1、Designation: G202 12Standard 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 p
2、arentheses 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 stat
3、ed 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 an
4、d 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 Inte
5、rlaboratory 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
6、 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 Use3.1 The rotating cage (RC) test system is relativ
7、ely 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 tes
8、t 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
9、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
10、 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.
11、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
12、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 d
13、escribed 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 M
14、etals and is the direct responsibility of Subcommittee G01.05 onLaboratory Corrosion Tests.Current edition approved Nov. 1, 2012. Published March 2013. Originallyapproved in 2009. Last previous edition approved in 2009 as G202-09. DOI:10.1520/G0202-12.2For referenced ASTM standards, visit the ASTM w
15、ebsite, 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
16、International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15. 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 onAnalytic
17、al 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 composition of the solution shall
18、 be determined andreported. Alternatively, standard brine (such as in PracticeD1141) shall be used. The solutions shall be prepared usinganalytical grade reagents and deionized water (in accordancewith Specification D1193).5.3 The solutions shall be deoxygenated by passing nitrogenor any other inert
19、 gas for sufficient time to reduce the oxygencontent below 5 ppb. The solution shall be kept underdeoxygenated conditions. The oxygen concentration in solu-tion depends on the quality of gases used to purge the solution.Any leaks through the vessel, tubing, and joints shall beavoided.5.4 WarningHydr
20、ogen sulfide (H2S) and carbon dioxide(CO2) are corrosive gases. H2S is poisonous and shall not bereleased to the atmosphere. The appropriate composition of gas4Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For Suggestions on the testing of rea
21、gents notlisted by the American Chemical Society, see Annual Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,MD.FIG. 1 Schematic Diagram of Rotating CageNOTE 1Gaps (typic
22、ally 0.85 6 0.01 cm) between the couponsintroduce localized turbulence.FIG. 2 Photo of Rotating Cage Containing CouponsG202 122can be obtained by mixing H2S and CO2streams from thestandard laboratory gas supply. Nitrogen can be used as adiluent to obtain the required composition of corrosive gases.A
23、lternatively, gas mixtures of the required compositions can bepurchased from suppliers of industrial gases. The concentra-tions of impurities, particularly oxygen, shall be kept below 5ppb.5.5 The solution pH before and after testing shall bemeasured, recorded, and reported (in accordance with TestM
24、ethods D1293).6. Test Specimens6.1 Methods for preparing specimens for tests and removingspecimens after the test are described in Practice G1. Standardlaboratory glassware shall be used for weighing and measuringreagent volumes.6.2 The coupon shall have the same metallographic struc-ture as that us
25、ed in the service components. The coupons shallbe ground to a surface finish of 150 grit. The grinding shallproduce a reproducible surface finish with no rust deposits,pits, or deep scratches. All sharp edges on the coupon shall beground. All loose dirt particles shall be removed.6.3 The coupons are
26、 rinsed with distilled water, degreasedby immersing in acetone (or any suitable alcohol), ultrasoni-cally cleaned for 1 min, and dried. The surface of thespecimens shall not be touched with bare hands. The speci-mens are weighed to the nearest 0.1 mg, the dimensions aremeasured to the nearest 0.1 mm
27、, and the surface areas arecalculated.6.4 Freshly prepared specimens are installed in the rotatingcage holder. If the test is not commenced within 4 h, theprepared coupons shall be stored in a desiccator to avoidpre-rusting.7. Procedure7.1 A detailed procedure to determine corrosion rates frommass l
28、oss is described in Practice G31.7.2 Solutions are prepared and presaturated with the experi-mental gas mixture. If the solution is prepared in a separatecontainer, it shall be transferred from the preparation vessel tothe experimental vessel under positive nitrogen pressure tominimize air contamina
29、tion during the transfer operation.7.3 The experiment shall be conducted at room temperature(21 to 24C).7.4 The pre-weighed coupons and holder (described in 4.2)are inserted into the apparatus.7.5 The lid of the apparatus is sealed such that oxygencannot leak into the system through the lid.7.6 Init
30、ially all ports of the experimental vessel (Inlet 1,Inlet 2, and outlet) are closed.Anitrogen gas (or any other inertgas) cylinder is hooked up to Inlet 2. The outlet is hooked to agas bubbler or gas trap which allows only one way flow of gas(flowing out of the apparatus). Both Inlet 2 and the outle
31、t areopened allowing the nitrogen gas to pass through the apparatus.The apparatus shall be deoxygenated by passing nitrogen for aminimum of 1 h/L of internal volume to reduce the oxygencontent below 5 ppb.7.7 Inlet 1 is hooked up to the container of the prepareddeoxygenated solution. Inlet 2 is clos
32、ed and Inlet 1 is opened.The deoxygenated solution is pumped into the apparatuswithout allowing the entry of oxygen. Inlet 1 is closed.7.8 The experimental gas mixture is hooked up to Inlet 2.Inlet 2 is opened allowing the experimental gas mixture toenter the apparatus. A continuous flow of gas shal
33、l be main-tained through the apparatus (entering Inlet 2 and exiting theNOTE 1Holes (typically 1.0 cm diameter, about 1.5 cm from the center) introduce localized turbulenceFIG. 3 Photo of Rotating Cage (Top View)G202 123outlet) throughout the experiment in order to avoid oxygencontamination. Precaut
34、ions shall be taken so that the gas doesnot entrain with the solution.7.9 The speed controller is used to set the rotation speed andstart the motor.7.10 The experiment is terminated (after 24 h), and thecorrosion rate is determined from the amount of mass loss inaccordance with Practices G1 and G31.
