1、Designation: D 6110 08Standard Test Method forDetermining the Charpy Impact Resistance of NotchedSpecimens of Plastics1This standard is issued under the fixed designation D 6110; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope*1.1 This test method is used to determine the resistance ofplastics to breakage by flexural shock as indicated by
3、 theenergy extracted from standardized (see Note 1) pendulum-type hammers, mounted in standardized machines, in breakingstandard specimens with one pendulum swing. This testmethod requires specimens to be made with a milled notch (seeNote 2). The notch produces a stress concentration whichpromotes a
4、 brittle, rather than a ductile, fracture. The results ofthis test method are reported in terms of energy absorbed perunit of specimen width (see Note 3).NOTE 1The machines with pendulum-type hammers have been stan-dardized in that they must comply with certain requirements including afixed height o
5、f hammer fall, which results in a substantially fixed velocityof the hammer at the moment of impact. Hammers of different initialenergies (produced by varying their effective weights), however, arerecommended for use with specimens of different impact resistance.Moreover, manufacturers of the equipm
6、ent are permitted to use differentlengths and constructions of pendulums with possible differences inpendulum rigidities resulting (see Section 5). Be aware that otherdifferences in machine design do exist.NOTE 2The specimens are standardized in that they have a fixedlength and fixed depth, however,
7、 the width of the specimens is permittedto vary between limits. One design of milled notch is allowed. The notchin the specimen serves to concentrate the stress, minimize plasticdeformation, and direct the fracture to the part of the specimen behind thenotch. Scatter in energy-to-break is thus reduc
8、ed. Because of differencesin the elastic and viscoelastic properties of plastics, however, response toa given notch varies among materials.NOTE 3Caution must be exercised in interpreting the results of thistest method. The following testing parameters have been shown to affecttest results significan
9、tly: method of specimen fabrication, including butnot limited to processing technology, molding conditions, mold design,and thermal treatment; method of notching; speed of notching tool; designof notching apparatus; quality of the notch; time between notching andtest; test specimen thickness; test s
10、pecimen width under notch; andenvironmental conditioning.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 practices and determine the applica-bili
11、ty of regulatory limitations prior to use.NOTE 4This standard resembles ISO 179 in title only. The content issignificantly different.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 647 Practice for Design of Molds for Test Specimens ofPlastic Molding
12、Materials3D 883 Terminology Relating to PlasticsD 4000 Classification System for Specifying Plastic Mate-rialsD 4066 Classification System for Nylon Injection and Ex-trusion Materials (PA)D 5947 Test Methods for Physical Dimensions of SolidPlastics SpecimensE 691 Practice for Conducting an Interlabo
13、ratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsFor definitions related to plastics, see Ter-minology D 883.4. Summary of Test Method4.1 A notched specimen is supported as a horizontal simplebeam and is broken by a single swing of the pendulum with theimpact line
14、midway between the supports and directly oppositethe notch.5. Significance and Use5.1 Before proceeding with this test method, refer to thematerial specification for the material being tested. Any testspecimen preparation, conditioning, dimensions and testingparameters required by the materials spec
15、ification shall takeprecedence over those required by this test method. Table 1 ofClassification D 4000 lists the ASTM materials standards that1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.10 on Mechanical Properties
16、.Current edition approved Aug. 1, 2008. Published September 2008. Originallyapproved in 1997. Last previous edition approved in 2006 as D 6110 - 06.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandar
17、ds volume information, refer to the standards Document Summary page onthe ASTM website.3Withdrawn.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.currently exist. If t
18、here is no material specification, then therequirements of this test method apply.5.2 The pendulum impact test indicates the energy to breakstandard test specimens of specified size under stipulatedconditions of specimen mounting, notching (stress concentra-tion), and pendulum velocity at impact.5.3
