Innovation

 

Aluminum Fasteners

 

Nedlite 

 

One of the greatest challenges faced in the automotive industry is to reduce CO2 emissions. In order to this achieve objective, it's crucial to produce vehicles that offers better fuel economy without compromising comfort, spaciousness and safety. And greater use of lightweight materials is a key part of the strategy to resolve this dilemma. Nedschroef therefore developed range of aluminum fasteners which enables the joining of lightweight components. 

 

Light metals have much larger thermal expansion coefficients than steel. This leads to extensive thermal induced stresses, if a bolted joint with steel screws and magnesium and/or aluminum components is operating at elevated temperatures, for example in a gearbox housing. This can easily cause overstressing of the lightweight material, so plastic deformation in the stressed zone occurs and the clamping force is reduced significantly. Such relaxation problems in practical applications are showing self-loosening, fatigue failure, sealing defects, noise from components under vibrations or intensive local corrosion caused by gaps between head and support area. A much better result is achieved, if for the same joint a screw made of aluminium instead of steel is used. Because of the similarity between the thermal expansion coefficients of aluminium and magnesium there is almost no stress increasing and, therefore, almost no increase of surface pressure.


Nedlite is the perfect solution for joining lightweight components operating at elevated temperatures.


Key applications

 

  • Magnesium cylinder head cover
  • Magnesium gearbox housing to engine
  • Gearbox applications


Properties

 

  • Material AW-6056
  • Ultimate tensile strength Rm > 400 MPa
  • Yield strength Rp0.2 > 350 MPa
  • Temperature resistant up to 150°C
  • Thermal expansion of 21•10-6 K-1
  • No contact corrosion if combined with magnesium