Model 3448 High Temperature Axial Extensometer - Epsilon Technology - #1

I 3448 Self-Supporting High Temperature Extensometers

technology corp

For vacuum furnaces, special models are available. Epsilon also can 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.

• May be left on through specimen failure.

• Full bridge, 350 ohm strain gaged design for compatibility with nearly any test system.

• Mechanical overtravel stops in both directions.

• All standard units meet existing ASTM class B-1 and ISO 9513, class 0,5 requirements for accuracy.

• All units come with high purity alumina ceramic rods

• Mount with flexible ceramic fiber cords. Very simple to install, this Epsilon exclusive design eliminates the need for external support brackets. Low contact force does not vary during testing like some externally supported extensometers.

• Includes high quality foam lined case, a spare set of ceramic rods, and eight ceramic fiber cords.

• Use without cooling to 1200 °C (2200 °F). Optional small fan improves stability at highest temperatures.

• Rugged, dual flexure design for strength and improved performance.

• Versions available for use in vacuum and controlled atmospheres. Radiant heat transfer cooled versions are available for these applications.

• May be used on nearly any furnace with side entry cut-out for extenso­meters. Alternate configuration available for insertion between coils of induction heaters.

Model 3448 Available Versions: ANY combination of gage length and measuring range listed below is available, except as noted. Ceramic rod lengths are made to fit furnaces as required. Please provide furnace dimensions at the time of order.

U.S.A.

0.500'¹ 1.000'¹ 2.000'¹

METRIC

10.0 mm 25.0 mm 50.0 mm

Epsilon has developed a very unique high temperature extensometer for testing metals, ceramics and composites at the high temperatures produced by furnaces and induction heating systems. A combination of new features make these extensometers easier to use and better in performance than other 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 mostly eliminated 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 (min 99.7%) 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. See page 97 for the benefits of each.

Most units operate equally well in tension and compres­sion. Thus tensile, compression and cyclic tests like low cycle fatigue can all be performed with a single unit.

Specification:

Operating Force: Options

5 to 10 VDC recommended, 12 VDC or VAC max. 2 to 4 mV/V, nominal, depending on model <0.15% of full scale measuring range, depending on model

Ambient to 1200 °C max (2200 °F), all versions Integral, ultra-flexible cable, 8 ft (2.5 m) standard Adjustable, approximately 200 g depending on configuration 10 to 20 g typical

Shunt calibration module (see page 96)

Ceramic cord orientation for furnaces or induction heaters (specify) Air-cooling fan, add suffix -AC Specify rod tip style desired. Available choice are: • Standard chisel, vee-chisel, and conical point (see page 97)

TYPICAL MODEL 3448 EXTENSOMETER DIMENSIONS: [mm] inches

20

21