ASTM C621-09(2018)

Standard Test Method for Isothermal Corrosion Resistance of Refractories to Molten Glass

SIGNIFICANCE AND USE
3.1 This test method provides a rapid, inexpensive method for comparing the corrosion resistance of refractories. The isothermal conditions of this test method represent the most severe static corrosion environment possible at the specified test temperature. This test method is suitable for quality control, research and development applications, and for product value studies on similar materials. Tests run at a series of temperatures are often helpful in determining the use temperature limitations of a particular material. Melt-line corrosion results are also a useful indication of relative resistance to both upward and downward drilling corrosion mechanisms. Examination of test specimens also provides information about the tendency for a particular refractory to form stones or other glass defects.  
3.2 Because this test method is both isothermal and static, and since most glass-contact refractories operate in a dynamic system with a thermal gradient, test results do not directly predict service in a furnace. The effects of differing thermal conductivities, refractory thickness, artificial cooling or insulation upon the refractory thermal gradient, and the erosive action of moving molten glass currents are not evaluated with this test.
SCOPE
1.1 This test method covers the determination of the corrosion resistance of refractories in contact with molten glass under static, isothermal conditions.  
1.2 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 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.  
1.4 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: Historical
• Publication Date: 30-Sep-2018
• ICS: 81.080 - Refractories
• Technical Committee: C08 - Refractories
• Drafting Committee: C08.10 - Refractories for Glass

