ASTM_E_1941_-_10.pdf

Designation:E194110Standard Test Method forDetermination of Carbon in Refractory and Reactive Metalsand Their Alloys by Combustion Analysis1This standard is issued under the fixed designation E1941;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 applies to the determination of carbonin refractory and reactive metals and their alloys in quantitiesfrom 20 g to 500 g.This corresponds to mass fractionsranging from 0.004 wt%to 0.100 wt%for a 0.5 g sample(seeNote 1).NOTE1Actual quantitative range might vary from manufacturer tomanufacturer and according to sample mass.Samples of higher mass mayallow for proportionally lower detection limits provided complete com-bustion of the sample is assured.1.2 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.Specific precau-tionary statements are given in Section 9.2.Referenced Documents2.1 ASTM Standards:2E50 Practices for Apparatus,Reagents,and Safety Consid-erations for Chemical Analysis of Metals,Ores,andRelated MaterialsE135 Terminology Relating to Analytical Chemistry forMetals,Ores,and Related MaterialsE1601 Practice for Conducting an Interlaboratory Study toEvaluate the Performance of an Analytical Method3.Terminology3.1 DefinitionsFor definitions of terms used in this testmethod,see Terminology E135.4.Summary of Test Method4.1 The metal specimen,contained in a single-use ceramiccrucible,is ignited(combusted)in an oxygen atmosphere in aninduction furnace.The carbon in the specimen is oxidized tocarbon dioxide or carbon monoxide,or both,and is eventuallycarried to the analyzer/detector.The amount of carbon presentis electronically processed and is displayed by the analyzerreadout.4.2 This test method is written for use with commerciallyavailable analyzers equipped to carry out the above operationsand calibrated using commercially available reference materi-als of known carbon content.5.Significance and Use5.1 This test method is intended to test for compliance withcompositional specifications.It is assumed that all who use thismethod will be trained analysts capable of performing commonlaboratory procedures skillfully and safely.It is expected thatthe work will be performed in a properly equipped laboratory.6.Interferences6.1 The elements ordinarily present in these alloys do notinterfere.Halides that are present in some sponge type sampleswill cause low carbon recovery.7.Apparatus7.1 Combustion Furnace and Measurement Apparatus,au-tomatic carbon determinator,consisting of an induction fur-nace;a dust/debris removal trap;an analytical gas streampurification system;an infrared detection system;and anautomatic readout(see Note 2).NOTE2Several models of commercial carbon determinators areavailable and presently in use in industry.Each has its own unique designcharacteristics and operational requirements.Consult the instrumentmanufacturers instruction manuals for operational details.7.2 Oxygen Tank and Regulator.7.3 Ceramic Crucibles and Lids,that meet or exceed theinstrument manufacturers specifications.Use of lids is op-tional.If they are used,they should have holes in them.7.4 Crucible Tongs,capable of handling recommended cru-cibles.7.5 Balance,capable of weighing to the nearest milligram.7.6 Furnace,capable of reaching and sustaining a tempera-ture of at least 700 C.1This test method is under the jurisdiction of ASTM Committee E01 onAnalytical Chemistry for Metals,Ores,and Related Materials and is the directresponsibility of Subcommittee E01.06 on Ti,Zr,W,Mo,Ta,Nb,Hf,Re.Current edition approved Dec.1,2010.Published February 2011.Originallyapproved in 1998.Last previous edition approved in 2004 as E1941 04.DOI:10.1520/E1941-10.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 8.Reagents8.1 Acetone(A.C.S.Reagent,or other suitable,degreasingreagents).8.2 Copper Accelerator,low carbon(see Note 3).8.3 High Purity Iron Chip Accelerator,low carbon(seeNote 3).8.4 Magnesium Perchlorate(Anhydrone),purity as speci-fied by equipment manufacturer.8.5 Oxygen,high purity(as specified by equipment manu-facturer).8.6 Tin Accelerator,low carbon(see Note 3).8.7 Tungsten Accelerator,low carbon(see Note 3).8.8 Sodium Hydroxide on Clay Base,commonly known asAscarite III(purity as specified by equipment manuf