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High Temperature Self-Supporting Furnace Extemsometers (1200°C- Model 3448)

Epsilon Model 3448 Extensometer

Designed for use with furnaces and induction heating systems, these extensometers use Epsilon’s exclusive, self-supporting design. A wide range of options cover most testing applications.

The first self-supporting, axial furnace extensometer using ceramic fiber cords to market in 1995.

Epsilon’s engineers performed evaluations of cord positions in both the standard ceramic fiber cord attachments (elevated above the ceramic rods) and the induction heater version (rods and fiber cord attachments parallel to one another), and found the performance of each to be identical.

Operation of these, and all of epsilon’s extensometers, are verified to either ASTM E83 or ISO 9513 standards using in-house calibration systems that are calibrated with epsilon’s laser interferometer system.


to the materials testing community, you know we will be there to stand behind our products when your critical application requires it.

Epsilon developed this unique high temperature extensometer for testing metals, ceramics, and composites at the high temperatures produced by furnaces and induction heating systems. A combination of features make these extensometers easier to use and better in performance than other similar high temperature extensometers.

The units are held on the specimen by light, flexible ceramic fiber cords. These make the extensometer self-supporting on the specimen. No furnace mounting brackets are required. The side load on the test sample is greatly reduced because of the self-supporting design and light weight of the sensor. Most materials testing furnaces with a side cut-out for an extensometer will readily accept a Model 3448. For induction heating systems, a different ceramic cord placement allows the extensometer to easily pass between the coils.

The combination of radiant heat shields and convection cooling fins allow this model to be used at specimen temperatures up to 1200 °C (2200 °F) without any cooling. An optional tiny air fan does enhance stability at the highest temperatures and is recommended for the highest accuracy and for tests with small elongations. The fan comes with a magnetic base for support so it can be mounted at any convenient location near the extensometer. Fan cooling is not generally needed for induction heated systems. High purity alumina ceramic rods are used. These are available in lengths as required to fit your furnace. A spare set is included with every extensometer. Specify chisel, vee chisel or conical contact points as desired.

Most units operate equally well in tension and compression. Tensile, compression and cyclic fatigue tests can all be performed with a single unit. For testing in strain control or to get the highest performance during cyclic fatigue tests, models 3549 or 7650A are recommended.

For vacuum furnaces, special models are available. Epsilon can also provide a radiant heat transfer cooled version. This requires that the extensometer module be surrounded by a water cooled enclosure with a front slot for the ceramic rods.

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