Quantitative X-Ray Tomography for the Development of a Piston Casting Process

Abstract

The development of castings for automotive components [1] can be accelerated by “statistical experimental design” or Taguchi-like methods [2] which use quantitative measures of the component quality to isolate and optimize the casting control parameters. In the present work the internal quality of aluminum pistons is determined using x-ray tomography. This technique allows internal voids such as shrink porosity to be detected. Both these defects occur when the gates or risers supplying molten aluminum freeze before the casting is completely solidified. These voids can be eliminated by carefully selected mold designs and casting conditions which lead to directional solidification. A casting development cycle is illustrated in Fig. 1 and shows how the casting parameters can be optimized during mold-tryout using statistical experimental design methods.