ASTM E634-96(2001)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E634–96 (Reapproved 2001)
Standard Practice for
Sampling of Zinc and Zinc Alloys for Optical Emission
Spectrometric Analysis
This standard is issued under the fixed designation E634; 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 (e) indicates an editorial change since the last revision or reapproval.
NOTE 1—Pure zinc metal (Special High Grade) is sampled using a
1. Scope
ceramic or graphite ladle, as the solubility of iron in Special High Grade
1.1 Thispracticecoversthesamplingofzincandzincalloys
Zinc is sufficient to cause a measurable contamination.
to obtain a sample suitable for quantitative optical emission
5.2 Sample Molds, designed to produce homogeneous chill-
spectrochemical analysis. Included are procedures for obtain-
cast specimens having smooth surfaces, free from surface
ing representative samples from molten metal, from fabricated
pockets and pores. The specimens shall be representative (in
or cast products that can be melted, and from other forms that
the region to be excited) of the product metal. The samples
cannot be melted.
shall have a spectrochemical response similar to the standards
1.2 This standard does not purport to address all of the
used in preparing the analytical curves. This is ensured by
safety concerns, if any, associated with its use. It is the
casting standards and specimens in the same manner.Also, the
responsibility of the user of this standard to establish appro-
specimens shall have a repeatability of measurement for major
priate safety and health practices and determine the applica-
elements from excitation-to-excitation with a relative error of
bility of regulatory limitations prior to use.
no more than 2%. Several types of molds have been found
2. Referenced Documents acceptable.
5.2.1 Type A, Pin Mold (Fig. 1)—This mold produces two
2.1 ASTM Standards:
diagonally cast pins with sprues at the top of the specimens.
E401 Practice for Bonding Thin Spectrochemical Samples
The mold dimensions are such as to produce pins approxi-
and Standards to a Greater Mass of Material
mately 100 mm (3.9 in.) in length by 11 mm (0.4 in.) in
3. Summary of Practice diameter. The mold is made of steel or cast iron and weighs
approximately 4.5 to 5.5 kg (10 to 12 lb). Pin specimens have
3.1 Molten metal representative of the furnace melt is
been found to be very homogeneous. If properly prepared,
pouredintoamoldtoproduceachill-castsample.Thesample,
these specimens provide very reliable results with only one
which must represent the average composition, is machined to
burn. However, pin specimens must be reshaped for each
a specified shape to produce an acceptable surface for excita-
additional burn.
tion.
5.2.2 Type B, Book Mold (Fig. 2)—This mold produces a
3.2 Fabricated or cast products are remelted and cast into
vertically cast disk with a sprue on the edge of the specimen.
molds or are excited directly without remelting.
The mold dimensions are such as to produce a disk of
4. Significance and Use
approximately 64 mm (2.5 in.) in diameter by 6 to 8 mm (0.2
to 0.3 in.) in thickness.Acircular central recess, 15 to 25 mm
4.1 This practice, used in conjunction with an appropriate
(0.6 to 1.0 in.) in diameter, on one side of the specimen
quantitative optical emission spectrochemical method, is suit-
facilitates machining of that side in preparation for excitation.
able for use in manufacturing control, material or product
Italsopromotesmoreuniformfreezingoftheraisedperipheral
acceptance, and development and research.
area. The mold is made of steel or cast iron and weighs
5. Apparatus
approximately 2 to 3 kg (4 to 7 lb). This mold works well for
high purity zinc grades, but with alloys may cause segregation
5.1 Ladle, of steel, designed to hold sufficient molten metal
due to solidification phenomena. Specimens should be excited
to completely fill the sample mold, with a handle of sufficient
onlyintheareasindicatedinFig.3,anditmaybenecessaryto
length to reach into a furnace, trough, pot, or crucible.
make several burns and report an average.The user is strongly
cautioned to thoroughly investigate specimen homogeneity for
This practice is under the jurisdiction ofASTM Committee E01 onAnalytical
each alloy system to be analyzed.
Chemistry for Metals, Ores and Related Materials and is the direct responsibility of
5.2.3 Type C, Center Pour Mold (Fig. 4)—This mold
Subcommittee E01.05 on Zn, Sn, Pb, Cd, Be, and Other Metals.
produces a horizontally cast disk with a sprue over the center
Current edition approved Oct. 10, 1996. Published December 1996. Originally
e1
published as E634–78. Last previous edition E634–78(1991) .
on the back side. The mold dimensions are such as to produce
Discontinued; see 1995 Annual Book of ASTM Standards, Vol 03.06.
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E634
FIG. 1 Type A Mold and Specimen
FIG. 2 Type B Mold and Specimen
adiskapproximately64mm(2.5in.)indiameterby8mm(0.3 The advantage of this mold is that the specimen obtained may
in.) in thickness.Acircular central recess, 10 to 20 mm (0.4 to beexcitedaroundtheentireannulararea.However,aswiththe
0.8 in.) in diameter, on one side of the specimen facilitates vertically cast disk specimens, although not as severe, segre-
machining of that side in preparation for excitation. It also gation can be a problem. Therefore, it may be necessary to
promotes more uniform freezing of the raised peripheral area, make several burns and report an average.
butthecorrespondingraisedportionofthemoldshallnotbeso
5.2.4 OtherMolds—Moldsofdifferenttypes,materials,and
large as to restrict the throat for the sprue. A slight taper, 1 to
dimensions may be used provided that the uniformity of the
2 deg, on the hinged portion of the mold facilitates opening
specimens obtained is comparable to the uniformity of speci-
when a specimen has been cast. The mold is made of steel or
mens obtained from Type A, B, or C molds. Further, the
cast iron and weighs approximately 3.5 to 4.5 kg (8 to 10 lb).
E634
NOTE 1—Shaded areas are acceptable for analysis.
FIG. 3 Specimens from Type A, B, and C Molds
FIG. 4 Type C Mold and Specimen
specimensshallhaveaspectrochemicalresponsesimilartothe clear area, well below the surface, and stir momentarily. Turn
standards used for preparing the analytical curves. the ladle upright and quickly withdraw. Heating the ladle
5.3 Lathe or Milling Machine, capable of machining a
preventsmetalfreezing,whileobtainingmetalwellbeneaththe
smooth flat surface. surface minimizes the danger of inclusion of oxide. Unless the
mold is already hot, cast and discard a preliminary specimen.
NOTE 2—When using pin specimens, reproducibility of the exact pin
Removeanyexcessmetalfromtheladle,dipitintothemolten
shapeisveryim
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