Standard Practices for Measurement of Liquidus Temperature of Glass by the Gradient Furnace Method

SIGNIFICANCE AND USE
3.1 These practices are useful for determining the maximum temperature at which crystallization will form in a glass, and a minimum temperature at which a glass can be held, for extended periods of time, without crystal formation and growth.
SCOPE
1.1 These practices cover procedures for determining the liquidus temperature (Note 1) of a glass (Note 1) by establishing the boundary temperature for the first crystalline compound, when the glass specimen is held at a specified temperature gradient over its entire length for a period of time necessary to obtain thermal equilibrium between the crystalline and glassy phases.  
Note 1: These terms are defined in Terminology C162.  
1.2 Two methods are included, differing in the type of sample, apparatus, procedure for positioning the sample, and measurement of temperature gradient in the furnace. Both methods have comparable precision. Method B is preferred for very fluid glasses because it minimizes thermal and mechanical mixing effects.  
1.2.1 Method A employs a trough-type platinum container (tray) in which finely screened glass particles are fused into a thin lath configuration defined by the trough.  
1.2.2 Method B employs a perforated platinum tray on which larger screened particles are positioned one per hole on the plate and are therefore melted separately from each other.2  
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 and health practices and determine the applicability of regulatory limitations prior to use.

General Information

Status
Historical
Publication Date
30-Apr-2015
Current Stage
Ref Project

Buy Standard

Standard
ASTM C829-81(2015) - Standard Practices for Measurement of Liquidus Temperature of Glass by the Gradient Furnace Method
English language
9 pages
sale 15% off
Preview
sale 15% off
Preview
Standard
REDLINE ASTM C829-81(2015) - Standard Practices for Measurement of Liquidus Temperature of Glass by the Gradient Furnace Method
English language
9 pages
sale 15% off
Preview
sale 15% off
Preview

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: C829 − 81 (Reapproved 2015)
Standard Practices for
Measurement of Liquidus Temperature of Glass by the
1
Gradient Furnace Method
This standard is issued under the fixed designation C829; 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.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 Other Document:
4
NIST Certificate for Liquidus Temperature, SRM 773
1.1 These practices cover procedures for determining the
liquidus temperature (Note 1) of a glass (Note 1) by establish-
3. Significance and Use
ing the boundary temperature for the first crystalline
3.1 Thesepracticesareusefulfordeterminingthemaximum
compound, when the glass specimen is held at a specified
temperature at which crystallization will form in a glass, and a
temperature gradient over its entire length for a period of time
minimum temperature at which a glass can be held, for
necessarytoobtainthermalequilibriumbetweenthecrystalline
extended periods of time, without crystal formation and
and glassy phases.
growth.
NOTE 1—These terms are defined in Terminology C162.
1.2 Two methods are included, differing in the type of 4. Apparatus
sample, apparatus, procedure for positioning the sample, and
4.1 The apparatus for determining the liquidus temperature
measurement of temperature gradient in the furnace. Both
shall consist essentially of an electrically heated gradient
methodshavecomparableprecision.MethodBispreferredfor
furnace, a device for controlling the furnace temperature,
veryfluidglassesbecauseitminimizesthermalandmechanical
temperature measuring equipment, and other items listed.
mixing effects.
4.1.1 Furnace:
1.2.1 Method A employs a trough-type platinum container
4.1.1.1 MethodA—Horizontal temperature gradient, electri-
(tray) in which finely screened glass particles are fused into a
cally heated furnace, tube type, as illustrated in Figs. 1-3 and
thin lath configuration defined by the trough.
described in A1.1.
1.2.2 Method B employs a perforated platinum tray on
4.1.1.2 Method B—An alternative furnace detail employing
which larger screened particles are positioned one per hole on
pregrooved Al O cores and dual windings, as illustrated in
2 3
2
the plate and are therefore melted separately from each other.
Figs. 4 and 5, and described in A1.2.
1.3 This standard does not purport to address all of the
4.1.1.3 Equivalenttemperaturegradientconditionsmayalso
safety concerns, if any, associated with its use. It is the
be obtained with furnaces having multiple windings equipped
responsibility of the user of this standard to establish appro-
with separate power and control, or a tapped winding shunted
priate safety and health practices and determine the applica-
with suitable resistances. For high precision, temperature
bility of regulatory limitations prior to use.
gradients in excess of 10°C/cm should be avoided.
4.1.2 Furnace Temperature Control:
2. Referenced Documents
4.1.2.1 Method A—A suitable temperature controller shall
3
2.1 ASTM Standards:
be provided to maintain a fixed axial temperature distribution
C162Terminology of Glass and Glass Products over the length of the furnace.
4.1.2.2 Method B—Arheostatshallbeusedtosupplypower
1 totheouterwinding.Aseparaterheostatandcontrollershallbe
These practices are under the jurisdiction of ASTM Committee C14 on Glass
and Glass Productsand are the direct responsibility of Subcommittee C14.04 on
usedfortheinnercorewinding.Thebasicfurnacetemperature
Physical and Mechanical Properties.
level is achieved by controlling power to both inner and outer
Current edition approved May 1, 2015. Published May 2015. Originally
core windings. The slope of the gradient is achieved by
approved in 1976. Last previous edition approved in 2010 as C829–81(2010).
adjusting power input to the outer core winding only. The
DOI: 10.1520/C0829-81R15.
2
FromNBSResearchPaperRP2096,Vol44,May1950,byO.H.GrauerandE.
establishedtemperaturegradientisthenmaintainedbycontrol-
H. Hamilton, with modification and improvement by K. J. Gajewski, Ford Motor
ling power to the inner core winding only.
Co., Glass Research and Development Office (work unpublished).
3
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
4
Standards volume information, refer to the standard’s Document Summary page on Available from National Institute of Standards and Technology (NIST), 100
the ASTM website. Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

