Effect of Pouring and Mold Shell Temperatures on Porosity in Complex Investment Castings of Stainless Steel 304
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Abstract
Investment casting offers a powerful combination of precision, design freedom, material versatility, and potential cost savings, making it an ideal choice for demanding applications across various industries. However, this technology also faces significant challenges that affect part quality, primarily due to the formation of porosity and air entrainment. These defects originate from inadequate solidification control and turbulent flow behavior during the mold filling process. This study aimed to investigate the effect of pouring and firing temperatures on the appearance of porosity in stainless steel 304 complex casting parts, to minimize casting defects. The casting geometry is characterized by intricate features and thin cross-sections, making it highly sensitive to thermal and flow behaviors. Six pouring temperatures (1580 °C, 1600 °C, 1620 °C, 1640 °C, 1660 °C and 1680 °C) and six firing temperatures (950 °C, 1000 °C, 1020 °C, 1040 °C, 1060 °C and 1080 °C) were evaluated. ProCAST software was used to analyze porosity formation and air entrainment, revealing that a pouring temperature of 1640 °C and shell temperature of 1040 °C achieved a minimal porosity (0.01 cm³) while reducing the air entrainment (0.5 mg/cm³). Additionally, the study also clarified that the relationship between pouring/shell temperature and casting defects is non-linear, with “trade-off” effects always happening in casting. Experimental validation via X-ray and microscopy inspection confirmed the simulation trends. The study recommends minimizing defects in thin-walled investment casting parts through precise thermal control, enhancing product quality and manufacturing efficiency.
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This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
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