1、Designation: D 3461 97 (Reapproved 2007)An American National StandardStandard Test Method forSoftening Point of Asphalt and Pitch (Mettler Cup-and-BallMethod)1This standard is issued under the fixed designation D 3461; the number immediately following the designation indicates the year oforiginal ad
2、option or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、asphalt and pitch in the range from 50 to 180Cby the cup-and-ball apparatus, and gives results comparable tothose obtained by Test Method D36.NOTE 1If the softening point of asphalt by this Mettler cup-and-ballmethod fails to meet specified requirements, tests may be rerun using theTest Method D36(r
4、ing-and-ball) softening point apparatus as a refereemethod.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bi
5、lity of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A 314 Specification for Stainless Steel Billets and Bars forForgingD36 Test Method for Softening Point of Bitumen (Ring-and-Ball Apparatus)D 140 Practice for Sampling Bituminous MaterialsD 4296 Practice for Sampli
6、ng Pitch3. Summary of Test Method3.1 In this test method the softening point is defined as thetemperature at which the specimen, suspended in a cylindricalcup with a 6.5-mm hole in the bottom and with a lead ball,8 mm in diameter, centered on top of the sample in the cup,flows downward a distance of
7、 19 mm to interrupt a light beam,as the sample is heated at a linear rate in air.4. Significance and Use4.1 Asphalt and pitch do not go through a solid-liquid phasechange when heated, and therefore do not have true meltingpoints. As the temperature is raised, they gradually soften orbecome less visc
8、ous. For this reason, the determination of thesoftening point must be made by an arbitrary, but closelydefined, method if the test values are to be reproducible.4.2 This test method is useful in determining the consis-tency as one element in establishing the uniformity of ship-ments or sources of su
9、pply.5. Apparatus5.1 A Mettler dropping point cell3can be used to determinesoftening points by this test method. These commerciallyavailable instruments consist of a control unit with a digitaltemperature indicator, matched furnace, sample cartridges, andaccessories. The control unit automatically r
10、egulates the heat-ing rate of the furnace. The softening point is indicated on thereadout, and the heating program stopped, when the sampleflow triggers a photocell detector. A general view of thecomponents of the Mettler apparatus is shown in Fig. 1.5.1.1 Control UnitThis unit shall provide a conti
11、nuous,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 aspecimen cup assembly, as described in 5.1.3, at a linear rate of2 6 0.3C/min. It shall include a sensing
12、system capable ofdetecting the softening point with a precision of 0.1C.5.1.3 Specimen Cup AssemblyA cup of chromium-platedbrass, or stainless steel conforming to the requirements forType 303 (UNS 530300) as prescribed in Specification A 314,with dimensions shown in Fig. 2. It shall be placed in the
13、assembly so that the test specimen will flow down a distance of19 mm before interrupting a light beam and stopping theheating program as the softening point is reached.1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lubricants and is the direct responsibili
14、ty of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved May 1, 2007. Published June 2007. Originallyapproved in 1976. Last previous edition approved in 2002 as D 3461 97 (2002).2For referenced ASTM standards, visit the ASTM website, www.astm.org,
15、orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from the Mettler Toledo, Inc., Balances and Instruments, 69Princeton-Hightstown Rd., Hightstown, NJ 08520-0071.1Copyrigh
16、t ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.1.4 Lead BallA lead ball weighing 3.20 6 0.10 g.A32-caliber lead shot is suitable for this purpose.6. Reagents6.1 Xylene, industrial grade.7. Calibration of Mettler Apparatus7.1 This step, req
17、uired only occasionally, is designed 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 thespecimen testing.7.2 ReagentUse either analytical reagent or primary stan-
18、dard grade benzoic acid for this calibration. 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 Specimen CupPlace the cup on a cle
19、an,flat surface. Add a small amount of benzoic acid crystals andpress down with a rod (4.5 mm in diameter). Check that thebottom 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 HeatingPr
20、eheat the Mettler furnace 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.FIG. 1 General View of the Mettler FP-5/53D 3461 97 (2007)2Wait for temperat
21、ure equilibration, that is, the furnace and thesample are in equilibrium at the preset temperature, but not lessthan 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
22、 steady on the readout.7.3.3 CleaningImmediately remove the cartridge assem-bly. Check to determine that the specimen has passed throughthe light beam and no pretriggering has occurred. If a malfunc-tion is suspected, the entire procedure must be repeated.Inspect the apparatus carefully to ensure th
23、at no residueremains. Use a spatula shaped to the contour of the cup toremove most of the remaining acid from the cup and from thebottom of the cartridge. Wash the cup and cartridge in xylene,or other suitable solvent, to remove the last traces of theresidue.7.3.4 InterpretationIf the result is not
24、123.5 6 0.5C,repeat the test. If the second value is 0.6C above or below123.5C, measure the dropping point of a fresh specimen ofbenzoic acid. If the deviation exceeds 0.6C, the instrumentrequires recalibration or repair. Consult the manufacturersinstruction manual.8. Sampling8.1 Samples from shipme
25、nts shall be taken in accordancewith Practice D 140 for asphalt and Practice D 4296 for pitchand shall be free of foreign substances. Thoroughly mix thesample before removing a representative portion for thedetermination or for dehydration.8.2 Pitch Sample Preparation:8.2.1 If a solid bulk sample co
26、ntains free water, air-dry arepresentative portion at 60C or below.8.2.2 If the sample is liquid, check for any surface foamwhich may indicate the presence of water. If foam is found,maintain the sample at a temperature of about 125C in an opencontainer until the surface is free of foam. Take care n
27、ot tooverheat. Remove from the heat source as soon as the foam hassubsided. Proceed as directed in 9.1.8.2.3 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 than50 mL, until it is ab