-----
...

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: C829 − 81 (Reapproved 2010) C829 − 81 (Reapproved 2015)
Standard Practices for
Measurement of Liquidus Temperature of Glass by the
1
Gradient Furnace Method
This standard is issued under the fixed designation C829; 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 These practices cover procedures for determining the liquidus temperature (Note 1) of a glass (Note 1) by establishing the
boundary temperature for the first crystalline compound, when the glass specimen is held at a specified temperature gradient over
its entire length for a period of time necessary to obtain thermal equilibrium between the crystalline and glassy phases.
NOTE 1—These terms are defined in Terminology C162.
1.2 Two methods are included, differing in the type of sample, apparatus, procedure for positioning the sample, and
measurement of temperature gradient in the furnace. Both methods have comparable precision. Method B is preferred for very fluid
glasses because it minimizes thermal and mechanical mixing effects.
1.2.1 Method A employs a trough-type platinum container (tray) in which finely screened glass particles are fused into a thin
lath configuration defined by the trough.
1.2.2 Method B employs a perforated platinum tray on which larger screened particles are positioned one per hole on the plate
2
and are therefore melted separately from each other.
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 and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
3
2.1 ASTM Standards:
C162 Terminology of Glass and Glass Products
2.2 Other Document:
4
NIST Certificate for Liquidus Temperature, SRM 773
3. Significance and Use
3.1 These practices are useful for determining the maximum temperature at which crystallization will form in a glass, and a
minimum temperature at which a glass can be held, for extended periods of time, without crystal formation and growth.
4. Apparatus
4.1 The apparatus for determining the liquidus temperature shall consist essentially of an electrically heated gradient furnace,
a device for controlling the furnace temperature, temperature measuring equipment, and other items listed.
4.1.1 Furnace:
4.1.1.1 Method A—Horizontal temperature gradient, electrically heated furnace, tube type, as illustrated in Fig. 1Figs. 1-3, Fig.
2, and Fig. 3 and described in A1.1.
1
These practices are under the jurisdiction of ASTM Committee C14 on Glass and Glass Productsand are the direct responsibility of Subcommittee C14.04 on Physical
and Mechanical Properties.
Current edition approved April 1, 2010May 1, 2015. Published May 2010May 2015. Originally approved in 1976. Last previous edition approved in 20052010 as
C829C829 – 81 (2010).-81 (2005). DOI: 10.1520/C0829-81R10.10.1520/C0829-81R15.
2
From NBS Research Paper RP2096, Vol 44, May 1950, by O. H. Grauer and E. H. Hamilton, with modification and improvement by K. J. Gajewski, Ford Motor Co.,
Glass Research and Development Office (work unpublished).
3
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 Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
4
Available from National Institute of Standards and Technology (NIST), 100 Bureau Dr., Stop 1070, Gaithersburg, MD 20899-1070, http://www.nist.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
C829 − 81 (2015)
NOTE 1—See A1.1 for further description.
1. Outer shell (stainless steel) 7. Outer protection tube
4 5
2. End plate (Transite) 8. Sil-O-Cel insulation
3. End plate (quartz) 9. Control thermocouple (platinum/rhodium)
4. Stand 10. Heating element wire
5. Inner protection tube 11. Specimen tray
6. Heating element tube
FIG. 1 Liquidus Furnace (Method A)
Material: 26-gageMaterial: 26-gauge stainless steel
FIG. 2 Liquidus Furnace Shell (Method A)
Millimetres
No. of Turns
A: 6 turns—4.8-mm turns—4.8 mm spacing
B: 13 turns—9.5-mm turns—9.5 mm spacing
C: 5 turns—6.4
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.