ASTM E716-94(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E716–94(Reapproved2002)
Standard Practices for
Sampling Aluminum and Aluminum Alloys for
Spectrochemical Analysis
This standard is issued under the fixed designation E716; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope num Alloys by Atomic Emission Spectrometry
1.1 These practices describe the sampling of aluminum and
3. Summary of Practices
aluminum-base alloys to obtain a chill-cast disk suitable for
3.1 Molten metal representative of the furnace melt is
quantitative optical emission spectrochemical analysis. The
poured into a specified mold to produce a chill-cast disk. The
disk in the region to be excited is representative of the melt or
disk is machined to a specified depth that represents the
product and gives a repeatability of results which approaches
average composition and produces an acceptable surface for
that of the reference materials used.
excitation.
1.2 These practices describe procedures for representative
3.2 Fabricated, cast, or wrought products are remelted and
sampling of molten metal, from fabricated or cast products
cast into molds, briquetted and remelted, bonded to more
which can be melted, and from other forms which cannot be
massive material, or excited directly without remelting.
melted.
3.3 Special practices are included for the sampling and
1.3 This standard does not purport to address all of the
analysis of aluminum-silicon alloys, containing greater than
safety problems, if any, associated with its use. It is the
14% silicon.
responsibility of the user of this standard to establish appro-
priate safety and health practices and determine the applica-
4. Significance and Use
bility of regulatory limitations prior to use. Specific precau-
4.1 These practices, used in conjunction with the following
tionary statements are given in 5.1 and 6.2.
appropriate quantitative optical emission spectrochemical
2. Referenced Documents methods, Test Methods E101, E227, E607, and E1251, are
2 suitable for use in manufacturing control, material or product
2.1 ASTM Standards:
acceptance, and research and development.
E101 Test Method for Spectrographic Analysis of Alumi-
num and Aluminum Alloys by the Point-to-Plane Tech-
5. Apparatus
nique
5.1 Ladle, capable of holding a minimum of 250 g (8.8 oz)
E227 Test Method for Optical Emission Spectrometric
ofmoltenmetal,withahandleofsufficientlengthtoreachinto
Analysis of Aluminum and Aluminum Alloys by the
a furnace, trough, or crucible. The ladle should be lightly
Point-to-Plane Technique
coated with a tightly adhering ladle wash that will not
E401 Practice for Bonding Thin Spectrochemical Samples
contaminate the sample (Note 1).
and Standards to a Greater Mass of Material
E607 Test Method for Atomic Emission Spectrometric
NOTE 1—Caution:Traces of moisture in the coating may cause dan-
Analysis Aluminum Alloys by the Point to Plane Tech- gerous spattering.
NOTE 2—Asuitable ladle wash may be prepared as follows: Mix 255 g
nique Nitrogen Atmosphere
(9 oz) of fine whiting (CaCO ) with 3.8 L(1 gal) of water and boil for 20
E1251 Test Method for Analysis of Aluminum and Alumi-
min.Add127g(4.5oz)ofsodiumsilicatesolution(40to42°Bé)andboil
for 30 min. Stir well before using.
These practices are under the jurisdiction of ASTM Committee E01 on 5.2 Sample Molds, capable of producing homogenous chill-
Analytical Chemistry for Metals, Ores, and Related Materials and are the direct
cast disks having smooth surfaces, free of surface pockets and
responsibility of Subcommittee E01.04 on Aluminum and Magnesium.
porosity. These castings should have a spectrochemical re-
Current edition approved Oct. 10, 2002. Published December 2002. Originally
sponse similar to the reference materials used in preparing the
approved in 1980. Last previous edition approved in 1994 as E716–94. DOI:
10.1520/E0716-94R02.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on Other proprietary ladle washes such as Dycote, available from Foseco, Inc., P.
the ASTM website. O. Box 8728, Cleveland, OH 44135; and Zirconite, available from TitaniumAlloy
Withdrawn. The last approved version of this historical standard is referenced Mfg. Co., 111 Broadway, New York, NY 10006, have been found suitable for this
on www.astm.org. purpose.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E716–94 (2002)
analyticalcurvesandmusthavearepeatabilityfromexcitation- 5.2.3 Vacuum Mold is shown in Fig. 4. This mold pro-
to-excitation of no more than 2% relative on major elements. duces disks that are 38 mm (1.5 in.) in diameter and 13 mm
They must be representative of the melt in the region excited. (0.5 in.) thick and weigh approximately 40 g (1.4 oz). The
Several types of molds have been found acceptable: mold consists of a solid copper base and a porous bronze wall
in the form of a composite mold insert which is located in a
5.2.1 TypeA, book mold, is shown in Fig. 1.The advantage
of this mold is simplicity and low cost. This mold produces a steel mold body. A graphite coated cast iron tip is attached to
themoldbodybyaspringclampassembly.Thevacuumsource
vertically cast disk with the sprue on its edge. The mold
dimensionsaresuchastoproduceadiskapproximately64mm can be either a small battery-operated vacuum pump or a
rubber syringe connected to the mold body.
