1、Designation: D 3104 99 (Reapproved 2005)An American National StandardStandard Test Method forSoftening Point of Pitches (Mettler Softening Point Method)1This standard is issued under the fixed designation D 3104; the number immediately following the designation indicates the year oforiginal adoption
2、 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 pitche
3、s having softening points in the range from50 to 180C by this test method, and gives results comparableto those obtained by Test Method D 2319 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,
4、 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-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2A 314 Specification for Stainless and Heat-R
5、esisting SteelBillets and Bars for ForgingD 2319 Test Method for Softening Point of Pitch (Cube-in-Air Method)D 4296 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
6、-mm hole in the bottom, flows downward a distance of19 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 rais
7、ed pitch gradually softens or becomesless viscous. For 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 e
8、stablishing the uniformityof shipments or sources of supply.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,
9、sample car-tridges, and accessories. The control unit automatically 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
10、 Fig. 1.5.1.1 Control UnitThis unit shall provide a continuous,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
11、linear rate of2 6 0.3C/min. It shall include a sensing 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 A 314,wi
12、th the dimensions shown in Fig. 2. It shall be placed in 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.1This test method is under the jurisdiction of ASTM Committee D02 onP
13、etroleum Products and Lubricants and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved March 1, 2005. Published March 2005. Originallyapproved in 1972. Last previous edition approved in 1999 as D 3104 99.2For refere
14、nced 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 known to the committee at th
15、is 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 careful consideration at a meet
16、ing 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.6. Reagents6.1 Xylene, industrial grade.6.2 Benzoic Acid.7. Calibration of the Mettler Apparatus7.1 This step, required o
17、nly 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 thetesting of pitch.7.2 ReagentUse either analytical reagent or primary stan-dard gr
18、ade benzoic acid for the 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 Sample CupPlace the cup on a clean, flatsur
19、face. Add a small amount of benzoic 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 Heatin
20、g Preheat 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.Wait for temperature equilibration, that is, the furnace and thesample a
21、re in equilibrium at the preset temperature, but not lessthan the 30 s after inserting the cartridge, start the automaticheating cycle at 0.2C/min. The temperature will rise steadilyFIG. 1 General View of the Mettler FP-5/53D 3104 99 (2005)2at the correct rate until the drop point is reached, and th
22、enremain steady on the readout.7.3.3 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 ensu
23、re that no residue remains. Use 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 i
24、s not 123.5 6 0.5C,repeat the 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 shi
25、pments shall be taken in accordancewith Practice D 4296, 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 draf
26、t oven at 50C.8.3 If the sample 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 t
27、he foam hassubsided. Proceed as 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 c
28、ontainer on a hot plate,or in an 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 tha
29、t forms must be skimmed off.8.4.2 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
30、 in the cup until firm, under coldwater 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 creat
31、ing an internal void which is not 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
32、 sample and crush to a size of 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 int
33、o the cup with a total force on 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 ac
34、tion causes the pitch to shear 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
35、 of all residual pitch to avoid 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 p
36、oint of pitches using either Mettler instru-ment has been developed to duplicate the results obtained byTest Method D 2319.9.2 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 thesamp
37、le cup in the cartridge and the 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 theca
38、rtridge, start the automatic heating 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 pu
39、rchaser and supplier shallagree on the exact starting temperature to be used.FIG. 2 Sample CupD 3104 99 (2005)39.3 Immediately remove the cartridge assembly uponcompletion of the test. Check to ensure that the sample haspassed the light beam and no pre-triggering has occurred. If amalfunction is sus
40、pected, reject the result and repeat 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 swirlingmotio
41、n to remove any remaining particles. 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.
42、2F. Experience indicates thatduplicate 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 resu
43、lt (95 % confidence level):11.1.1 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 Bi
44、asThis test method has no bias because 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.
45、FIG. 3 Upper Half of Mold Assembly for Pressure Molding Pitch into a Sample CupD 3104 99 (2005)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 CupD 3
46、104 99 (2005)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 su
47、ch 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 five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for addi
48、tional standardsand should be addressed 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 th
49、e ASTM Committee on Standards, at the 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).FIG. 5 Assembly of Mold for Pressure Molding Pitch into a Sample CupD 3104 99 (2005)6
