ASTM C1223-19(2023)

Standard Test Method for Testing of Glass Exudation from AZS Fusion-Cast Refractories

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.  
4.2 The results may be considered as representative of the potential for an AZS refractory (specifically, in the tested region) to contribute to glass defect formation during the furnace production operation.  
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.
SCOPE
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.

General Information

• Status: Published
• Publication Date: 31-Jul-2023
• ICS: 81.080 - Refractories
• Technical Committee: C08 - Refractories
• Drafting Committee: C08.10 - Refractories for Glass

Relations

• Refers: ASTM C20-00(2005) - Standard Test Methods for Apparent Porosity, Water Absorption, Apparent Specific Gravity, and Bulk Density of Burned Refractory Brick and Shapes by Boiling Water
• Effective Date: 01-Dec-2005
• Refers: ASTM C20-00 - Standard Test Methods for Apparent Porosity, Water Absorption, Apparent Specific Gravity, and Bulk Density of Burned Refractory Brick and Shapes by Boiling Water
• Effective Date: 10-Apr-2000

Overview

ASTM C1223-19(2023), "Standard Test Method for Testing of Glass Exudation from AZS Fusion-Cast Refractories," sets out standardized procedures for evaluating the exudation of glassy phases from alumina-zirconia-silica (AZS) fusion-cast refractories. Developed by ASTM International, this test method is designed for use as a quality assurance and process control tool by manufacturers, as well as a reference for glass producers when selecting refractories for glass-melting furnace designs. The results of the test are especially relevant in identifying the potential for AZS refractories to contribute to glass defect formation during furnace operation.

Key Topics

• Test Procedure: The standard describes a method to cause and measure glass exudation by subjecting fusion-cast AZS specimens to high temperatures that simulate glass furnace operating conditions. The exudate is quantified as the percent increase in specimen volume after cooling.
• Sampling and Specimens: Requirements are specified for removing cores or bars from refractory castings, with considerations given to casting size, sampling location, and maintaining specimen uniformity.
• Measurements and Equipment:
  • Use of precise laboratory balances and electric kilns capable of glass-melting temperatures.
  • Use of platinum foil cups to capture exudate during testing.
  • Procedures for dry/wet weighing for accurate volume calculations.
• Data Analysis: Provides a calculation approach for determining the percent of exudation, and allows observations on characteristics such as clarity, color, and extent of exudate.
• Reheating Cycles: Guidance on additional heating cycles to assess further exudation, relevant for understanding performance under repeated operating conditions.
• Interlaboratory Precision: Includes statistical information for precision and reproducibility of the test results across laboratories.

Applications

• Process Control for Refractory Manufacturers: Used to monitor and refine the production quality of AZS fusion-cast refractories by detecting excessive glass phase exudation that can compromise material performance.
• Glass Furnace Design and Selection: Assists glass manufacturers in selecting suitable refractories that minimize the risk of defects in glass production, ensuring optimal furnace longevity and product quality.
• Defect Prevention in Glass Production: Identifies regions within a refractory casting more likely to contribute to defect formation, supporting targeted material improvement and sampling strategies.
• Quality Assurance: Provides a reliable method for comparing different refractory products and manufacturing batches, fostering consistency in high-temperature applications.
• Broader Refractory Uses: Procedures may be extended to other refractory types and applications-such as skid rail bricks used in reheat furnaces-where glass exudation is a concern.

Related Standards

• ASTM C20: Test Methods for Apparent Porosity, Water Absorption, Apparent Specific Gravity, and Bulk Density of Burned Refractory Brick and Shapes by Boiling Water. This standard is referenced for preparation and weighing of specimens.
• International Standards Principles: ASTM C1223-19(2023) aligns with guidelines set by the World Trade Organization Technical Barriers to Trade (TBT) Committee for internationally recognized testing and standardization practices.
• Other ASTM Refractory Standards: Consider additional ASTM standards developed by Committee C08 on Refractories for comprehensive evaluation and specification of refractory materials in high-temperature applications.

By following ASTM C1223-19(2023), manufacturers and users of AZS fusion-cast refractories ensure consistent assessment of exudation behavior, contributing to better quality control, improved furnace operations, and safer, more reliable glass production processes. Incorporating this standard effectively supports defect minimization and optimal refractory selection.

Standards Content (Sample)

