Masters Theses

Abstract

"Investment casting is a process in which a ceramic shell is prepared on a wax or foam pattern. The wax is melted out or the foam is burnt out and the shell is sintered to have sufficient strength to withstand casting conditions. The investment casting process is very important as it produces near net shape castings which reduce the need for subsequent operations of castings like machining etc. Investment casting shells are subjected to a number of heating cycles during pattern removal, firing, preheating before pouring and finally during solidification. The thermo-physical properties of the shell play an important role during these processes. One focus area of this research was measuring the thermal conductivity and the specific heat capacity of investment casting shells. The measured properties were included in a simulation software database (Magmasoft). A second focus area of the research was casting surface defects due to liquid steel - ceramic shell interactions. A special cube-shaped specimen with a deep pocket region was designed and simulated using Magmasoft. Three different types of shells were prepared with silica, zircon and alumina flour in the prime coat slurries. For comparison, shells prepared around the same pattern were obtained from three industrial foundries. Shells were preheated to 800⁰C and poured with HY130 steel. Shell samples in contact with the steel were taken from the pocket region of the castings, polished and SEM/EDS analyzed. Multiple interaction products included complex Mn-Si-O, Al-Si-Mn-O and Fe-Si-Mn-Al-O oxides were experimentally identified. The experimental results are discussed with respect to the thermodynamic predictions. The results can be used for shell material selection and to identify casting procedures that would limit these defects"--Abstract, page iii.

Advisor(s)

Richards, Von

Committee Member(s)

Lekakh, S. N. (Semen Naumovich)
Chandrashekhara, K.

Department(s)

Materials Science and Engineering

Degree Name

M.S. in Materials Science and Engineering

Sponsor(s)

Steel Founders' Society of America
Benét Laboratories

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2011

Pagination

xi, 92 pages

Rights

© 2011 Chirag Rajendra Mahimkar, All rights reserved.

Document Type

Thesis - Open Access

File Type

text

Language

English

Subject Headings

Matter -- PropertiesPrecision casting -- DefectsPrecision casting -- Thermal propertiesThermal conductivity

Thesis Number

T 9875

Print OCLC #

785397844

Electronic OCLC #

756203051

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