Weight Reduction Through Thixocasting Associated With Shot Peening

摘要

This comprehensive study of wheel disc weight reduction shows that the technology of thixocasting complies with wheel specifications, providing surface quality is under control, and has the best potential among the material-process solutions studied for causing a change in the compromise between "Weight Reduction/Freedom of Style" at a competitive cost, but without achieving the weight reduction aimed for. For this part, originally designed to be forged, the thixocast solution is less competitive economically than the low-pressure cast solution. The most pertinent wheel dimensioning criterion, confirmed by experiment, is the rotating bending endurance limit with exponent n=2/3. Prestressed treatment at an Almen intensity F23-F30A on both sides of wheel discs made of the thixoformed AlSi7Mg0.6 T5 alloy, the 6082 T6 forged alloy, and the low-pressure cast AlSi11Mg0.2 F alloy introduced high intensity compressive stresses, the values of which appear in direct proportion to the yield strength of the material prior to prestressing treatment. For the three alloys, maximum compressive stress is reached at a depth of 0.15 mm and a significant level (100 MPa) is still present at 0.4 mm.