1、Designation: D2240 15Standard Test Method forRubber PropertyDurometer Hardness1This standard is issued under the fixed designation D2240; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parent
2、heses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This test method covers twelve types of rubber hardnessmeasuremen
3、t devices known as durometers: Types A, B, C, D,DO, E, M, O, OO, OOO, OOO-S, and R. The procedure fordetermining indentation hardness of substances classified asthermoplastic elastomers, vulcanized (thermoset) rubber, elas-tomeric materials, cellular materials, gel-like materials, andsome plastics i
4、s also described.1.2 This test method is not equivalent to other indentationhardness methods and instrument types, specifically thosedescribed in Test Method D1415.1.3 This test method is not applicable to the testing ofcoated fabrics.1.4 All materials, instruments, or equipment used for thedetermin
5、ation of mass, force, or dimension shall have trace-ability to the National Institute for Standards and Technology,or other internationally recognized organizations parallel innature.1.5 The values stated in SI units are to be regarded asstandard. The values given in parentheses are for informationo
6、nly. Many of the stated dimensions in SI are direct conver-sions from the U. S. Customary System to accommodate theinstrumentation, practices, and procedures that existed prior tothe Metric Conversion Act of 1975.1.6 This standard does not purport to address all of thesafety concerns, if any, associ
7、ated 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:2D374 Test Methods for Thickness of Solid Electrical Insu-la
8、tion (Withdrawn 2013)3D618 Practice for Conditioning Plastics for TestingD785 Test Method for Rockwell Hardness of Plastics andElectrical Insulating MaterialsD1349 Practice for RubberStandard Conditions for Test-ingD1415 Test Method for Rubber PropertyInternationalHardnessD4483 Practice for Evaluati
9、ng Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesF1957 Test Method for Composite Foam Hardness-Durometer Hardness2.2 ISO Standard:4ISO/IEC 17025: 1999 General Requirements for the Com-petence of Testing and Calibration Laboratories3. Summary of Test Method3
10、.1 This test method permits hardness measurements basedon either initial indentation or indentation after a specifiedperiod of time, or both. Durometers with maximum readingindicators used to determine maximum hardness values of amaterial may yield lower hardness when the maximum indi-cator is used.
11、3.2 The procedures for Type M, or micro hardnessdurometers, accommodate specimens that are, by their dimen-sions or configuration, ordinarily unable to have their durom-eter hardness determined by the other durometer types de-scribed. Type M durometers are intended for the testing ofspecimens having
12、 a thickness or cross-sectional diameter of1.25 mm (0.050 in.) or greater, although specimens of lesserdimensions may be successfully accommodated under theconditions specified in Section 6, and have aType M durometerhardness range between 20 and 90. Those specimens whichhave a durometer hardness ra
13、nge other than specified shall useanother suitable procedure for determining durometer hard-ness.1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand is the direct responsibility of Subcommittee D11.10 on Physical Testing.Current edition approved Aug. 1, 2015. Published Jan
14、uary 2016. Originallyapproved in 1964. Last previous edition approved in 2010 as D2240 05 (2010).DOI: 10.1520/D2240-15.2For 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
15、to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from International Organization for Standardization (ISO), 1 rue deVaremb, Case postale 56, CH-1211, Geneva 20, Switzerland.Copyright ASTM Internat
16、ional, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14. Significance and Use4.1 This test method is based on the penetration of a specifictype of indentor when forced into the material under specifiedconditions. The indentation hardness is inversely related to t
17、hepenetration and is dependent on the elastic modulus andviscoelastic behavior of the material. The geometry of theindentor and the applied force influence the measurementssuch that no simple relationship exists between the measure-ments obtained with one type of durometer and those obtainedwith ano
18、ther type of durometer or other instruments used formeasuring hardness. This test method is an empirical testintended primarily for control purposes. No simple relationshipexists between indentation hardness determined by this testmethod and any fundamental property of the material tested.For specif
