ASTM G2 G2M-2006 Standard Test Method for Corrosion Testing of Products of Zirconium Hafnium and Their Alloys in Water at 680&176 F [360&176 C]or in Steam at 750&176 F [400&176 C]《.pdf

1、Designation: G 2/G 2M 06Standard Test Method forCorrosion Testing of Products of Zirconium, Hafnium, andTheir Alloys in Water at 680F 360C or in Steam at 750F400C1This standard is issued under the fixed designation G 2/G 2M; the number immediately following the designation indicates the year oforigi

2、nal 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.1. Scope1.1 This test method covers (1) the determination of massgain, and

3、(2) the surface inspection of products of zirconium,hafnium, and their alloys when corrosion tested in water at680F 360C or in steam at 750F 400C.1.2 This test method is to be utilized in its entirety to theextent specified herein as a product acceptance test.1.3 This test method may be used on wrou

4、ght products,castings, powder metallurgy products, and weld metals.1.4 Unless a single unit is used, for example corrosion massgain in mg/dm2, the values stated in either inch-pound or SIunits are to be regarded separately as standard. The valuesstated in each system are not exact equivalents; there

5、fore eachsystem must be used independently of the other. SI valuescannot be mixed with inch-pound values.1.5 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

6、 health practices and determine the applica-bility of regulatory limitations prior to use. For specificprecautionary statements, see Section 9.2. Referenced Documents2.1 ASTM Standards:2D 888 Test Methods for Dissolved Oxygen in WaterE29 Practice for Using Significant Digits in Test Data toDetermine

7、 Conformance with Specifications3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 control coupons, nzirconium alloy specimens ofknown performance used to monitor the validity of the test.3.1.2 etching, na process for removal of surface metal byaction of acids in water.3.1.3 Grad

8、e A water, npurified water having a pH of 5.0to 8.0 and an electrical resistivity of not less than 1.0 MVcm.3.1.4 Grade B water, nwater prepared with deionized ordemineralized water having a minimum electrical resistivity of0.5 MVcm.3.1.5 The stated values of pH and electrical resistivity are tobe m

9、et after the measured values are corrected to 77F 25C.3.1.6 high mass gain coupons, nzirconium alloy speci-mens that have been specially heat-treated to produce a massgain higher than the maximum specified as acceptable valueused for verifying the severity of the test.3.1.7 reagent grade, nThe grade

10、 of chemicals normallyused for analytical purposes.4. Summary of Test Method4.1 Specimens of zirconium, hafnium, or their alloys areexposed to high-pressure water or steam at elevated tempera-tures for 72 or 336 h. The corrosion is normally measured bythe gain in mass of the specimens and by the app

11、earance of theoxide film on the specimen surfaces. In some instances, such asweld evaluation, mass gain measurements are either impracti-cal to make or not required. When so specified, appearance ofthe specimen shall be the sole criterion for acceptance.5. Significance and Use5.1 This test method is

12、 primarily used as an acceptance testfor products of zirconium, hafnium, and their alloys. Thisstandard has been widely used in the development of newalloys, heat treating practices, and for evaluation of weldingtechniques.1This test method is under the jurisdiction ofASTM Committee B10 on Reactivea

13、nd Refractory Metals and Alloys and is the direct responsibility of SubcommitteeB10.02 on Zirconium and Hafnium.Current edition approved March 1, 2006. Published March 2006. Originallyapproved in 1967. Last previous edition approved in 2002 as G288(2002).2For referenced ASTM standards, visit the AST

14、M 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, Unite

15、d States.5.2 Specimens are normally tested after careful etching andrinsing. Specimens with as-manufactured surfaces may also betested without further surface removal.5.3 When tubing with a second material clad on the innersurface is to be tested, the inner cladding shall be removedprior to the test

16、.6. Interferences6.1 Autoclave loads that have one or more specimensshowing gross oxidation may affect results on other specimensin the autoclave by contamination of the environment.7. Apparatus7.1 The apparatus consists of equipment for (1) etching thespecimens when required, (2) measuring the spec

17、imen surfacearea and mass, the water resistivity and pH, test temperatureand pressure, etch and rinse temperature, and (3) performingthe water or steam corrosion test at elevated temperature andpressure.7.1.1 EtchingAn acid bath, a flowing rinse, and a deion-ized water rinse are needed for proper me

18、tal removal andstain-free rinsing. Polyethylene or polypropylene tanks arecommonly used with a bottom feed for flowing water rinses.Specimen hangers are generally made of Type 300 seriesstainless steel. When many specimens are processed, a me-chanical dipper for the etching process is useful.7.1.2 A