28、out half full. Place the container on a hotplate, or in an oven or a bath. Do not use an open flame formelting pitch. After melting is complete, stir gently butthoroughly, avoiding incorporation of air bubbles. The maxi-mum temperature of the molten pitch should not exceed theexpected softening poin
29、t by more than 50C. Any foam thatforms must be skimmed off.8.3 Asphalt Sample Preparation:8.3.1 Heat the sample, with care to prevent local overheat-ing, constantly stirring until it has become sufficiently fluid topour. In no case, however, shall the temperature be raised morethan 110C (200F) above
30、 the expected softening point forasphalt. Avoid incorporating air bubbles in the sample.8.3.2 Bring the asphalt sample to the pouring temperature innot more than 2 h.9. Test Specimen9.1 Prepare the test specimen by slightly overfilling thespecimen cup, which rests on a brass plate. Keep the lip of t
31、hecontainer close to the top of the cup to minimize entrainmentof air bubbles. Underpouring past the blade of a spatula ishelpful in this respect. Cool the specimen in the cup until firm,under cold water if necessary. Trim the specimen flush with thetop of the cup by pressing with a heated knife or
32、spatula whiledrawing it toward you. Support the cup with tweezers orforceps or in a wood block with holes sized to fit the cup. Donot trim by cutting across the top with a forward or sidewardmotion as this tends to lift the specimen out of the mold, thuscreating an internal void which is not easily
33、detected, andwhich significantly alters the result.9.2 An alternative method which avoids possible loss ofvolatiles in remelting, is to press the cold, solid specimen intothe specimen cup. Select clean, dry, dust-free lumps from therepresentative portion of the sample and crush to a size of lessthan
34、 2 mm. Place a sample cup in the mold (see Fig. 3, Fig. 4,and Fig. 5). Place the assembled mold, with the knockout pinin position, on the bottom plate of a hydraulic press. Pour about2 g of the crushed specimen into the top of the mold and insertthe top ram. Compress the specimen into the cup with a
35、 totalforce on the ram of 22.24 kN (5000 lbf). Hold this pressure fora minimum of 15 s. Excessive molding pressure can cause thespecimen cup to fail by shearing. Remove the mold assemblyfrom the press and rotate the upper half while keeping thelower half of the mold stationary. This action causes th
36、especimen to shear horizontally at the top of the cup. Separatethe two parts of the mold and remove the specimen cup fromthe bottom half. It may be necessary to dislodge it by pressingagainst the knockout pin. A small-diameter rod mounted on thebase plate may be used for this. Clean the mold of all
37、residualmaterial to avoid misalignment or binding during subsequentuse. This procedure does not work well for pitches havingsoftening points below 80C unless the mold is precooledbelow room temperature.FIG. 2 Specimen CupD 3461 97 (2007)310. Procedure10.1 The procedure described in this test method
38、for mea-suring the softening point of asphalts and pitches using aMettler instrument has been developed to duplicate the resultsobtained by Test Method D36.10.2 Preset the temperature of the furnace from 20 to 25Cbelow the expected softening point of the specimen andmaintain at this temperature for
39、a few minutes (see Note 2).Place the specimen cup in the cartridge with the lead ballcarefully centered on top of the specimen. The ball may bewarmed slightly to form a small indentation and ensure itsproper positioning in the furnace during the test. Place thecartridge assembly in the furnace, taki
40、ng care that the slits forthe light beam are properly positioned. Wait for temperatureequilibration, that is, the furnace and the sample are inequilibrium at the preset temperature, but not less than 30 safter inserting the cartridge, start the automatic heating cycle at2C/min. Heating will be maint
41、ained at this rate until the droppoint is reached, after which a steady temperature will bedisplayed on the digital readout. Record this temperature as thesoftening point of the specimen.NOTE 2In the event of a dispute, the purchaser and supplier shallagree on the exact starting temperature to be us
42、ed.10.3 Immediately remove the cartridge assembly uponcompletion of the test. Check to ensure that the sample haspassed through the light beam and no pretriggering hasoccurred. If a malfunction is suspected, reject the result andrepeat the test. Inspect the apparatus closely to ensure that noparticl
43、es of residue remain.10.4 Clean the specimen cups by placing them upside downon a hard surface and punching out any residual material. Usea spatula, shaped to the contour of the cup, with a swirlingmotion to remove any remaining particles. Inspect and cleanthe lead ball to remove any residue. Take c
44、are to avoid anydistortion during this step. Washing with xylene, or othersuitable solvent, may be necessary to get the apparatus com-pletely clean.11. Report11.1 Report the softening point, as indicated by the digitalreadout, to the nearest 0.1C. If converting to degrees Fahren-heit, report to the
45、nearest 0.2F. Experience indicates thatNOTE 1Diameters 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 Assembly for Pressure Molding Asphalt and Pitch into a Specimen CupD 3461 97 (2007)4dupl
46、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.12. Precision12.1 The following criteria shall be used for judging theacceptability of any result (95 % confidence level):12.1.1 Repeatab
47、ilityDuplicate values by the same opera-tor shall not be considered suspect unless they differ by morethan 0.5C.12.1.2 ReproducibilityThe values reported by each of twolaboratories shall not be considered suspect unless they differby more than 1.5C.12.1.3 BiasThe procedure in Test Method D 3461 fors
48、oftening point has no bias because the value of softening pointis defined only in the terms of this test method.13. Keywords13.1 asphalt; mettler; pitch; softening pointNOTE 1Diameters are concentric. These two parts will be made of stainless steel. All dimensions are in millimetres.FIG. 4 Lower Hal
49、f of Mold Assembly for Pressure Molding Asphalt and Pitch into a Specimen CupD 3461 97 (2007)5ASTM International takes 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 responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every
