1、Designation: F1957 99 (Reapproved 2011)Standard Test Method forComposite Foam Hardness-Durometer Hardness1This standard is issued under the fixed designation F1957; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method describes a type of composite foamhardness measurement device known as durometer: Type CF.The procedure for
3、 determining indentation hardness of sub-stances comprised of two or more elastomeric materials, one ofwhich is a foam or foam like material. These are classified ascomposite foam structures. The composite foam product mayhave an armature made of a material suitable for addingstructural integrity in
4、cluding but not limited to metal, plastic,or wood. This construction is typical for lapbar restraints,seating, and other restraint devices, as well as some showelements.1.2 This test method is not equivalent to other indentationhardness methods and instrument types, specifically thosedescribed in Te
5、st Methods D1415 and D2240.1.3 The values stated in SI units are to be regarded asstandard. The 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
6、 that existed prior tothe Metric Conversion Act of 1975.1.4 All materials, instruments, or equipment used for thedetermination of mass or dimension shall have traceability tothe National Institute for Standards and Technology (NIST) orother internationally recognized organizations.1.5 This test meth
7、od is not a safety standard as it pertains toride legislation. The use of this test method is optional basedupon an agreement between customers and suppliers of foamproducts.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibil
8、ity 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-lationD618 Practice for Conditioning Plas
9、tics for TestingD785 Test Method for Rockwell Hardness of Plastics andElectrical Insulating MaterialsD1349 Practice for RubberStandard Temperatures forTestingD1415 Test Method for Rubber PropertyInternationalHardnessD2240 Test Method for Rubber PropertyDurometerHardnessD4483 Practice for Evaluating
10、Precision for Test MethodStandards in the Rubber and Carbon Black ManufacturingIndustries3. Summary of Test Method3.1 This test method permits hardness measurements basedon either initial indentation or indentation after a specifiedperiod of time, or both.3.2 Those specimens, which have a durometer
11、hardnessrange other than specified, shall use another suitable procedurefor determining durometer hardness.4. Significance and Use4.1 This test method is based on the penetration by aspecific type of indentor when forced into the material underspecified conditions. The indentation hardness is relate
12、d in-versely to the penetration and is dependent on the elasticmodulus and viscoelastic behavior of the material. The geom-etry of the indentor and the applied force influence themeasurements, such that no simple relationship exists betweenthe measurements obtained with one type of durometer andthos
13、e obtained with another type of durometer or otherinstruments used for measuring hardness. This test method is1This test method is under the jurisdiction of ASTM Committee F24 onAmusement Rides and Devices and is the direct responsibility of F24.10 on TestMethods.Current edition approved Jan. 15, 20
14、11. Published June 2011. Originallyapproved in 1999. Last previous edition approved in 2004 as F1957 99 (2004).DOI: 10.1520/F1957-99R11.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume in
15、formation, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.an empirical test intended primarily for control purposes. Nosimple relationship exists between indentation ha
16、rdness deter-mined by this test method and any fundamental property of thematerial tested. For specification purposes it is recommendedthat Test Method D785 be used for hard materials and TestMethod D2240 be used for solid elatomers.5. Apparatus5.1 Hardness measurement apparatus, or durometer, consi
17、st-ing of the following components:5.1.1 Presser Foot, with an orifice (to allow for the protru-sion of the indentor) having a diameter as specified in Fig. 1with the center a minimum of 38.0 mm (1.5 in.) from any edgeof the flat circular presser foot.5.1.2 Indentor, formed from steel rod, shaped in
18、 accordancewith Fig. 2, polished over the contact area so that no flaws arevisible under 203 magnification and with an indentor exten-sion of 7.62 6 0.04 mm (.300 6 0.002 in.).5.1.3 Indentor Extension Indicating Display, (analog ordigital electronic), having a display that is an inverse functionof t
19、he indentor extension.5.1.3.1 Digital Electronic Indicating Displays shall indi-cate from 0 to 100, with no less than 100 equal divisionsthroughout the range, at a rate of one hardness point for each0.50 mm (0.002 in.) of indentor movement.5.1.3.2 Analog Indicating Displays shall indicate from 0 to1
