1、Designation: D3104 99 (Reapproved 2010)Standard Test Method forSoftening Point of Pitches (Mettler Softening Point Method)1This standard is issued under the fixed designation D3104; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, t
2、he year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the soft-ening point of pitches having softening points in the
3、 range from50 to 180C by this test method, and gives results comparableto those obtained by Test Method D2319 above 176F (80C).1.2 The values stated in SI units are to be regarded as thestandard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use.
4、 It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A314 Specification for Stainless Steel Billets and Bars forForgingD2319 Test
5、Method for Softening Point of Pitch (Cube-in-Air Method)D4296 Practice for Sampling Pitch3. Summary of Test Method3.1 In this test method, the softening point is defined as thetemperature at which pitch, suspended in a cylindrical cup witha 6.35-mm hole in the bottom, flows downward a distance of19
6、mm to interrupt a light beam, as the sample is heated at alinear rate in air.4. Significance and Use4.1 Pitch does not go through a solid-liquid phase changewhen heated, and therefore does not have a true melting point.As the temperature is raised pitch gradually softens or becomesless viscous. For
7、this reason, the determination of the softeningpoint must be made by an arbitrary, but closely defined, methodif the test values are to be reproducible.4.2 This test method is useful in determining the consis-tency of pitches as one element in establishing the uniformityof shipments or sources of su
8、pply.5. Apparatus5.1 A Mettler dropping point cell3shall be used to deter-mine pitch softening points by this test method. These com-mercially available instruments consist of a control unit with adigital temperature indicator, matched furnace, sample car-tridges, and accessories. The control unit a
9、utomatically regu-lates the heating rate of the furnace. The softening point isindicated on the readout, and the heating program stopped,when the sample flow triggers a photocell detector. A generalview of the contents of the Mettler is shown in Fig. 1.5.1.1 Control UnitThis unit shall provide a con
10、tinuous,linear temperature increase from 25 to 250C at a rate of2C/min. A digital readout shall indicate the temperature to0.1C throughout.5.1.2 Furnace UnitThis unit shall be capable of heating asample cup assembly, as described in 5.1.3, at a linear rate of2 6 0.3C/min. It shall include a sensing
11、system capable ofdetecting the softening point with a precision of 0.1C.5.1.3 Sample Cup AssemblyA cup of chromium-platedbrass, or of stainless steel conforming to the requirements forType 303 (UNS S30300) as prescribed in Specification A314,with the dimensions shown in Fig. 2. It shall be placed in
12、 theassembly so that the pitch sample will flow downward adistance of 19 mm before interrupting a light beam andstopping the heating program as the softening point is reached.6. Reagents6.1 Xylene, industrial grade.6.2 Benzoic Acid.1This test method is under the jurisdiction of ASTM Committee D02 on
13、Petroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved May 1, 2010. Published May 2010. Originallyapproved in 1972. Last previous edition approved in 2005 as D3104 99 (2005).DOI: 10.
