What is a bi-metal screw?

A bi-metal screw is a type of screw designed for specific applications where temperature changes or electrical currents are factors. It consists of two different metals bonded together: typically steel and copper or steel and aluminum. The head of the screw is made of one metal, while the threaded portion is made of another.

The purpose of this design is to take advantage of the different thermal expansion coefficients of the two metals. When the screw is subjected to temperature changes or electrical currents, the two metals expand or contract at different rates. This differential expansion can create a locking effect, helping to prevent the screw from loosening over time due to vibrations or thermal cycling.

In electrical applications, bi-metal screws are often used to secure electrical components, such as circuit breakers or terminal blocks, to metal surfaces. The combination of metals helps maintain a secure connection even as the temperature fluctuates or as electrical currents pass through the components.

Overall, bi-metal screws provide a reliable and durable fastening solution for applications where temperature variations or electrical currents may otherwise cause traditional screws to loosen or fail.