HDT Thermal deflection temperature
Laboratory > Test speciment ISO - ASTM
| Thermal deflection temperature (HDT) | ||
The HDT (ISO 75 and ASTM D648) involves a sample subjected to bending stress in correspondence with a given initial force while immersed in a constant velocity. The temperature at which the test sample is subjected to the deflation of a set value. Deflection of heat is defined as the standard in which a standard test bar deflects a specific distance under a load. It is used to determine heat resistance in the short term. It is possible to distinguish between high and low temperatures. |  | |
| Test procedure | ||
The bars are placed below the deflection measuring device. A load of 0.45 MPa or 1.80 MPa is placed in each specimen. The samples are then lowered to a silicone oil bath where the temperature rises to 2 ° C per minute until they deviate 0.25 mm for ASTM, 0.32 mm for ISO in plane, and 0.34 mm for ISO in a clockwise direction. Sample size: ASTM uses a standard 5 "x ½" x ¼ "ISO bar in edge tests using 120 mm x 10 mm x 4 mm bars, ISO flat test uses 80 mm x 10 mm x 4 mm bars. |