14、1520/D3104-99R10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3The sole source of supply of the apparatus
15、known to the committee at this timeis available from the Mettler Toledo, Inc., Balances and Instruments, 69 Princeton-Hightstown Rd., Hightstown, NJ 08520-0071. If you are aware of alternativesuppliers, please provide this information to ASTM International Headquarters.Your comments will receive car
16、eful consideration at a meeting of the responsibletechnical committee,1which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Calibration of the Mettler Apparatus7.1 This step, required only occasionally, is designed
17、 toestablish that the temperature indicated by the instrument is inagreement with a known standard. A special cup with a bottomorifice of 2.8 mm is used instead of the one prescribed for thetesting of pitch.7.2 ReagentUse either analytical reagent or primary stan-dard grade benzoic acid for the cali
18、bration. As this material ishygroscopic it must be stored in a tightly sealed container, andreplaced with fresh material from a newly opened supply ifhydration or other contamination is suspected.7.3 Procedure:7.3.1 Filling the Sample CupPlace the cup on a clean, flatsurface. Add a small amount of b
19、enzoic acid crystals and pressdown with a rod (approximately 4.5 mm in diameter). Checkthat the bottom orifice is completely filled. Refill and repeat thepressing step until the cup is filled with benzoic acid. Removeany crystals from the exterior of the cup.7.3.2 Heating Preheat the Mettler furnace
20、 to 121C, andmaintain it at that temperature. Place the cartridge assemblycontaining the benzoic acid in position in the furnace, takingcare that the slits for the light beam are properly positioned.Wait for temperature equilibration, that is, the furnace and thesample are in equilibrium at the pres
21、et temperature, but not lessthan the 30 s after inserting the cartridge, start the automaticheating cycle at 0.2C/min. The temperature will rise steadilyat the correct rate until the drop point is reached, and thenremain steady on the readout.FIG. 1 General View of the Mettler FP-5/53D3104 99 (2010)
22、27.3.3 CleaningImmediately remove the cartridge assem-bly. Check to determine that the sample has passed through thelight beam and no pre-triggering has occurred. If a malfunctionis suspected, the entire procedure must be repeated. Inspect theapparatus carefully to ensure that no residue remains. Us
23、e aspatula shaped to the contour of the cup to remove most of theremaining acid from the cup and from the bottom of thecartridge. Wash the cup and cartridge in xylene, or othersuitable solvent, to remove the last traces of the residue.7.3.4 InterpretationIf the result is not 123.5 6 0.5C,repeat the
24、test. If the second value is 0.6 above or below123.5C, measure the dropping point of a fresh sample ofbenzoic acid. If the deviation exceeds 0.6C, the instrumentrequires recalibration or repair. Consult the manufacturersinstruction manual.8. Sampling8.1 Samples from shipments shall be taken in accor
25、dancewith Practice D4296, and shall be free of foreign substances.Thoroughly mix the sample before removing a representativeportion for the determination or for dehydration.8.2 If a solid bulk sample contains free water, air-dry arepresentative portion in a forced draft oven at 50C.8.3 If the sample
26、 is liquid, check for any surface foam whichmay indicate the presence of water. If foam is found, maintainthe sample at a temperature of about 125C in an opencontainer until the surface is free of foam. Take care not tooverheat. Remove from the heat source as soon as the foam hassubsided. Proceed as
27、 directed in 8.4.2.8.4 Filling the Sample Cup:8.4.1 Crush air-dry lumps of pitch to a size of 6 to 12 mm.Add the material to a container, having a height equal to orexceeding its width, and having a volume of not less than 50mL, until it is about half full. Place the container on a hot plate,or in a
28、n oven or a bath. Do not use an open flame to melt pitch.After melting is complete, stir gently but thoroughly, avoidingincorporation of air bubbles. The maximum temperature of themolten pitch should not exceed the expected softening point bymore than 50C. Any foam that forms must be skimmed off.8.4
29、.2 Prepare the sample by slightly overfilling the samplecup, which rests on a brass plate. Keep the lip of the containerclose to the top of the cup to minimize entrainment of airbubbles. Underpouring past the blade of a spatula is helpful inthis respect. Cool the pitch in the cup until firm, under c
30、oldwater if necessary. Trim the sample flush with the top of thecup by pressing with a heated knife or spatula while drawing ittoward you. Do not trim by cutting across the top with aforward or sideward motion as this tends to lift the sample outof the mold, thus creating an internal void which is n
