1、Designation: E 1306 07Standard Practice forPreparation of Metal and Alloy Samples by Electric ArcRemelting for the Determination of Chemical Composition1This standard is issued under the fixed designation E 1306; the number immediately following the designation indicates the year oforiginal adoption
2、 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 practice covers the preparation of solid samples ofreactive and refrac
3、tory metals and alloys by electric arcremelting. The samples for melting may be in the form ofchips, turnings, wires, and sponge. Powdered metals need to becompacted before melting.1.1.1 This practice is also suitable for preparation of solidsamples of other metals, such as steels, stainless steels,
4、 toolsteels, nickel, nickel alloys, cobalt, and cobalt alloys by electricarc remelting.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
5、and determine the applica-bility of regulatory limitations prior to use. Specific hazardstatements are given in Section 9.2. Referenced Documents2.1 ASTM Standards:2E 135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related Materials3. Terminology3.1 DefinitionsFor definitions o
6、f terms used in this prac-tice, refer to Terminology E 135.4. Summary of Practice4.1 Metal chips, turnings, or wires are melted into a buttonapproximately 114 in. in diameter and approximately14-in.thick using an electric arc furnace. The action of the arc createsagitation and mixing of the molten m
7、etal which produces ahomogeneous sample.5. Significance and Use5.1 This sampling practice is useful for converting chips,turnings, and wires taken from ingots or other solid materialsinto a homogeneous solid sample suitable for direct excitationon an optical emission or X-ray fluorescence spectromet
8、er. Theresultant button may itself be chipped to provide samples forplasma emission, atomic absorption, and wet chemical analy-sis.5.2 This practice has been used extensively for the prepa-ration of zirconium, zirconium alloy, titanium, and titaniumalloy materials, and is applicable to other reactiv
9、e, refractory,ferrous and nonferrous alloys, such as cobalt, cobalt alloys,columbium (niobium), nickel, nickel alloys, stainless steels,tantalum, tool steels, and tungsten.6. Interferences6.1 Test samples of known composition shall be used todetermine if there is any selective volatilization or segr
10、egationof the impurity elements. Elements known to volatilize arebismuth, cadmium, chlorine, lead, magnesium, sodium, tellu-rium, thallium, uranium, and zinc. Other elements that maychange in content are the interstitial gases, oxygen, nitrogen,and hydrogen, plus carbon, which may be added due to th
11、egraphite anode. A tungsten anode may be substituted if carbonpickup is a concern. Tungsten contamination may occur if thiselectrode is used. Copper contamination also may be intro-duced from the melting crucible.7. Apparatus7.1 Electric Arc Remelt FurnaceAn apparatus suitable forthis practice is sh
12、own schematically in Fig. 1.3It shall beequipped as follows:7.1.1 Water-Cooled Upper Housing (1), approximately 6-in.diameter and 614 in. high, and having a smooth, flat sealingsurface.1This practice is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for Metals, Ores and Related
13、Materials and is the direct responsibility ofSubcommittee E01.20 on Fundamental Practices.Current edition approved Jan. 15, 2007. Published January 2007. Originallyapproved in 1989. Last previous edition approved in 2004 as E 1306 94 (2004).2For referenced ASTM standards, visit the ASTM website, www
14、.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 sole source of supply of the apparatus known to the committee at this timeis a commercially available unit, includi
15、ng expendable parts, manufactured byCianflone Scientific Instruments Corp., Pittsburgh, PA. If you are aware ofalternative suppliers, please provide this information to ASTM InternationalHeadquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee
16、,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7.1.2 Rubber Boot (2), shall cover the anode manipulatorassembly to prevent electrical shock.7.1.3 The top of the housing shall be fabricated from anelectrical an
17、d thermal insulating material, such as Bakelite, andshall support the following items:7.1.3.1 Relief Valve (3), to relieve excessive pressure dur-ing the melting process.7.1.3.2 Inlet Fitting (4), for argon.7.1.3.3 Outlet Fitting (5), for connecting to a vacuumpump.7.1.4 Water-Cooled Lower Housing (
18、6), approximately 534-in. diameter and 512 in. high containing the copper meltingcrucible. Its upper surface shall be fitted with a neopreneO-ring to seal against the upper anode housing.7.1.4.1 The lower housing shall be capable of being invertedfor removal of the button after it has cooled.7.1.5 H
19、ydraulic Jack (7), to raise the lower housing againstthe upper anode housing, compressing the O-ring and sealingthe crucible chamber.7.2 D-C Electric Welder (8), to provide an arc current of400 to 600 A.7.3 Pressure Regulator (9), two-stage, for argon gas.7.4 Vacuum Pump (10), having an initial pump
20、ing rate of50 L/min.7.5 Wire Brushes, to clean the crucible.7.6 Tamping Rod, suitable for packing the sample into thecrucible.7.7 Foot Switch, to provide low and high power settings(optional). If a foot switch is not available, the low to highpower and the high to low power transition can be perform
21、edwith the rheostat designed for adjusting the current.7.8 Control Panel (11), containing the master power switchand rheostat for adjusting the current.8. Reagents and Materials8.1 Argon, 99.99 %, gas or liquid.8.2 Anode, graphite,12-in. diameter and 212 in. long with atapered tip.9. Hazards9.1 Wear
