ASTM E634-96

NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
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Designation: E 634 – 96
Standard Practice for
Sampling of Zinc and Zinc Alloys for Optical Emission
Spectrometric Analysis
This standard is issued under the fixed designation E 634; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
ceramic or graphite ladle, as the solubility of iron in Special High Grade
1. Scope
Zinc is sufficient to cause a measurable contamination.
1.1 This practice covers the sampling of zinc and zinc alloys
5.2 Sample Molds, designed to produce homogeneous chill-
to obtain a sample suitable for quantitative optical emission
cast specimens having smooth surfaces, free from surface
spectrochemical analysis. Included are procedures for obtain-
pockets and pores. The specimens shall be representative (in
ing representative samples from molten metal, from fabricated
the region to be excited) of the product metal. The samples
or cast products that can be melted, and from other forms that
shall have a spectrochemical response similar to the standards
cannot be melted.
used in preparing the analytical curves. This is ensured by
1.2 This standard does not purport to address all of the
casting standards and specimens in the same manner. Also, the
safety concerns, if any, associated with its use. It is the
specimens shall have a repeatability of measurement for major
responsibility of the user of this standard to establish appro-
elements from excitation-to-excitation with a relative error of
priate safety and health practices and determine the applica-
no more than 2 %. Several types of molds have been found
bility of regulatory limitations prior to use.
acceptable.
2. Referenced Documents
5.2.1 Type A, Pin Mold (Fig. 1)—This mold produces two
diagonally cast pins with sprues at the top of the specimens.
2.1 ASTM Standards:
The mold dimensions are such as to produce pins approxi-
E 401 Practice for Bonding Thin Spectrochemical Samples
mately 100 mm (3.9 in.) in length by 11 mm (0.4 in.) in
and Standards to a Greater Mass of Material
diameter. The mold is made of steel or cast iron and weighs
3. Summary of Practice
approximately 4.5 to 5.5 kg (10 to 12 lb). Pin specimens have
been found to be very homogeneous. If properly prepared,
3.1 Molten metal representative of the furnace melt is
these specimens provide very reliable results with only one
poured into a mold to produce a chill-cast sample. The sample,
burn. However, pin specimens must be reshaped for each
which must represent the average composition, is machined to
additional burn.
a specified shape to produce an acceptable surface for excita-
5.2.2 Type B, Book Mold (Fig. 2)—This mold produces a
tion.
vertically cast disk with a sprue on the edge of the specimen.
3.2 Fabricated or cast products are remelted and cast into
The mold dimensions are such as to produce a disk of
molds or are excited directly without remelting.
approximately 64 mm (2.5 in.) in diameter by 6 to 8 mm (0.2
4. Significance and Use
to 0.3 in.) in thickness. A circular central recess, 15 to 25 mm
(0.6 to 1.0 in.) in diameter, on one side of the specimen
4.1 This practice, used in conjunction with an appropriate
quantitative optical emission spectrochemical method, is suit- facilitates machining of that side in preparation for excitation.
It also promotes more uniform freezing of the raised peripheral
able for use in manufacturing control, material or product
acceptance, and development and research. area. The mold is made of steel or cast iron and weighs
approximately 2 to 3 kg (4 to 7 lb). This mold works well for
5. Apparatus
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 only in the areas indicated in Fig. 3, and it may be necessary to
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
NOTE 1—Pure zinc metal (Special High Grade) is sampled using a
each alloy system to be analyzed.
5.2.3 Type C, Center Pour Mold (Fig. 4)—This mold
This practice is under the jurisdiction of ASTM Committee E-1 on Analytical
produces a horizontally cast disk with a sprue over the center
Chemistry for Metals, Ores and Related Materials and is the direct responsibility of
on the back side. The mold dimensions are such as to produce
Subcommittee E01.05 on Zn, Sn, Pb, Cd, Be, and Other Metals.
Current edition approved Oct. 10, 1996. Published December 1996. Originally
a disk approximately 64 mm (2.5 in.) in diameter by 8 mm (0.3
e1
published as E 634 – 78. Last previous edition E 634 – 78 (1991) .
in.) in thickness. A circular central recess, 10 to 20 mm (0.4 to
Discontinued; see 1995 Annual Book of ASTM Standards, Vol 03.06.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
E 634
FIG. 1 Type A Mold and Specimen
FIG. 2 Type B Mold and Specimen
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.
but the corresponding raised portion of the mold shall not be so
5.2.4 Other Molds—Molds of different types, 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).
specimens shall have a spectrochemical response similar to the
The advantage of this mold is that the specimen obtained may
standards used for preparing the analytical curves.
be excited around the entire annular area. However, as with the
E 634
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
5.3 Lathe or Milling Machine, capable of machining a prevents metal freezing, while obtaining metal well beneath the
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
Remove any excess metal from the ladle, dip it into the molten
shape is very important. To maintain the integrity of the pin shapes it may
be necessary to equip a micrometer cross-fed lathe with a special metal as before, and fill the mold using an
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