(2.5 in.) in diameter by 6 to 8 mm (0.24 to 0.32 in.) in
thickness.Acircularcentralrecess15to25mm(0.6to1.0in.) 5.2.4 OtherTypesofMolds—Othermoldsofdifferenttypes,
materials,anddimensionsmaybesubstitutedprovidedthatthe
indiameterononesideofthediskfacilitatesmachiningofthat
side in preparation for excitation. It also promotes more uniformity of the samples so obtained is comparable to the
uniformity of samples obtained from Type A or B molds, and
uniform freezing of the raised peripheral area. The mold
material should be steel or cast iron and should weigh furthermorethatsuchsampleshaveaspectrochemicalresponse
approximately 2 to 3 kg (5 to 7 lb). similar to the reference materials used for preparing the
analytical curve.
5.2.2 Type B, center-pour mold, is shown in Fig. 2. The
5.3 Lathe, capable of machining a smooth flat surface and
advantage of this mold is that the sample obtained may be
having automatic cross feed. A milling machine may also be
excited around the entire annular area. This mold produces a
used.
horizontallycastdiskwiththesprueoverthecenterontheback
5.4 Tool Bits—Either alloy steel or cemented carbide is
side. The mold dimensions are such as to produce a disk
recommended. The best shape of the tool varies with the type
approximately64mm(2.5in.)indiameterby6to13mm(0.24
and speed of the lathe, but in general, soft metals require less
to 0.50 in.) in thickness.Acircular central recess 10 to 20 mm
top and side rake than steel. For example, for pure aluminum,
(0.4 to 0.8 in.) in diameter on one side of the disk facilitates
a top rake of 0° and a side rake of 0 to 6° should prove
machining of that side in preparation for excitation. It also
satisfactory. Also a side clearance of about 6° and a front
promotes more uniform freezing of the raised peripheral area,
clearance of 15° should be satisfactory for all aluminum disk
butthecorrespondingraisedportionofthemoldmustnotbeso
samples. The nose of the tool should be rounded. A tool bit
large as to restrict the throat for the sprue. A slight taper, 1 to
design that has been found satisfactory for most aluminum
2 deg, on the hinged portion of the mold facilitates opening
alloys is shown in Fig. 5.
when a disk has been cast. The mold material should be steel
5.5 Portable Electric Melting Furnace, equipped with a
orcastironandshouldweighapproximately3.5to4.5kg(8to
graphitecruciblewithaminimumcapacityof200g(7.1oz)of
10 lb).
moltenaluminum,andcapableofmaintainingtemperaturesfor
NOTE 3—Prepare the surface of the mold cavity to minimize the
melting aluminum alloys.
formationofgaspocketsonthesurfaceofthecastingsandtoresistrusting
of the mold cavity surface.To do this, blast the inner surface with a sharp
6. Materials
grit that cuts rather than peens. The resulting finely roughened face is
6.1 Graphite Rods—6.15 by 300-mm (0.242 by 12-in.)
essential for obtaining a smooth and uniform surface on the cast disk.
Next,degreasethemold,placeinacoldfurnace,andraisethetemperature spectroscopic electrodes are satisfactory.
to400°C(752°F).Atthistemperatureandthroughouttheremainderofthe
6.2 Phosphorus, red, amorphous.
heating cycle, introduce steam into the furnace. Raise the temperature to
NOTE 4—Caution:Provide adequate ventilation when phosphorus is
540°C(1004°F)andmaintainfor4h.Theresultingblackoxidecoatingis
added to molten metal.
tenacious and of a dull black appearance.
5.2.2.1 Special Type B Mold, which produces a disk 6 mm
7. Preparation of Samples
(0.24 in.) thick, is required for undiluted aluminum-silicon
7.1 Molten Metal:
alloys containing greater than 14% silicon.
7.1.1 Chill-Cast Disk by Molds A or B:
7.1.1.1 When a furnace or crucible of molten metal is to be
sampled, the temperature must be well above the point at
which any solid phase could be present. Using the ladle or a
separate skimming tool, coated with a dry, tightly adhering
mold wash (Note 2) and free of any remaining previous metal,
push any dross away from the sampling area. Next, dip the
ladle sideways into the clear area well below the surface and
stir momentarily. Then turn the ladle upright, and quickly
withdraw. Two things are thus accomplished, namely, heating
Aportable Vacuum Sampler, available fromAluminum Company ofAmerica,
Alcoa Center, PA 15069, has been found suitable for this purpose.
AJelrusHandy-Meltfurnaceandgraphitecrucible,availablefromCole-Parmer
Instrument Co., 74
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