ASTM C1276-94(2005)
(Test Method)Standard Test Method for Measuring the Viscosity of Mold Powders Above Their Melting Point Using a Rotational Viscometer (Withdrawn 2009)
Standard Test Method for Measuring the Viscosity of Mold Powders Above Their Melting Point Using a Rotational Viscometer (Withdrawn 2009)
SIGNIFICANCE AND USE
The viscosity of a molten mold flux is a very important property for the correct functioning of a mold powder. This procedure is designed for producers and users of mold powders to develop the viscosity-temperature relationships of the molten mold flux for quality control or specification purposes, or both. Practice C 965 was developed for glasses that are significantly higher in viscosity than mold powders. Also, sample preparation is very different for the glass products covered.
Note 1—Warning: Use caution when discharging molten sample into water since this can cause an explosion.
SCOPE
1.1 This test method covers measurement of the viscosity of mold powders above their melting point through the use of a platinum spindle immersed in a platinum crucible containing the molten mold flux. Developed by differential angular velocity between the crucible and spindle, spindle torque is measured and used to calculate the viscosity. Data are generally taken as a function of temperature to describe the viscosity-temperature relationship for the molten mold flux.
1.2 This test method uses a high-temperature furnace and measurements on molten material. Personal protection equipment to wear include high-temperature resistant insulating gloves, coveralls, and a full-face shield.
1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
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 and health practices and determine the applicability of regulatory limitations prior to use. A specific warning statement is given in Note 1.
WITHDRAWN RATIONALE
This test method covers measurement of the viscosity of mold powders above their melting point through the use of a platinum spindle immersed in a platinum crucible containing the molten mold flux. Developed by differential angular velocity between the crucible and spindle, spindle torque is measured and used to calculate the viscosity. Data are generally taken as a function of temperature to describe the viscosity-temperature relationship for the molten mold flux.
Formerly under the jurisdiction of Committee C08 on Refractories, this test method was withdrawn in September 2009. This test method is being withdrawn due to lack of interest and support for its continued use.
General Information
Relations
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: C 1276 – 94 (Reapproved 2005)
Standard Test Method for
Measuring the Viscosity of Mold Powders Above Their
Melting Point Using a Rotational Viscometer
This standard is issued under the fixed designation C 1276; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Significance and Use
3.1 The viscosity of a molten mold flux is a very important
1.1 This test method covers measurement of the viscosity of
mold powders above their melting point through the use of a property for the correct functioning of a mold powder. This
platinum spindle immersed in a platinum crucible containing procedureisdesignedforproducersandusersofmoldpowders
the molten mold flux. Developed by differential angular to develop the viscosity-temperature relationships of the mol-
velocity between the crucible and spindle, spindle torque is ten mold flux for quality control or specification purposes, or
measured and used to calculate the viscosity. Data are gener- both. Practice C 965 was developed for glasses that are
ally taken as a function of temperature to describe the significantly higher in viscosity than mold powders. Also,
viscosity-temperature relationship for the molten mold flux. sample preparation is very different for the glass products
1.2 This test method uses a high-temperature furnace and covered.
measurements on molten material. Personal protection equip-
NOTE 1—Warning: Use caution when discharging molten sample into
ment to wear include high-temperature resistant insulating
water since this can cause an explosion.
gloves, coveralls, and a full-face shield.
1.3 The values stated in inch-pound units are to be regarded 4. Apparatus
as the standard. The values given in parentheses are for
4.1 Electrically Heated Furnace, equipped with a tempera-
information only.
ture controller, temperature measuring equipment, a spindle, a
1.4 This standard does not purport to address all of the
crucible, a device to rotate the spindle, and equipment to
safety concerns, if any, associated with its use. It is the
measure the torque or viscosity.
responsibility of the user of this standard to establish appro-
4.1.1 Any electrically heated furnace capable of providing a
priate safety and health practices and determine the applica-
uniform and stable temperature in the testing zone of the
bility of regulatory limitations prior to use. Aspecific warning
furnace can be used. The furnace must be capable of maintain-
statement is given in Note 1.
ing a temperature 180°F (82°C) above the maximum test
temperature. The atmosphere in the furnace should be air or
2. Referenced Documents
oxidizing.
