ASTM D6395-2005 Standard Test Method for Flatwise Flexural Impact Resistance of Rigid Plastics《硬质塑料耐平面柔性冲击性的标准试验方法》.pdf

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1、Designation: D 6395 05Standard Test Method forFlatwise Flexural Impact Resistance of Rigid Plastics1This standard is issued under the fixed designation D 6395; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revisi

2、on. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope*1.1 The resistance of plastics to breakage by flexural shockmay be determined by test methods such as those contained inTest Method

3、 D 256. Specimens used in those test methodsfeature a milled notch to promote brittle fracture. The testspecimens are struck by a pendulum with the depth dimensionparallel to the direction of pendulum swing. This test method isdifferentiated from the others by its application to the assess-ment of t

4、he affect on impact resistance of changes in thesurface of specimens resulting from weathering or otherexposure. In this test method, specimens are struck by apendulum with the depth dimension perpendicular to thedirection of pendulum swing. Test Method D 5420 may also beused to conduct testing of w

5、eathered or exposed specimens.This test method is differentiated from Gardner Impact by thesmaller size of the specimens, which may result in substantiallyhigher productivity of accelerated weathering instruments.Additionally, this test method provides multiple data from asingle specimen for charact

6、erization of within specimen vari-ability.1.2 This test method describes the determination of theresistance of rigid plastic strip specimens to breakage orpermanent deformation when one end of the specimen issubjected to an impact upon its wide face while the other endof the specimen is firmly clamp

7、ed.1.3 This test method is applicable to specimens of 1.60 mm0.0625 in. thickness. However, the limits of applicability ofthe test are not sharply defined, and specimens having otherdimensions may frequently be used. For specimens of thick-nesses other than 1.60 mm 0.0625 in. the ratio of the distan

8、cebetween the top of the clamp and the centerline of the roundedstriking edge to the specimen thickness must be 2.5 6 0.1.1.4 This test method measures the relative impact resistanceof samples having approximately the same thickness. Normal-ization of the impact resistance to unit cross-sectional ar

9、ea onlypartly compensates for the effects of specimen thicknessvariation because, at the fixed cantilever length, the ratio ofshear stress to tensile stress in bending increases with thick-ness, and the importance of these effects in contributing to theenergy absorbed is greater for ductile than for

10、 brittle failure.1.5 This test method is used primarily as a means ofassessing, for a series of samples, changes relative to a controldue to some treatment such as weathering or exposure to activeenvironments. It has been particularly useful as a sensitiveindicator of the development of surface crac

11、ks or a brittlesurface. The existence or formation of cracks in an inherentlybrittle surface produces marked lowering of impact strengthwhen that surface is the one subjected to tension in the test.1.6 This test method is not generally applicable to materialssuch as elastomers or nonrigid plastics i

12、n which there is nofracture, permanent deformation, or other change due toyielding in flexure. However, it may be desirable to test suchmaterials as file samples to establish reference points when thetest is applied as described in 1.5.1.7 The values stated in SI units are to be regarded as thestand

13、ard. The values given in brackets are for information only.1.8 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 practices and determine the applica-bi

14、lity of regulatory limitations prior to use.NOTE 1There is no equivalent or similar ISO standard.2. Referenced Documents2.1 ASTM Standards:2D 256 Test Method for Determining the Pendulum ImpactResistance of Notched Specimens of PlasticsD 618 Practice for Conditioning Plastics for TestingD 883 Termin

15、ology Relating to PlasticsD 5420 Test Method for Impact Resistance of Flat, RigidPlastic Specimen by Means of a Striker Impacted by aFalling Weight (Gardner Impact)D 5947 Test Methods for Physical Dimensions of SolidPlastic Specimens1This test method is under the jurisdiction of ASTM Committee D20 o

16、n Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties.Current edition approved Nov. 1, 2005. Published December 2005. Originallyapproved in 1999. Last previous edition approved in 1999 as D 6395 - 99.2For referenced ASTM standards, visit the ASTM website, www.ast

17、m.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.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO B

18、ox C700, West Conshohocken, PA 19428-2959, United States.3. Terminology3.1 Definitions used in this test method are in accordancewith Terminology D 883.4. Significance and Use4.1 The flatwise flexural impact test is a test in which thekinetic energy lost by a moving pendulum during impact isused to

