Simple Solutions That Work! Issue 18

Continued on next page M ost aluminum foundries know how to use the reduced pressure tester to control hydrogen and oxide removal from the melt. The spectrometer is to control chemistry variations. On the other hand, thermal analysis of the melt has been regarded as not repeatable; not worth implementing versus value added or simply not shop-floor ready. Furthermore, the previous systems were only for grain refinement and eutectic modification control with limited precision. The important secondary phases and fraction solid curve were not available and the calibration of the system was expensive. How to use Thermal Analysis (TA) in Aluminum Foundries SFTA launched an innovative thermal analysis system a year ago, using a variation of the Newtonian principle and higher order derivatives. The accuracy and precision are much better compared to previous algorithms relying on time and temperature. As the liquid metal solidifies, it transforms into different solid phases that release or absorb heat. With each sample, important variations in phase formation are detected for Mg2Si, Al2Cu, iron intermetallics, late eutectics, etc. The fraction solid curve is plotted for more accurate casting simulation inputs. Today with Industry 4.0, all the operator has to do is take a sample to generate all the data on solidification properties. The complete analysis is automated and the data is recorded on the server. Only a portion of the results is displayed to the operator or the supervisor and it’s customizable (Figure 1). Melt FRANÇOIS AUDET Solutions Fonderie ARTICLE TAKEAWAYS: • Thermal Analysis data helps to find the root cause of casting defects • Thermal Analysis is important to validate the melt treatment and record/cor- rect melt variations • Qualify new ingots based on metallurgy to avoid problems, not just chemistry 25 HOW TO ISSUE Figure 1. Thermal Analysis software interface displaying A356 data before (left) and after (right) grain refinement and strontium additions.