Epsilon MODEL 3448 High Temperature Extensometers

The MODEL 3448 high temperature extensometers have been developed to be used with induction heating systems and furnaces and these extensometers use the exclusive, self-supporting design of Epsilon. A broad range of options are offered covering most testing applications.

This innovative high temperature extensometer has been developed by Epsilon for testing ceramics, metals and composites at high temperatures produced by induction heating systems and furnaces. A number of features together render these extensometers convenient for use and enables higher performance than other similar high temperature extensometers.

The units are positioned on the specimen by flexible, light ceramic fiber cords. These render the extensometer self-supporting on the specimen. There is no need for any furnace brackets. The side load on the test sample is considerably reduced due to the light weight and self-supporting design of the sensor.

Model 3448 can be fitted with most materials testing furnaces having a side cut-out for an extensometer. In the case of induction heating systems, a distinct ceramic cord placement enables the extensometer to pass easily between the coils.

Convection cooling fins and radiant heat shields enable the use of this model at specimen temperatures 1200 °C (2200 °F) without any cooling. An optional miniature air fan is available that improves stability at the highest temperatures and can be used to obtain very high accuracy and for tests having small elongations.

The fan can be positioned at any location close to the extensometer as it has a magnetic base for support. For induction heated systems, fan cooling is not required. High purity alumina ceramic rods are used that are offered in customized lengths to fit the furnace. With every extensometer, a spare set is included. The customer can specify vee or conical chisel contact points as needed. In both compression and tension, most units operate perfectly.

Hence it is possible to perform compression, tensile and cyclic tests such as low cycle fatigue with one unit. Special models are available for vacuum furnaces. A radiant heat transfer cooled version can also be offered by Epsilon. This necessitates surrounding the extensometer module by a water-cooled enclosure having front slot for ceramic rods.

Key Features

The key features of MODEL 3448 include:

The instrument may be left on through specimen failure

Full bridge, 350Ω strain gaged design for being compatible with almost any test system

Mechanical overtravel stops in both directions

Most standard units satisfy existing ASTM class B-1 and ISO 9513, class 0,5 requirements for accuracy. Rod length configurations can impact the final class rating

All units come with high purity alumina ceramic rods

It can be mounted with flexible ceramic fiber cords

Very simple to install, this Epsilon exclusive design eliminates the need for external support brackets

There is no change in the low contact force during testing like certain externally supported extensometers

The extensometer comprises a high quality foam lined case, a spare set of ceramic rods, and eight ceramic fiber cords

Use without cooling to 1200 °C (2200 °F)

An optional small fan can enhance stability at highest temperatures

Rugged, dual flexure design for strength and improved performance

Versions available for use in controlled and vacuum atmospheres

For these applications, radiant heat transfer cooled versions are available

It can be used on almost any furnace with side entry cut-out for extensometers

Alternate configuration available for insertion between coils of induction heaters

Model 3448 Available Versions

Any gauge length and measuring range combination listed below is available. Ceramic rod lengths are made to fit furnaces as required.

Optional Accessories

Options include:

Air cooling fan, add suffix -AC

Ceramic cord orientation for furnaces or induction heaters (specify)

Rod tip styles available are straight chisel, vee chisel, conical tip

Epsilon MODEL 3448 High Temperature Extensometers

Model 3448 with 25 mm gauge length and 20% measuring rangeModel 3448 with 25 mm gauge length and 20% measuring rangeModel 3448 with 10 mm gauge length for use with an induction heaterModel 3448 with 25 mm gauge length and 20% measuring rangeModel 3448 with 25 mm gauge length and 20% measuring rangeModel 3448RCIH-010m-015 with 10.0 mm gauge length and ±15% radiant cooled induction heated