19、determine the energy to break or deform a testspecimen.4.2 The standard Izod test apparatus as described in TestMethod D 256 is retrofitted with clamping jaws, which hold thetest specimen such that the flat face of the specimen is struckby the pendulum during a test.4.3 The pendulum shall be a stand

20、ard Izod pendulum asdescribed in Test Method D 256. It shall be capable ofdelivering an energy of 2.71 6 0.14 J 2.00 6 0.10 ft.-lbf.Except as detailed in 10.5, this basic pendulum shall be usedwith all specimens that extract less than 85 % of the availableenergy. Higher energy pendulums or a basic p

21、endulum towhich weights are added to increase its available energy shallbe used with specimens that require more energy to break. Aseries of energy levels such that each has twice the energy ofthe next lighter one will be found convenient. The striking noseof the pendulum shall contact one of the fl

22、at faces of thespecimen at a specified distance above the clamp edge. Theratio of the distance between the top of the clamp and thecenterline of the rounded striking edge to the specimenthickness shall be 2.5 6 0.1.4.4 The type of failure of each specimen tested shall beassigned one of the following

23、 categories:Complete Break (C) A break in which the specimen isseparated into two or more pieces.Hinge Break (H)Anearly complete break in which there islittle or no spring back when the free end is bent or displaced.Partial Break (P)An incomplete break in which fractureextends through at least 50 %

24、of the specimen thickness, andsuch that the free end can be bent with relatively little effort yethas considerable spring back.Nonbreak (N)A result where there is no fracture or thefracture extends less than 50 % of the specimen thickness.4.5 The value of this impact test is to determine the changei

25、n impact properties that may result from a material havingbeen exposed to one or a series of environments, such asweathering at different intervals or different intensities whenthese data are compared to a file sample exposed only to thestandard laboratory environment or other agreed upon condi-tion

26、s.4.6 The flatwise impact resistance is calculated as energyabsorbed per unit of cross-sectional area.4.7 Before proceeding with this test method, referenceshould be made to the specification of the material being tested.Any test specimen preparation, conditioning, dimensions,and/or testing paramete

27、rs covered in the material specificationshall take precedence over those mentioned in this test methodexcept in cases where to do so would conflict with the purposefor conducting testing. If there are no material specifications,then the default conditions apply.5. Interferences5.1 Use of an improper

28、 shim will result in test values eithertoo large or too small depending upon whether the shim in useis too short or too long.5.2 Orientation and molded-in stresses due to flow andcooling history result in variation in properties within injectionmolded specimen, especially at the ends and at the gate

29、 region.The effects of such variations can be minimized by avoidingtests close to the gate or the ends of the specimen.5.3 The clearance between the pendulum and the clamp asthe pendulum passes the clamp at its closest point during a testsignificantly affects the results of this test. If the specime

30、nthickness is greater than about one half of the clearance, a largeenergy loss due to friction occurs in ductile specimens. Theratio of shear to surface tensile stress increases and the natureof failure may change abruptly over a narrow range ofspecimen thickness. The clearance is dictated by the ra

31、tio of thedistance between the pendulum nose centerline and the clamptop to the specimen thickness (2.5 6 0.1). The movable jawface and fixed jaw face set used for the thickness of specimenbeing tested shall either be of proper dimensions for this ratioor be adjustable in design to allow the ratio t

32、o be achieved.5.4 The use of excessive clamping force may inducestresses in test specimens causing variation in test results.6. Apparatus6.1 Testing MachineThe testing machine shall consist ofthe standard Izod test instrument as detailed in Test MethodD 256 but with a modified clamping arrangement.

33、Figs. 1-3illustrate typical clamping arrangements applicable to someinstruments. Other clamping arrangements may be used pro-vided that they maintain the specified ratio of the distancebetween the top of the clamp and the centerline of thependulum nose to the specimen thickness (2.5 6 0.1). Otherarr

34、angements must also provide uniform clamping along theclamped length of the specimen and position the specimen suchthat when the pendulum is freely hanging, the striking edge iswithin 0.2 % of full scale of touching the front face of thespecimen as required by Test Method D 256. As indicated bythese

35、 figures, the specimen clamp faces may be bolted orotherwise firmly attached to the existing Izod fixed andmovable jaws. To avoid compromising the instruments capa-bility for Izod testing, using either a dedicated set of fixed andmovable Izod jaws or clamping faces mounted in such a wayas to not alt

