1、Designation:B95313Standard Practice forSampling Magnesium and Magnesium Alloys forSpectrochemical Analysis1This standard is issued under the fixed designation B953;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revi
2、sion.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This practice describes the sampling of magnesium andmagnesium-base alloys to obtain a chill-cast sample suitablefor quantitative a
3、tomic emission spectrochemical analysis.Thedisk in the region to be excited is representative of the melt andgives a repeatability of results that approach that of thereference materials used.1.2 This practice describes the procedure for representativesampling of molten metal.1.3 The values stated i
4、n SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.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
5、 practices and determine the applica-bility of regulatory limitations prior to use.Specific precau-tionary statements are given in 5.1.2.Referenced Documents2.1 ASTM Standards:2B954 Test Method for Analysis of Magnesium and Magne-sium Alloys by Atomic Emission SpectrometryB881 Terminology Relating t
6、o Aluminum-and Magnesium-Alloy ProductsE135 Terminology Relating to Analytical Chemistry forMetals,Ores,and Related MaterialsE1257 Guide for Evaluating Grinding Materials Used forSurface Preparation in Spectrochemical Analysis3.Summary of Practice3.1 Molten metal representative of the furnace melt i
7、spoured directly into a specified mold(described in 5.2.1)toproduce a chill-cast disk.The disk is machined to a specificdepth that represents the average melt composition and pro-duces an acceptable surface for excitation.3.2 Fabricated,cast,or wrought products may be exciteddirectly without remelti
8、ng;however,accuracy of results maysuffer in highly alloyed samples due to the potential forelemental segregation.4.Significance and Use4.1 This practice,used in conjunction with the followingquantitative atomic emission spectrochemical test method,B954,is suitable for use in manufacturing control,ma
9、terial orproduct acceptance,certification,and research and develop-ment.5.Apparatus5.1 Ladle,capable of holding a minimum of 400 g(7.7 oz)of molten metal,with a handle of sufficient length to reach intoa furnace,trough,or crucible sufficiently deep to obtain asample representative of the melt being
10、cast.The ladle may belightly coated with a tightly adhering ladle wash that will notcontaminate the sample.Boron nitride can be applied atelevated temperatures to form a tenacious coating.WarningTrace moisture in the coating or on the tool may causedangerous spattering.Preheat all sampling tools and
11、 moldsprior to use.5.2 Sample Molds,capable of producing homogeneouschill-cast disks having smooth surfaces,free of surface pocketsand porosity.These castings should have a spectrochemicalresponse similar to the reference materials used in preparingthe analytical curves and must have a repeatability
12、 fromexcitation-to-excitation of no more than 2%relative on majoralloying elements.They must be representative of the melt inthe region excited.Several types of molds have been foundacceptable:5.2.1 Type A,open cavity mold,is shown in Fig.1.Theadvantage of this mold is its simple design and ability
13、toproduce a sample disk that can be excited around the entireannular area.Mold dimensions can be modified to produce adisk size ranging from approximately 44 to 64 mm(1.75 to 2.5in.)in diameter by 10 to 15 mm(0.4 to 0.6 in.)in thickness.Acircular central recess 10 to 20 mm(0.4 to 0.8 in.)in diameter
14、1These practices are under the jurisdiction of ASTM Committee B07 on LightMetals and Alloys and are the direct responsibility of Subcommittee B07.04 onMagnesium Alloy Cast and Wrought Products.Current edition approved May 1,2013.Published June 2013.Originallyapproved in 2007.Last previous edition ap
15、proved in 2007 as B953 07.DOI:10.1520/B0953-13.2For 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.*A Summary of Chang
16、es section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 on one side of the disk(analytical side)facilitates machining ofthat side in preparation for excitation.It also promotes a moreuniform freezing of the raised peripheral area.The moldmaterial should be mild steel and should weigh approximately2 to 3 kg(4.5 to 6.5 lb).5.2.2 Type B,center pour mold,is shown in Fig.2.Theadvantage of this mold is
