ASTM D256-24

Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics

ASTM International , 12/01/2024

Publisher: ASTM

File Format: PDF

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Description

Standard By:ASTM International , 12/01/2024

Published:12/01/2024

Pages:20

File Size:1 file , 860 KB

Language:English

Note:This product is restricted and cannot be purchased in the following countries Russia, Ukraine, Belarus

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 and C, the notch produces a stress concentration that increases the probability of a brittle, rather than a ductile, fracture. Results 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.

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 test methods appear in the following order:

Sections Test Method A-Cantilever Beam Test 6 to 11 Test Method C-Cantilever Beam Test for Materials of Less than 27 J/m (0.5 ft·lbf/in.) 12 to 17

1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.

1.4 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, health, and environmental 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.

1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

ASTM D256-24

Standard Test Methods for Determining the Izod Pendulum Impact Resistance of Plastics

ASTM D256-24 History

ASTM D256-24

ASTM D256-23e1

ASTM D256-23

ASTM D256-10(2018)

ASTM D256-10

ASTM D256-10e1

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