Fastening to aluminum and composite materials has become a bigger issue today with the increased use of these materials in manufacturing due to the weight savings and/or lower cost these materials may offer relative to steel.
An automotive OEM was developing an accessory for a vehicle that required aluminum as the base material for weight reduction requirements and corrosion protection. Sherex conducted a study to determine the best fastener to attach the component to the vehicle.
Spin out (the torque required to turn a rivet nut in the base material) and corrosion resistance where the two primary concerns for the fastener. An M8 thread size was selected by the OEM, with an assembly torque of 21 Nm for the mating screw. Sherex testing procedure was to install rivet nuts of various materials and configurations to determine the best option. The following results were obtained:
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Material Thickness: 2 mm |
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Base Material: Aluminum |
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Rivet Nut Style |
Spin Out (Nm) |
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M8 Aluminum |
13 |
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M8 Steel |
18.2 |
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M8 Steel, Wedgehead |
23.6 |
From this data, the M8 steel wedgehead rivet nut was chosen as it offered spin out values that were higher than the assembly torque. This eliminated any spin out issues due to cross threading which would cost the OEM downtime on the assembly line.
To prevent corrosion, Sherex treated the rivet nut with our CR series corrosion resistant plating which offers over 1,000 hrs of protection during a salt spray test.
Contact Sherex to review your application so we can work to find the best solution for your fastening requirements.
Sherex
www.sherex.com
::Design World::
Filed Under: Fastening + joining, Screws • nuts • bolts • rivets
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