19、ication purposes, it is recommended that Test MethodD785 be used for materials other than those described in 1.1.5. Apparatus5.1 Hardness Measuring Apparatus, or Durometer, and anOperating Stand, Type 1, Type 2, or Type 3 (see 5.1.2)consisting of the following components:5.1.1 Durometer:5.1.1.1 Pres
20、ser Foot, the configuration and the total area ofa durometer presser foot may produce varying results whenthere are significant differences between them. It is recom-mended that when comparing durometer hardness determina-tions of the same type (see 4.1), that the comparisons bebetween durometers of
21、 similar presser foot configurations andtotal area, and that the presser foot configuration and size benoted in the Hardness Measurement Report (see 10.2.4 and5.1.1.3).5.1.1.2 Presser Foot, Types A, B, C, D, DO, E, O, OO,OOO, and OOO-S, with an orifice (to allow for the protrusionof the indentor) ha
22、ving a diameter as specified in Fig. 1 (a, b,c, d, e, f, and g), with the center a minimum of 6.0 mm (0.24in.) from any edge of the foot. When the presser foot is not ofa flat circular design, the area shall not be less than 500mm2(19.7 in.2).NOTE 1The Type OOO and the Type OOO-S, designated herein,
23、differ in their indentor configuration, spring force, and the resultsobtained. See Table 1 and Fig. 1 (e and g).5.1.1.3 Presser Footflat circular designs designated asType xR, where x is the standard durometer designation and Rindicates the flat circular press foot described herein, forexample, Type
24、 aR, dR, and the like. The presser foot, having acentrally located orifice (to allow for the protrusion of theindentor) of a diameter as specified in Fig. 1 (a through g). Theflat circular presser foot shall be 18 6 0.5 mm (0.71 6 0.02 in.)in diameter. These durometer types shall be used in anoperat
25、ing stand (see 5.1.2).(a) Durometers having a presser foot configuration otherthan that indicated in 5.1.1.3 shall not use the Type xRdesignation, and it is recommended that their presser footconfiguration and size be stated in the Hardness MeasurementReport (see 10.2.4).5.1.1.4 Presser Foot, Type M
26、, with a centrally locatedorifice (to allow for the protrusion of the indentor), having adiameter as specified in Fig. 1 (d), with the center a minimumof 1.60 mm (0.063 in.) from any edge of the flat circularpresser foot. The Type M durometer shall be used in a Type 3operating stand (see 5.1.2.4).5.
27、1.1.5 Indentor, formed from steel rod and hardened to 500HV10 and shaped in accordance with Fig. 1 (a, b, c, d, e, or g),polished over the contact area so that no flaws are visible under20 magnification, with an indentor extension of 2.50 6 0.04mm (0.098 6 0.002 in.).5.1.1.6 Indentor, Type OOO-S, fo
28、rmed from steel rod andhardened to 500 HV10, shaped in accordance with Fig. 1 (f),polished over the contact area so that no flaws are visible under20 magnification, with an indentor extension of 5.00 6 0.04mm (0.198 6 0.002 in.).5.1.1.7 Indentor, Type M, formed from steel rod and hard-ened to 500 HV
29、10 and shaped in accordance with Fig. 1 (d),polished over the contact area so that no flaws are visible under50 magnification, with an indentor extension of 1.25 6 0.02mm (0.049 6 0.001 in.).5.1.1.8 Indentor Extension Indicator, analog or digitalelectronic, having a display that is an inverse functi
30、on of theindentor extension so that:FIG. 1 (a) Type A and C IndentorD2240 152(1) The display shall indicate from 0 to 100 with no lessthan 100 equal divisions throughout the range at a rate of onehardness point for each 0.025 mm (0.001 in.) of indentormovement,(2) The display for Type OOO-S duromete
31、rs shall indicatefrom 0 to 100 with no less than 100 equal divisions throughoutthe range at a rate of one hardness point for each 0.050 mm(0.002 in.) of indentor movement,(3) The display for Type M durometers shall indicate from0 to 100 with no less than 100 equal divisions at a rate of onehardness
32、point for each 0.0125 mm (0.0005 in.) of indentormovement, and(4) In the case of analog dial indicators having a display of360, the points indicating 0 and 100 may be at the same pointon the dial and indicate 0, 100, or both.5.1.1.9 Timing Device (optional), capable of being set to adesired elapsed
33、time, signaling the operator or holding thehardness reading when the desired elapsed time has beenreached. The timer shall be automatically activated when thepresser foot is in contact with the specimen being tested, forexample, the initial indentor travel has ceased. Digital elec-tronic durometers
34、may be equipped with electronic timingFIG. 1 (b) Type B and D Indentor (continued)FIG. 1 (c) Type O, DO, and OO Indentor (continued)FIG. 1 (d) Type M Indentor (continued)D2240 153devices that shall not affect the indicated reading or determi-nations attained by more than one-half of the calibrationt