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: C1223 − 19 (Reapproved 2023)
Standard Test Method for
Testing of Glass Exudation from AZS Fusion-Cast
Refractories
This standard is issued under the fixed designation C1223; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method covers a procedure for causing the 3.1 Acronyms:
exudation of a glassy phase to the surface of fusion-cast 3.1.1 AZS—Alumina-Zirconia-Silica
specimens by subjecting them to temperatures corresponding
4. Significance and Use
to glass furnace operating temperatures.
1.2 This test method covers a procedure for measuring the 4.1 This test method was developed for use both by manu-
facturers as a process control tool for the production of AZS
exudate as the percent of volume increase of the specimen after
cooling. fusion-cast refractories, and by glass manufacturers in the
selection of refractories and design of glass-melting furnaces.
1.3 Units—The values stated in inch-pound units are to be
4.2 The results may be considered as representative of the
regarded as standard. The values given in parentheses are
potential for an AZS refractory (specifically, in the tested
mathematical conversions to SI units that are provided for
region) to contribute to glass defect formation during the
information only and are not considered standard.
furnace production operation.
1.3.1 Exception—The balance required for this test method
uses only SI units (Section 7).
4.3 The procedures and results may be applied to other
1.4 This standard does not purport to address all of the refractory types or applications (that is, reheat furnace skid rail
safety concerns, if any, associated with its use. It is the brick) in which glass exudation is considered to be important.
responsibility of the user of this standard to establish appro-
5. Apparatus and Materials
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
5.1 Scale—A laboratory scale or balance rigged for suspen-
1.5 This international standard was developed in accor-
sion of specimens for dry/wet weight determinations to an
dance with internationally recognized principles on standard-
accuracy of 0.01 g.
ization established in the Decision on Principles for the
5.2 Kiln—An electric kiln to accommodate several 4-in.
Development of International Standards, Guides and Recom-
(102 mm) specimen cores placed vertically on end, and for
mendations issued by the World Trade Organization Technical
service at 2750 °F (1510 °C), with a variation of <10 °F (6 °C).
Barriers to Trade (TBT) Committee.
5.3 Foil—Cups formed from 2 ⁄4-in. (56 mm) squares of
2. Referenced Documents platinum foil (Pt, 5 % Au alloy, 0.003 in. (0.076 mm) thick).
One cup required per specimen.
2.1 ASTM Standards:
C20 Test Methods for Apparent Porosity, Water Absorption, 5.4 AZS Casting—A virgin casting having no prior thermal
Apparent Specific Gravity, and Bulk Density of Burned history except that of its own formation, and of a size and
Refractory Brick and Shapes by Boiling Water casting process equivalent to the intended application (such as
an arch block) in which exudation potential is of interest.
6. Test Specimens and Sampling
This test method is under the jurisdiction of ASTM Committee C08 on
Refractories and is the direct responsibility of Subcommittee C08.10 on Refracto-
6.1 Specimens may be removed from the original casting
ries for Glass.
either as drilled cores or as sawed bars, depending on labora-
Current edition approved Aug. 1, 2023. Published August 2023. Originally
tory capability. Specimen cores or bars should be 4 in.
approved in 1992. Last previous edition approved in 2019 as C1223 – 19. DOI:
10.1520/C1223-19R23.
(102 mm) long and either 1 in. (25.4 mm) in diameter or 1 in.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
by 1 in. (25.4 mm by 25.4 mm) in cross section. The length
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
dimension of the specimen should be perpendicular to the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. surface of the block from which it is removed.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1223 − 19 (2023)
6.2 The dimensions of the prepared specimen core are not (as cast). This lower region, which often becomes the top
critical but should be maintained as specified, with minimal “metal line” when the casting is inverted, has been found to be
specimen-to-specimen variation. Excessive thickness can pre- not representative of the overall casting.
vent isothermal heating within the specimen. Height and width
can affect the positioned stability of the specimen in the kiln
7. Procedure
during heating.
7.1 Weights must be obtained individually for both the
6.3 The size of the original casting may influence the untested specimen cores and the foil squares on which the
results. Evaluations of the product should be made relative to cores will be placed. This is because each core and its foil will
only the intended application. For example, a conveniently usually be fused together at the end of testing and cannot be
sized bottom paver might not be representative of a larger
separated before weighing without risk of lost exudate. Once
superstructure casting because (for example) casting mold paired, each set of core-and-foil must remain together through-
types and solidification rates may have been different during
out testing and subsequent calculation of data (see Fig. 1).
manufacture.
7.2 To account for the possible presence of surface-
6.4 The location and depth of specimens within the original connected porosity in specimen cores, the treatments (drying
casting can influence the results. Regions closely underlying and boiling) as specified by Test Methods C20 must be applied,
the surface of the casting (particularly near the corners and as described as follows:
edges) are thermally quenched and have aligned microstruc-
7.3 Dry the specimen cores to constant weight by heating to
tures that are atypical of more slowly cooled regions. Deeper in
220 °F to 230 °F (105 °C to 110 °C), and determine the dry
a casting, glass-phase pockets and crystal sizes are larger, and
weight (Wd ) to the nearest 0.01 g.
certain shifts in chemical stratification exist due to fractional
7.4 Place the specimen cores in water and boil for 2 h. Keep
crystallization during solidification. No single point in an AZS
the specimens entirely covered with water during the boiling
casting represents the whole entirely.
period, and permit no contact with the heated bottom of the
6.5 Regular-cast AZS blocks, approximately 8 in. to 12 in.
container.
(203 mm to 305 mm) thick, such as is typical of furnace
7.5 After the boiling period, cool the test specimens to room
superstructure and sidewall sizes, are sampled by drilling or
temperature, while still covered completely with water, for a
plunge-cutting perpendicularly to the bottom surface (the
minimum of 12 h before weighing.
surface opposite the casting scar).
6.5.1 The location of entry (by drilling or sawing) should be
7.6 Determine the specimen core wet weight (Ww ) of each
at least 4 in. (102 mm) away from any edge, yet not
specimen core after boiling and while suspended in water to the
immediately under the casting scar.
nearest 0.01 g.
6.
...