19、utoclaves, constructed of Type 300 series stainlesssteel or nickel base alloys such as UNS grade N06600 orN06690 and are manufactured to conform toASME (AmericanSociety for Mechanical Engineers) and government regulationsgoverning unfired pressure vessels. The autoclave is fitted withdevices for mea

20、surement and control of pressure and tempera-ture, safety devices, and venting valves. Control systems forpressure and temperature adequate to meet the requirements ofthis standard are needed. Sample holders and other internalaccessories are also constructed of Type 300 or 400 seriesstainless steel,

21、 or nickel-base alloys such as UNS gradeN06600 or N06690.NOTE 1If autoclave heating is performed in an oven, the oven and notthe autoclave will have the automatic temperature-control equipment.7.1.3 Measuring Equipment, capable of measuring speci-men dimensions to 0.002 in. 5 by 105m and a balanceca

22、pable of weighing specimens to 1 by 104g are needed.8. Reagents and Materials8.1 Argon Gas, welding grade.8.2 Grade A Water.8.3 Grade B Water.8.4 Detergents and Solvents, for specimen cleaning includ-ing reagent grade ethanol and reagent grade acetone.8.5 Hydrofluoric Acid (HF), reagent grade.8.6 Ni

23、tric Acid (HNO3), reagent grade.8.7 Sulfuric Acid (H2SO4), reagent grade.8.8 Nitrogen Gas, for purging or controlling oxygen con-tent.8.9 Argon-Hydrogen Mixed Gas, for purging or controllingoxygen content.9. Hazards9.1 The chemicals used in preparing specimens for this testare hazardous. Detailed in

24、formation on safe handling oforganic compounds, acids and products of zirconium, hafnium,and their alloys should be obtained from competent sources.9.2 High-temperature, high-pressure autoclave operationmust be in accordance with government regulations andmanufacturers instructions.9.3 Hydrogen gas

25、used for addition to the autoclave steamsupply must be handled in accordance with guidelines forexplosives and flammables.9.4 Do not add cold water directly to the autoclave vessel inorder to accelerate cooling upon completion of testing.10. Sampling, Test Specimens, and Test Units10.1 The size and

26、the quantity of the test specimens, themethod of selection, surface preparation, and test acceptancecriteria shall be specified in the product specification or byagreement between the purchaser and the seller as stated in thepurchase contract.10.2 Each specimen and control coupons shall be individu-

27、ally identified.11. Preparation of Apparatus11.1 General requirements for new or reworked autoclavesand parts of autoclaves previously used for testing materialsother than to this standard are as follows:11.1.1 Before specimens are tested in a new or reworkedautoclave, or in one having new valves, t

28、ubing, gaskets, etc.,which contact the test specimen, clean the apparatus thor-oughly, wipe with reagent grade ethanol or acetone, and rinsetwice with Grade B water. Dry the autoclave or auxiliaryequipment by vacuum cleaning or drain and wipe with a clean,lint-free cloth, and inspect carefully to en

29、sure freedom fromcontamination.There shall be no visible contamination, such aslubricant, residues, dust or dirt, loose oxides or rust, and oil orgrease film on the water surface, internal surface, gasket, orhead surfaces.11.1.2 Clean all new and reworked fixtures and jigs to beused in the autoclave

30、, rinse in hot Grade B water.Autoclave thefixtures and jigs for at least 1 day at 750F 400C in 1500 psi10.3 MPa steam or at 680F 360C in water. Inspect theparts for corrosion product. If corrosion product is found orelectrical resistivity of the residual water after the test measuresless than 0.1 MV

31、cm, the parts should be cleaned and auto-claved again.11.2 General requirements for autoclaves and parts in con-tinuous use for corrosion testing under this standard are asfollows:11.2.1 With Grade B water rinse all autoclaves, fixtures,parts, and jigs that have been in continuous use and haveshown

32、satisfactory behavior in prior tests. Inspect the fixturesand jigs for corrosion products after each test and rework andre-prepare items showing loose corrosion product.12. Calibration and Standardization12.1 High Mass Gain Coupon PreparationThese couponsshall be selected from a previously tested lo

33、t. The selectedG 2/G 2M 062material shall be heat treated to produce the desired mass gain.Heating for8hat1652 6 5F (900 6 3C and cooling to 5726 5F 300 6 3C at a rate not exceeding 6F/min 3.3C/min will normally produce the desired mass gain.12.2 Autoclaves:12.2.1 Prior to use for product acceptance

