Metals have highly unique and different physical-mechanical characteristics, but in the case of bimetallic products it is possible to draw considerable advantages from the combination of two different materials. Let us analyze the specifications and uses of bimetallic sheets in industrial sectors.
Bi metal: what is and how is manufactured
The term “bimetallic” refers to a material composed of two distinct metals which are joined together in two layers (unlike alloys, that are composed of a mixture of metals).
The most renowned type of bi metals are bimetallic sheets: this product has two sheets of different metals “bonded” together, by means of a high-pressure compression and rolling process, which allows the two layers to adhere perfectly to the adjacent sides.
Many products originate from bimetallic sheets for miscellaneous uses: bimetallic strips rolled on reels, bimetallic plates and various types of bimetallic profiles.
Main characteristics of bimetallic sheets
The main advantage of bimetallic sheets is the acquisition of different physical and mechanical specifications of both materials at the same time, such as:
– mechanical resistance and corrosion;
– electromagnetic conductivity,
– thermal expansion, etc.
In fact, thermal expansion of bimetallic sheets is the most renowned and appreciated feature. The combination of two metals with markedly different thermal expansion coefficients generates a specific curvature of the material as the heat level changes.
If the two strips of a metal sheet occupy a specific position when cool, as the temperature rises one of the two sheets will stretch further, forcing the entire sheet to bend towards the side of the metal that is less heat sensitive. When cooled to the initial temperature, the sheet will return to its original position.
This type of mechanical deflection, caused by the different expansion and contraction of the two materials, is used in a wide range of industrial applications on a regular basis.
Bimetallic applications and components
The thermal expansion of bi metals is often applied in electrical circuit switching systems or in temperature indicating instruments.
Below are a few examples of these methods applied to the industrial world:
- Bimetallic strips: used to regulate clock, watch and timer mechanisms which are particularly sensitive to changes in temperature over time;
- Bimetallic thermal switches: in order to protect circuits against overcurrent in industrial power supplies, time relays, safety valves, flashing lights and warning signs,
- Bimetallic thermostats and thermometers: to regulate the heating and cooling by means of a moving part which expands or contracts as the temperature changes.
In fact, the advantages of bimetals are not simply related to thermal expansion:
- Terminals, connectors and thermocouples exploiting the conductivity of noble metals;
- Cutting blades: the combination of two metals boosts strength and flexibility aspects;
- Continuous placcato: for the production of special profiles and jewelry applications,
- Hollow aggrafato: for the forming of precious sheets with metal inner cores.
Processing of bi metals with INVIMEC
Invimec’s extensive experience in the rolling and profiling of metals allows the company to identify bespoke solutions for the production of bimetallic sheets and bimetallic profiles, in particular for the jewelery, watchmaking and mechanical industry sectors.
Our special application machines are capable of processing precious, ferrous and non-ferrous metals, special alloys, bi metals and multi-metallic materials to fully satisfy all production demands. If you don’t believe us, contact us and put us to the test!