1、Designation: D 61 75 (Reapproved 2004)An American National StandardStandard Test Method forSoftening Point of Pitches (Cube-in-Water Method)1This standard is issued under the fixed designation D 61; the number immediately following the designation indicates the year of originaladoption or, in the ca
2、se of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscriptepsilon (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 pitches below 176F (80C)
3、. Pitches of highersoftening point should be tested by Test Method D 2319 or TestMethod D 3104.1.2 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 pr
4、actices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D 140 Practice for Sampling Bituminous MaterialsD 2319 Test Method for Softening Point of Pitch (Cube-in-Air Method)D 3104 Test Method for Softening Point of Pitches (MettlerSof
5、tening Point Method)E1 Specification for ASTM Thermometers3. Summary of Test Method3.1 Two cubes of pitch, supported on wire hooks, are heatedat a controlled rate in water in a glass container. The softeningpoint is defined as the mean of the temperatures at which thecubes sag downwards a distance o
6、f 25 mm.4. Significance and Use4.1 Pitch does not go through a solid-liquid phase changewhen heated, and therefore it does not have a true meltingpoint. As the temperature rises, pitch softens and becomes lessviscous. The softening point is arbitrarily defined and shall beestablished by a closely co
7、ntrolled method which shall becarefully followed if test results are to be reproducible.4.2 This test is useful in determining the consistency ofpitch as one element in establishing the uniformity of ship-ments or sources of supply.5. Apparatus5.1 MoldA mold suitable for forming two12-in. (12.7-mm)
8、cubes of pitch, having cylindrical core pins 12 gage (2.05mm) in diameter located in the base plate of the assembly toproduce accurately centered suspension holes in the cubes.(See Fig. 1.)5.2 HooksTwo L-shaped hooks, made of 12-gage (2.05-mm) copper wire. The foot of the hook shall be 1-in. (25-mm)
9、long and at a right angle to the upright portion for insertion intothe center hole of the pitch cube.5.3 ContainerA glass vessel that can be heated, not lessthan 85 mm in diameter and 105 mm deep. (A standard600-mL low-form beaker meets these requirements).5.4 ThermometerAn ASTM Low Softening Point
10、Ther-mometer having a range from 30 to 180F (2 to 80C) andconforming to the requirements for Thermometer 15F (15C) asdescribed in Specification E1.5.5 Heat Source:5.5.1 Electric HeaterA hot plate or immersion heaterprovided with a variable transformer or other device suitablefor regulating the tempe
11、rature of the heating element.5.5.2 Gas HeaterA bunsen-type burner, fitted with achimney.6. Sampling6.1 Samples from shipments shall be taken in accordancewith Practice D 140 and shall be free of foreign substances.Thoroughly mix the sample before removing a representativeportion for the determinati
12、on or for dehydration.6.2 If the presence of water is indicated by surface foam onheating, maintain the sample at a temperature of about 260F(125C) in an open container until the surface is free of foam.Take care not to overheat, and remove from the heat source assoon as the foam has subsided.7. Tes
13、t Specimens7.1 Coat the inner surfaces and core pins of the mold verylightly with silicone oil or silicone grease. Form the pitch intotruly shaped cubes either by pressing (7.2) or by pouring (7.4),the latter being preceded by melting (7.3) if the sample is solid.Use an excess of pitch in either cas
14、e. Cool until firm andremove the surplus material by drawing the heated blade of aputty knife or spatula across the surface of the mold so that thecubes are pressed into the cavities. Then open the mold and1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products and Lub
15、ricants and is the direct responsibility of SubcommitteeD02.05 on Properties of Fuels, Petroleum Coke and Carbon Material.Current edition approved Nov. 1, 2004. Published November 2004. Originallyapproved in 1919. Last previous edition approved in 1999 as D 61 75 (1999).2For referenced ASTM standard
16、s, 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.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 1