31、ot easilydetected, and which significantly alters the result.8.4.3 An alternative method which avoids possible loss ofvolatiles in remelting, is to press the cold, solid sample into thesample cup. Select clean, dry, dust-free lumps from therepresentative portion of the sample and crush to a size of
32、lessthan 2 mm. Place a sample cup in the mold (see Figs. 3-5).Place the assembled mold, with the knockout pin in position,on the bottom plate of a hydraulic press. Pour about 2 g of thecrushed pitch into the top of the mold and insert the top ram.Compress the pitch into the cup with a total force on
33、 the ramof 22.24 kN (5000 lbf). Hold this pressure for a minimum of 15s. Excessive molding pressure can cause the sample cup to failby shearing. Remove the mold assembly from the press androtate the upper half while keeping the lower half of the moldstationary. This action causes the pitch to shear
34、horizontally atthe top of the cup. Separate the two parts of the mold andremove the sample cup from the lower half. It may benecessary to dislodge it by pressing against the knockout pin.A small-diameter rod mounted in the base plate may be usedfor this. Clean the mold of all residual pitch to avoid
35、 misalign-ment or binding during subsequent use. This procedure doesnot work well for pitches having softening points below 80Cunless the mold is precooled below room temperature.9. Procedure9.1 The procedure described in this test method for measur-ing the softening point of pitches using either Me
36、ttler instru-ment has been developed to duplicate the results obtained byTest Method D2319.9.2 Preset the temperature of the furnace to 20 to 25Cbelow the expected softening point of the sample and maintainthis temperature for a few minutes (see Note 1). Place thesample cup in the cartridge and the
37、cartridge assembly in thefurnace, taking care that the slits for the light beam are properlypositioned. Wait for temperature equilibration, that is, thefurnace and the sample are in equilibrium at the presettemperature, but not less than the 30 s after inserting thecartridge, start the automatic hea
38、ting cycle at 2.0C/min.Heating will be maintained at this rate until the drop point isreached, after which a steady temperature will be displayed onthe digital readout. Record this temperature as the softeningpoint of the sample.NOTE 1In the event of a dispute, the purchaser and supplier shallagree
39、on the exact starting temperature to be used.9.3 Immediately remove the cartridge assembly uponcompletion of the test. Check to ensure that the sample hasFIG. 2 Sample CupD3104 99 (2010)3passed the light beam and no pre-triggering has occurred. If amalfunction is suspected, reject the result and rep
40、eat the test.Inspect the apparatus closely to ensure that no particles ofresidue remain.9.4 Clean the sample cups by placing them upside down ona hard surface and punching out any residual material. Use aspatula, shaped to the contour of the cup, with a swirlingmotion to remove any remaining particl
41、es. Washing withxylene, or other suitable solvent, may be necessary to get theapparatus completely clean.10. Report10.1 Report the softening point, as indicated by the digitalreadout, to the nearest 0.1C. If converting to degrees Fahren-heit, report to the nearest 0.2F. Experience indicates thatdupl
42、icate determinations are unnecessary. If any error occurs,or is suspected, in carrying out the details of this procedure,discard the results and make a second run.11. Precision and Bias11.1 The following criteria shall be used for judging theacceptability of any result (95 % confidence level):11.1.1
43、 RepeatabilityDuplicate values by the same opera-tor shall not be considered suspect unless they differ by morethan 0.5C.11.1.2 ReproducibilityThe values reported by each of twolaboratories shall not be considered suspect unless they differby more than 1.5C.11.1.3 BiasThis test method has no bias be
44、cause thevalue of softening point is defined in terms of this test method.12. Keywords12.1 Mettler; pitch; softening pointNOTEDiameters are concentric. These two parts will be hardened tool steel and then ground to final dimensions. All dimensions are in millimetres.FIG. 3 Upper Half of Mold Assembl
45、y for Pressure Molding Pitch into a Sample CupD3104 99 (2010)4NOTEDiameters are concentric. These two parts will be made of Type 303 stainless steel. All dimensions are in millimetres.FIG. 4 Lower Half of Mold Assembly for Pressure Molding Pitch into a Sample CupD3104 99 (2010)5ASTM International ta
46、kes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own r
47、esponsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addre
48、ssed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at t
49、he address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).FIG. 5 Assembly of Mold for Pres
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