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Lighter, stronger chassis

  • Magazine Feature Article
  • 14AUTP06_03
Published June 03, 2014 by SAE International in United States
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  • English

Development of a new high-strength aluminum casting alloy for the production of suspension components.

The Counter Pressure Casting (CPC) process is particularly suited for the production of aluminum suspension components such as wheel carriers and steering knuckles. Using a typical AlSi7Mg alloy such as A356 or EN AC-42100, with yield strength above 260 MPa (37.7 ksi) and elongation rates above 8%, is possible in high-volume production. Although these are very good values for aluminum castings, the yield strength has to be improved to increase the lightweight potential of such components, according to researchers from KSM Castings Group GmbH.

They believe this goal is achievable through the development of a new aluminum casting alloy. Besides the modification of Si and Mg content, the addition of Cr leads to an additional dispersion hardening effect. In this way, yield strength above 310 MPa (45.0 ksi) combined with an elongation of 7% can be assured in the CPC process after a T6 heat treatment. The researchers conducted fundamental microstructural investigations as well as tensile tests, high-temperature strength, corrosion behavior, and static and dynamic component testing.