not purport to address the safetyconcerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety andhealth practices and determine the applicability of regulatorylimitations prior to use.2. R
9、eferenced Documents2.1 ASTM Standards:2D130 Test Method for Corrosiveness to Copper from Petro-leum Products by Copper Strip TestD923 Practices for Sampling Electrical Insulating LiquidsE11 Specification for Woven Wire Test Sieve Cloth and TestSieves2.2 Other Document:ANSI B74.10 Grading of Abrasive
10、 Microgrits3DIN 51 353 Testing of Insulating Oils; detection of corrosivesulfur, silver strip test43. Significance and Use3.1 In most of their uses, insulating liquids are continuallyin contact with metals that are subject to corrosion. Thepresence of elemental sulfur or corrosive sulfur compoundswi
11、ll result in deterioration of these metals and cause conductiveor high resistive films to form. The extent of deterioration isdependent upon the quantity and type of corrosive agent and1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and is
12、the direct responsibility of Subcom-mittee D27.06 on Chemical Test.Current edition approved Nov. 15, 2015. Published January 2016. Originallyapproved in 1953. Last previous edition approved in 2006 as D1275 06 which waswithdrawn January 2015 and reinstated in December 2015. DOI: 10.1520/D1275-15.2Fo
13、r referenced ASTM standards, visit the ASTM website, www.astm.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 American National Standards Institute, 25 W. 43r
14、d St., 4thFloor, New York, NY 10036, USA.4Available from Deutsches Institut fr Normung e.V.(DIN), Am DIN-Platz,Burggrafenstrasse 6, 10787 Berlin, Germany, http:/www.din.de or http:/www.bleuth.deCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United
15、 States1time and temperature factors. Detection of these undesirableimpurities, even though not in terms of quantitative values, isa means for recognizing the hazard involved.3.2 Two methods are provided, one for copper corrosion andone for silver corrosion. Copper is slightly less sensitive tosulfu
16、r corrosion than silver but the results are easier to interpretand less prone to error. The silver corrosion procedure isprovided especially for those users who have applicationswhere the insulating liquid is in contact with a silver surface.4. Apparatus4.1 BathA hot-air oven or liquid bath provided
17、 withsuitable means of heating to, and controlling at 140 or 150 62C. A circulating hot-air oven is preferred.4.2 Bottles5Heavy-walled, 250-mL, bottles of chemicallyresistant glass constructed with necks to receive a polytetra-fluoroethylene (PTFE) threaded plug equipped with a fluoro-elastomer O-ri
18、ng. Bottles of such capacity and design arerequired in order to allow sufficient space for expansion of theinsulating liquid and to eliminate intrusion from atmosphericgases. Flat bottomed bottles are preferred.4.3 Copper Foil, 99.9+ % pure, 0.127 to 0.254 mm (0.005to 0.010 in.) in thickness.4.4 Sil
19、ver Foil, 99.99+ % pure, 0.5 mm thick.4.5 Polishing Material, consisting of 240-grit silicon car-bide paper or cloth (refer to Specification E11), and also230-mesh silicon carbide grains and pharmaceutical absorbentcotton.NOTE 1It should be noted that 240-grit silicon carbide paper and230-mesh silic
20、on carbide grains have particle sizes of about the same size(63 m). In the United States, abrasive papers are classified in accordancewith ANSI B74.10. Abrasive powders are classified by ASTM mesh size.5. Reagents5.1 Acetone, ACS reagent grade.5.2 Hydrochloric AcidACS reagent grade, 36.5 to 38.0 %as
21、say.5.3 Nitrogen GasCommercial cylinders of nitrogen gasare satisfactory for this purpose.5.4 Suitable Solventtechnical grade acetone, heptane,hexane and pentane.5.5 Water, distilled.6. Summary of Test Methods6.1 Copper Corrosion220 mL of insulating liquid is agedin a sealed heavy-walled bottle for
22、48 h at 150C in thepresence of a copper strip.6.2 Silver Corrosion220 mLof insulating liquid is aged ina sealed heavy-walled bottle for 48 h at 150C in the presenceof a silver strip.7. Preparation of Apparatus7.1 Chemically clean bottles and PTFE screw plugs withsolvents to remove insulating liquid
