Steel vs. Aluminum Alloy

Strain-gage-based transducers are commercially made from either alloy steel and aluminum alloys. Which is best?

Performance-wise, there isn’t much difference. Both quality and accurate load cells can be made from either steel or aluminum. The differences are more subtle.  Steel, either plated or stainless, is more corrosion-resistant than aluminum alloys. Aluminum is lighter and usually less expensive. The big difference has to do with a property called elastic modulus. Steel has nearly 3X higher elastic modulus than aluminum. This means that for the same transducer design, steel has approximately 3X higher capacity than aluminum for the same mv/v sensitivity. For this reason aluminum alloys are normally offered for lower load capacities and steel is used for higher capacities. Steel is rarely used for low capacities because the spring flexures would need to be exceedingly thin.

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Jim Weidner

Chief Applications Engineer