ASTM D256-06ae1
(Test Method)Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
SCOPE
1.1 These test methods cover the determination of the resistance of plastics to "standardized" (see Note 0) pendulum-type hammers, mounted in "standardized" machines, in breaking standard specimens with one pendulum swing (see Note 0). The standard tests for these test methods require specimens made with a milled notch (see Note 0). In Test Methods A, C, and D, the notch produces a stress concentration that increases the probability of a brittle, rather than a ductile, fracture. In Test Method E, the impact resistance is obtained by reversing the notched specimen 180 in the clamping vise. The results of all test methods are reported in terms of energy absorbed per unit of specimen width or per unit of cross-sectional area under the notch. (See Note 0.)Note 0
The machines with their pendulum-type hammers have been "standardized" in that they must comply with certain requirements, including a fixed height of hammer fall that results in a substantially fixed velocity of the hammer at the moment of impact. However, hammers of different initial energies (produced by varying their effective weights) are recommended for use with specimens of different impact resistance. Moreover, manufacturers of the equipment are permitted to use different lengths and constructions of pendulums with possible differences in pendulum rigidities resulting. (See Section .) Be aware that other differences in machine design may exist. The specimens are "standardized" in that they are required to have one fixed length, one fixed depth, and one particular design of milled notch. The width of the specimens is permitted to vary between limits.Note 0
Results generated using pendulums that utilize a load cell to record the impact force and thus impact energy, may not be equivalent to results that are generated using manually or digitally encoded testers that measure the energy remaining in the pendulum after impact.Note 0
The notch in the Izod specimen serves to concentrate the stress, minimize plastic deformation, and direct the fracture to the part of the specimen behind the notch. Scatter in energy-to-break is thus reduced. However, because of differences in the elastic and viscoelastic properties of plastics, response to a given notch varies among materials. A measure of a plastic's "notch sensitivity" may be obtained with Test Method D by comparing the energies to break specimens having different radii at the base of the notch.Note 0
Caution must be exercised in interpreting the results of these standard test methods. The following testing parameters may affect test results significantly:
1.2 The values stated in SI units are to be regarded as standard. The values given in brackets are for information only.
This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
These test methods resemble ISO 180:1993 in regard to title only. The contents are significantly different.
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´1
Designation:D256–06a
Standard Test Methods for
Determining the Izod Pendulum Impact Resistance of
1
Plastics
This standard is issued under the fixed designation D256; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1
´ NOTE—Removed research report footnote from Section 31 editorially in September 2008.
of a plastic’s “notch sensitivity” may be obtained with Test Method D by
1. Scope*
comparing the energies to break specimens having different radii at the
1.1 These test methods cover the determination of the
base of the notch.
resistanceofplasticsto“standardized”(seeNote1)pendulum-
NOTE 4—Caution must be exercised in interpreting the results of these
type hammers, mounted in “standardized” machines, in break-
standard test methods. The following testing parameters may affect test
ingstandardspecimenswithonependulumswing(seeNote2). results significantly:
The standard tests for these test methods require specimens
Method of fabrication, including but not limited to processing
technology, molding conditions, mold design, and thermal
made with a milled notch (see Note 3). In Test MethodsA, C,
treatments;
and D, the notch produces a stress concentration that increases
Method of notching;
the probability of a brittle, rather than a ductile, fracture. In Speed of notching tool;
Design of notching apparatus;
Test Method E, the impact resistance is obtained by reversing
Quality of the notch;
thenotchedspecimen180°intheclampingvise.Theresultsof
Time between notching and test;
all test methods are reported in terms of energy absorbed per Test specimen thickness,
Test specimen width under notch, and
unitofspecimenwidthorperunitofcross-sectionalareaunder
Environmental conditioning.
the notch. (See Note 4.)
1.2 The values stated in SI units are to be regarded as
NOTE 1—The machines with their pendulum-type hammers have been
standard.Thevaluesgiveninbracketsareforinformationonly.
“standardized” in that they must comply with certain requirements,
1.3 This standard does not purport to address all of the
includingafixedheightofhammerfallthatresultsinasubstantiallyfixed
safety concerns, if any, associated with its use. It is the
velocity of the hammer at the moment of impact. However, hammers of
responsibility of the user of this standard to establish appro-
different initial energies (produced by varying their effective weights) are
recommended for use with specimens of different impact resistance. priate safety and health practices and determine the applica-
Moreover, manufacturers of the equipment are permitted to use different
bility of regulatory limitations prior to use.
lengths and constructions of pendulums with possible differences in
NOTE 5—These test methods resemble ISO180:1993 in regard to title
pendulum rigidities resulting. (See Section 5.) Be aware that other
only. The contents are significantly different.
differences in machine design may exist. The specimens are “standard-
ized” in that they are required to have one fixed length, one fixed depth,
2. Referenced Documents
and one particular design of milled notch. The width of the specimens is
2
permitted to vary between limits.
