Vicat softening point

Vicat softening temperature or Vicat hardness is the determination of the softening point for materials that have no definite melting point, such as plastics. It is taken as the temperature at which the specimen is penetrated to a depth of 1 mm by a flat-ended needle with a 1 mm2 circular or square cross-section. For the Vicat A test, a load of 10 N is used. For the Vicat B test, the load is 50 N.

Standards to determine Vicat softening point include ASTM D 1525 and ISO 306, which are largely equivalent.[1]

The vicat softening temperature can be used to compare the heat-characteristics of different materials.

Four different methods may be used for testing.

Method Load (N) Heating rate (K/h)
A50 10 50
B50 50 50
A120 10 120
B120 50 120

ISO 10350 Note

ISO 10350 Vicat values are tested using the B50 method.

Similar Standards: ASTM D1525

Vicat needle for cement paste solidification time measurement


  1. ^ Vicat Softening Point: Definition Archived April 24, 2010, at the Wayback Machine
Heat deflection temperature

The heat deflection temperature or heat distortion temperature (HDT, HDTUL, or DTUL) is the temperature at which a polymer or plastic sample deforms under a specified load. This property of a given plastic material is applied in many aspects of product design, engineering and manufacture of products using thermoplastic components.


Instron (an ITW company) is a manufacturer of test equipment designed to evaluate the mechanical properties of materials and components, such as universal testing machines.

In 1946, Harold Hindman and George Burr, who worked together at Massachusetts Institute of Technology (MIT), teamed up to determine the properties of new materials to be used in parachutes. Together, they designed a material testing machine based on strain gauge load cells and servo-control systems. This led to the formation of Instron Engineering Corporation.CEAST (Now operating within Instron) was founded in 1953 by Dr. Mario Grosso and focused initially on refurbishing instruments shipped from America through the Marshall plan[1]. Later, the company used its experience to develop polymer testing instruments. Today the company is based in Pianezza, Turin, and specializes in impact, rheology and HDT/Vicat testing of polymers, typically thermoplastics. In 2008 CEAST was acquired by Instron but continues to operate semi-autonomously.


Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily worked, molded, and thermoformed. Because of these properties, polycarbonates find many applications. Polycarbonates do not have a unique resin identification code (RIC) and are identified as "Other", 7 on the RIC list.

ISO standards by standard number

This page is based on a Wikipedia article written by authors (here).
Text is available under the CC BY-SA 3.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.