ASTM C467-97(2002)
(Classification)Standard Classification of Mullite Refractories
Standard Classification of Mullite Refractories
SIGNIFICANCE AND USE
The mullite content of an alumina-silica refractory material has an important influence on volume stability, load bearing properties, and its satisfactory use in refractory applications. This classification is considered useful for purchase specifications and quality control.
SCOPE
1.1 This classification covers refractory products consisting predominantly of mullite (3 Al2O32 SiO2) crystals that are formed by either converting any of the sillimanite group of minerals, or synthesizing from appropriate materials in a melt or sinter process.
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Designation: C 467 – 97 (Reapproved 2002)
Standard Classification of
Mullite Refractories
This standard is issued under the fixed designation C 467; 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.
1. Scope
Alumina content, % 56 to 79
A
Impurities, max, % 5
1.1 This classification covers refractory products consisting
B
Deformation, max, % 5
predominantly of mullite (3 Al O ·2 SiO ) crystals that are
2 3 2
A
Impurities refer to metal oxides other than those of aluminum and silicon.
formed by either converting any of the sillimanite group of
B
When tested in accordance with 6.1.2.
minerals, or synthesizing from appropriate materials in a melt
or sinter process.
5. Test Specimens
5.1 Testing for compliance with this classification shall be
2. Referenced Documents
1 1
performed on 9 by 4 ⁄2 by 2 ⁄2 -in. (228 by 114 by 64-mm)
2.1 ASTM Standards:
rectangular brick as made, or on specimens of this size cut
C 16 Test Method for Load Testing Refractory Brick at
from larger shapes, utilizing existing plane surfaces as much as
High Temperatures
possible.
NOTE 1—Chemical analysis of refractory products are determined by a
6. Test Methods
combination of x-ray fluorscence (XRF) and inductively coupled plazma
(ICP) using standard reference materials (SRM), including various types
6.1 The properties enumerated in this classification shall be
of minerals and refractory materials which are available from the National
determined in accordance with the following ASTM meth-
Institute of Standards and Technology and other appropriate sources.
ods:
C 832 Test Method of Measuring the Thermal Expansion
6.1.1 Alumina Content—XRF and ICP.
and Creep of Refractories Under Load
6.1.2 Load Test—Schedule 6 of Table 1 in Test Method
C 16.
3. Significance and Use
6.1.3 Thermal Expansion and Creep—Method C 832.
3.1 The mullite content of an alumina-silica refractory
material has an important influence on volume stability, load
7. Retests
bearing properties, and its satisfactory use in refractory appli-
7.1 Because of possible variables that may result from
cations. This classification is considered useful for purchase
sampling or an unsatisfactory reproducibility of tests by
specifications and quality control.
different
...
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SIGNIFICANCE AND USE
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3.2 These test methods are for determining the room temperature flexural strength in three-point bending (cold modulus of rupture) or compressive strength (cold crushing strength), or both, for all refractory products.
3.3 Considerable care must be used to compare the results of different determinations of the cold crushing strength or modulus of rupture. The specimen size and shape, the nature of the specimen faces (that is, as-formed, sawed, or ground), the orientation of those faces during testing, the loading geometry, and the rate of load application may all significantly affect the numerical results obtained. Comparisons of the results between different determinations should not be made if one or more of these parameters differ between the two determinations.
3.4 The relative ratio of the largest grain size to the smallest specimen dimension may significantly affect the numerical results. For example, smaller cut specimens containing large grains may present different results than the bricks from which they were cut. Under no circumstances should 6 in. by 1 in. by 1 in. (152 mm by 25 mm by 25 mm) specimens be prepared and tested for materials containing grains with a maximum grain dimension exceeding 0.25 in. (6.4 mm).
3.5 This test method is useful for research and development, engineering application and design, manufacturing process control, and for developing purchasing specifications.
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SIGNIFICANCE AND USE
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SIGNIFICANCE AND USE
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3.2 These test methods are primary standard methods that are suitable for use in quality control, research and development, establishing criteria for and evaluating compliance with specifications, and providing data for design purposes.