19、 For this test method, the energy lost by the pendulumduring the breakage of the specimen is the sum of the energiesrequired to initiate fracture of the specimen; to propagate thefracture across the specimen; to throw the free ends of thebroken specimen (toss energy); to bend the specimen; toproduce
20、 vibration in the pendulum arm; to produce vibration orhorizontal movement of the machine frame or base; to over-come friction in the pendulum bearing and in the indicatingmechanism, and to overcome windage (pendulum air drag); toindent or deform, plastically, the specimen at the line ofimpact; and
21、to overcome the friction caused by the rubbing ofthe striking nose over the face of the bent specimen.NOTE 5The toss energy, or the energy used to throw the free ends ofthe broken specimen, is suspected to represent a very large fraction of thetotal energy absorbed when testing relatively dense and
22、brittle materials.No procedure has been established for estimating the toss energy for theCharpy method.5.4 For tough, ductile, fiber-filled, or cloth-laminated mate-rials, the fracture propagation energy is usually large comparedto the fracture initiation energy. When testing these materials,energy
23、 losses due to fracture propagation, vibration, frictionbetween the striking nose and the specimen has the potential tobecome quite significant, even when the specimen is accuratelymachined and positioned, and the machine is in good conditionwith adequate capacity (see Note 6). Significant energy lo
24、ssesdue to bending and indentation when testing soft materialshave also been observed.NOTE 6Although the frame and the base of the machine must besufficiently rigid and massive to handle the energies of tough specimenswithout motion or excessive vibration, the pendulum arm cannot be madevery massive
25、 because the greater part of its mass must be concentratednear its center of percussion at its striking nose. Locating the striking noseprecisely at the center of percussion reduces the vibration of the pendulumarm when used with brittle specimens. Some losses due to pendulum armvibration (the amoun
26、t varying with the design of the pendulum) will occurwith tough specimens even when the striking nose is properly positioned.5.5 In a well-designed machine of sufficient rigidity andmass, the losses due to vibration and friction in the pendulumbearing and in the indicating mechanism will be very sma
27、ll.Vibrational losses are observed when wide specimens of toughmaterials are tested in machines of insufficient mass, or inmachines that are not securely fastened to a heavy base.5.6 Since this test method permits a variation in the width ofthe specimens and since the width dictates, for many materi
28、als,whether a brittle, low-energy break (as evidenced by little or nodrawing down or necking and by a relatively low energyabsorption) or a ductile, high-energy break (as evidenced byconsiderable drawing or necking down in the region behind thenotch and by a relatively high energy absorption) will o
29、ccur, itis necessary that the width be stated in the specificationcovering that material and that the width be stated along withthe impact value.5.7 This test method requires that the specimen breakcompletely. Results obtained when testing materials with apendulum that does not have sufficient energ
30、y to complete thebreaking of the extreme fibers and toss the broken pieces shallbe considered a departure from standard and shall not bereported as a standard result. Impact values cannot be directlycompared for any two materials that experience different typesof failure.5.8 The value of this impact
31、 test method lies mainly in theareas of quality control and materials specification. If twogroups of specimens of supposedly the same material showsignificantly different energy absorptions, critical widths, orcritical temperatures, it is permitted to assume that they weremade of different materials
32、 or were exposed to differentprocessing or conditioning environments. The fact that amaterial shows twice the energy absorption of another underthese conditions of test does not indicate that this samerelationship will exist under another set of test conditions.6. Apparatus6.1 Pendulum Impact Machin
33、eThe machine shall consistof a massive base on which are mounted a pair of supports forholding the specimen and to which is connected, through arigid frame and bearings, one of a number of pendulum-typehammers having an initial energy suitable for use with theparticular specimen to be tested (or one
34、 basic pendulumdesigned to accept add-on weights), plus a pendulum holdingand releasing mechanism and a mechanism for indicating thebreaking energy of the specimen. The specimen anvil, pendu-lum, and frame shall be sufficiently rigid to maintain correctalignment of the striking edge and specimen, bo
