What is ISO 75-1 about?
ISO 75-1 discusses plastics, and elaborates on test methods for determining the deflection temperature of plastic.
ISO 75-1 discusses temperature of deflection under load (flexural stress under three-point loading). Different types of test specimens and different constant loads are defined to suit different types of material. ISO 75-1 specifies preferred dimensions for the test specimens.
The heat distortion temperature (HDT) test method is 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 modulus.
Note: Data obtained using ISO 75-1 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.
Who is ISO 75-1 for?
ISO 75-1 on the HDT test method for plastic is useful for:
- The plastics industry
- Quality control personnel
- Product designers
Why should you use ISO 75-1?
The deflection temperature is a measure of a plastic's ability to bear a given load at high temperatures. ISO 75-1 describes the HDT test method to determine the deflection temperature of plastic to give an indication at what temperature materials start to ‘soften’ when exposed to a fixed load at high temperatures, and to determine short-term heat resistance and the difference between materials that can sustain light loads at high temperatures and with those who lose their rigidity over a narrow temperature range.
Using the HDT test described in ISO 75-1, you can analyze the endurance of the material at elevated temperatures.
What’s changed since the last update?
BS EN ISO 75-1:2020 supersedes ISO 75-1:2013. BS EN ISO 75-1:2020 includes some technical and editorial changes with respect to ISO 75-1:2013. These include:
- Specification for the temperature difference between the middle and the ends of the test specimens has been removed
- Specification for the position of the tip of the temperature sensor has been widened
- Editorial changes have been applied