3.3 Fundamental assumptions inherent in these test methods are:
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3.3.4 Deviation from any of these assumptions adversely affects the test results.
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SCOPE
1.1 These test methods cover the determination of the following properties of refractory shapes:
1.1.1 Apparent porosity,
1.1.2 Liquid absorption,
1.1.3 Apparent specific gravity, and
1.1.4 Bulk density.
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1.3 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3.1 Exception—The apparatus used in this standard is only available in SI units.
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Note 1: Test Methods C20 cover procedures for testing properties of refractories that are not attacked by water.
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4.5.6 The test method has been conducted in a meticulous manner.
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1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.2.1 Exception—In 7.3, the equivalent SI unit is expressed in parentheses.
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Note 1: Test Methods C830 and Test Method C914 are also used to determine bulk density of refractory brick, by different procedures.
1.2 The test methods appear in the following order:
Sections
Size and Bulk Density
4 through 7
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8 through 10
Squareness of Refractory Brick
11 through 14
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SIGNIFICANCE AND USE
4.1 This test method was developed for use both by manufacturers as a process control tool for the production of AZS fusion-cast refractories, and by glass manufacturers in the selection of refractories and design of glass-melting furnaces.
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4.3 The procedures and results may be applied to other refractory types or applications (that is, reheat furnace skid rail brick) in which glass exudation is considered to be important.
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1.1 This test method covers a procedure for causing the exudation of a glassy phase to the surface of fusion-cast specimens by subjecting them to temperatures corresponding to glass furnace operating temperatures.
1.2 This test method covers a procedure for measuring the exudate as the percent of volume increase of the specimen after cooling.
1.3 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.
1.3.1 Exception—The balance required for this test method uses only SI units (Section 7).
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 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.
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2.1 This test method provides a guide for evaluating the resistance of refractories in glass-melting furnace superstructures to vapor attack. This test method may also be useful for evaluating refractories in other applications where vapor attack occurs.
2.2 An electric-heated furnace is recommended. Water vapor and other atmospheric components in a gas- or fuel-fired furnace may participate in the chemical and physical reactions being studied. Results may differ, therefore, depending upon the nature and type of firing employed.
2.3 The degree of correlation between this test method and service performance is not fully determinable. This is intended to be an accelerated test method that generates a substantial degree of reaction in a relatively short amount of time. This acceleration may be accomplished by changing the composition and/or concentration of the reactants, increasing temperatures, or by performing the test in an isothermal environment.
2.4 Since the test method may not accurately simulate the service environment, observed results of this test method may not be representative of those found in service. It is imperative that the user understand and consider how the results of this test method may differ from those encountered in service. This is particularly likely if the reaction products, their nature, or their degree differ from those normally found in the actual service environment.
2.5 It is incumbent upon the user to understand that this is an aggressive, accelerated test method and to be careful in interpreting the results. If, for example, the reaction species have never been found in a real-world furnace, then this test method should not necessarily be considered valid to evaluate the refractory in question.
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1.1 This test method covers a procedure for comparing the behavior of refractories in contact with vapors under conditions intended to simulate the environment within a glass-melting or other type of furnace when refractories are exposed to vapors from raw batch, molten glass, fuel, fuel contaminants, or other sources. This procedure is intended to accelerate service conditions for the purpose of determining in a relatively short time the interval resistance to fluxing, bloating, shrinkage, expansion, mineral conversion, disintegration, or other physical changes that may occur.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
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SIGNIFICANCE AND USE
3.1 Fireclay steel-teeming nozzles and sleeves are classified by volume reheat change. Bloating of some refractories results in irregular reheat dimensions, which are difficult to measure. This practice determines the volume without depending upon physical linear measurements.
3.2 Blast furnace checkers that have irregular cross-sections are classified by “creep properties.” This practice determines the average cross-sectional area.
SCOPE
1.1 This practice covers the methods of calculating areas, volumes, and linear changes of irregularly shaped refractory specimens.
1.2 The specimens must have a constant cross-sectional area over a length (L).
1.3 The values stated in SI units are to be regarded as the standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.5 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.
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