1、Designation: E1306 11Standard Practice forPreparation of Metal and Alloy Samples for ChemicalAnalysis by Electric Arc Remelting1This standard is issued under the fixed designation E1306; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisi
2、on, 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 practice covers the preparation of solid samples ofreactive and refractory metals and alloys by e
3、lectric 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, toolsteels, nickel, nickel
4、 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 and determine the applica-b
5、ility of regulatory limitations prior to use. Specific hazardstatements are given in Section 9.2. Referenced Documents2.1 ASTM Standards:2E135 Terminology Relating to Analytical Chemistry forMetals, Ores, and Related Materials3. Terminology3.1 DefinitionsFor definitions of terms used in this prac-ti
6、ce, refer to Terminology E135.4. 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 metal which produces ahomogene
7、ous 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 atomic emission or X-ray fluorescence spectrometer. Theresultant button may it
8、self be chipped to provide specimens fortest methods requiring solutions or chips.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 reactive, refractory,ferrous and nonferrous alloys, such
9、 as cobalt, cobalt alloys,niobium, nickel, nickel alloys, stainless steels, tantalum, toolsteels, and tungsten.6. Interferences6.1 Test samples of known composition shall be used todetermine if there is any selective volatilization or segregationof the impurity elements. Elements known to volatilize
10、 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 thegraphite anode. A tungsten anode may be substituted if carbo
11、npickup 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 FurnaceThis section describesthe various components of an electric arc remelt furnace. Referto Fig. 1 to see how
12、 each component is arranged. The numberassigned to each component in the following descriptioncorresponds to the number in the schematic.7.1.1 Water-Cooled Upper Housing (1), approximately 6-in.diameter and 614 in. high, and having a smooth, flat sealingsurface.7.1.2 Rubber Boot (2), shall cover the
13、 anode manipulatorassembly to prevent electrical shock.7.1.3 The top of the housing shall be fabricated from anelectrical and thermal insulating material, such as Bakelite, andshall support the following items:1This practice is under the jurisdiction of ASTM Committee E01 on AnalyticalChemistry for
14、Metals, Ores, and Related Materials and is the direct responsibility ofSubcommittee E01.20 on Fundamental Practices.Current edition approved Nov. 1, 2011. Published December 2011. Originallyapproved in 1989. Last previous edition approved in 2007 as E1306 07. DOI:10.1520/E1306-11.2For referenced AST
15、M 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 Harbor Drive, PO Box C700, West Conshoho
16、cken, PA 19428-2959, United States.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 (6), approximately 534-in. diameter and 512 in. high
17、 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 Jack (7), to raise the lower housing against the upp
18、eranode housing, compressing the O-ring and sealing the cru-cible chamber.7.2 DC Electric Welder (8), to provide an arc current of 400to 600 A.7.3 Pressure Regulator (9), two-stage, for argon gas.7.4 Vacuum Pump (10), having an initial pumping rate of50 L/min.7.5 Wire Brushes, to clean the crucible.
19、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 performedwith the rheostat designed for adjusting the current.7.8 C
20、ontrol 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 safety glasses with side shields, or full face shield.9.2 W
21、ear 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 installed over the furnace toremove any harmful fumes that may
22、 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 flow rate to34 L/min.10.1.2 Attach the argon supply and adjust the two-stageregulator output to 6 psi (41 kPa).10.1.3 Attach the vacuum p
23、ump.10.1.4 Attach the dc 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 the molten metal.When this procedure is used, it is imperativ
24、e 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 powersetting will be 400 A and the high power setting will be 800 A
25、.A fixed power between 400 A and 800 A can also be used.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 the sam
26、ple which can be placed intothe crucible. Be certain that the entire 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 cruc
27、ible.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 cru-cib
28、le with the jack until the O-ring is firmly seated against theupper 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.NOTE 3The pump will b
29、ecome quiet when a partial pressure ofapproximately 300 millitorr is reached.Legend:(1) Anode Housing (7) Jack(2) Rubber Boot (8) DC 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 Housi
30、ng (12) Power CableFIG. 1 Schematic of Electric Arc Remelt FurnaceE1306 11211.4.2 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 procedureif desired.11.4.4 Leave the argon
31、valve open after the last flush tomaintain a positive pressure during the melting process.11.4.5 Turn off the vacuum pump or close vacuum shut offvalve.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 t
32、he 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
33、without 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. T
34、hen bring it upquickly to clear the metal.11.5.3 After 30 s minimum at high power, release the footswitch and guide the manipulator assembly upward to its raisedposition.11.5.4 To prevent oxidation and maintain a bright shinysurface, allow the button to cool for at least 60 s before openingthe chamb
35、er.11.6 Removal of the Sample:11.6.1 Open the chamber by releasing the pressure on thejack.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 not
36、, 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 test methods requiring solutions or chips.12. Keywords12.1 arc melting; button melt
37、ing; 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 patent rights, and t
38、he 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 either for revision
39、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 hearing you shoul
40、dmake 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).E1306 113
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