ASTM D 1822 tensile-impact testing for plastics: key facts and steps

Key points about ASTM D 1822 for plastic testing applications

Overview of ASTM D 1822

ASTM D 1822 is a standard test method used for determining the tensile-impact energy associated with plastic specimens. This method focuses on measuring the amount of energy absorbed by a standardized plastic sample when subjected to rapid deformation under tension. The test provides valuable information related to the toughness and impact resistance of plastics, facilitating comparison between different materials for engineering applications.

Establishes a consistent approach for evaluating tensile-impact properties of plastics.
The method is especially relevant for materials used in products requiring high toughness or resistance to sudden forces.
Tensile-impact values obtained using this method can serve as a useful quality control and material selection tool.

Specimen and apparatus details

Specimens used for ASTM D 1822 testing are precisely machined or molded according to specified dimensions, such as die type “S” or “L” bars. The testing apparatus applies a sudden tensile load via a pendulum or falling weight system, ensuring standardized rates and impact energy. Measurements are recorded in terms of absorbed energy and energy per unit cross-sectional area. This enables reliable comparisons across materials and batches.

Applications and typical use cases

ASTM D 1822 is widely used in both research and industry for product development, material quality assessment and performance verification. The standard is applicable for a wide range of thermoplastics and thermosetting materials, supporting selection of resins and compounds for applications where impact resistance is critical. Results from ASTM D 1822 often complement data from tensile strength and Izod impact tests when a comprehensive profile of plastic properties is required.

Takeaway

ASTM D 1822 provides essential data on the impact behavior of plastics under tensile stress, helping users make informed decisions about material suitability, performance and reliability in demanding end-use conditions.

Standardized methodology for tensile-impact measurements
Applies to a wide range of plastic materials
Critical for quality control and product development
Complements other mechanical test methods

How to perform ASTM D 1822 tensile-impact testing step by step

Preparation and specimen requirements

To conduct ASTM D 1822 testing, ensure all specimens are prepared according to the standard’s geometric requirements, typically as die type “S” or “L” specimens. Use properly calibrated equipment and maintain consistent ambient conditions as outlined in the standard. Conditioning of samples at specified temperature and humidity prior to test is also required for reproducible results.

Test equipment and set-up

Set up the tensile-impact tester, which usually includes a pendulum or falling weight mechanism with an adjustable striking speed. Securely place the specimen in the grips of the apparatus, ensuring alignment and minimizing any slack. Verify that the recording device measures energy absorbed directly or can calculate energy loss during specimen breakage.

Check calibration and zero point of the apparatus
Confirm correct specimen placement and grip alignment
Set impact speed and pendulum mass as per standard

Conducting the test

Release the pendulum or weight so it applies a rapid tensile force to the specimen until fracture occurs. The device records the energy absorbed by the specimen, either directly or by difference in pendulum height before and after impact. Remove broken specimen and repeat the procedure for each replicate necessary to get a reliable average.

Reporting and calculation

The energy absorbed is recorded in joules (or ft-lbf) and divided by the minimum cross-sectional area of the specimen to calculate tensile-impact strength. Report the type of specimen, number tested, absorbed energies and calculated tensile-impact strengths, as well as test temperature and humidity.

Include all relevant specimen and test condition details
Report individual and average test values
State specimen condition (molded, machined, etc.)
Cite instrument and calibration data
Note any deviations from standard procedure

Quality control and best practices

Repeat tests with at least five specimens for each material to account for inherent variability within plastics. Regularly check apparatus condition, and always follow ASTM D 1822 directions for consistent, comparable results. Thorough documentation supports traceability in both research and production environments.

Summary

ASTM D 1822 provides a systematic approach for evaluating the tensile-impact strength of plastics, enabling objective comparison and quality monitoring. Attention to sample preparation, testing conditions and accurate data reporting ensures that the results are dependable and actionable across applications.