34、 testing, an auto-clave shall be profiled thermally as in 12.4.2 and shalldemonstrate acceptability by testing at least three controlcoupons, one each at the top, middle, and bottom of usefulvolume. The test results shall be incorporated in the certifica-tion document for the autoclave acceptance te

35、st. When desired,high mass gain coupons may also be used.12.2.2 Establishing Mass Gain Mean and Standard Devia-tion of Control CouponsThe control coupon lot and, whendesired, the high mass gain coupon lot mass gain mean andstandard deviation shall be established by a minimum of oneautoclave test as

36、follows:12.2.2.1 Randomly select 12 specimens from the controlcoupon lot or the high mass gain coupon lot respectively.12.2.2.2 Prepare all specimens per the pretest requirementsof this test method.12.2.2.3 Locate the 12 or 24 specimens in a fixture or jig, inaccordance with Fig. 1, and place the fi

37、xture or jig inside theuseful volume of the autoclave.12.2.2.4 Complete the steam or water corrosion test inaccordance with any one of the four methods in 14.3.12.2.2.5 Remove specimens and weigh in accordance withthe requirement of this test method.12.2.2.6 Calculate and establish the mass gain mea

38、n andstandard deviation (n-1 method) of each set of coupons for thetest method used.12.2.2.7 For product acceptance tests the mean value andstandard deviation for the control coupons may be the valueestablished in 12.2.2.6 or may be calculated periodically usingall accepted values determined over th

39、e preceding 3-monthperiod but not less than 21 values.12.2.3 An alternative method for establishing the mass gainmean and standard deviation for the control coupons which areused repeatedly is:12.2.3.1 Expose the control coupons to be used in threedifferent tests, once each in the top, middle, and b

40、ottom of anautoclave, and determine mass gain.12.2.3.2 The mean value of each control coupon is the meanfor the three tests.12.2.3.3 The standard deviation for the control coupon lot iscalculated by the (n-1) method using the data from all of thecontrol coupons taken from the same material lot.12.2.

41、4 The new or used autoclave is considered acceptableif each control coupon mass gain is reproducible within thepreviously established control coupon mean mass gain 63standard deviations.12.3 Use of Control Coupons:12.3.1 Each autoclave run used for acceptance of productshall contain at least three c

42、ontrol coupons with one at the top,one at the middle, and one at the bottom of the specimen load.12.3.2 The control coupons may be as manufactured oretched before testing, but if etched, the surfaces should exhibitno stains, pits, or areas of abnormal etching attack.12.3.3 An autoclave test is consi

43、dered acceptable only ifeach post-test control coupon mass gain is not less than theestablished mean value minus 3 standard deviations and thevisual appearance of each control coupon is equal to or betterthan the product acceptance standard. If a control couponpost-test mass gain exceeds the mean va

44、lue plus 3 standarddeviations, or the specified mass gain value, and one or moretest specimens from the corresponding location in the auto-clave failed to meet the mass gain acceptance criterion, thefailed specimen(s) may be discarded and a new test made todetermine conformance.12.3.4 Control coupon

45、s may be reused after removal ofoxide film.12.4 Calibration:12.4.1 The temperature measurement and recording systemsused to determine conformance shall be calibrated at leastevery 6 months and shall not deviate more than 65F 63Cfrom calibration standards traceable to NBS or other knownnational stand

46、ards.12.4.2 Vertical thermal profiles of the autoclaves at the testtemperatures shall be made at least once in each 6-monthperiod, or whenever the heaters or the control thermocouplesare adjusted or replaced. The axial extent of the autoclave usedfor performing the product acceptance testing shall b

47、e re-stricted to the volume shown to be within 65F 63C of therecorded autoclave temperature, after temperature compensa-tion for calibration of the thermocouples. This volume isFIG. 1 Control Coupon and High Mass Gain Coupon Positioningfor Establishing Mass Gain Mean and Standard DeviationG 2/G 2M 0

48、63considered the useful volume. The profile thermocouples maybe located at the center or near the radial extremity of theautoclave volume.12.4.3 Pressure-measuring devices shall be calibrated annu-ally and the recorded reading shall be within 650 psi60.35MPa of the calibration standard over the rang

49、e used fortesting.13. Conditioning13.1 Test Water QualityThe water used to conduct thecorrosion test shall be Grade A water and have an oxygencontent not exceeding 45 ppb. The oxygen content specifica-tion may be met either by direct measurement using theappropriate method in Test Methods D 888 or by the use ofVenting Method A or B of 14.3.13.2 Autoclave Load RestrictionsThe surface area ofspecimens loaded in a static autoclave shall not exceed 0.1m2/L of autoclave volume.13.3 Test Conditions:13.3.1 Temperature