ASTM D256-02e1

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 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 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 breakage by flexural shock as indicated by the energy extracted from 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—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 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, 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 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 processingtechnology, molding conditions, mold design, and thermaltreatments;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, andEnvironmental conditioning.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses 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.

General Information

• Status: Historical
• Publication Date: 09-Aug-2002
• ICS: 29.035.20 - Plastics and rubber insulating materials
• Technical Committee: D20 - Plastics
• Drafting Committee: D20.10 - Mechanical Properties

Relations

• Replaces: ASTM D256-02 - Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
• Effective Date: 10-Aug-2002
• Replaced By: ASTM D256-03 - Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics
• Effective Date: 01-Dec-2003
• Referred By: ASTM D4673-23 - Standard Classification System for and Basis for Specification for Acrylonitrile–Butadiene–Styrene (ABS) Plastics and Alloys Molding and Extrusion Materials
• Effective Date: 10-Aug-2002
• Referred By: ASTM F561-19 - Standard Practice for Retrieval and Analysis of Medical Devices, and Associated Tissues and Fluids
• Effective Date: 10-Aug-2002
• Referred By: ASTM C470/C470M-23 - Standard Specification for Molds for Forming Concrete Test Cylinders Vertically
• Effective Date: 10-Aug-2002
• Referred By: ASTM D5204-22 - Standard Classification System and Basis for Specification for Polyamide-Imide (PAI) Molding and Extrusion Materials
• Effective Date: 10-Aug-2002
• Referred By: ASTM F412-23 - Standard Terminology Relating to Plastic Piping Systems
• Effective Date: 10-Aug-2002
• Referred By: ASTM D707-15(2023) - Standard Classification System and Basis for Specification for Cellulose Acetate Butyrate Molding and Extrusion Compounds (CAB)
• Effective Date: 10-Aug-2002
• Referred By: ASTM F3333-20 - Standard Specification for Chopped Carbon Fiber Reinforced (CFR) Polyetheretherketone (PEEK) Polymers for Surgical Implant Applications
• Effective Date: 10-Aug-2002
• Referred By: ASTM D3641-21 - Standard Practice for Injection Molding Test Specimens of Thermoplastic Molding and Extrusion Materials
• Effective Date: 10-Aug-2002
• Referred By: ASTM D4762-18 - Standard Guide for Testing Polymer Matrix Composite Materials
• Effective Date: 10-Aug-2002
• Referred By: ASTM F3430-20 - Standard Specification for Closed-Cell Cellular Polypropylene (PP) Corrugated Wall Stormwater Collection Chambers
• Effective Date: 10-Aug-2002
• Referred By: ASTM D4101-17e1 - Standard Classification System and Basis for Specification for Polypropylene Injection and Extrusion Materials
• Effective Date: 10-Aug-2002
• Referred By: ASTM C1355/C1355M-96(2020) - Standard Specification for Glass Fiber Reinforced Gypsum Composites
• Effective Date: 10-Aug-2002
• Referred By: ASTM D4020-18 - Standard Specification for Ultra-High-Molecular-Weight Polyethylene Molding and Extrusion Materials
• Effective Date: 10-Aug-2002

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
e1
Designation: D 256 – 02
Standard Test Methods for
Determining the Izod Pendulum Impact Resistance of
1
Plastics
This standard is issued under the fixed designation D 256; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1
e NOTE—Editorially corrected the latest referenced revision year in the Summary of Changes section in September 2002.
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.
resistance of plastics to “standardized” (see Note 1) 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
ing standard specimens with one pendulum swing (see Note 2). 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 Methods A, 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 breakage by
Quality of the notch;
flexural shock as indicated by the energy extracted from by
Time between notching and test;
reversing the notched specimen 180° in the clamping vise. The Test specimen thickness,
Test specimen width under notch, and
results of all test methods are reported in terms of energy
Environmental conditioning.
absorbed per unit of specimen width or per unit of cross-
1.2 The values stated in SI units are to be regarded as the
sectional area under the notch. (See Note 4.)
standard. The values given in parentheses are for information
NOTE 1—The machines with their pendulum-type hammers have been
only.
“standardized” in that they must comply with certain requirements,
1.3 This standard does not purport to address all of the
including a fixed height of hammer fall that results in a substantially fixed
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
priate safety and health practices and determine the applica-
recommended for use with specimens of different impact resistance.
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 ISO 180:1993 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
permitted to vary between limits. 2.1 ASTM Standards:
2
NOTE 2—Results generated using pendulums that utilize a load cell to
D 618 Practice for Conditioning Plastics for Testing
record the impact force and thus impact energy, may not be equivalent to 2
D 883 Terminology Relating to Plastics
results that are generated using manually or digitally encoded testers that
D 3641 Practice for Injection Molding Test Specimens of
measure the energy remaining in the pendulum after impact.
3
Thermoplastics Molding Extrusion Materials
NOTE 3—The notch in the Izod specimen serves to concentrate the
D 4000 Classification System for Specifying Plastic Mate-
stress, minimize plastic deformation, and direct the fracture to the part of
3
rials
the specimen behind the notch. Scatter in energy-to-break is thus reduced.
However, because of differences in the elastic and viscoelastic properties
D 4066 Classification System for Nylon Injection and Ex-
3
of plastics, response to a given notch varies among materials. A measure
trusion Materials
D 4812 Test Methods for Unnoticed Cantilever Beam Im-
4
pact Resistance of Plastics
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. Annual Book of ASTM Standards
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