ASTM E2050-2012 Standard Test Method for Determination of Total Carbon in Mold Powders by Combustion-Infrared Absorption Spectrometry《用燃烧红外线吸收法测定压型粉中碳总含量的标准试验方法》.pdf

《ASTM E2050-2012 Standard Test Method for Determination of Total Carbon in Mold Powders by Combustion-Infrared Absorption Spectrometry《用燃烧红外线吸收法测定压型粉中碳总含量的标准试验方法》.pdf》由会员分享，可在线阅读，更多相关《ASTM E2050-2012 Standard Test Method for Determination of Total Carbon in Mold Powders by Combustion-Infrared Absorption Spectrometry《用燃烧红外线吸收法测定压型粉中碳总含量的标准试验方法》.pdf（4页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: E2050 12Standard Test Method forDetermination of Total Carbon in Mold Powders byCombustion-Infrared Absorption Spectrometry1This standard is issued under the fixed designation E2050; the number immediately following the designation indicates the year oforiginal adoption or, in the case

2、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 the determination of totalcarbon in mold powders in the concentration

3、 range from 1 % to25 %.NOTE 1As used in this test method, “percentage” or “%” refers to amass fraction of the form (wt / wt %) (g/100g).1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.3 This test method has been evaluated

4、in accordance withPractice E1601 and Guide E1763. Unless otherwise noted inthe precision and bias section, the lower limit in the scope ofeach method specifies the lowest analyte content that may beanalyzed with acceptable error (defined as a nominal 5 % riskof obtaining a 50 % or larger relative di

5、fference in results onthe same test sample in two laboratories).1.4 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 appli

6、ca-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E29 Practice for Using Significant Digits in Test Data toDetermine Conformance with SpecificationsE50 Practices for Apparatus, Reagents, and Safety Consid-erations for Chemical Analysis of Metals, Ores, andRe

7、lated MaterialsE135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related MaterialsE882 Guide for Accountability and Quality Control in theChemical Analysis LaboratoryE1019 Test Methods for Determination of Carbon, Sulfur,Nitrogen, and Oxygen in Steel, Iron, Nickel, and CobaltAll

8、oys by Various Combustion and Fusion TechniquesE1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical MethodE1763 Guide for Interpretation and Use of Results fromInterlaboratory Testing of Chemical Analysis Methods3. Terminology3.1 DefinitionsFor definitio

9、ns of terms used in this testmethod, refer to Terminology E135.3.2 Definitions of Terms Specific to This Standard:3.2.1 mold powder, nin the continuous-casting of steel, ametallurgical flux used to provide lubrication of the mold,enhance heat transfer at the strand-mold interface, and providethermal

10、 insulation of the liquid metal surface to preventunwanted solidification.3.2.1.1 DiscussionKey chemical components of thesepowders are fluorides, the oxides of silicon and calcium, andcarbon.4. Summary of Test Method4.1 Carbon in the test sample is converted in a furnace to amixture of carbon dioxi

11、de and carbon monoxide by combus-tion in a stream of oxygen. Full conversion of carbon monox-ide to carbon dioxide occurs by the passage of sample gasesthrough a catalytic heater assembly. The amount of carbon1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry fo

12、r Metals, Ores, and Related Materials and is the directresponsibility of Subcommittee E01.02 on Ores, Concentrates, and Related Metal-lurgical Materials.Current edition approved Jan. 15, 2012. Published March 2012. Originallyapproved in 1999. Last previous edition approved in 2004 as E205099(2004).

13、DOI:10.1520/E2050-12.2For 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.1Copyright ASTM International, 100 Barr

14、Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.dioxide is measured by infrared absorption. Any interferencefrom halogens in the sample is eliminated by placement of ahalogen trap between the furnace and the analyzer.5. Significance and Use5.1 This test method for the dete

15、rmination of total carbon inmold powders is primarily intended to test such materials forcompliance with compositional specifications. It is assumedthat all who use this test method will be trained analystscapable of performing common laboratory procedures skill-fully and safely. It is expected that

16、 the work will be performedin a properly equipped laboratory and that proper wastedisposal procedures will be followed. Appropriate qualitycontrol practices must be followed such as those described inGuide E882.6. Rounding Calculated Values6.1 Calculated values shall be rounded in accordance withPra

17、ctice E29.7. Interferences7.1 Halogens, normally present in mold powders as fluoride,will interfere with this test method. A halogen trap, asdescribed in 8.4, must be installed in the measure line betweenthe furnace and analyzer to prevent this interference.8. Apparatus8.1 Combustion-Infrared Absorp

