The master’s thesis was carried out to reduce and eliminate the penetration defect in two castings with codes 358 and 088 of grey cast iron castings with lamellar graphite. The penetration defect repeatedly occurred in the same parts of both casting systems and was caused by high casting temperature, the velocity of molten metal through the mold, and pressure at the final filling of the casting cavity.
First, we calculated the casting processes in both casting systems in the ProCast program. In the program, we prepared the appropriate geometry with meshing, heat transfer coefficients between volumes, and defined material properties and boundary conditions. As a result, we obtained simulations of molten metal velocity, pressure in the mold, temperature field, erosion of the mold, and solidification of the alloy. From the simulations, we concluded that at the location of the penetration defect, thermal load on the sand mixture, the faster velocity of molten metal, and erosion of the mold was increased. Pressure upon filling, which is a consequence of the last filling place of the casting cavity, was also increased.
As part of the master’s thesis, we conducted a test in the laboratory on the influence of parameters on the sand mixture where we monitored the penetration of molten metal and consequently the reaction of sand to the casting. During the experiment, we varied the stiffness and moisture of the sand mixture and heated the surface of the casting cavity. After analyzing the castings, we found that the moisture of the sand mixture influences penetration the most.
By changing the pouring time and casting temperature, we significantly reduced the penetration defect in both casting systems in the simulation. For the casting with code 358, we additionally optimized the elements of the casting-feeding system to reduce the velocity of the molten metal.
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