23、residue, then wash thebottles with a suitable solvent such as heptane or hexane, or usa phosphate-type cleaning powder or liquid. Rinse with tapwater, then with distilled water, and dry in an oven. Replace thefluoro-elastomer O-ring before each test to avoid cross con-tamination.7.2 Polish a larger
24、piece of copper or silver foil from which,after the final polishing, several strips of the proper size may becut. Remove blemishes from both surfaces of the copper orsilver foils with the 240-grit silicon carbide paper. Cut a strip(s)of copper or silver foil 6 by 25 mm (14 by 1 in.). Strips may best
25、ored in sulfur-free acetone at this point for future use. Do thefinal polishing of the strip by removing it from the acetone,holding it in the fingers protected with ashless filter paper ornitrile gloves, and rubbing with 230-mesh silicon carbidegrains picked up from a glass plate with a pad of abso
26、rbentcotton moistened with a drop of acetone. Wipe the strip withfresh pads of cotton and subsequently handle only withstainless steel forceps (do not touch with fingers). Rub in thedirection of the long axis of the strip. Clean all metal dust andabrasive from the strip, using successive clean cotto
27、n pads untila fresh pad remains unsoiled. Bend the clean strip in a V-shapeat approximately a 60 angle and wash successively in acetone,distilled water, and acetone. Dry in an oven for 3 to 5 min at 80to 100C and immediately immerse the copper or silver strip inthe prepared test specimen of insulati
28、ng liquid (Note 2). Do notuse compressed air or an inert gas to dry the metal strip.NOTE 2This method of cleaning has been adapted from Test MethodD130.8. Copper Corrosion Procedure8.1 Retrieve a sample for testing in accordance with Prac-tices D923. Use the insulating liquid to be tested as receive
29、d.Do not filter the insulating liquid.8.2 Promptly place the prepared copper strip in a clean250-mL bottle to which has been added 220 mL of theinsulating liquid to be tested. Place the bent copper stripstanding on its long edge so that no flat surface lies along theglass bottom of the vessel. Bubbl
30、e nitrogen through theinsulating liquid in the bottle by means of a 1.5 mm innerdiameter (approximately116 in. inner diameter) glass orstainless steel tube connected to the reduction or needle valveof the cylinder (connections must be sulfur-free) for 5 min at arate of 0.5 L/min. Quickly screw in th
31、e PTFE plug equippedwith fluoro-elastomer O-ring (Note 3).8.3 Place the bottle with the test specimen in the oven at150C. If needed, after 15 min of heating at 150C, partiallyunscrew the PTFE plug to release the pressure and then screwit back down. Remove the bottle after heating for 48 h 6 20min at
32、 150 6 2C. Allow to cool. Carefully take the copperstrip from the bottle and wash with acetone or other suitable5The sole source of supply of the Bottles and PTF screw plugs known to thecommittee at this time is Prism Research Glass, P.O. Box 14187, Research TrianglePark, NC 27709, part number DOB-B
33、250. If you are aware of alternative suppliers,please provide this information to ASTM International Headquarters. Your com-ments will receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend. Laboratories already using bottles from AceGlass can continu
34、e.D1275 152solvent to remove all of the insulating liquid and let air dry. Donot use pressurized air to dry the copper strip.8.4 To inspect, hold the test strip in such a manner so thatlight reflected from it at an angle of approximately 45 will beobserved. Interpret and report the results as define
35、d in Sections9 and 10. If there is difficulty in determining whether thecopper strip is considered to be noncorrosive or corrosive, referto 8.5 and 8.5.1.8.5 If a specimen is borderline or unclear (between noncor-rosive and corrosive), cut the strip in half along the bentportion of the copper strip.