18、tion Carbon Analyzer,equipped with a combustion chamber, oxygen carrier stream,halogen trap, catalytic heater assembly, and infrared absorptiondetector, suitable for the analysis of carbon from 1 % to 25 %in mold powders. Instruments, such as those in Test MethodsE1019, which can be shown to give eq

19、uivalent results may alsobe used for this test method.8.2 CruciblesUse ceramic crucibles that meet or exceedthe specifications of those recommended by the manufacturerof the instrument.8.3 Crucible Tongs, capable of handling recommended cru-cibles.8.4 Halogen (Fluorine/Chlorine) Trap3, available fro

20、m theinstrument manufacturer as a kit, consisting of the parts andnecessary reagents for assembly. Follow the manufacturersinstructions for the assembly, installation, use, and propermaintenance of the trap.8.5 Metal Scoop, for dispensing metal chips.9. Reagents and Materials9.1 Iron Chip, high puri

21、ty (6 mesh to +20 mesh).9.2 Oxygen, 99.5 % purity recommended. Other grades ofoxygen may be used if low and consistent blank readings areobtained.9.3 Tungsten/Tin Accelerator, high purity.NOTE 2Copper chip accelerator (20 mesh to +30 mesh) may be usedin place of Tungsten/Tin.10. Hazards10.1 For prec

22、autions to be observed in the use of reagentsand apparatus in this method, refer to Practices E50 and TestMethods E1019.10.2 Use care when handling hot crucibles and whenoperating furnaces to avoid personal injury by either burn orelectrical shock.11. Sampling and Sample Preparation11.1 Materials Sa

23、fetySamples must be prepared, stored,and disposed of in accordance with the materials and safetyguidelines in Practices E50.11.2 Prepared SamplePulverize or grind the laboratorysample until 100 % passes a No. 100 (150-m) sieve. Store ina suitable glass or plastic container.12. Preparation of Apparat

24、us12.1 Test the furnace and analyzer to ensure the absence ofleaks. Prepare the analyzer for operation in accordance with themanufacturers instructions.13. Calibration13.1 Calibration Reference MaterialsTungsten carbide(6.10 % total carbon), NIST SRM 276b, or equivalent; siliconcarbide (29.43 % tota

25、l carbon), NIST SRM 112b, or equivalent(Note 1).13.2 Determination of Blank:13.2.1 Enter 1.000-g weight into the weight stack, followingthe instrument manufacturers recommended procedure.13.2.2 Add 1.000 6 0.005 g of accelerator and 1.000 60.005 g of iron chip to the crucible.13.2.3 Place the crucib

26、le on the furnace pedestal and ana-lyze in accordance with the manufacturers instructions.13.2.4 Repeat 13.2.1-13.2.3 a minimum of three times.3Fluorine/Chlorine Trap Kits, available from the LECO Corp., 3000 LakeviewAvenue, St. Joseph, Michigan 49085, +1-269-982-5497, http:/ havebeen found satisfac

27、tory for this purpose. Part number 769-741-HAZ (for olderLECO instruments) and Part number 617-249-HAZ (for newer LECO instruments)were available on 01 April 2011.TABLE 1 Statistical Information, Carbon Combustion/Infrared MethodTest Material Number ofLaboratoriesCarbon Found, % Minimum SD (SM,E1601

28、)Reproducibility SD,(Sg, E1601)Reproducibility Index(R, E1601)Rrel%B 7 1.2046 0.00601 0.02960 0.08288 6.88A 7 3.1219 0.01269 0.04843 0.13559 4.34C 7 6.5514 0.04774 0.09215 0.25803 3.94D 7 10.5121 0.05788 0.10579 0.29620 2.82E 7 15.1121 0.04964 0.14730 0.41244 2.73F 7 19.7121 0.11949 0.25294 0.70824

29、3.59G 7 29.4250 0.38830 0.60179 1.6850 5.73E2050 12213.2.5 Enter the average blank following the routine out-lined in the manufacturers instruction manual.13.3 Calibration Procedure:13.3.1 Weigh approximately 0.25 g of tungsten carbidecalibration reference material into a ceramic crucible and entert

30、he weight into the weight stack, following the instrumentmanufacturers recommended procedure.13.3.2 Add 1.000 g 6 0.005 g of accelerator and 1.000 g 60.005 g of iron chip to the crucible.13.3.3 Place the crucible on the furnace pedestal and ana-lyze in accordance with the manufacturers instructions.