22、 safety glasses with side shields, or full face shield.9.2 Wear insulated gloves when changing hot electrodes andhandling hot buttons.9.3 An electrical shock hazard exists if the rubber boot isremoved from around the anode manipulator assembly at thetop of the furnace.9.4 An exhaust vent shall be in
23、stalled over the furnace toremove any harmful fumes that may be given off during themelting cycle.10. Preparation of Apparatus10.1 Initial SetupRefer to Fig. 1.10.1.1 Attach the cooling water to the apparatus and adjustthe flowrate to34 L/min.10.1.2 Attach the argon supply and adjust the two-stagere
24、gulator output to 6 psi (41 kPa).10.1.3 Attach the vacuum pump.10.1.4 Attach the d-c electric welder to the apparatus at thecontrol panel.10.1.5 Attach the graphite anode to the manipulator assem-bly.10.2 Preparation of AnodeThe lifetime of the anode canbe extended significantly by dipping it into t
25、he molten metal.When this procedure is used, it is imperative that there be aseparate anode for each type of metal or alloy to prevent crosscontamination of the samples.11. Procedure11.1 Turn on the water valve and the master power switch.Adjust the current at the control box so that the low powerse
26、tting will be 400 A and the high power setting will be 800 A.11.2 Clean the melting crucible with a wire brush beforeeach melt.11.3 Charging the Crucible:11.3.1 Weigh sufficient sample to fill the crucible. Materialdensity and the form and size of the chips or turnings willdetermine the weight of th
27、e sample which can be placed intothe crucible. Be certain that all of the sample is containedwithin the crucible and none is above the top edge. Carefullypack the sample into the crucible with the tamping rod.NOTE 1It will take approximately 40 g of zirconium and zirconiumalloy materials to fill the
28、 crucible.NOTE 2It shall be determined experimentally the exact quantity ofmaterial to charge the crucible and the correct current and time to producea sample. The maximum melt time should also be determined to avoiddamaging furnace components.11.3.2 Rotate the lower body into position. Raise the cr
29、u-cible with the hydraulic jack until the O-ring is firmly seatedagainst the upper body to close the furnace.11.4 Flushing the Crucible:11.4.1 Turn the vacuum pump on and open the vacuumvalve. Evacuate the chamber until the anode manipulatorassembly has been pulled down to its lowest position.Legend
30、:(1) Anode Housing (7) Hydraulic Jack(2) Rubber Boot (8) D-C Electrical Welder(3) Relief Valve (9) Pressure Regulator(4) Inlet Fittings for Argon (10) Vacuum Pump(5) Outlet Fitting for Vacuum (11) Control Panel(6) Crucible Housing (12) Power CableFIG. 1 Schematic of Electric Arc Remelt FurnaceE13060
31、72NOTE 3The pump will become quiet when a partial pressure ofapproximately 300 millitorr is reached.11.4.2 Close the vacuum valve and open the argon valveuntil the anode manipulator assembly has returned to its fullyextended position.11.4.3 Repeat the evacuation and argon flushing proceduretwo more
32、times.11.4.4 Leave the argon valve open after the last flush tomaintain a positive pressure during the melting process.11.4.5 Turn off the vacuum pump.11.5 Melting the Sample:11.5.1 Place both hands on the anode manipulator assembly.Depress and hold the foot switch in the low-power position.Lower th
33、e manipulator assembly until the arc is initiated.Continue to lower the manipulator assembly, without touchingthe sample, until the charge is completely melted.11.5.2 Without interrupting the circuit, increase to highpower with the foot switch. Hold for 30 s. Keep the anode closeto the molten pool w
34、ithout touching it. The current can becontrolled by moving the anode closer or further from themolten pool.NOTE 4To coat the anode with metal as suggested in 10.2, with thepower still on high, thrust the anode down quickly through the moltenpool of metal until it just touches the crucible bottom. Th
35、en bring it upquickly to clear the metal.11.5.3 After 30 s at high power, release the foot switch andguide the manipulator assembly upward to its raised position.11.5.4 To prevent oxidation and maintain a bright shinysurface, allow the button to cool for at least 60 s before openingthe chamber.11.6
36、Removal of the Sample:11.6.1 Open the chamber by releasing the pressure on thehydraulic jack.11.6.2 Invert the lower body to remove the button. Allow itto cool to room temperature before handling.11.6.3 Examine the sample to assure that all material hasbeen melted and the sample is homogeneous. If n
37、ot, invert thesample and remelt.11.7 Preparation of the Sample for Analysis:11.7.1 Machine the surface of the button flat and smooth,suitable for analysis.11.7.2 The button may also be chipped to provide speci-mens for plasma emission, atomic absorption, and chemicalanalyses.12. Keywords12.1 arc mel
38、ting; button melting; melting; remelting;sample preparationASTM International takes no position respecting the 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 pat
39、ent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is 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 eit
40、her for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. 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
41、hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard 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 serviceastm.org (e-mail); or through the ASTM website(www.astm.org).E1306073
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