Alumentary: Aluminum vs. Steel – these are the differences

Whether aluminum or steel is the better choice depends heavily on the specific application. Both materials have clear strengths and limitations in industrial practice. In many areas of fastening technology, however, aluminum offers specific advantages, particularly when low weight is required.

A key difference lies in density: At about 2.7 g/cm³, aluminum has only about one-third the density of steel. This allows components and fasteners to be manufactured with significantly lower mass. Depending on the application, this can have a positive impact on energy consumption, dynamic performance, and handling.

The aluminum-to-aluminum material pairing really comes into its own when dealing with temperature fluctuations. Because the thermal expansion of the screw and the component is similar, temperature-induced changes in preload are often smaller compared to steel screws. In contrast, when steel screws are used in aluminum components or structures, the preload can decrease more significantly under thermal stress due to the markedly different expansion behavior.

For aluminum-to-aluminum connections, the risk of galvanic contact corrosion is often lower than for steel-to-aluminum combinations, since the electrochemical potential difference is smaller. Depending on the operating conditions, this can reduce the need for additional protective measures such as coatings. ESKA Aludrive® screws are therefore supplied as standard with only a lubricant coating to precisely adjust the coefficient of friction.

The best material to use always depends on the intended application and the specific requirements.