31、13.3.4 Repeat 13.3.1-13.3.3 a minimum of three times andcalibrate the instrument following the calibration procedure inaccordance with the manufacturers instruction manual.13.3.5 Verify the calibration by analyzing the calibrationreference material again. The obtained value shall agree withthe certi

32、ficate value within the range given by the publisheduncertainty or it shall agree within the limits of a predictioninterval calculated using Eq 1. The prediction interval isdefined as the range of values bounded by the analysis value -pand the analysis value +p. If the prediction interval does noten

33、compass the certified value, determine and correct the cause,and repeat calibration (Note 3). Either acceptance limit crite-rion is acceptable for routine operation.NOTE 3See the instrument manufacturers instructions concerning thetroubleshooting and correcting of errant calibration.p 5 t *S1 11=nD*

34、 s (1)where:p = one-half the prediction interval,n = number of replicates used in 13.3.4,t = students t chosen for the 95 % confidence level for nreplicate measurements (for example: t = 4.30 when n= 3; 3.18 when n = 4; 2.78 when n = 5), ands = standard deviation of n replicates in 13.3.4 (Note 4).N

35、OTE 4Here, s should be comparable to Sm, the repeatability standarddeviation, given in Table 1.Ifs much greater than Sm, there is evidencethat the repeatability of the particular instrument is not acceptable for usewith this test method. The user should determine and correct the cause,and repeat 13.

36、3.4 through 13.3.5.13.3.6 Verify linearity of the instrument response by ana-lyzing a silicon carbide certified (29.43 % total carbon) certi-fied reference material. Results should fall within the uncer-tainties of the certificate value expected tolerance. If not,identify and correct the problem bef

37、ore proceeding with theanalysis of samples (Note 1).14. Procedure14.1 Assemble the apparatus and condition it in accordancewith Section 12.14.2 Sample Analysis:14.2.1 Weigh, to the nearest 0.1 mg, an appropriate mass ofsample into a ceramic crucible, in accordance with the follow-ing:Carbon, % Appro

38、ximate Sample Mass, g1 - 6 0.256 - 10 0.2010 - 20 0.1520 - 25 0.075Enter the sample mass into the mass stack, following theinstrument manufacturers recommended procedure.14.2.2 Add 1.000 g 6 0.005 g of accelerator and 1.000 g 60.005 g of iron chip to the crucible.14.2.3 Place the crucible on the fur

39、nace pedestal and ana-lyze.14.2.4 Analyze each sample in duplicate, recording eachvalue.14.2.5 Check instrument calibration (see 13.3.5) after every2 sets of duplicate sample runs.15. Calculation15.1 Most commercially available instruments calculate thetotal carbon content directly, including correc

40、tions for blankand sample weight, so calculations by the analyst are notrequired. If, however, the analyzer does not compensate forblank and sample values, then use the following formula:Carbon, % 5A B! 3 CD(2)where:A = DVM reading for sample,B = DVM reading for blank,C = weight compensator setting,

41、 andD = sample weight, g.15.2 Round the results and report to 2 decimal places forvalues less than 10 % carbon, and to 1 decimal place for valuesequal to or greater than 10 % carbon. Examples: 4.15 %,15.6 % (Note 1).16. Precision and Bias416.1 PrecisionSeven laboratories cooperated in testingthis te

42、st method.Table 1 summarizes the precision information.4A research report is available from ASTM International headquarters. RequestRR:E01-1029.TABLE 2 Predicted Reproducibility at Various Carbon ContentsCarbon, % RRref%0.5 0.079 15.71.0 0.083 8.32.0 0.109 5.45.0 0.178 3.610.0 0.329 3.320.0 0.645 3.

43、2E2050 123Table 2 displays the reproducibility expected for results at anumber of carbon values.16.2 BiasThe accuracy of this test method could not beevaluated because certified reference materials of mold pow-ders were unavailable. Table 3 compares the means from thistest method with results on the

44、 same materials by thecombustion/gravimetric carbon test method. The differencesshow that the combined bias of both test methods does notexceed 60.1 % carbon (Note 1).17. Keywords17.1 carbon; combustion; infrared absorption spectrometry;mold powdersASTM International takes no position respecting the

45、 validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is

46、 subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Hea

47、dquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This st

48、andard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or

49、serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).TABLE 3 Comparison Between IR and Gravimetric CarbonTest Material IR Carbon, % GravimetricCarbon, %IR - GravimetricCarbon, %B 1.205 1.30 0.095A 3.122 3.17 0.048C 6.551 6.57 0.019D 10.512 10.51 0.002E 15.112 15.07 0.042F 19.712 19.60 0.112E2050 124