2.1 ASTM Standards:
NOTE 2—Results generated using pendulums that utilize a load cell to
D618 Practice for Conditioning Plastics for Testing
record the impact force and thus impact energy, may not be equivalent to
D883 Terminology Relating to Plastics
results that are generated using manually or digitally encoded testers that
D3641 Practice for Injection Molding Test Specimens of
measure the energy remaining in the pendulum after impact.
Thermoplastic Molding and Extrusion Materials
NOTE 3—The notch in the Izod specimen serves to concentrate the
D4066 Classification System for Nylon Injection and Ex-
stress, minimize plastic deformation, and direct the fracture to the part of
thespecimenbehindthenotch.Scatterinenergy-to-breakisthusreduced. trusion Materials (PA)
However, because of differences in the elastic and viscoelastic properties
D5947 Test Methods for Physical Dimensions of Solid
of plastics, response to a given notch varies among materials.Ameasure
Plastics Specimens
E691 Practice for Conducting an Interlaboratory Study to
1
These test methods are under the jurisdiction of ASTM Committee D20 on
Plastics and are the direct responsibility of Subcommittee D20.10 on Mechanical
2
Properties. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2006. Published December 2006. Originally contact ASTM C
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation:D256–06 Designation:D256–06a
Standard Test Methods for
Determining the Izod Pendulum Impact Resistance of
1
Plastics
This standard is issued under the fixed designation D256; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1
´ NOTE—Removed research report footnote from Section 31 editorially in September 2008.
1. Scope*
1.1 These test methods cover the determination of the resistance of plastics to “standardized” (see Note 1) pendulum-type
hammers, mounted in “standardized” machines, in breaking standard specimens with one pendulum swing (see Note 2). The
standard tests for these test methods require specimens made with a milled notch (see Note 3). In Test MethodsA, C, and D, the
notch produces a stress concentration that increases the probability of a brittle, rather than a ductile, fracture. In Test Method E,
the impact resistance is obtained by reversing the notched specimen 180° in the clamping vise. The results of all test methods are
reported in terms of energy absorbed per unit of specimen width or per unit of cross-sectional area under the notch. (See Note 4.)
NOTE 1—The machines with their pendulum-type hammers have been “standardized” in that they must comply with certain requirements, including
a fixed height of hammer fall that results in a substantially fixed velocity of the hammer at the moment of impact. However, hammers of different initial
energies (produced by varying their effective weights) are recommended for use with specimens of different impact resistance. Moreover, manufacturers
of the equipment are permitted to use different lengths and constructions of pendulums with possible differences in pendulum rigidities resulting. (See
Section 5.) Be aware that other differences in machine design may exist. The specimens are “standardized” in that they are required to have one fixed
length, one fixed depth, and one particular design of milled notch. The width of the specimens is permitted to vary between limits.
NOTE 2—Resultsgeneratedusingpendulumsthatutilizealoadcelltorecordtheimpactforceandthusimpactenergy,maynotbeequivalenttoresults
that are generated using manually or digitally encoded testers that measure the energy remaining in the pendulum after impact.
NOTE 3—The notch in the Izod specimen serves to concentrate the stress, minimize plastic deformation, and direct the fracture to the part of the
specimen behind the notch. Scatter in energy-to-break is thus reduced. However, because of differences in the elastic and viscoelastic properties of
plastics,responsetoagivennotchvariesamongmaterials.Ameasureofaplastic’s“notchsensitivity”maybeobtainedwithTestMethodDbycomparing
the energies to break specimens having different radii at the base of the notch.
NOTE 4—Caution must be exercised in interpreting the results of these standard test methods. The following testing parameters may affect test results
significantly:
Method of fabrication, including but not limited to processing
technology, molding conditions, mold design, and thermal
treatments;
Method of notching;
Speed of notching tool;
Design of notching apparatus;
Quality of the notch;
Time between notching and test;
Test specimen thickness,
Test specimen width under notch, and
Environmental conditioning.
1.2 The values stated in SI units are to be regarded as standard. The values given in brackets are for information only.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
NOTE 5—These test methods resemble ISO 180:1993 in regard to title only. The contents are significantly different.
1
These test methods are under the jurisdiction ofASTM Committee D20 on Plastics and are the direct responsibility of Subcommittee D20.10 on Mechanical Properties
.
Current edition approved March 15,Dec. 1, 2006. Published MarchDecember 2006. Originally approved in 1926. Last previous edition approved in 20052006 as
D256-05a.D256-06.
*A Summary of Changes section appears at the end of this standard.
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...
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