20、00, with no less 100 equal divisions throughout the range oralternatively with no less than 90 equal divisions throughout arange from 10 to 100, at a rate of one hardness point for each0.050 mm (0.002 in.) of indentor movement.5.1.4 Maximum Indicators (optional), maximum indicatingpointers are auxil
21、iary analog indicating hands designed toFIG. 1 Presser Foot DetailFIG. 2 Indentor DetailF1957 99 (2011)2remain at the maximum hardness value attained until reset bythe operator. Electronic maximum indicators are digital dis-plays electronically indicating and maintaining the maximumvalue hardness va
22、lue achieved, until reset by the operator.5.1.4.1 Analog maximum indicating pointers have beenshown to have a nominal influence on the values attained;however, this influence is greater on durometers of lesser totalmainspring forces. The influence of a maximum indicatingpointer shall be noted at the
23、 time of calibration in thecalibration report (see 10.1.4) and when reporting hardnessdeterminations (see 10.2.4).5.1.4.2 Digital electronic durometers may be equipped withelectronic maximum indicators that shall not influence theindicated reading or determinations attained by more than onehalf of t
24、he calibration tolerance stated in Table 1.5.1.5 Calibrated Spring, for applying force to the indentorand capable of applying the forces as specified in Table 1.6. Test Specimen6.1 The test specimen, herein referred to as “specimen” or“test specimen” interchangeably, shall be at least 25.4 mm(1.00 i
25、n.) thick, herein, unless it is known that results equiva-lent to the 25.4 mm (1.00 in.) values are obtained with a thinnertest specimen. On specimens with solid armatures, it issuggested that readings not be taken in areas close to thearmature as this may affect the readings.6.1.1 The lateral dimen
26、sions of the test 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.6.1.2 The surfaces of the test specimen shall be flat andparallel over a suf
27、ficient area to permit the presser foot tocontact the specimen over an area having a radius of at least30.0 mm (1.18 in.) from the indentor point if possible.Variations are acceptable as agreed upon between laboratoriesor between customer and supplier. The test specimen shall besupported suitably to
28、 provide for positioning and stability. Asuitable hardness determination may be difficult to obtain on anuneven or rough point of contact with the indentor.7. Calibration7.1 Calibration DeviceThe durometer spring shall becalibrated by supporting the durometer in a calibrating devicein a vertical pos
29、ition and applying a measurable force to theindentor tip. The force may be measured by means of a balanceor by an electronic force cell. The calibrating device shall becapable of measuring applied force to within 50 % of thecalibration tolerance described in Table 1. Care should be takento ensure th
30、at the force is applied vertically to the indentor tip,as lateral force will cause errors in calibration.7.2 Indentor ExtensionIndentor extension and shape shallbe in accordance with 5.1.2 and Fig. 2.7.3 Indentor Extension Adjustment Procedure:7.3.1 Dimensional Gage Blocks:7.3.1.1 The presser foot m
31、ust be attached to the durometergage before adjustment. This allows a nominal indentor exten-sion of 7.62 mm (.300 in.).7.3.1.2 Place precision ground dimensional blocks (Grade Bor better) on the test specimen support table and beneath thedurometer presser foot and indentor. Arrange the blocks so th
32、atthe durometer presser foot contacts the larger block and theindentor tip is at the moment of contact with the smaller block(Fig. 3).7.3.1.3 A combination of dimensional gage blocks may beused to achieve a difference of 7.62 +0.00, 0.0254 mm (0.300+0.00, 0.001 in.) between them:7.3.2 Indentor Exten
33、sion Adjustment:7.3.2.1 Carefully lower the durometer presser foot untilcontact with the largest dimensional block, the indentor tipshould be at the point of contact with the smaller block,verifying full indentor extension.7.3.2.2 Adjust the indentor extension to 7.620 6 0.04 mm(0.300 6 0.002 in.),
34、following the manufacturers recom-mended procedure.7.3.2.3 When performing the procedures in 7.3, care shouldbe used as not to cause damage to the indentor tip.7.3.2.4 Parallelism of the durometer presser foot to the testspecimen support surface (table), and hence the dimensionalgage blocks, at the
