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Deflection Temperature Under Load

ASTM D648, ISO 75

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Heat deflection temperature is defined as the temperature at which a standard test bar deflects a specified distance under a load. It is used to determine short-term heat resistance. It distinguishes between materials that are able to sustain light loads at high temperatures and those that lose their rigidity over a narrow temperature range.

Test Procedure:
The bars are placed under the deflection measuring device. A load of 0.45 MPa or 1.80 MPa is placed on each specimen. The specimens are then lowered into a silicone oil bath where the temperature is raised at 2 C per minute until they deflect 0..25 mm for ASTM, 0.32 mm for ISO flatwise, and 0.34 mm for ISO edgewise.

Specimen size:
A standard bar 5" x " x " is used for ASTM
ISO edgewise testing uses a bar 120mm x 10mm x 4mm
ISO flatwise testing uses a bar 80mm x 10mm x 4mm

The temperature at the specified load and deflection is given.

Equipment Used:
Atlas HDV2 DTUL/ Vicat tester.

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**Please note that this test description is intentionally generic in nature and aimed at providing a descriptive summary to enhance test understanding. For more information please contact a Intertek PTL Technical Representative at . Due to copyright restrictions, we are not able to provide copies of standards. Standards can be obtained from appropriate standards authorities.

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