2.1 ASTM Standards:
4.2 Thermocouple, calibrated in accordance with Test
C 965 Practice for Measuring of Viscosity of Glass Above
Method E 220. It is preferred that the thermocouple be im-
the Softening Point
mersed in the molten mold flux, in which case only the bare
C 1095 Practice for Calculating Precision Data on Refrac-
metal of the thermocouple should be immersed, since immer-
tories (C08) from Interlaboratory Test Results
sion of the thermocouple sheath may result in a reaction
E 220 Test Method for Calibration of Thermocouples by
between the sheath and the molten flux. Alternatively, the
Comparison Techniques
thermocouple can be placed outside the crucible containing the
E 691 Practice for Conducting an Interlaboratory Study to
molten mold flux, providing that the temperature difference
Determine the Precision of a Test Method
between the flux and the position where the thermocouple is
placed is no more than 9°F (5°C).
4.3 SpindleandCrucible,platinumoraplatinumalloy. The
spindle is attached to the rotating device using platinum
This test method is under the jurisdiction of ASTM Committee C08 on
RefractoriesandisthedirectresponsibilityofSubcommitteeC08.10onRefractories
extension wires inside the furnace and other suitable wires
for Glass.
outside the furnace, for example, stainless steel.
Current edition approved March 1, 2005. Published March 2005. Originally
4.3.1 The dimensions of the crucible and spindle shall be
approved in 1994. Last previous edition approved in 1999 as C 1276 - 94(1999).
For referenced ASTM standards, visit the ASTM website, www.astm.org, or such that, when the crucible is filled with molten mold flux, the
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. An alloy such as zirconia grain-stabilized (ZGS) platinum has been used
Withdrawn. successfully.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1276 – 94 (2005)
6. Calibration of the Torque Viscometer
6.1 Clean the spindle thoroughly prior to running this
calibration test. Conduct this test out of the furnace at 77 6
0.2°F (25.0 6 0.1°C) using standard viscosity silicone oils.
This calibration procedure must be run with silicone oils of
various viscosities and using various spindle r/min. The types
of silicone oils tested should have viscosities in the same range
as those of the molten mold flux. Fill the crucible with the
standard viscosity silicone oil, and stabilize the temperature by
placing into a water bath set at 77 6 0.2°F (25.0 6 0.1°C).
6.2 Lower the spindle into the crucible, and position it in
such a manner that it meets the dimensional tolerances as
specified in 4.3.1.
6.3 Switch the viscometer on at a selected speed of rotation
(r/min). Observe the reading on the viscometer.
6.4 Calculate the calibration constant from the following
formula:
calibration constant 5~viscosity of standard!/
~viscometer reading! at given r/min
6.5 If the standard silicone oil has a viscosity of 3.0 poise
and the viscometer reading at 30 r/min is 40, the constant is
0.075 at 30 r/min.
6.6 If the viscometer reading on the molten mold flux is 48
at 30 r/min, the calculated viscosity is 3.6 poise.
7. Procedure
7.1 Fill the crucible with decarburized (see 5.1) mold
powder to within 0.4 in. (1 cm) of the top of the crucible. If the
moldpowdercontainscarbonates,itshouldbeaddedinsmaller
increments to avoid possible boil out during the melting
FIG. 1 Typical Crucible/Spindle Configuration
process.
7.2 The crucible containing the mold powder can be placed
in the furnace either hot or cold. Control the furnace tempera-
body of the spindle can be immersed fully to at least a depth of ture to approximately 2372°F (1300°C), and allow the initial
0.4 in. (1 cm) and the distance between the spindle and the charge of mold powder to melt.
crucible bottom and all crucible walls shall be at least 0.4 in. (1 7.3 When the powder has melted complete
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