1、Designation: D2240 151Standard 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 paren
2、theses 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.1NOTEEditorially corrected 8.3 in November 2017.1. Scope1.1 This test method
3、 covers twelve types of rubber hardnessmeasurement 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
4、materials, gel-like materials, andsome plastics is 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 material
5、s, instruments, or equipment used for thedetermination 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
6、 values given in parentheses are for informationonly. 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
7、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, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was d
8、eveloped in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced
9、Documents2.1 ASTM Standards:2D374 Test Methods for Thickness of Solid Electrical Insu-lation (Metric) D0374_D0374MD618 Practice for Conditioning Plastics for TestingD785 Test Method for Rockwell Hardness of Plastics andElectrical Insulating MaterialsD1349 Practice for RubberStandard Conditions for T
10、est-ingD1415 Test Method for Rubber PropertyInternationalHardnessD4483 Practice for Evaluating Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustriesF1957 Test Method for Composite Foam Hardness-Durometer Hardness2.2 ISO Standard:3ISO/IEC 17025: 1999 General Requir
11、ements for the Com-petence of Testing and Calibration Laboratories3. Summary of Test Method3.1 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 maximu
12、m hardness values of amaterial may yield lower hardness when the maximum indi-cator is used.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 d
13、urometer types de-scribed. Type M durometers are intended for the testing of1This test method is under the jurisdiction of ASTM Committee D11 on Rubberand Rubber-like Materials and is the direct responsibility of Subcommittee D11.10on Physical Testing.Current edition approved Aug. 1, 2015. Published
14、 January 2016. Originallyapproved in 1964. Last previous edition approved in 2010 as D2240 05 (2010).DOI: 10.1520/D2240-15E01.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information,
15、 refer to the standards Document Summary page onthe ASTM website.3Available from International Organization for Standardization (ISO), 1 rue deVaremb, Case postale 56, CH-1211, Geneva 20, Switzerland.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.
16、United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barr
17、iers to Trade (TBT) Committee.1specimens having 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. Th
18、ose specimens whichhave a durometer hardness range other than specified shall useanother suitable procedure for determining durometer hard-ness.4. Significance and Use4.1 This test method is based on the penetration of a specifictype of indentor when forced into the material under specifiedcondition
19、s. The indentation hardness is inversely related to thepenetration 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
20、with one type of durometer and those obtainedwith another 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 f
21、undamental property of the material tested.For specification 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
22、the following components:5.1.1 Durometer:5.1.1.1 Presser 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 (s
23、ee 4.1), that the comparisons bebetween durometers of 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 or
24、ifice (to allow for the protrusionof the indentor) having 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
25、 1The Type OOO and the Type OOO-S, designated herein,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 c
26、ircular press foot described herein, forexample, Type 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 diam
27、eter. These durometer types shall be used in anoperating 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 Measur
28、ementReport (see 10.2.4).5.1.1.4 Presser Foot, Type M, 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 shal
29、l be used in a Type 3operating stand (see 5.1.2.4).5.1.1.5 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
30、 (0.098 6 0.002 in.).5.1.1.6 Indentor, Type OOO-S, formed 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,
31、Type M, formed from steel rod and hard-ened to 500 HV10 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.).FIG. 1 (a) Type A and C IndentorD2240 15125.1.1.8 Indent
32、or Extension Indicator, analog or digitalelectronic, having a display that is an inverse function of theindentor extension so that:(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 in
33、dentormovement,(2) The display for Type OOO-S durometers 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 l
34、ess than 100 equal divisions at a rate of onehardness 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
35、 (optional), capable of being set to adesired elapsed time, signaling the operator or holding thehardness reading when the desired elapsed time has beenreached. The timer shall be automatically activated when theFIG. 1 (b) Type B and D Indentor (continued)FIG. 1 (c) Type O, DO, and OO Indentor (cont
36、inued)FIG. 1 (d) Type M Indentor (continued)D2240 1513presser foot is in contact with the specimen being tested, forexample, the initial indentor travel has ceased. Digital elec-tronic durometers may be equipped with electronic timingdevices that shall not affect the indicated reading or determi-nat
37、ions attained by more than one-half of the calibrationtolerance 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 indicat
38、ors are digital dis-plays electronically indicating and 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
39、 totalmainspring loads; for example, the effect of a maximumindicating 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
40、 shall be noted at the time of calibration in thecalibration 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
41、electronic maximum indicators that shall not affect theindicated 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
42、 the forces as specified in Table 1.5.1.2 Operating Stand (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 par
43、allel-ism shall be verified each time the test specimen support tableFIG. 1 (e) Type OOO Indentor (continued)FIG. 1 (f) Type OOO-S Indentor (continued)D2240 1514is adjusted to accommodate specimens of varying dimensions.This may be accomplished by applying the durometer presserfoot to the point of c
44、ontact with the specimen support table andmaking adjustments 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 Op
45、erating Stand, Type 2 (indentor to specimentype), shall 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
46、M durometers)shall be capable of controlling the rate of 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 fo
47、r Type Mdurometer operation.5.1.2.5 The entire instrument 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 theoperati
48、ng stand, and having a solid flat surface. The specimensupport 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 inde
49、ntorto the center of the insert, or the point at which the 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 least 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 necess
