68th Annual Technical Conference & Exposition WEDNESDAY, NOVEMBER 10, 2021 8:00 a.m. - 8:05 a.m. WELCOME INTRODUCTION
8:05 a.m. - 9:05 a.m. Keynote Address: Awareness Brings Change Shayla Rivera – Keynote Speaker
9:05 a.m. - 9:45 a.m.
Paper No. 18: Enhancing Porosity & Permeability of Ceram- ic Shells For Investment Casting through Pre-wetting Noel O’Sullivan, University of Limerick Ceramic shells for investment casting are heterogeneously built and contain a porous granular structure. Flexural strength and permeability of the ceramic shell are key properties to withstand the weight of the high temperature alloy and to alleviate hot gases during casting, respectively. In this study, a method known as pre-wetting is applied between the multilayer ceramic shells to enhance porosity while sustaining flexural strength. Pre-wetting consists predominately of de-ionized water and aqueous silica solution that enhances the rheology of the refractory slurry in complex areas. Porosity is then developed where the pre-wetting is applied due to the evaporation of the aqueous phase during drying and firing. The morphology of the ceramic shells are characterized by x-ray computed microtomography, mercury intrusion porosimetry, gas adsorption methods and pore network modelling. Three-point flexural testing at both low and high temperatures analysed any deviations in fracture load, while permeability was analysed at 1000ºC. Permeability increased by a factor of two and correlated with results from MIP that exhibited a stepwise increase in intrusion volume in the high pressure regime. Both green and fired flexural strength for different shell types reduced on average by 8.7-15.6% and 18.7-28.5%, whereas hot strength increased by 20-25%.
AGENDA
9:45 a.m. - 10:25 a.m. Paper No. 19: Tensile Bar Castings Mark White, IMPRO Industries USA In new casting development projects there exists some form of an agreement between the casting purchaser and the casting manufacturer which outlines the technical requirements for qualification to production. These agreements may range from more comprehensive specific dimensional and metallurgical requirements associated with aerospace fixed processes to a lone AS9102 dimensional requirement, which may apply to an industrial part application. There exists a gap, in the middle where casting designer/purchaser assume metallurgical requirements including the notion that machined from casting (MFC) test bars are intended to and must meet ASTM requirements. Oftentimes, the designer/ purchaser requires MFC expecting ASTM properties. Many times casting houses agree, because they think there is no other choice and the designer must be correct. This can cost the casting producer in terms of excessive mechanical testing and lost production. This paper is offered to the 68th Technical Conference as a service to both sides of this topic -casting purchaser and casting manufacturer. My paper thoroughly discusses metallurgical differences and the inimitability of cast shapes and includes case studies, mechanical and process data, a metallurgical summary, photos and a practical guide to manage this topic. The paper represents collaboration with and data from our foundries where we successfully worked through these customer situations. My hope in offering this work to the 68th Technical Conference and Expo, is that the audience gains valuable information to go on and successfully handle this topic in their own companies where the situation is turned from “production-stopping “hot button” to smooth production.
10:25 a.m. - 10:30 a.m. Best Paper Award, Closing Remarks and Adjournment Joseph Fritz, ICI Executive Director
Thank you to our Event Sponsors
26 ❘ October 2021 ®
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