ASTM C24-09(2022)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C24 − 09 (Reapproved 2022)
Standard Test Method for
Pyrometric Cone Equivalent (PCE) of Fireclay and High-
Alumina Refractory Materials
This standard is issued under the fixed designation C24; 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.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope E220 Test Method for Calibration of Thermocouples By
Comparison Techniques
1.1 This test method covers the determination of the pyro-
E691 Practice for Conducting an Interlaboratory Study to
metric cone equivalent (PCE) of fire clay, fireclay brick,
Determine the Precision of a Test Method
high-alumina brick, and silica fire clay refractory mortar by
comparison of test cones with standard pyrometric cones under
3. Terminology
the conditions prescribed in this test method.
3.1 Definitions—For definitions of terms used in this test
1.2 Units—The values stated in inch-pound units are to be
method, see Terminology C71.
regarded as standard. The values given in parentheses are
mathematical conversions to SI units that are provided for
4. Summary of Test Method
information only and are not considered standard.
4.1 This test method consists of preparing a test cone from
1.2.1 Exceptions—Certain weights are in SI units with
a refractory material and comparing its deformation end point
inch-pound in parentheses. Also, certain figures have SI units
to that of a standard pyrometric cone. The resultant PCE value
without parentheses. These SI units are to be regarded as
is a measure of the refractoriness of the material.
standard.
4.2 Temperature equivalent tables for the standard cones
1.3 This standard does not purport to address all of the
have been determined by the National Institute of Standards
safety concerns, if any, associated with its use. It is the
andTechnology when subjected to both slow and rapid heating
responsibility of the user of this standard to establish appro-
rates.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
5. Significance and Use
1.4 This international standard was developed in accor-
dance with internationally recognized principles on standard-
5.1 The deformation and end point of a cone corresponds to
ization established in the Decision on Principles for the a certain heat-work condition due to the effects of time,
Development of International Standards, Guides and Recom-
temperature, and atmosphere.
mendations issued by the World Trade Organization Technical
5.2 The precision of this test method is subject to many
Barriers to Trade (TBT) Committee.
variables that are difficult to control.Therefore, an experienced
operatormaybenecessarywherePCEvaluesarebeingutilized
2. Referenced Documents
for specification purposes.
2.1 ASTM Standards:
5.3 PCE values are used to classify fireclay and high-
C71 Terminology Relating to Refractories
alumina refractories.
E11 Specification for Woven Wire Test Sieve Cloth and Test
Sieves 5.4 This is an effective method of identifying fireclay
variations, mining control, and developing raw material speci-
fications.
This test method is under the jurisdiction of ASTM Committee C08 on
Refractories and is the direct responsibility of Subcommittee C08.02 on Thermal
5.5 Although not recommended, this test method is some-
Properties.
times applied to materials other than fireclay and high alumina.
Current edition approved Nov. 1, 2022. Published November 2022. Originally
Such practice should be limited to in-house laboratories and
approved in 1919. Last previous edition approved in 2018 as C24 – 09 (2018). DOI:
never be used for specification purposes.
10.1520/C0024-09R22.
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
6. Procedure
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 6.1 Preparation of Sample:
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C24 − 09 (2022)
6.1.1 Clay or Brick—Crush the entire sample of fire clay or
fireclay brick, in case the amount is small, by means of rolls or
a jaw crusher to produce a particle size not larger than ⁄4 in.
(6 mm). If the amount is large, treat a representative sample
obtained by approved methods. Then mix the sample thor-
oughly and reduce the amount to about 250 g (0.5 lb) by
quartering (see Note 1). Then grind this portion in an agate,
porcelain, or hard steel mortar and reduce the amount again by
quartering. The final size of the sample shall be 50 g and the
fineness capable of passing anASTM No. 70 (212-µm) sieve .
(equivalent to a 65-mesh Tyler Standard Series). In order to
avoid excessive reduction to fines, remove them frequently
during the process of reduction by throwing the sample on the
sieve and continuing the grinding of the coarser particles until
all the sample passes through the sieve (see Note 2). Take
precautions to prevent contamination of the sample by steel
particles from the sampling equipment during crushing or
grinding.
NOTE 1—Take care during the crushing and grinding of the sample to
prevent the introduction of magnetic material.
NOTE 2—The requirement to grind the coarser particles is particularly
important for highly siliceous products; excessively fine grinding may
reduce their PCE by as much as two cones.
NOTE 1—Dimensions are in inches.
6.1.2 Silica Fire Clay (see 3.1)—In the case of silica fire
clay, test the sample obtained by approved methods as received SI Equivalents
without grinding or other treatment. in. mm
0.075 1.90
6.2 Preparation of Test Cones:
0.272 6.91
6.2.1 After preparing samples of unfired clays (Note 3), or
0.281 7.14
1.081 27.46
of mixes containing appreciable proportions of raw clay, in
1.125 28.58
accordance with 6.1.1, heat them in an oxidizing atmosphere in
the temperature range from 1700 to 1800 °F (925 to 980 °C)
FIG. 1 Standard Pyrometric Test Cone
for not less than 30 min.
NOTE3—Someunfiredclaysbloatwhentheyareformedintoconesand
arecarriedthroughthehigh-temperatureheattreatmentprescribedin6.2.1
without preliminary calcining. The substances that cause bloating can, in
be ⁄16 in. (24 mm) and the face of the cone (about which
most cases, be expelled by heating the clay samples before testing.
bending takes place) shall be inclined at an angle of 82° with
6.2.2 The clay sample may be given the heat treatment
the horizontal. Arrange the test cones with respect to the PCE
prescribed in 6.2.1 after it has been formed into a cone (see
cones as shown in Fig. 3, that is, alternate the test cones with
6.2.3), but this procedure has been found not as effective as the
the PCE cones in so far as is practical (see Note 5). The plaque
treatment of the powdered material. If cones so prepared bloat
may be any convenient size and shape and may be biscuited
during the PCE test, heat a portion of the original sample in its
before using, if desired.
powdered condition as prescribed in 6.2.1 and then retest it.
NOTE 4—A satisfactory cone plaque mix consists of 85 % fused
6.2.3 Thoroughly mix the dried sample, and after the
alumina and 15 % plastic refractory clay. For tests that will not go above
addition of sufficient dextrine, glue, gum tragacanth, or other
Cone 34, the plastic refractory clay may be increased to 25 % and the
alkali-free organic binder and water, form it in a metal mold
alumina may be replaced with brick grog containing over 70 % alumina.
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