Mahle Ventiltrieb GmbH produces valve seat rings in shell molds in its plant in Zell im Wiesental. One shell mold typically consists of a cluster of several cast rings along with the gating system.
Porosities, which could not be tolerated, were identified during casting trials for a certain valve seat ring. These porosities were especially evident in the area of the ingates. To find the root cause of the defects, the current casting design and process was simulated with MAGMASOFT®. The illustration below shows a solidification result for a specific point in time. A small isolated pocket of melt within the casting could be identified, explaining the feeding problems. Additionally, the simulation showed that the gating solidified earlier than the casting. Therefore, the hotspots were to be found in the part and not in the gating system.