17、9428-2959, United States.remove the cubes carefully to avoid distortion. Inspect eachspecimen for possible cracks or bubbles and reject any whichare not perfect.7.2 Pitches with softening points up to about 140F (60C)can usually be pressed into the mold by hand at, or slightlyabove, room temperature
18、. If too soft, they may be pressedunder water at about 40F (5C).7.3 To melt a dry pitch sample, add the material to acontainer having a height equal to or exceeding its width anda volume of not less than 50 mL, until it is about half full. Placethe container on a hot plate, or in an oven or bath. Do
19、 not usean open flame for melting pitch. After melting is complete, stirgently but thoroughly, avoiding the incorporation of airbubbles. The maximum temperature should not exceed theexpected softening point by more than 90F (50C). Any foamthat forms shall be skimmed off.7.4 Pour a slight excess of t
20、he liquid pitch into the moldwith the lip of the container close to the surface so as tominimize the entrainment of air bubbles. Underpouring pastthe blade of a spatula is helpful in this respect. Even smallbubbles markedly affect the weight of the cube and theobserved softening point. Cool the spec
21、imens in the mold untilfirm, under cold water if necessary; then trim and inspect thecubes as directed in 7.1.8. Procedure8.1 Pitches Having Softening Points Between 110 and176F (43 and 80C):FIG. 1 Apparatus for Cube-in-Water MethodD 61 75 (2004)28.1.1 Assemble the apparatus as shown in Fig. 1. Fill
22、 thecontainer to a depth of about 100 mm with freshly boileddistilled water cooled to 60F (15C) (Notes 1 and 2). Placetwo cubes of pitch on hooks as shown in Fig. 1, warming thehooks slightly before inserting them in the center holes ifnecessary. Suspend the specimens in the bath so that the lowered
23、ges are 1 in. (25 mm) above the bottom of the container.Position the thermometer so that the bulb is between the cubesand within 6 mm, but not touching either cube. The bottom ofthe bulb should be level with the bottom of the cubes. Allowthe specimens to remain in the bath at 60F (15C) for 15 minbef
24、ore applying heat.NOTE 1The use of freshly boiled water is essential to prevent theformation of air bubbles on its surface which may retard the sinking of thecube.NOTE 2A sheet of filter paper that will sink when wet may be placedon the bottom of the container to prevent the pitch from sticking to t
25、heglass.8.1.2 Apply heat in such a manner that the temperature ofthe water is raised 9F (5C)/min. The rate shall be uniformand shall not be averaged over the period of the test. Themaximum permissible variation for any 1-min period, after thefirst three, shall be 61F (0.5C). Reject all tests in whic
26、h therate of rise is outside these limits.8.1.3 The softening point is the average of the temperaturesat which the two cubes touch the bottom of the container.Estimate individual readings to the nearest 0.5F (0.2C).Repeat the determination if the individual values differ by morethan 2F (1C).8.2 Pitc
27、hes Having Softening Points Below 110F (43C)Follow the procedures described in 8.1, but cool the water bathto 40F (5C). After immersing the specimens in the bath,maintain the temperature for at least 15 min before applyingheat.9. Report9.1 Report the average value found in 8.1.3, rounded to theneare
28、st 1F (0.5C) as the softening point (cube-in-water).10. Precision10.1 The following criteria shall be used for judging theacceptability of the results (95 % confidence level):10.1.1 RepeatabilityDuplicate values by the same opera-tor shall not be considered suspect unless they differ by morethan 3F
29、(1.5C).10.1.2 ReproducibilityThe values reported by each of twolaboratories shall not be considered suspect unless they differby more than 5F (3C).10.1.3 BiasThe procedure in Test Method D 61 for soft-ening point has no bias because the value of softening point isdefined only in the terms of this te
30、st method.11. Keywords11.1 cube-in-water; pitch; softening pointASTM 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 suc
31、h 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 five years andif not revised, either reapproved or withdrawn. Your comments are invite
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33、fair hearing you shouldmake your views known to the 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).D 61 75 (2004)3
