Hex nuts are typically made from various metals, with the nuts we commonly see being mainly made of iron or copper. Iron tends to rust in damp conditions and has lower conductivity than copper, hence copper nuts are often used in everyday life. Copper nuts are resistant to rust, corrosion-resistant, and have good conductivity, making them commonly applied in environments where rust prevention, high-temperature conductivity, such as in faucets, valves, or electrical appliances.

Another function of the square nut is injection molding. After heating, it can be embedded into the plastic part or directly molded. As previously mentioned, copper has excellent thermal conductivity. Embedding the nut after heating not only quickly warms it up to speed up work efficiency but also rapidly transfers heat to the plastic, causing the surrounding area of the plastic to soften gradually, which is beneficial for pressing it into the hole. If a steel nut is used for injection molding, cracks or loose connections may occur at the contact point between the two. Therefore, it is advisable to use a copper nut instead of a steel nut during injection molding.