ISO 10329:2025
(Main)Hard coal — Determination of plastic properties — Constant-torque Gieseler plastometer method
Hard coal — Determination of plastic properties — Constant-torque Gieseler plastometer method
This document specifies a method for obtaining a relative measure of the plastic behaviour of hard coal when heated under prescribed conditions. The method is used to obtain values of the plastic properties of coals and blends used in carbonization and in other situations where determination of plastic behaviour of coals is of practical importance. NOTE The empirical nature of this test requires proper equipment calibration to produce fluidity readings which are a true indication of the relative plastic behaviour of the coal.
Houille — Détermination des propriétés plastiques — Méthode du plastomètre Gieseler à couple constant
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Standards Content (Sample)
International
Standard
ISO 10329
Third edition
Hard coal — Determination of
2025-05
plastic properties — Constant-
torque Gieseler plastometer method
Houille — Détermination des propriétés plastiques — Méthode
du plastomètre Gieseler à couple constant
Reference number
© ISO 2025
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Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Calibration . 4
7 Sample . 4
8 Procedure . 4
9 Cleaning of the apparatus .12
10 Calculation and expression of results .12
11 Precision of the method .13
11.1 Repeatability . 13
11.2 Reproducibility . 13
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 27, Coal and coke, Subcommittee SC 5, Methods
of analysis.
This third edition cancels and replaces the second edition (ISO 10329:2017), which has been technically
revised.
The main changes are as follows:
— updated the scope of this document, it is only applicable to hard coal;
— clarified reporting requirements for the various ranges of dd/min.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
International Standard ISO 10329:2025(en)
Hard coal — Determination of plastic properties — Constant-
torque Gieseler plastometer method
1 Scope
This document specifies a method for obtaining a relative measure of the plastic behaviour of hard coal
when heated under prescribed conditions. The method is used to obtain values of the plastic properties of
coals and blends used in carbonization and in other situations where determination of plastic behaviour of
coals is of practical importance.
NOTE The empirical nature of this test requires proper equipment calibration to produce fluidity readings which
are a true indication of the relative plastic behaviour of the coal.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 13909-1, Coal and coke — Mechanical sampling — Part 1: General introduction
ISO 13909-2, Coal and coke — Mechanical sampling — Part 2: Sampling of coal from moving streams
ISO 13909-3, Coal and coke — Mechanical sampling — Part 3: Sampling of coal from stationary lots
ISO 13909-4:2016, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples
ISO 18283, Coal and coke — Manual sampling
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
dial division per minute
dd/min
measure of stirrer rotation rate, as used in the constant-torque Gieseler plastometer method
Note 1 to entry: There are 100 dial divisions for each full 360° rotation of the stirrer. The fluidity result is expressed as
total dial divisions turned by the stirrer in a 1 min time period, i.e. dd/min.
3.2
initial softening temperature
temperature at which dial movement or electronic readout indicates a stirring shaft movement of one dial
division per minute (3.1), with continued indication of movement of at least 1 dd/min thereafter
3.3
maximum fluidity temperature
temperature at which stirring shaft rotation reaches the maximum rate
3.4
plastic range
difference between the initial softening temperature and the solidification temperature
3.5
final fluidity temperature
temperature at which the last 1 dd/min stirrer rotation rate is reached
3.6
solidification temperature
temperature at which the stirring shaft stops
3.7
maximum fluidity
maximum rate of rotation for the stirring shaft in dial divisions per minute (3.1)
3.8
jamming
swelling up of coal into the retort tube during the test
Note 1 to entry: Jamming can produce a lower fluidity result than expected and can only be noted after visual
inspection of the disassembled crucible and retort at the conclusion of the test.
3.9
breaking
free spinning behaviour of coal, either by rotating at maximum motor speed or by abrupt changes in rotation
Note 1 to entry: Breaking occurs as a result of a molten ball of coal forming around the base of the stirrer, and makes
reporting of the true maximum fluidity (3.7) of the coal difficult.
