Fluid flow through liquid interdendritic channels of a partially remelted lead-tin casting has been measured directly, with gravity as the driving force. The results were shown to be consistent with Darcy's Law. The permeability of the dendritic array was found to be a function of the square of the primary dendrite spacing, and was observed to increase with time due to coarsening of the dendritic structure. The formation of casting defects in lead-tin alloys was studied with isothermal and unidirectional solidification experiments. Solute convection was observed when the liquid close to the bottom of the solid-liquid region was less dense than the liquid above, using radioactive tracer techniques. Macrosegregation was shown to be related to the solidification conditions, and channel-type defects, resembling freckles and A segregates, were formed when the rising interdendritic liquid dissolved dendrite branches in its path. A simple mathematical model is proposed, which predicts the composition profiles in vertical, directionally solidified lead-tin castings, as a function of the structure, growth rate, and temperature gradient. The model is shown to agree qualitatively with the experiments, and can be used to recommend specific changes in casting practice to reduce gravity segregation effects. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate

No description available.

Thesis PlanB (M.S.)--University of Wisconsin--Stout, 2009. / Includes bibliographical references.

Thesis (PhD) - Swinburne University of Technology, Industrial Research Institute Swinburne - 2006. / A thesis submitted to the Industrial Research Institute Swinburne, Swinburne University of Technology in fulfilment of the requirements to the degree of Doctor of Philosophy, 2006. Typescript. Includes bibliographical references (p. 199-211).

"Theoretical issues relating to the aerospace sand casting simulation are laid out, identifying parameters used in the model. A sensitivity analysis is performed to examine the mold-metal heat transfer coefficient, mold thermal conductivity, wall friction factor, pouring basin pour temperature, and pouring basin head pressure through doing coupled flow simulations on thin-walled castings using the commercial casting simulation software, MAGMASOFT. A verification exercise is done to match simulation with reality with the knowledge that mold-metal heat transfer coefficient and mold thermal conductivity are the most influential parameters of the five. Validation on a real production casting is performed using the tuned parameters from the verification exercise."

Semi-Solid Metal (SSM) forming has distinct advantages: strength, near net shape, thick and thin sections and a large scope of materials able to be cast. The aim of this project is to produce a near net shape component using SSM casting with A356 primary Semi Solid Aluminum feed stock from SAG. The selected Short Arm Component was identified as a suitable component for SSM forming, it is used as part of an insulated securing mechanism in overhead pylons, demands high strength and has relatively thick sections. A combination of full and short shot castings from the component and modular die were produced, on the real time shot controlled 62.5 ton high pressure die casting machine, at varying casting parameters of die temperature between 140-250°C, gate velocities of between 1.01-2.87ms_1 and a billet temperature of between 578-582°C. To understand fluid flow and locate possible defects, X-ray radiography and naked eye surface observations of the castings were used to locate possible defects and irregularities, which were cross sectioned and analysed using a Scanning Electron Microscope with an Energy Dispersion Spectroscopy module. It was apparent from the current project, as well as from literature, that increases in the die cross-sectional area reduce the shear surface area and increase the viscosity causing undesirable mould filling behaviour. / Thesis (M.Sc.)-University of KwaZulu-Natal, Durban, 2006.

Call number: LD2668 .T4 1978 A67 / Master of Science

Thesis (M.S.)--Brigham Young University. Dept. of Mechanical Engineering, 2005. / Includes bibliographical references (p. 100-104).

Investment casting has been an important form of metal casting for many years, but little is understood about the fluid flows that occur during mold filling. A key to quality castings is the understanding and control of the fluid flows that are present when the mold is filled with molten metal. It is thought that with a greater understanding of these flows, better control can be maintained and the end result will be a more efficient process that produces better parts. The subject of this thesis is the experimental study of the fluid mechanics of filling a small part mold. The experiments included tests on different downsprues, wells, runners, and chokes. The collected data were analyzed and the following recommendations were made: The shape of the downsprue, whether tapered or straight, does not seem to be important as long as the minimum area is small enough to provide the required choking. The use of a well has contributed to the smoothness of a flow, but its effect can be provided instead by chokes. Overflow chokes in the horizontal portions of the mold seem to be more effective than choking in the downsprue, but the use of both improves the flow. While runner extensions and underflow chokes might help to reduce impurities, they do little to help the smoothness of the flow. / Graduation date: 1991

A cast modular connector (MC) has been developed for use in seismic-resistant steel moment frames. The MC is a field bolted beam flange connection intended to serve as the frame's special energy-dissipating detail. The connector is specifically configured for optimal seismic performance through a casting process. The MC possesses inherent ductility through variable-section arms that minimize plastic strain demand and a reliable yet economical fastening method through a base end-region that virtually eliminates prying forces on bolts.The dissertation presents three journal papers. The first paper describes the portion of the analytical research focused on establishing the optimum geometry for the energy dissipating arm elements. Key parameters were evaluated through parametric studies using nonlinear (material and geometry) finite element analysis and supported by basic theoretical models. The outcome was a set of optimum geometric ratios covering width reduction, length to thickness, aspect ratio, and fillet radius.The second paper describes the development process of the isolated connector rather than full-connection behavior. Designs were alternately evaluated for structural performance and castability through the electronic exchange of solid model files with steel foundry industry partners. The analytical results indicate the potential for excellent ductility and energy dissipation characteristics in the MC Beta prototype.The third paper focuses on the prototyping and experimental verification of the MC Beta prototype. Steel foundry industry partners cast the MC Beta prototype at approximately half-scale. The scaled MC Beta prototype was tested in isolated fashion under monotonic and cyclic loading. The experimental results confirmed the performance of the analytically-based designs. The MC Beta prototype exhibited exceptional performance in terms of stable energy dissipation, far exceeding qualifying rotational ductility capacities. In direct comparisons to a WT section of similar stiffness and strength, the MC Beta prototype possessed greatly enhanced ductility and energy dissipation characteristics.With the MC Beta prototype developed and experimentally verified under isolated conditions, an experimental verification of beam-to-column joints containing the scaled MCs were performed using accepted testing protocols. The preliminary test results indicate that the connection exceeded qualifying rotational ductility capacities and showed promise as a special energy-dissipating detail in seismic-resistant steel moment frames.