35、th at themoment of impact and during the propagation of the fracture,and to minimize energy losses due to vibration. The base shallbe sufficiently massive so that the impact will not cause it tomove. The machine shall be designed, constructed, and main-tained so that energy losses due to pendulum ai
36、r drag (wind-age), friction in the pendulum bearings, and friction and inertiain the indicating mechanism are held to a minimum.6.1.1 PendulumThe simple pendulum shall consist of asingle or multi-membered arm with a bearing on one end anda head, containing the striking nose, on the other. Although a
37、large proportion of the mass of the simple pendulum isconcentrated in the head, the arm must be sufficiently rigid tomaintain the proper clearances and geometric relationshipsbetween the machine parts and the specimen and to minimizevibrational energy losses, which are always included in themeasured
38、 impact value. A machine with a simple pendulumdesign is illustrated in Fig. 1. Instruments with a compound-pendulum design also have been found to be acceptable foruse. A compound-pendulum design is illustrated in Fig. 2.6.1.1.1 The machine shall be provided with a basic pendu-lum capable of delive
39、ring an energy of 2.7 6 0.14 J (2.0 60.10 ft-lbf). This pendulum shall be used for specimens thatextract less than 85 % of this energy when breaking a speci-men. Heavier pendulums or additional weights designed toattach to the basic pendulum shall be provided for specimensthat require more energy to
40、 break. A series of pendulums suchthat each has twice the energy of the next lighter one has beenfound convenient.D61100826.1.1.2 The effective length of the pendulum shall bebetween 0.325 and 0.406 m (12.8 and 16.0 in.) so that therequired elevation of the striking nose is obtained by raising thepe
41、ndulum to an angle between 60 and 30 above the horizontal.6.1.2 Striking EdgeThe striking edge (nose) of the pen-dulum shall be made of hardened steel, tapered to have anincluded angle of 45 6 2 and shall be rounded to a radius of3.17 6 0.12 mm (0.125 6 0.005 in.). The pendulum shall bealigned in su
42、ch a way that when it is in its free hangingposition, the center of percussion of the pendulum shall liewithin 62.54 mm (0.10 in.) of the middle of the line of contactmade by the striking nose upon the face of a standard specimenof square cross section. The distance from the axis of supportto the ce
43、nter of percussion is determined experimentally fromthe period of motion of small amplitude oscillations of thependulum by means of the following equation:L 5g/4p2! p2(1)where:L = distance from the axis of support to the center ofpercussion, m,g = local gravitational acceleration (known to an accura
44、cyof one part in one thousand), m/s2p = 3.1416 (4p2= 39.48), andp = period, in s, of a single complete swing (to and fro)determined from at least 20 consecutive and uninter-rupted swings. The angle of swing shall be less than 5each side of center.6.1.3 Pendulum Holding and Releasing MechanismThemech
45、anism shall be designed, constructed, and operated so thatit will release the pendulum without imparting acceleration orvibration to the pendulum. The position of the pendulumholding and releasing mechanism shall be such that the verticalheight of fall of the striking nose shall be 610 6 2 mm (24.06
46、 0.005 in.). This will produce a velocity of the striking noseFIG. 1 Simple Beam (Charpy-Type) Impact MachineFIG. 2 Example of CompoundPendulumType MachineD6110083at the moment of impact of approximately 3.46 m (11.4 ft)/s asdetermined by the following equation:v 5 =2gh (2)where:v = velocity of the
47、striking nose at the moment of impact,g = local gravitational acceleration, andh = vertical height of fall of the striking nose.This assumes no windage or friction.6.1.4 Specimen SupportsThe test specimen shall be sup-ported against two rigid anvils in such a position that its centerof gravity and t
48、he center of the notch shall lie on tangent to thearc of travel of the center of percussion of the pendulum drawnat the position of impact. The edges of the anvils shall berounded to a radius of 3.17 6 0.12 mm (0.125 6 0.005 in.) andthe anvils lines of contact (span) with the specimen shall be101.6
49、6 0.5 mm (4.0 6 0.02 in.) apart (see Fig. 3). Somemachine manufacturers supply a jig for positioning the speci-men on the supports.NOTE 7Some machines currently in use employ a 108.0-mm span.Data obtained under these conditions are valid.46.1.5 IndicatorMeans shall be provided for determiningthe energy expended by the pendulum in breaking the speci-men. This is accomplished using either a pointer and dialmechanism or an electronic system consisting of a digitalindicator and sensor (typically an encoder or resolver). Ineither case, the indicated breaking energy is
