ASTM_D_1275_-_03.pdf

Designation:D 1275 03315/98Standard Test Method forCorrosive Sulfur in Electrical Insulating Oils1This standard is issued under the fixed designation D 1275;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 parentheses indicates the year of last reapproval.Asuperscript epsilon(e)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 was adopted as an ASTM-IP Standard.1.Scope1.1 This test method describes the detection of corrosivesulfur compounds(both inorganic and organic)in electricalinsulating oils of petroleum origin.1.2 Mineral insulating oils may contain substances thatcause corrosion under certain conditions of use.This testmethod is designed to detect the presence of free sulfur andcorrosive sulfur compounds by subjecting copper to contactwith oil under prescribed conditions.1.3 The values stated in inch-pound units are to be regardedas the standard.SI units are included for informational pur-poses.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.Referenced Documents2.1 ASTM Standards:D 130 Test Method for Detection of Copper Corrosion fromPetroleum Products by the Copper Strip Tarnish Test2E 11 Specification for Wire-Cloth and Sieves for TestingPurposes32.2Other Document:ANSI B74.10 Grading of Abrasive Microgrits43.Significance and Use3.1 In most of their uses,insulating oils are continually incontact with metals that are subject to corrosion.The presenceof corrosive sulfur compounds will result in deterioration ofthese metals.The extent of deterioration is dependent upon thequantity and type of corrosive agent and time and temperaturefactors.Detection of these undesirable impurities,even thoughnot in terms of quantitative values,is a means for recognizingthe hazard involved.4.Apparatus4.1 BathA hot-air oven or oil bath provided with suitablemeans of heating to,and controlling at,140 6 2C.Acirculating hot-air oven is preferred.4.2 ContainersNarrow-mouth,250-mL,ground-glassstoppered flasks,of chemically resistant glass,capable ofholding 270 to 280 mL when filled completely to the stopper.Flasks of such capacity are required in order to allow sufficientspace for expansion of the oil.4.3 Copper Foil,99.9+%pure,0.127 to 0.254 mm(0.005to 0.010 in.)in thickness.4.4 Polishing Material,consisting of 240-grit silicon car-bide paper or cloth,and also 230-mesh silicon carbide grainsand pharmaceutical absorbent cotton.NOTE1It should be noted that 240-grit silicon carbide paper and230-mesh silicon 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,cp.5.2 Nitrogen GasCommercial cylinders of nitrogen gasare satisfactory for this purpose.6.Preparation of Apparatus6.1 Chemically clean flasks with solvents to remove oil,then wash the flasks with phosphate-type cleaning powder orliquid.Rinse with tap water,then with distilled water,and dryin an oven.6.2 Cut a strip of copper 6 by 25 mm(14by 1 in.)(Note 2)and remove blemishes from surfaces with the 240-grit siliconcarbide paper.Strips may be stored in sulfur-free acetone at this1This test method is under the jurisdiction of ASTM Committee D27 onElectrical Insulating Liquids and Gases and is the direct responsibility of Subcom-mittee D27.06 on Chemical Tests.Current edition approved March 10,2003.Published May 2003.Originallyapproved in 1953.Last previous edition approved in 1996 as D 1275 96a.2Annual Book of ASTM Standards,Vol 05.01.3Annual Book of ASTM Standards,Vol 14.02.4Available from American National Standards Institute,25 W.43rd St.,4thFloor,New York,NY 10036.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.point for future use.Do the final polishing of the strip byremoving it from the acetone,holding it in the fingers protectedwith ashless filter paper,and rubbing with 230-mesh siliconcarbide grains picked up from a glass plate with a pad ofabsorbent cotton moistened with a drop of acetone.Wipe thestrip with fresh pads of cotton and subsequently handle onlywith stainless steel forceps(do not touch with the fingers).Rubin the direction of the long axis of the strip.Clean all metal dustand abrasive from the strip,using successive clean cotton padsuntil a fresh pad remains unsoiled.Bend the clean strip in aV-shape at approximately a 60 angle and wash successively inacetone,distilled water,and acetone.Dry in an oven for only afew minutes and immediately immerse in the