ASTM C1351M-96(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: C1351M − 96 (Reapproved 2022)
Standard Test Method for
Measurement of Viscosity of Glass Between 10 Pa·s and
10 Pa·s by Viscous Compression of a Solid Right Cylinder
[Metric]
This standard is issued under the fixed designation C1351M; 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 3. Terminology
3.1 parallel plate viscometer—a device used to determine
1.1 This test method covers the determination of the viscos-
4 8
4 8
the viscosity of glass from approximately 10 Pa·s to 10 Pa·s
ity of glass from 10 Pa·s to 10 Pa·s by measuring the rate of
by measuring the rate of change in thickness of a cylindrical
viscous compression of a small, solid cylinder.
specimenbetweenparallelplatesmovingperpendiculartotheir
1.2 The values stated in SI units are to be regarded as the
commoncentralaxis.Theequationforcalculatingviscosityby
standard.
the parallel plate method is:
1.3 This standard does not purport to address all of the
Mgh
safety concerns, if any, associated with its use. It is the
η 5 2π (1)
30V ~dh/dt!~2πh 1V!~11αT!
responsibility of the user of this standard to establish appro-
priate safety, health, and environmental practices and deter- where:
mine the applicability of regulatory limitations prior to use.
η = viscosity, Pa·s,
1.4 This international standard was developed in accor- M = applied load, g,
dance with internationally recognized principles on standard- g = acceleration due to gravity, 980 cm/s ,
t = time, s,
ization established in the Decision on Principles for the
V = specimen volume, cm ,
Development of International Standards, Guides and Recom-
h = specimen thickness at time t, cm,
mendations issued by the World Trade Organization Technical
dh/dt = compression rate, cm/s, and
Barriers to Trade (TBT) Committee.
α = glass mean coefficient of thermal expansion, 25°C
to the measurement temperature, T, m/m/°C. See
2. Referenced Documents
Note 1.
2.1 ASTM Standards:
NOTE 1—The term (1+αT) corrects for the specimen dimensional
changes due to thermal expansion. For low thermal expansion glasses, it
C338Test Method for Softening Point of Glass
-6
can be ignored. However, for a glass with an α of 20×10 /°C at a
C965Practice for Measuring Viscosity of Glass Above the
measurement temperature of 1000°C, this term produces a correction of
Softening Point
2%. Only an estimate of α is necessary since the correction is small. Use
C1350MTest Method for Measurement of Viscosity of
twice the room temperature coefficient if data are unavailable.
Glass Between Softening Point and Annealing Range
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(Approximately 10 Pa·s to Approximately 10 Pa·s) by
4. Significance and Use
Beam Bending (Metric)
4.1 This test method is well suited for measuring the
viscosity of glasses between the range within which rotational
viscometry (see Practice C965) is useful and the range within
This test method is under the jurisdiction of ASTM Committee C14 on Glass
which beam bending viscometry is useful (see Test Method
and Glass Products and is the direct responsibility of Subcommittee C14.04 on
C1350M). It can be used to determine the viscosity/
Physical and Mechanical Properties.
temperature curve in the region near the softening point (see
Current edition approved Feb. 1, 2022. Published March 2022. Originally
Test Method C338). This test method is useful for providing
approved in 1996. Last previous edition approved in 2017 as C1351M–96(2017).
DOI: 10.1520/C1351M-96R22.
information related to the behavior of glass as it is formed into
Fontana, E. H., “A Versatile Parallel-Plate Viscometer For Glass Viscosity
an object of commerce, and in research and development.
Measurements to 1000°C,” Bulletin of the American Ceramic Society, Vol 49, No.
6, 1970, pp. 594–597.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 5. Apparatus
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
5.1 The apparatus shall consist of a furnace, a means of
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. controlling and measuring its temperature and heating rate,
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1351M − 96 (2022)
specimen holders and loading rod, and a means of measuring
the rate of viscous compression of the glass specimen.
5.2 Furnace:
5.2.1 The furnace shall be electrically heated by resistance
elements. The dimensions and details of the furnace construc-
tion are not critical; its cross-section can be circular of 75mm
(≈3 in.) diameter or square of sides of 75 mm. The furnace
should have a constant temperature zone that covers the
specimen geometry, including the compression range. Differ-
ences in temperature greater than 2°C within the constant
temperature zone are unacceptable.
5.3 Temperature Measuring and Indicating Instruments:
5.3.1 For the measurement of temperature, there shall be
provided a calibrated Type K, R, or S thermocouple. The
thermocouple shall be housed in a double-bore alumina tube
with its junction placed within 5mm of the specimen near the
axis of the furnace. The thermocouple shall be referenced to
0°C by means of an ice bath, and its emf measured with a
calibrated potentiometer that can be read with a sensitivity
equivalentto 60.1°Candanaccuracyof 60.5°C.Precautions
shall be taken to ensure that the ice bath is maintained at 0°C
throughoutthetest.Alternately,theoutputofthethermocouple
can be measured on a calibrated, direct reading meter (elec-
tronic thermometer) that can be read with a sensitivity of
60.1°C and an accuracy of 60.5°C. See Note 3 for tempera-
ture lag-lead corrections.
5.4 Furnace Control:
5.4.1 Suitable means shall be provided for maintaining the
furnace at a fixed control point and for controlling the heating
and cooling rates. Commercially available programming
equipment provides excellent control. A variable transformer FIG. 1 A Typical Parallel Plate Viscometer
withmanualcontrolisaninexpensive,butlessadequatemeans
of accomplishing the required control.
5.5 Specimen Holder and Loading Rod:
measured translation. This will limit the minimum translation
5.5.1 A typical configuration is presented in Fig. 1. Posi-
that may be used in calculation.Alinearly variable differential
tioned horizontally on top of the support stand is a stationary
transformer(LVDT)issuitableforthispurpose,asisanyother
plate (see Note 2),6mm(; ⁄4 in.) thick by diameter of the
device (for example, optical or capacitative), provided that
support stand. A movable plate, 6 mm thick by 44 mm
length changes are reliably measured as specified.
minimum diameter is placed parallel and concentrically above
5.7 Micrometer Calipers:
the fixed plate. (See parallel plates in Fig. 1.) Attached to the
5.7.1 Micrometercalipers,whichcanbereadtoanaccuracy
top center of the movable plate in a shrink fit configuration is
of at least 0.01 mm are required for measuring specimen
a 9mm (; ⁄8-in.) diameter centerless-ground alumina rod of
dimensions.
lengthsufficienttoreachapproximately150mm(6in.)beyond
the top of the furnace or its supporting structure, or both. This
6. Preparation of Test Specimen
assembly provides a means for loading the specimen during
6.1 Specimens required for this test method are small, right,
measurement. Bushings attached to the external frame guide
the shaft with a minimum amount of friction. circular cylinders. Nominal dimensions are 6 mm (; ⁄4 in.) to
12mm(; ⁄2in.)diameterand3mmto6mmthick.Specimens
NOTE 2—Alumina and vitreous silica are suitable materials for the
can be either core-drilled from flat stock or sliced from a rod.
assemblycomponents,asarenobleorlowexpansionmetalsusedinpairs.
In both cases, the flat surfaces must be ground and polished to
The user must observe temperature limitations for these alternate materi-
als. be plane-parallel to 60
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