4 Principle
Measurements of the plastic properties of coals are made by applying a constant torque to a stirrer placed in
a crucible into which the coal is charged. The crucible is immersed in a bath and the temperature increased
uniformly. The rotation of the stirrer is recorded in relation to increase in temperature.
5 Apparatus
5.1 Gieseler plastometer retort, composed of the following component parts (see Figure 1).
5.1.1 Retort crucible, cylindrical, with (21,4 ± 0,1) mm inside diameter, and (35,0 ± 0,3) mm in depth
with exterior threads for joining the crucible to the barrel.
The crucible shall have a (2,38 ± 0,02) mm diameter notch with an included angle of 70° in the centre of its
inside base to serve as a seat for the stirrer.
5.1.2 Retort crucible cover, with interior threads for joining the crucible cover to the crucible and
exterior threads for joining the crucible cover to the barrel.
The inside diameter of the hole which accommodates the stirrer shall be (9,5 ± 0,1) mm.
5.1.3 Guide sleeve, provided near the upper end of the stirrer to guide the latter within the barrel with a
clearance of between 0,05 mm and 0,10 mm.
5.1.4 Gas exit hole, provided on the barrel to afford an exit for the volatile products during a test, placed,
for example, at the midpoint of the barrel; as an option, a tube may be fitted if desired.
5.1.5 Barrel, (121,0 ± 2,5) mm long, having an inside diameter of (9,5 ± 0,1) mm.
The top end of the barrel shall be 12,7 mm in inside diameter to a depth sufficient to allow the fitting of a
guide sleeve through which the axle of the stirrer passes when the apparatus is assembled.
5.1.6 Steel stirrer, provided with a straight shaft (3,95 ± 0,05) mm in diameter and equipped with four
rabble arms.
The lower end of the stirrer shall be tapered to a point having an included angle of 60°. The rabble arms on
the stirrer shall be (1,60 ± 0,05) mm in diameter, (6,4 ± 0,05) mm in length, and shall be placed perpendicular
to the shaft at 90° intervals around the shaft and (3,2 ± 0,05) mm apart centre to centre along the shaft. The
middle two rabble arms shall be set at 180° to each other, and likewise, the remaining two arms at 180° to
each other. The lowest rabble arm shall be set to give (1,60 ± 0,05) mm clearance between it and the bottom
of the crucible when the stirrer is in place. The upper end of the stirrer shall be cut to fit into a slot on the
lower end of the axle in the plastometer head.
The rabble arms shall be checked before each test to ensure that they are clean and free from distortion
or other visual damage. It is essential that the dimensions of the rabble arms on the stirrer meet the
requirements in this clause and in Figure 2 and it is important that these dimensions are checked on a
regular basis, e.g. every 50 determinations. If after use, it is found by accurate measurement that any of the
dimensions are outside the specified limits, the rabble arms shall be replaced or the stirrer discarded.
5.2 Plastometer head
The plastometer head, shown schematically in Figure 3, shall consist of a fixed-speed motor (approximately
300 r/min) connected directly to a magnetic clutch or hysteresis brake capable of adjustment over a
reasonable range on either side of a torque value of 101,6 g⋅cm (9,66 Nm). A dial drum, attached to the
clutch brake output shaft, shall be graduated into 100 divisions for 360°. Each complete drum revolution or
100 dial divisions shall be recorded on a counter actuated by an electric eye or other suitable method. As an
alternative, an electronic device capable of measuring rotation rates between 0,01 r/min and 300 r/min may
be attached to the clutch or brake output shaft. Using this latter technique, rotation rates can be converted
directly to dial divisions per minute (dd/min) and can be displayed or recorded once a minute on a suitable
electronic readout or printer.
NOTE Care is needed in the maintenance and lubrication of all bearings, particularly after the instrument has
been used with a coal high in volatile matter. Using bearings
...
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