(715) 831-6353 info@senasys.com

What is bimetal anyway?

Bi-Metal Snap Disc Thermostats

You’ll see the term bimetal used quite a bit on this website so we thought it would be a good idea to tell you exactly what that means in regards to our products. Give us a call for for more information or visit our online store to purchase.

Our snap disc thermostats are created with bimetal discs in them that react to temperature changes (rise or fall) and ‘snap’ causing the circuit to open or close.

Bimetal Snap Disc
These discs have been stamped out of a strip of bimetal and then heat treated.

We form our discs from one of three bimetal compositions.  You can see the compositions below.

Type                                 Composition

High Expansion Low Expansion Alloy%
2400 (B1) 22 Ni, 3 Cr, Bal. Fe 36 Ni, Bal. Fe 50/50
2800 (E3) 25 Ni, 8.5 Cr, Bal. Fe 42 Ni, Bal. Fe 50/50
6650 (P6775R) 72 Mn, 18 Cu, 10 Ni 36 Ni, Bal. Fe 55/45


As the temperature changes the metals will flex and pull against each other.  Since the metals expand and contract at different rates, each side can be formed to flex (snap) at a desired temp.

There’s a great technical explanation with diagrams available here.

Click here for more information about our bi-metal snap disc thermostats.

To view our standard temperature options visit our online store.

For more information about our bi-metal snap disc thermostats, contact our direct technical support at 715-831-6353.

For general information about our snapdiscs, take a look at our catalog.

Senasys designs and manufactures snap disc thermostat switches. Senasys switches are UL and CUL Recognized. The majority of our switches are made in the United States and our direct customer service would be happy to help you find the right switch for your application. Senasys snap disc thermostats are single pole, single throw, fixed thermostat which may be used in applications such as industrial and HVAC equipment.

Bi-metal Snap Disc Thermostat Options Purchase Bi-Metal Snap Disc Thermostats Contact us about our bi-metal snap disc thermostats.

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