36、 Retain one half and treat the otherhalf as described in 8.5.1.8.5.1 Submerge the half of the copper strip completely in a1:1 solution of HCl and distilled water at room temperature andwait 20 6 2 min while gently swirling on occasion. If thedeposit in question is still present and did not fade or d
37、iscolor,then interpret and report the result as corrosive in Sections 9and 10. If the deposit has been removed or has turnedtan/beige, then corrosive sulfur is not present and the result isto be reported as noncorrosive. The tarnish level is thendetermined on the untreated portion of the copper stri
38、p. Reportthe tarnish level of the untreated portion of the copper strip aslisted in 9.1 disregarding the color on the strip that made itunclear in the initial inspection of the strip.NOTE 3The corrosive effects of unstable sulfur compounds present inthe insulating liquid are reduced when aged under
39、strong oxidizingconditions such as when oxygen is present. It is imperative to keep thebottle well sealed after nitrogen bubbling. If the insulating liquid visiblydarkens during testing then most likely oxygen has entered the test bottleand oxidized the insulating liquid. In these cases, the test pr
40、ocedure hasbecome compromised and must be repeated.9. Interpretation of Results9.1 Classify the insulating liquid as corrosive or noncorro-sive in accordance with Table 1. Classification of corrosive ornoncorrosive is to be aided through the use of ASTM CopperStrip Corrosion Standards as referenced
41、in Test Method D130.Often there are several different tarnish levels on a copper strip.In these cases, report the most tarnished classification. Adescription of the tarnish levels is provided in Table 2 forreference only.10. Report10.1 Report the following information:10.1.1 Sample identification,10
42、1.2 Test specimen as being corrosive or noncorrosive,10.1.3 Tarnish level according to Test Method D130,10.1.4 HCl treated if the strip was treated per 8.5.1, and10.1.5 This Method, Copper Corrosion.11. Silver Corrosion Procedure11.1 Using a silver strip, instead of a copper strip, repeat theinstru
43、ctions provided in 8.1 8.3.11.2 To inspect after the 48 h heating, hold the test strip insuch a manner so that light reflected from it at an angle ofapproximately 45 will be observed. Interpret and report theresults as defined in Table 3 (Note 4). If there is difficulty indetermining whether the sil
44、ver strip is considered to benoncorrosive or corrosive, refer to 11.3.11.3 On occasion, it can be difficult to accurately determinethe coloration of the silver strip and thus whether or not theinsulating liquid specimen is corrosive or noncorrosive. Inthose cases, use energy dispersive X-ray spectro
45、scopy (EDX orEDS) to determine the concentrations of silver and sulfur onthe silver strip.11.3.1 Mount the silver strip on an aluminum electronmicroscopy stub with conductive adhesive. Do not coat thesilver strip as it is already conductive. Place the silver strip intothe sample chamber and apply va
46、cuum in accordance with themanufacturers instructions.11.3.2 The following parameters have been found satisfac-tory when performing the analysis:11.3.2.1 Working distance: 19 to 30 mm.11.3.2.2 Variable pressure mode at around 30 Pa or columnvacuum at 1.7 107.11.3.2.3 Accelerating voltage: variable a
47、round 20.0 kV.11.3.2.4 Probe current: dependent on manufacturer butaround 93 A.11.3.2.5 QC on daily basis when instrument is in use, usingaluminum, copper or cobalt standards.TABLE 1 Copper Strip ClassificationsClassification DescriptionNoncorrosive Orange, red, lavender, multicolored with lavender
48、blue orsilver, or both, overlaid on claret red, silvery, brassy orgold, magenta overcast on brassy strip, multicolored withred and green showing (peacock) but no grayCorrosive Transparent black, dark gray or dark brown, graphite orlusterless black, glossy or jet black, any degree of flakingTABLE 2 C
49、opper Strip Tarnish Level Classifications, Test MethodD130Classi-ficationDesignation DescriptionFreshlyPolishedStrip. Unable to reproduce upon aging so no description isprovided1 Slight tarnish a. Light orange, almost the same as freshly polishedstrip. b. Dark orange2 Moderate tarnish a. Claret red. b. Lavender. c. Multicolored with lavender blue or silver, or both,overlaid on claret red. d. Silvery. e. Brassy or gold3 Dark tarnish a. Magenta overcast on brassy strip. b. Multicolored with red and green showing (peacock),but no gray4 Corrosion a. Tr
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