Castability and Strength of Potassium Chloride-Ceramic Composite Salt Cores
Jun Yaokawa *, Koichi Anzai ** Youji Yamada *** Hiroshi Yoshii *** and Hiroyuki Fukui ***
Development of high strength water-soluble salt cores is required for manufacturing undercut shaped products by die casting. In this study, the strength of potassium chloride core composites reinforced by ceramic particles or whiskers was evaluated by the 4-point support bending test. Moreover, castability was examined by surface roughness observations and X-ray tests of internal solidification shrinkage. As a result, it was found that the strength of salt cores can be enhanced by increasing the ceramic content. For potassium chloride with AlisB O33 whisker, the examined strength (30 MPa) was about five times stronger than commonly used sand cores. On the other hand, there were surface folds on all specimens. In addition, internal shrinkage occurred in all specimens. The amount of shrinkage decreased with increasing ceramic content. However, excess ceramic content was found to cause high apparent viscosity, resulting in extremely low formability. Keywords: salt, core, potassium chloride, ceramic, whisker, castability,bending strength, surface fold, shrinkage
Fig.1 Schematic drawing of mold design.Fig.2 Schematic drawing of bending test.
(a) set up of bending test. (b) assumption of Eq.1.
(c) size of typical test pieces.Fig3. Schematic drawing of meltingFig.5 Macro structure of pure potassium chlo-ride coreFig.6 X-ray photos of potassium chloride with
-325 mesh mullite cores.
(a)0 mass%, (b)7.6 mass%, (c)13.9 mass%, (d)27.7
mass%, (e)42.3 mass%.