35、olerance stated in Table 1.5.1.1.10 Maximum Indicators (optional), maximum indicat-ing pointers are auxiliary analog indicating hands designed toremain at the maximum hardness value attained until reset bythe operator. Electronic maximum indicators are digital dis-plays electronically indicating and
36、 maintaining the maximumvalue hardness valued achieved until reset by the operator.5.1.1.11 Analog maximum indicating pointers have beenshown to have a nominal effect on the values attained,however, this effect is greater on durometers of lesser totalmainspring loads; for example, the effect of a ma
37、ximumindicating pointer on Type D durometer determinations will beless than those determinations achieved using a Type Adurometer. Analog style durometers may be equipped withmaximum indicating pointers. The effect of a maximumindicating pointer shall be noted at the time of calibration in thecalibr
38、ation report (see 10.1.5), and when reporting hardnessdeterminations (see 10.2.4). Analog Type M, OO, OOO, andType OOO-S durometers shall not be equipped with maximumindicating pointers.5.1.1.12 Digital electronic durometers may be equippedwith electronic maximum indicators that shall not affect the
39、indicated reading or determinations attained by more than onehalf of the spring calibration tolerance stated in Table 1.5.1.1.13 Calibrated Spring, for applying force to theindentor, in accordance with Fig. 1 (a through g) and capableof applying the forces as specified in Table 1.5.1.2 Operating Sta
40、nd (Fig. 2):5.1.2.1 Type 1, Type 2, and Type 3 shall be capable ofsupporting the durometer presser foot surface parallel to thespecimen support table (Fig. 3) throughout the travel of each.The durometer presser foot to specimen support table parallel-ism shall be verified each time the test specimen
41、 support tableis adjusted to accommodate specimens of varying dimensions.This may be accomplished by applying the durometer presserfoot to the point of contact with the specimen support table andFIG. 1 (e) Type OOO Indentor (continued)FIG. 1 (f) Type OOO-S Indentor (continued)D2240 154making adjustm
42、ents by way of the durometer mounting assem-bly or as specified by the manufacturer.5.1.2.2 Operating Stand, Type 1 (specimen to indentortype), shall be capable of applying the specimen to the indentorin a manner that minimizes shock.5.1.2.3 Operating Stand, Type 2 (indentor to specimentype), shall
43、be capable of applying the indentor to the specimenin a manner that minimizes shock.5.1.2.4 Operating Stand, Type 3 (indentor to specimentype), hydraulic dampening, pneumatic dampening, or electro-mechanical (required for the operation of Type M durometers)shall be capable of controlling the rate of
44、 descent of theindentor to the specimen at a maximum of 3.2 mm/s (0.125in./s) and applying a force sufficient to overcome the calibratedspring force as shown in Table 1. Manual application, Type 1or Type 2 operating stands are not acceptable for Type Mdurometer operation.5.1.2.5 The entire instrumen
45、t should be plumb and level,and resting on a surface that will minimize vibration. Operatingthe instrument under adverse conditions will negatively affectthe determinations attained.5.1.2.6 Specimen Support Table,(Fig. 3) integral to theoperating stand, and having a solid flat surface. The specimens
46、upport platform may have orifices designed to accept variousinserts or support fixtures (Fig. 3) to provide for the support ofirregularly configured specimens. When inserts are used tosupport test specimens, care must be taken to align the indentorto the center of the insert, or the point at which t
47、he indentor isto contact the specimen. Care should be exercised to assure thatthe indentor does not abruptly contact the specimen supporttable as damage to the indentor may result.6. Test Specimen6.1 The test specimen, herein referred to as “specimen” or“test specimen” interchangeably, shall be at l
48、east 6.0 mm (0.24in.) in thickness unless it is known that results equivalent to the6.0-mm (0.24-in.) values are obtained with a thinner specimen.6.1.1 Aspecimen may be composed of plied pieces to obtainthe necessary thickness, but determinations made on suchspecimens may not agree with those made o
49、n solid specimens,as the surfaces of the plied specimens may not be in completecontact. The lateral dimensions of the specimen shall besufficient to permit measurements at least 12.0 mm (0.48 in.)from any edge, unless it is known that identical results areobtained when measurements are made at a lesser distancefrom an edge.FIG. 1 (g) Type E Indentor (continued)TABLE 1 Durometer Spring Force CalibrationAAll Values are in NIndicated Value Type A, B, E, O Type C, D, DO Type M Type OO, OOO Type OOO-S0 0.55 0 0.324 0.203 0.16710 1.3 4.445 0.368 0.294 0.34320 2.05 8.89 0.412
