This part of ISO 75 provides a general test method for determining the heat deflection temperature of plastics under load (bending stress under three-point loading). Different test specimens and different constant loads are specified for different types of materials. ISO 75-2 specifies specific requirements for plastics (including filled plastics and long-fiber-reinforced plastics where the fiber length before processing is up to 7.5 mm) and hard rubber, while ISO 75-3 specifies specific requirements for high-strength, hardenable laminates and long-fiber-reinforced Shows plastics in which the fiber length is more than 7.5 mm. The established methods are suitable for estimating the relative behavior of different materials at elevated temperature when the temperature is increased under load at a specified heating rate. The results obtained do not necessarily represent the maximum operating temperatures because in practice important factors such as time, loading conditions and bending stress may differ from the test conditions. Real comparability of the data can only be achieved for materials with the same flexural modulus at room temperature. The procedures determine the preferred dimensions of the test specimens. The data determined using the test procedures described are not intended to predict usability. The data is not intended to analyze the design and dimensioning or predict the long-term behavior (service life) at elevated temperatures of materials. This procedure is commonly known as HDT testing (en: Heat Deflection Test or Heat Distortion Test), although there is no official document using this term.
ISO 291:2008 Plastics - Standard atmospheres for conditioning and testing
ISO 75-2:2013 Plastics - Determination of temperature of deflection under load - Part 2: Plastics and ebonite
ISO 75-3:2004 Plastics - Determination of temperature of deflection under load - Part 3: High-strength thermosetting laminates and long-fibre-reinforced plastics
EN ISO 75-1:2013 history
2020EN ISO 75-1:2020 Plastics - Determination of temperature of deflection under load - Part 1: General test method (ISO 75-1:2020)
2013EN ISO 75-1:2013 Plastics - Determination of temperature of deflection under load - Part 1: General test method
2004EN ISO 75-1:2004 Plastics - Determination of temperature of deflection under load - Part 1: General test method ISO 75-1:2004
1996EN ISO 75-1:1996 Plastics - Determination of Temperature of Deflection under Load - Part 1: General Test Method (ISO 75-1 : 1993)