Vicat softening temperature or Vicat hardness is the determination of the softening point for materials that do not have a fixed melting point, such as plastics. It is taken as the temperature at which the sample is penetrated to a depth of 1mm by a flat-ended needle with a circular or square cross-section of 1mm.
The Vicat softening temperature is determined and the heat deflection temperature under load on plastics and thermoplastics.
The test specimens are charged with a constant load and immersed in a bath, where the temperature is raised to a standard velocity. The achievable heat resistance rate of plastic materials is a widely required parameter for product characterization, for quality control and for evaluating conformance to previewed applications.
The unit consists of a temperature-controlled oil bath with three test stations, each of which can be configured for either HDT or Vicat test methods. The internal shower is made of stainless steel and the designed volume ensures a good thermal exchange. The rod and frame members have the same linear thermal expansion coefficient. An optional weight loading mechanism automatically lowers and increases weight. The test specimens are lowered and automatically lifted into/from the oil bath.
The Tinius Olsen system is robust and suitable for use in industrial environments as well as laboratory layouts. HDT Vicat tester complies with ASTM D 1525, ASTM D 648, ISO 306 and ISO 75 standards.