35、 The samples areexamined and evaluated for pitting corrosion in accordancewith Guide G46. The average, standard deviation, and coeffi-cient of variation of the coupons corrosion rate for each runshall be calculated using the method presented in Guide G16.If pitting corrosion is observed, then the ge
36、neral corrosion ratedetermined from mass loss could be invalid.8. Report8.1 All information and data shall be recorded as com-pletely as possible. Practice G31 provides a checklist forreporting corrosion data.8.2 Average corrosion rates and the standard deviation ateach rotation rate shall be report
37、ed.8.3 The following checklist is a recommended guide forreporting important information:8.3.1 Solution chemistry and concentration (any changesduring test);8.3.2 Volume of test solution;8.3.3 Volume of the experimental vessel;8.3.4 Duration of the test;8.3.5 Chemical composition or tradename of met
38、al;8.3.6 Number, form, and metallurgical conditions of speci-men;8.3.7 Exact size, shape, and area of each specimen;8.3.8 Method used to clean specimens after experiment andthe extent of any error expected by this treatment;8.3.9 Initial and final masses and actual mass losses; and8.3.10 Evaluation
39、of attack if other than general, such as pitdepth and distribution, standard deviation and coefficient ofvariation, crevice corrosion, and results of microscopicalexamination.9. Precision and Bias59.1 PrecisionThe precision of this test method was deter-mined by an interlaboratory test study, ILS, w
40、ith sevenlaboratories participating. The results of this program wereanalyzed using Practice E691. Three other laboratories submit-ted data that was found to be unsuitable for a variety ofreasons.9.1.1 RepeatabilityThe repeatability, r, (within laboratoryvariation) and the repeatability standard dev
41、iation, sr, weredetermined from the results of the seven laboratories partici-pating in the ILS. The results included in this analysis were theaverage corrosion rate based on the eight specimens in thecage, Cave, the standard deviation of these eight results, SD,and the coefficient of variation of t
42、he data set, CVr. Theseresults are summarized in Table 1.9.1.2 ReproducibilityThe reproducibility, R, (betweenlaboratory variation), the reproducibility standard deviation,sR, and the reproducibility coefficient of variation, CVR, werealso determined from the ILS. These results are summarized inTabl
43、e 2.9.1.3 BiasThis test method has no bias because the(property measured) is defined only in terms of this testmethod.10. Keywords10.1 laboratory evaluation; mass loss; rotating cage (RC)5Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Rep
44、ort RR:G01-1025. ContactASTM CustomerService at serviceastm.org.TABLE 1 Repeatability StatisticsAItem Unit Ave srrCavempy 23.1 4.7 13.3SD mpy 1.76 1.12 3.11Cavemm/yr 0.587 0.119 0.334SD mm/yr 0.045 0.028 0.079CVr% 7.7 4.9 13.7AIt should be noted that the SD and CV values cannot be negative so that t
45、helimits on these values range from zero to the sum of the average value plus therepeatability or reproducibility value.G202 124REFERENCES(1) Papavinasam, S., Revie, R. W., Attard, M., Demoz, A., Michaelian,K., “ Comparison of Laboratory Methodologies to Evaluate CorrosionInhibitors for Oil and Gas
46、Pipelines,” Corrosion , Vol 59, No. 10, Oct.2003, pp. 897-912.(2) Schmitt, G. A., Bruckhoff, W., Faessler, K., and Blummel, G., “FlowLoop Versus Rotating ProbesExperimental Results and ServiceApplications ,” CORROSION Conference 90, Paper #23, NACE,Houston, Texas, 1990.(3) Stegmann, D. W., Hausler,
47、R. H., Cruz, C. I., and Sutanto, H.,“Laboratory Studies on Flow Induced Localized Corrosion in CO2/H2S Environments: I. Development of Test Methodology,” CORRO-SION Conference 90, Paper #5, NACE, Houston, Texas, 1990.(4) Hausler, R. H., Stegmann, D. W., Cruz, C. I., and Tjandroso, D.,“Laboratory Stu
48、dies on Flow Induced Localized Corrosion in CO2/H2S Environments: II. Parametric Study on the Effects of H2S,Condensate, Metallurgy, and Flowrate,” CORROSION Conference90, Paper #6, NACE, Houston, Texas, 1990.(5) Hausler, R. H., Stegmann, D. W., Cruz, C. I., and Tjandroso, D.,“Laboratory Studies on
49、Flow Induced Localized Corrosion in CO2/H2S Enivronments: III. Chemical Corrosion Inhibition,” CORRO-SION Conference 90, Paper #7, NACE, Houston, Texas, 1990.(6) Schmitt, G. A., Bruckhoff, W., Faessler, K., and Blummel, G., “FlowLoop Versus Rotating ProbesExperimental Results and ServiceApplications ,” Materials Performance, Feb. 1991, p. 85.(7) Papavinasam, S., Revie, R. W., Attard, M., Demoz, A., Sun, H., et al,“ Laboratory Methodologies for Corrosion Inhibitor Selection,” Ma-terials Performance, Vol 39, Issue 8, Aug. 2000, pp. 58-60.(8) Ramachandran, S., Jovancice
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