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This paper examines some processing and design factors which affect the impact performance of cast A356 aluminum wheels, as measured by SAE J175 (13° lateral impact test). Wheel impact performance is discussed with respect to two different failure criteria: (a) failure due to cracking in the hub or spokes, and (b) failure due to total loss of tire air pressure. The general influence of heat treatment on impact behavior is described, and then examined in light of a particular wheel example. Peak-aging heat treatments are compared with underaging treatments, in terms of the critical link between processing, material properties of strength and ductility, and their influence on wheel impact behavior. The effects of the rim flange geometry and other design features are then explored, and illustrated with examples.

Aluminum castings have been replacing iron castings and steel fabrications with significant weight savings. Casting designers face the challenges of selecting the casting process best suited for the casting configuration and selecting the alloy most suited to meet the part function. Casting processes currently proven and applicable to high integrity aluminum castings are briefly described. The available alloys are listed along with their properties. General guidelines are offered for the selection of casting processes and alloys. The scope for further work is defined. The emerging technologies to be harnessed are identified.

Knuckle castings for the automotive industry have traditionally been made from ductile iron, but engineers are now looking to aluminum castings as a lightweight alternative. Amcast Automotive has been involved in the development and manufacture of A206 aluminum knuckle castings since 1989 when it first supplied Aluminum castings for Ford Motor Co. (MN-12 platform). Recently, several new high volume automotive knuckle castings have been introduced using A356 aluminum alloy with T-6 temper. This paper presents mechanical property information on both A206 and A356 aluminum alloys to assist engineers in the design of knuckle castings in aluminum. In addition to microstructural evaluation, mechanical properties will be obtained from test bars cut from actual heat-treated knuckle castings.

A detailed analysis of maximum aluminum substrate porosity for chrome platability of low pressure permanent mold(LPPM) wheels has been performed in a controlled environment. This includes a porosity comparison of different wheel casting processes, results of a laser drilled aluminum wheel section (providing verification of the real world information), results of several design of experiments (DOE) trials to determine critical LPPM casting variables and successful chrome platiblity of LPPM wheels without copper buff.