|Description / Abstract
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|This part of ISO 75 gives a general test method for the
determination of the temperature of deflection under load (flexural
stress under three-point loading) of plastics. Different types of
test specimen and different constant loads are defined to suit
different types of material.
ISO 75-2 gives specific requirements for plastics (including
filled plastics and fibre-reinforced plastics in which the fibre
length, prior to processing, is up to 7,5 mm) and ebonite, while
ISO 75-3 gives specific requirements for high-strength
thermosetting laminates and long-fibre-reinforced plastics in which
the fibre length is greater than 7,5 mm.
The methods specified are suitable for assessing the relative
behaviour of different types of material at elevated temperature
under load at a specified rate of temperature increase. The results
obtained do not necessarily represent maximum applicable
temperatures because in practice essential factors, such as time,
loading conditions and nominal surface stress, can differ from the
test conditions. True comparability of data can only be achieved
for materials having the same room-temperature flexural
The methods specify preferred dimensions for the test
Data obtained using the test methods described are not intended
to be used to predict actual end-use performance. The data are not
intended for design analysis or prediction of the endurance of
materials at elevated temperatures.
This method is commonly known as the HDT test (heat deflection
test or heat distortion test), although there is no official
document using this designation.
|Additional Supplemental Documents