ASTM D746-07 - 1.3.2007
 
Significance and Use

This test method establishes the temperature at which 50 % of the specimens tested fail when subjected to the conditions specified herein. The test provides for the evaluation of long-time effects such as crystallization, or those effects that are introduced by low-temperature incompatibility of plasticizers in the material under test. Plastics and elastomers are used in many applications requiring low-temperature flexing with or without impact. Use data obtained by this method to predict the behavior of plastic and elastomeric materials at low temperatures only in applications in which the conditions of deformation are similar to those specified in this test method. This test method has been found useful for specification purposes, but does not necessarily measure the lowest temperature at which the material is suitable for use.

FIG. 1 Dimensional Requirements Between Specimen Clamp and Striking Edge (Type A)

FIG. 2 Typical Clamp (Type A)

Note—Dimensions are in millimetres.

FIG. 3 Dimensional Details of Striking Edge and Clamping Device, Type B (Positioning of Unnotched Test Specimen)

FIG. 4 Assembled Clamp with Test Specimens, Type B

 
1. Scope

1.1 This test method covers the determination of the temperature at which plastics and elastomers exhibit brittle failure under specified impact conditions. Two routine inspection and acceptance procedures are also provided.

Note 1—When testing rubbers for impact brittleness use Test Methods D 2137.

1.2 The values stated in SI units are to be regarded as the standard.

1.3 Due to the potential safety and environmental hazards associated with mercury-filled thermometers, the use of alternative temperature measuring devices (such as thermocouples and RTDs) is encouraged.

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 and health practices and determine the applicability of regulatory limitations prior to use.

Note 2—This test method and ISO 974 (E) are technically equivalent when using the Type B fixture and the Type III specimen, however, the minimum number of specimens that are required to be tested is significantly different when using this test method. The ISO method requires that a minimum of 100 specimens be tested.

 
2. Referenced Documents

E1137/E1137M-08(2020)

Standard Specification for Industrial Platinum Resistance Thermometers

ISO?974

Plastics--Determination of the Brittleness Temperature by Impact ISO Standards Handbook 21, Vol 1. ISO Standards are available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036.

Detailed Drawing of a Typical Clamp A detailed drawing of a typical clamp may be obtained from ASTM Headquarters. Order Adjunct : .

D832-07(2024)

Standard Practice for Rubber Conditioning For Low Temperature Testing

D883-26

Standard Terminology Relating to Plastics

D1790-21

Standard Test Method for Brittleness Temperature of Plastic Sheeting by Impact

D2137-11(2025)

Standard Test Methods for Rubber Property—Brittleness Point of Flexible Polymers and Coated Fabrics

E1-14(2025)

Standard Specification for ASTM Liquid-in-Glass Thermometers

E77-14(2021)

Standard Test Method for Inspection and Verification of Thermometers

D618-21

Standard Practice for Conditioning Plastics for Testing

E608/E608M-24

Standard Specification for Mineral-Insulated, Metal-Sheathed Base Metal Thermocouples