Grain Refining of Aluminum Casting Alloys
G. Sigworth GKS Engineering Services, USA A review is given of grain refining practices in several common casting alloys. In many cases today's practice is employed largely for historical reasons, which were developed long before modern Ti-B refiners became available. The results of tests made in Al-Si, Al-Si-Cu, Al-Cu, Al-Mg and Al-Zn-Mg alloys are presented. The grain refining response is different in each alloy system. Some recommendations are given for improvement of the practice in each of the alloys. Significant cost savings may be realized, and better resistance to hot cracking is found with improved grain refinement in 2xx and 7xx alloys. |