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C621 − 09 (Reapproved 2018)
Standard Test Method for
Isothermal Corrosion Resistance of Refractories to Molten
1
Glass
This standard is issued under the fixed designation C621; 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 uct value studies on similar materials. Tests run at a series of
temperatures are often helpful in determining the use tempera-
1.1 This test method covers the determination of the corro-
ture limitations of a particular material. Melt-line corrosion
sion resistance of refractories in contact with molten glass
results are also a useful indication of relative resistance to both
under static, isothermal conditions.
upward and downward drilling corrosion mechanisms. Exami-
1.2 The values stated in inch-pound units are to be regarded
nation of test specimens also provides information about the
as standard. The values given in parentheses are mathematical
tendency for a particular refractory to form stones or other
conversions to SI units that are provided for information only
glass defects.
and are not considered standard.
3.2 Because this test method is both isothermal and static,
1.3 This standard does not purport to address all of the
and since most glass-contact refractories operate in a dynamic
safety concerns, if any, associated with its use. It is the
system with a thermal gradient, test results do not directly
responsibility of the user of this standard to establish appro-
predict service in a furnace. The effects of differing thermal
priate safety, health, and environmental practices and deter-
conductivities, refractory thickness, artificial cooling or insu-
mine the applicability of regulatory limitations prior to use.
lation upon the refractory thermal gradient, and the erosive
1.4 This international standard was developed in accor-
action of moving molten glass currents are not evaluated with
dance with internationally recognized principles on standard-
this test.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4. Apparatus
mendations issued by the World Trade Organization Technical
4.1 Glass-Melting Test Furnace, heated with some type of
Barriers to Trade (TBT) Committee.
electrical resistor (Note 1) and having a chamber large enough
2. Referenced Documents to receive four crucible assemblies of the type used in the test
2
(Fig. 1) is required. The zone of the furnace in which the
2.1 ASTM Standards:
crucibles will rest should possess a maximum transverse
E220 Test Method for Calibration of Thermocouples By
thermal gradient of 61.8 °F (61 °C). Fig. A1.1 shows a
Comparison Techniques
schematic drawing of a furnace that is satisfactory for this test.
3. Significance and Use
NOTE 1—It has been demonstrated that gas-fired furnaces show greater
variability and higher average corrosion with this test method and are
3.1 This test method provides a rapid, inexpensive method
therefore generally unsuitable.
for comparing the corrosion resistance of refractories. The
isothermal conditions of this test method represent the most 4.2 Temperature-Control Instrumentation, capable of main-
taining the desired temperature to 61.8 °F (61 °C).
severe static corrosion environment possible at the specified
test temperature. This test method is suitable for quality
4.3 Thermocouple, for use as the temperature measuring
control, research and development applications, and for prod-
device. The type of thermocouple chosen will depend on the
normal use temperature of the furnace. Since thermocouples
age with a consequent drift in the signal fed to the control
1
This test method is under the jurisdiction of ASTM Committee C08 on
instrument, check the couple before each test run with a
RefractoriesandisthedirectresponsibilityofSubcommitteeC08.10onRefractories
for Glass.
calibrated thermocouple. Test Method E220 specifies calibra-
Current edition approved Oct. 1, 2018. Published October 2018. Originally
tion procedures for thermocouples. If drift becomes severe,
approved in 1968. Last previous edition approved in 2014 as C621 – 09 (2014).
replace the thermocouple. Position the thermocouple hot junc-
DOI: 10.1520/C0621-09R18.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or tion in the furnace to coincide with the level of the glass line
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
of the test samples.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 4.4 Platinum Crucibles (Fig. 1).
Copyright © ASTM International,
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C621 − 09 (Reapproved 2014) C621 − 09 (Reapproved 2018)
Standard Test Method for
Isothermal Corrosion Resistance of Refractories to Molten
1
Glass
This standard is issued under the fixed designation C621; 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
1.1 This test method covers the determination of the corrosion resistance of refractories in contact with molten glass under
static, isothermal conditions.
1.2 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 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 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.
2. Referenced Documents
2
2.1 ASTM Standards:
E220 Test Method for Calibration of Thermocouples By Comparison Techniques
3. Significance and Use
3.1 This test method provides a rapid, inexpensive method for comparing the corrosion resistance of refractories. The isothermal
conditions of this test method represent the most severe static corrosion environment possible at the specified test temperature. This
test method is suitable for quality control, research and development applications, and for product value studies on similar
materials. Tests run at a series of temperatures are often helpful in determining the use temperature limitations of a particular
material. Melt-line corrosion results are also a useful indication of relative resistance to both upward and downward drilling
corrosion mechanisms. Examination of test specimens also provides information about the tendency for a particular refractory to
form stones or other glass defects.
3.2 Because this test method is both isothermal and static, and since most glass-contact refractories operate in a dynamic system
with a thermal gradient, test results do not directly predict service in a furnace. The effects of differing thermal conductivities,
refractory thickness, artificial cooling or insulation upon the refractory thermal gradient, and the erosive action of moving molten
glass currents are not evaluated with this test.
4. Apparatus
4.1 Glass-Melting Test Furnace, heated with some type of electrical resistor (Note 1) and having a chamber large enough to
receive four crucible assemblies of the type used in the test (Fig. 1) is required. The zone of the furnace in which the crucibles
will rest should possess a maximum transverse thermal gradient of 61.8°F (61°C).61.8 °F (61 °C). Fig. A1.1 shows a schematic
drawing of a furnace that is satisfactory for this test.
NOTE 1—It has been demonstrated that gas-fired furnaces show greater variability and higher average corrosion with this test method and are therefore
generally unsuitable.
1
This test method is under the jurisdiction of ASTM Committee C08 on Refractories and is the direct responsibility of Subcommittee C08.10 on Refractories for Glass.
Current edition approved Sept. 1, 2014Oct. 1, 2018. Published November 2014October 2018. Originally approved in 1968. Last previous edition approved in 20092014
as C621 – 09.C621 – 09 (2014). DOI: 10.1520/C0621-09R14.10.1520/C0621-09R18.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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C621 − 09 (2018)
SI Equivalents
in. mm
0.030 0.76
13
⁄64 5
1
⁄2 13
33
⁄64 13
17
⁄32 13
1 25
1
1 ⁄4 32.8
NOTE 1—All undesignated dimensions are in inches.
FIG. 1 Crucible Ass
...