36、er the existing Izod jaws is recommended.6.2 Specimen Clamp FacesSpecial clamp faces (see Fig.2) for both the fixed and the movable jaws of the clamp shallbe used to clamp the test specimen flatwise with its long axisvertical and its thickness direction parallel to the direction ofthe pendulum swing

37、. The clamp faces constitute a set. Somedimensions within the set are dictated by the thickness of thespecimen being tested and by the particular Izod instrumentbeing used. Fig. 2 provides the dimensions for clamp faceswhen used with one type of Izod instrument to test 1.60 mm0.062 in. thick specime

38、n.6.2.1 For 1.60 mm 0.062 in. thick specimens the distancebetween the upper edge of the clamp and the striking nose ofthe pendulum is 4.0 mm 0.161 in. providing a clearanceD6395052between the clamp and the lowest part of the pendulumsstriking nose of 3.20 mm 0.126 in.NOTE 2The required dimensions of

39、 hardware may vary from thoseprovided in the figures as a result of individual tolerances necessary tomate with preexisting components. The cumulative tolerances of indi-vidual hardware components must result in the required ratio of thedistance between the top of the clamp and the centerline of the

40、 roundedstriking edge to the specimen thickness of 2.5 6 0.1.6.3 ShimsAset of steel blocks (see Fig. 3) shall be used toprovide spacing between the lower end of the jaw faces to keepthe faces as parallel as possible during testing. A shim shall beselected to provide a spacing between the clamp faces

41、 matchedas closely as possible to the thickness of the specimen beingtested. In no case shall the shim protrude beyond the jaw faceby less than the specimen thickness or insufficient clamping ofthe specimen may result. Fig. 3 provides the dimensions for aset of shims spanning a typical range of thic

42、kness for thetesting of 1.60 mm 0.0625 in. thick specimen.6.4 MicrometersSuitable micrometers with a resolution of0.025 mm 0.001 in. or better shall be used to measure thethickness of the test specimen. The micrometer shall conformto the applicable provisions of Test Method D 5947.7. Sampling, Test

43、Specimen, and Test Units7.1 The standard test specimen shall have a rectangularcross-section and an approximate length of 65 mm 2.5 in.Most specimens should be 12.7 mm 0.500 in. wide by 1.60mm 0.0625 in. thick, but for some materials, such as thosewhich are glass reinforced, it may be desirable to u

44、se speci-mens of other thicknesses. The specimens may be molded orcut from flat sheet, but they shall be of uniform dimensionswithin any given set.7.2 Trim or sand off any protrusions that might interferewith clamping or positioning the specimen in the instrumentclamps. Do not introduce notches or s

45、cratches in the test faceof the specimen.7.3 Injection-molded specimens shall have at least 6 mm0.25 in. cut from the end to be tested first so that when thespecimen is clamped in the testing machine, the clamp edgewill be no less than 12 mm 0.5 in. from the original end of thespecimen. The clamp ed

46、ge shall also be at least 6 mm 0.25 in.from a gate. Whenever this test is used for assessing agingeffects, cut off any portion of the test specimen end which hasnot been uniformly exposed to the aging environment so thatthe edge of the clamp will be at least 6 mm 0.25 in. from theunexposed region.8.

47、 Calibration and Standardization8.1 Check the flatwise impact tester periodically for con-formance to the provisions of Test Method D 256.8.2 The proper movable jaw face, fixed jaw face, and shimshall be installed for the thickness of the specimen being tested.The dimensional relationships between t

48、he various combina-tions of hardware components for a 1.60 mm 0.0625 in. thickspecimen is provided in Fig. 1.8.3 The clearance between the pendulum and the upper gripsurface at their closest point shall be checked frequently toconfirm that the correct clearance is being used for thethickness of the

49、specimen being tested and that the clearanceplus striker radius meets the required ratio.8.4 Adequate file samples for each group of treated samplesshall be tested, preferably at the same time that the treatedsamples are tested.9. Conditioning9.1 ConditioningCondition the test specimens at 23 62C 73.4 6 3.6F and 50 6 5 % relative humidity for not lessthan 40 h prior to test in accordance with Procedure A ofPractice D 618, unless otherwise specified by contract orrelevant material specification, or unless it has been shown thatconditio