35、time of instrument calibration shall be inaccordance with Test Methods D374, machinists micrometers.7.4 Indicator Display Adjustment (Analog and Digital):7.4.1 After adjusting the indentor extension as indicated in7.3, use an identical arrangement of dimensional gage blocks toverify the linear relat
36、ionship between indentor travel andindicated display at two points: 0 and 100. Following themanufacturers recommendations, make adjustments so thatthe indicator displays a value equal to the indentor travelmeasured to within:612 durometer units measured at 0;612 durometer units measured at 100, and6
37、112 durometer units at all points enumerated in 7.5.7.4.2 Each durometer point indicated is equal to 0.050 mm(0.002 in.) of indentor travel.7.5 Spring CalibrationThe durometer spring shall becalibrated at displayed readings 20, 30, 40, 50, 60, 70, 80, andTABLE 1 Durometer Spring Force CalibrationInd
38、icated Value Force, N Force, lbf0 1.099 0.24710 9.928 2.23220 18.757 4.21730 27.586 6.20240 36.415 8.18650 45.244 10.17160 54.073 12.15670 62.902 14.14180 71.731 16.12690 80.560 18.111100 89.389 20.095Calibration Tolerance 60.893 60.200F1957 99 (2011)390. The measured force (9.8 3 mass in kilograms)
39、 shall bewithin the calibration tolerance specified in Table 1, whichidentifies the measured force applied to the indentor for theentire range of the instrument, although it is necessary only toverify the spring calibration at points listed herein.7.6 Spring Calibration Procedure:7.6.1 Assure that t
40、he indentor extension has been adjustedin accordance with 7.3 and the linear relationship betweenindentor travel and indicated display is as specified in 7.4.7.6.2 Place the durometer in the calibration device (see 7.1).Apply the forces indicated in Table 1 so that the forces appliedare aligned with
41、 the centerline of the indentor in a fashion thateliminates shock or vibration and adjust the durometer inaccordance with the manufacturers recommendations.7.7 The metal or rubber reference blocks provided forchecking durometer operation and state of calibration are not tobe relied upon as calibrati
42、on standards. The calibration proce-dures outlined in Section 7 are the only valid calibrationprocedures.7.8 Spring force calibration tolerance is 61.0 durometerunit. Spring force calibration tolerance is calculated as 1 %.7.9 Spring Force Combinations:7.9.1 For Type CF Durometers:force, N 5 1.0987
43、1 0.8829 HCF(1)where:HCF= one durometer unit on Type CF durometers.8. Instrument and Test Specimen Conditioning8.1 Tests or instrument calibrations shall be conducted at23.0 6 2.0 C (73.4 6 3.6 F).8.2 The instrument and specimen(s) to be tested shall bemaintained at 23.0 6 2.0 C (73.4 6 3.6 F) for a
44、 minimum of12 h prior to performing a test or calibration.8.3 For materials whose hardness depends on relative hu-midity, the test specimens shall be conditioned in accordancewith Procedure A of Practice D618 and tested under the sameconditions.8.3.1 Accordingly, the relative humidity at the time of
45、 a testshall be reported in 10.2.2.8.3.2 The relative humidity may be reported in 10.2.2 whenthe influence of relative humidity on the hardness of the testspecimen is not known.8.3.3 The relative humidity at the time of instrument cali-bration shall be reported in 10.1.6.8.4 No conclusive evaluation
46、 has been made on durometersat temperatures other than 23.0 6 2.0 C (73.4 6 3.6 F).Conditioning at temperatures other than the above may showchanges in calibration. Durometer use at temperatures otherthan the above should be decided between customer andsupplier (see Practice D1349).8.5 These procedu
47、res may be modified if agreed uponbetween laboratories or between customer and supplier.9. Procedure9.1 Manual (Hand-Held) Durometer Testing:9.1.1 Care shall be exercised to minimize the exposure ofthe instrument to environmental conditions that are adverse tothe performance of the instrument or adv
48、ersely influence testresults.9.1.2 Place the test specimen on a flat, hard, horizontalsurface. Hold the durometer in a vertical position with theindentor tip at a distance from any edge of the test specimen asdescribed in Section 6, unless it is known that identical resultsare obtained when measurem
49、ents are made with the indentor ata lesser distance.9.1.3 Apply the indentor to the test specimen, maintainingthe durometer in a vertical position keeping the presser footparallel to the test specimen, with a firm smooth downwardaction that will avoid shock, rolling of the presser foot over thetest specimen, or the application of lateral force to the indentor.Apply sufficient pressure to assure firm contact between thepresser foot and the test specimen (see 5.2).FIG. 3 Indentor Extension Calibration SetupF1957 99 (2011)49.1.4 For any material covered in 1.1
