Standard Test Method for Softening Point of Pitches (Mettler Softening Point Method)

SIGNIFICANCE AND USE
Pitch does not go through a solid-liquid phase change when heated, and therefore does not have a true melting point. As the temperature is raised pitch gradually softens or becomes less viscous. For this reason, the determination of the softening point must be made by an arbitrary, but closely defined, method if the test values are to be reproducible.
This test method is useful in determining the consistency of pitches as one element in establishing the uniformity of shipments or sources of supply.
SCOPE
1.1 This test method covers the determination of the softening point of pitches having softening points in the range from 50 to 180°C by this test method, and gives results comparable to those obtained by Test Method D2319 above 176°F (80°C).  
1.2 The values stated in SI units are to be regarded as the standard.
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.

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ASTM D3104-99(2010) - Standard Test Method for Softening Point of Pitches (Mettler Softening Point Method)
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D3104 − 99(Reapproved 2010)
Standard Test Method for
Softening Point of Pitches (Mettler Softening Point Method)
This standard is issued under the fixed designation D3104; 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 pointmustbemadebyanarbitrary,butcloselydefined,method
if the test values are to be reproducible.
1.1 This test method covers the determination of the soft-
eningpointofpitcheshavingsofteningpointsintherangefrom
4.2 This test method is useful in determining the consis-
50 to 180°C by this test method, and gives results comparable
tency of pitches as one element in establishing the uniformity
to those obtained by Test Method D2319 above 176°F (80°C).
of shipments or sources of supply.
1.2 The values stated in SI units are to be regarded as the
5. Apparatus
standard.
1.3 This standard does not purport to address all of the 5.1 A Mettler dropping point cell shall be used to deter-
mine pitch softening points by this test method. These com-
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- mercially available instruments consist of a control unit with a
digital temperature indicator, matched furnace, sample
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. cartridges, and accessories. The control unit automatically
regulates the heating rate of the furnace. The softening point is
2. Referenced Documents
indicated on the readout, and the heating program stopped,
when the sample flow triggers a photocell detector. A general
2.1 ASTM Standards:
view of the contents of the Mettler is shown in Fig. 1.
A314 Specification for Stainless Steel Billets and Bars for
5.1.1 Control Unit—This unit shall provide a continuous,
Forging
linear temperature increase from 25 to 250°C at a rate of
D2319 Test Method for Softening Point of Pitch (Cube-in-
2°C/min. A digital readout shall indicate the temperature to
Air Method)
0.1°C throughout.
D4296 Practice for Sampling Pitch
5.1.2 Furnace Unit—This unit shall be capable of heating a
3. Summary of Test Method
sample cup assembly, as described in 5.1.3, at a linear rate of
2 6 0.3°C/min. It shall include a sensing system capable of
3.1 In this test method, the softening point is defined as the
detecting the softening point with a precision of 0.1°C.
temperatureatwhichpitch,suspendedinacylindricalcupwith
5.1.3 Sample Cup Assembly—A cup of chromium-plated
a 6.35-mm hole in the bottom, flows downward a distance of
brass, or of stainless steel conforming to the requirements for
19 mm to interrupt a light beam, as the sample is heated at a
Type 303 (UNS S30300) as prescribed in Specification A314,
linear rate in air.
with the dimensions shown in Fig. 2. It shall be placed in the
assembly so that the pitch sample will flow downward a
4. Significance and Use
distance of 19 mm before interrupting a light beam and
4.1 Pitch does not go through a solid-liquid phase change
stopping the heating program as the softening point is reached.
when heated, and therefore does not have a true melting point.
Asthetemperatureisraisedpitchgraduallysoftensorbecomes
6. Reagents
less viscous. For this reason, the determination of the softening
6.1 Xylene, industrial grade.
6.2 Benzoic Acid.
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
D02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.
Current edition approved May 1, 2010. Published May 2010. Originally
approved in 1972. Last previous edition approved in 2005 as D3104 – 99 (2005). The sole source of supply of the apparatus known to the committee at this time
DOI: 10.1520/D3104-99R10. is available from the Mettler Toledo, Inc., Balances and Instruments, 69 Princeton-
For referenced ASTM standards, visit the ASTM website, www.astm.org, or Hightstown Rd., Hightstown, NJ 08520-0071. If you are aware of alternative
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM suppliers, please provide this information to ASTM International Headquarters.
Standards volume information, refer to the standard’s Document Summary page on Your comments will receive careful consideration at a meeting of the responsible
the ASTM website. technical committee, which you may attend.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D3104 − 99 (2010)
FIG. 1 General View of the Mettler FP-5/53
7. Calibration of the Mettler Apparatus 7.3.1 Filling the Sample Cup—Place the cup on a clean, flat
surface.Add a small amount of benzoic acid crystals and press
7.1 This step, required only occasionally, is designed to
down with a rod (approximately 4.5 mm in diameter). Check
establish that the temperature indicated by the instrument is in
thatthebottomorificeiscompletelyfilled.Refillandrepeatthe
agreement with a known standard.Aspecial cup with a bottom
pressing step until the cup is filled with benzoic acid. Remove
orifice of 2.8 mm is used instead of the one prescribed for the
any crystals from the exterior of the cup.
testing of pitch.
7.3.2 Heating— Preheat the Mettler furnace to 121°C, and
7.2 Reagent—Use either analytical reagent or primary stan-
maintain it at that temperature. Place the cartridge assembly
dard grade benzoic acid for the calibration. As this material is
containing the benzoic acid in position in the furnace, taking
hygroscopic it must be stored in a tightly sealed container, and
care that the slits for the light beam are properly positioned.
replaced with fresh material from a newly opened supply if
Wait for temperature equilibration, that is, the furnace and the
hydration or other contamination is suspected.
sampleareinequilibriumatthepresettemperature,butnotless
7.3 Procedure: than the 30 s after inserting the cartridge, start the automatic
D3104 − 99 (2010)
mL,untilitisabouthalffull.Placethecontaineronahotplate,
or in an oven or a bath. Do not use an open flame to melt pitch.
After melting is complete, stir gently but thoroughly, avoiding
incorporation of air bubbles. The maximum temperature of the
molten pitch should not exceed the expected softening point by
more than 50°C. Any foam that forms must be skimmed off.
8.4.2 Prepare the sample by slightly overfilling the sample
cup, which rests on a brass plate. Keep the lip of the container
close to the top of the cup to minimize entrainment of air
bubbles. Underpouring past the blade of a spatula is helpful in
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
FIG. 2 Sample Cup
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 sa
...

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