ASTM D3104-99

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An American National Standard
Designation:D3104–99
Standard Test Method for
Softening Point of Pitches (Mettler Softening Point Method)
This standard is issued under the fixed designation D 3104; 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 4.2 This test method is useful in determining the consis-
tency of pitches as one element in establishing the uniformity
1.1 This test method covers the determination of the soft-
of shipments or sources of supply.
eningpointofpitcheshavingsofteningpointsintherangefrom
50 to 180°C by this test method, and gives results comparable
5. Apparatus
to those obtained by Test Method D 2319 above 176°F (80°C).
5.1 A Mettler dropping point cell shall be used to deter-
1.2 The values stated in SI units are to be regarded as the
mine pitch softening points by this test method. These com-
standard.
mercially available instruments consist of a control unit with a
1.3 This standard does not purport to address all of the
digital temperature indicator, matched furnace, sample car-
safety concerns, if any, associated with its use. It is the
tridges, and accessories. The control unit automatically regu-
responsibility of the user of this standard to establish appro-
lates the heating rate of the furnace. The softening point is
priate safety and health practices and determine the applica-
indicated on the readout, and the heating program stopped,
bility of regulatory limitations prior to use.
when the sample flow triggers a photocell detector. A general
2. Referenced Documents view of the contents of the Mettler is shown in Fig. 1.
5.1.1 Control Unit—This unit shall provide a continuous,
2.1 ASTM Standards:
linear temperature increase from 25 to 250°C at a rate of
A 314 Specification for Stainless and Heat-Resisting Steel
2°C/min. A digital readout shall indicate the temperature to
Billets and Bars for Forging
0.1°C throughout.
D 2319 Test Method for Softening Point of Pitch (Cube-in-
5.1.2 Furnace Unit—This unit shall be capable of heating a
Air Method)
sample cup assembly, as described in 5.1.3, at a linear rate of
D 4296 Practice for Sampling Pitch
2 6 0.3°C/min. It shall include a sensing system capable of
3. Summary of Test Method detecting the softening point with a precision of 0.1°C.
5.1.3 Sample Cup Assembly—A cup of chromium-plated
3.1 In this test method the softening point is defined as the
brass, or of stainless steel conforming to the requirements for
temperature at which pitch, suspended in a cylindrical cup with
Type 303 (UNS S30300) as prescribed in Specification A 314,
a 6.35-mm hole in the bottom, flows downward a distance of
with the dimensions shown in Fig. 2. It shall be placed in the
19 mm to interrupt a light beam, as the sample is heated at a
assembly so that the pitch sample will flow downward a
linear rate in air.
distance of 19 mm before interrupting a light beam and
4. Significance and Use
stopping the heating program as the softening point is reached.
4.1 Pitch does not go through a solid-liquid phase change
6. Reagents
when heated, and therefore does not have a true melting point.
6.1 Xylene, industrial grade.
Asthetemperatureisraisedpitchgraduallysoftensorbecomes
6.2 Benzoic Acid.
less viscous. For this reason the determination of the softening
pointmustbemadebyanarbitrary,butcloselydefined,method
7. Calibration of the Mettler Apparatus
if the test values are to be reproducible.
7.1 This step, required only occasionally, is designed to
establish that the temperature indicated by the instrument is in
This test method is under the jurisdiction of ASTM Committee D-2 on agreement with a known standard.Aspecial cup with a bottom
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
orifice of 2.8 mm is used instead of the one prescribed for the
D02.05.OFon Industrial Pitches.
testing of pitch.
Current edition approved Oct. 10, 1999. Published March 2000. Originally
published as D 3104 – 72. Last previous edition D 3104 –97.
Annual Book of ASTM Standards, Vol 01.03.
3 5
Annual Book of ASTM Standards, Vol 05.01. Available from the Mettler Toledo, Inc., Balances and Instruments, 69
Annual Book of ASTM Standards, Vol 05.02. Princeton-Hightstown Rd., Hightstown, NJ 08520-0071.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D3104
FIG. 1 General View of the Mettler FP-5/53
7.2 Reagent— Use either analytical reagent or primary containing the benzoic acid in position in the furnace, taking
standard grade benzoic acid for the calibration.As this material care that the slits for the light beam are properly positioned.
is hygroscopic it must be stored in a tightly sealed container, Wait for temperature equilibration, that is, the furnace and the
and replaced with fresh material from a newly opened supply sampleareinequilibriumatthepresettemperature,butnotless
if hydration or other contamination is suspected. than the 30 s after inserting the cartridge, start the automatic
7.3 Procedure: heating cycle at 0.2°C/min. The temperature will rise steadily
7.3.1 Filling the Sample Cup—Place the cup on a clean, flat at the correct rate until the drop point is reached, and then
surface.Add a small amount of benzoic acid crystals and press remain steady on the readout.
down with a rod (approximately 4.5 mm in diameter). Check 7.3.3 Cleaning— Immediately remove the cartridge assem-
thatthebottomorificeiscompletelyfilled.Refillandrepeatthe bly. Check to determine that the sample has passed through the
pressing step until the cup is filled with benzoic acid. Remove light beam and no pretriggering has occurred. If a malfunction
any crystals from the exterior of the cup. is suspected, the entire procedure must be repeated. Inspect the
7.3.2 Heating— Preheat the Mettler furnace to 121°C, and apparatus carefully to ensure that no residue remains. Use a
maintain it at that temperature. Place the cartridge assembly spatula shaped to the contour of the cup to remove most of the
D3104
this respect. Cool the pitch in the cup until firm, under cold
water if necessary. Trim the sample flush with the top of the
cup by pressing with a heated knife or spatula while drawing it
toward you. Do not trim by cutting across the top with a
forward or sideward motion as this tends to lift the sample out
of the mold, thus creating an internal void which is not easily
detected, and which significantly alters the result.
8.4.3 An alternative method which avoids possible loss of
volatiles in remelting, is to press the cold, solid sample into the
sample cup. Select clean, dry, dust-free lumps from the
representative portion of the sample and crush to a size of less
than 2 mm. Place a sample cup in the mold (see Fig. 3, Fig. 4,
and Fig. 5). Place the assembled mold, with the knockout pin
inposition,onthebottomplateofahydraulicpress.Pourabout
2 g of the crushed pitch into the top of the mold and insert the
top ram. Compress the pitch into the cup with a tot
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