An investigation of material properties and geometrical dimensions of aluminium extrusions

The increasing demand for aluminium extrusions calls for relevant statistical data to establish objective measures of uncertainties associated with the material description and cross sectional geometry. A total of 392 tensile test specimens are machined from 49 rectangular hollow section extrusions in order to investigate how the material properties are distributed. The Kolmogorov-Smirnov hypothesis test indicates that the normal as well as lognormal distribution represents the observed data fairly well. Several model parameters are involved in the study, including two alloys, three angles with respect to the extrusion direction, two thicknesses and two tensile test coupon sizes. Regarding the geometrical dimensions, the thickness, width and height are measured, finding that the dimensions usually are somewhat smaller than the nominal values.