ASTM_G_202_-_12_2016.pdf

Designation:G20212(Reapproved 2016)Standard Test Method forUsing Atmospheric Pressure Rotating Cage1This standard is issued under the fixed designation G202;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()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers a generally accepted procedureto conduct the rotating cage(RC)experiment under atmo-spheric pressure.1.2 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.3 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 establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2D1141 Practice for the Preparation of Substitute OceanWaterD1193 Specification for Reagent WaterD1293 Test Methods for pH of WaterE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodG1 Practice for Preparing,Cleaning,and Evaluating Corro-sion Test SpecimensG16 Guide for Applying Statistics to Analysis of CorrosionDataG31 Guide for Laboratory Immersion Corrosion Testing ofMetalsG46 Guide for Examination and Evaluation of Pitting Cor-rosionG170 Guide for Evaluating and Qualifying Oilfield andRefinery Corrosion Inhibitors in the LaboratoryG184 Practice for Evaluating and Qualifying Oil Field andRefinery Corrosion Inhibitors Using Rotating Cage3.Significance and Use3.1The rotating cage(RC)test system is relatively inex-pensive and uses simple flat specimens that allow replicates tobe run with each setup.(1-11).33.2 The RC method can be used to evaluate either corrosioninhibitors,or materials,or both.Guide G184 describes theprocedure to use rotating cage to evaluate corrosion inhibitors.3.3 In this test method,a general procedure is presented toobtain reproducible results using RC to simulate the effects ofdifferent types of coupon materials,inhibitor concentrations,oil,gas and brine compositions,temperature,and flow.Oil fieldfluids may often contain sand;however,this test method doesnot cover erosive effects that occur when sand is present.4.Apparatus4.1 Fig.1 shows the schematic diagram of the RC system.The vessel is manufactured from acrylic.At the bottom of thecontainer,a PTFE base is snugly fitted.At the center of thebase,a hole is drilled,into which the lower end of the rotatingshaft is placed.This arrangement stabilizes the rotating shaftand the coupons.The length of the rotating shaft between thetop and bottom covers is 40 cm(15.7 in.).The rotating cage isattached to the shaft in such a way that the top of the cage is30 cm(11.8 in.)from the bottom cover.4.2 Eight coupons(each of length 75 mm,width 19 mm,thickness 3 mm,and surface area 34.14 cm2)are supportedbetween two PTFE disks(of 80-mm diameter)mounted 75 mmapart on the stirring rod(Fig.2).Holes(diameter 10 mm)about15 mm away from the center are drilled in the top and bottomPTFE plates of the cage to increase the turbulence on the insidesurface of the coupon(Fig.3).This experimental setup can beused at rotation speeds up to 1000 rpm.4.3 Flow patterns inside the RC depend on the rotationspeed,the volume of the container,and the nature of the fluidsused.The flow patterns are described in Guide G170.4.4 Volume of solution to the surface area of the specimenhas some effect on the corrosion rate.The minimum solutionvolume(cm3)to metal surface area(cm2)is not less than 14 cm(cm3/cm2)(10).1This test method is under the jurisdiction of ASTM Committee G01 onCorrosion of Metals and is the direct responsibility of Subcommittee G01.05 onLaboratory Corrosion Tests.Current edition approved Nov.1,2016.Published November 2016.Originallyapproved in 2009.Last previous edition approved in 2012 as G202 12.DOI:10.1520/G0202-12R16.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The boldface numbers in parentheses refer to a list of references at the end ofthis standard.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 5.Reagents5.1 Purity of ReagentsReagent-grade chemicals shall beused in all tests.Unless otherwise indicated,it is intended thatall reagents conform to the specifications of the Committee onAnalytical Reagents of the American Chemical Society wheresuch specifications are available.4Other grades may be used,provided it is first ascertained that the reagent is of sufficientlyhigh purity to permit its use without lessening the accuracy ofthe determination.5.2 The