perience with radiography ratings and casting performance. No correlation between radiography and ultrasonic ASTM ratings presently exists. Therefore, no one is sure how ASTM UT ratings correlate with casting performance or radiography.


The goal of the project is to determine the repeatability of UT inspection on steel castings. Additionally, the project will correlate UT ratings to radiographic ratings. This will assist foundries in understanding UT and enable them to appropri- ately use the technology.


Status Update: This project is now complete and the final re- port is being written. Anyone seeking information on the project should contact Prof. Bob Tuttle, Saginaw Valley State University, at rtuttle@svsu.edu.


Aging and Machinability Interactions in Ductile Iron (08-09#02)


Coordinator: Missouri University of Science and Technology (MS&T) and AFS Cast Iron Division (5)


The proposed overall program will complete the understanding of how age strengthening affects machinability so that foundries may be able to utilize the strength improvement with age strengthening to cast equivalent grades at higher carbon equivalent (CE), lower alloy or lower pearlite content without the requirement to hold castings before machining. The objective of the proposed work is to explain the mechanism by which age strengthening changes the machinability of graphitic cast irons to investigate ductile irons.


Little is known about age strengthening effects on machin- ability of ductile iron. It has been shown that age hardening of the free ferrite microstructure component of ductile iron exceeds the tensile strength increase of the bulk material. Work with ductile iron would not only provide information specific to ductile iron but could shed light on the general mechanism for age-strengthening effects on machinability in graphitic cast irons due to the larger amount of free ferrite that can be obtained in as cast alloys such as 65-45-12.


Status Update: The AFS funded portion of the project work is complete and a final report has been written. DOE-E- SMARTT work is ongoing. Progress was reported in papers given at CastExpo’10 & Congress. Those interested in the work of this project or committee should contact Prof. Von Richards, Missouri University of Science and Technology, at vonlr@mst.edu.


Optimizing Mechanical Properties of Cast Aluminum Alloys by Molten Metal Treatment (Phase I A356/Phase II)—CWRU (Agreements 08-09#04/10-11#01)


Coordinator: Case Western Reserve University and AFS Alu- minum Division (2)


Mechanical properties of cast aluminum products can exhibit wide variation even when the same alloy is used. Best practices


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to achieve maximum properties encompass: high molten metal quality (clean metal, degassing), metal treatments (modification, grain refining), good gating practices, filtration, directional so- lidification, fast cooling rates and adequate risering. The indus- try would benefit from a well-defined set of “potential” (i.e. maximized) properties that can be achieved for any given alloy when best practices are applied.


This project proposes to establish a data base with “potential” properties of cast aluminum alloys, in other words, if Best Practices in melting the aluminum and treating it are carefully followed, a high cooling rate is applied and shrinkage porosity is eliminated, what would the properties be?


Status Update: The first phase is complete and a report was given at CastExpo’10 & Congress. Phase II was recently ap- proved by the AFS Research Board. This will focus on im- provements resulting from metal treatments and heat treat- ment. Progress reports are given at Aluminum Division meetings. Those interested in the work of this committee should contact Steering Committee Chair David Neff, thenef- fers@sbcglobal.net, or David Schwam, Case Western Reserve University, at dxx11@cwru.edu.


Ductile & CG Iron Casting Skin—Evalua- tion, Effect on Fatigue Strength & Elimination Phase II (09-10#01)


Coordinator: Ohio State University and AFS Cast Iron Division (5)


The elimination of the flake skin is one of the key elements of unlocking the full design potential of Compacted Graphite Iron (CGI). Capitalizing on the results of a previously AFS sponsored effort 04-05#02, “Study of the Effect of the Cast- ing Skin on the Tensile Properties of Light Weight Ductile Iron Castings”, the Department of Materials Science and Engineering at The Ohio State University (OSU) propos- es to conduct research with the goal of understanding the mechanism of formation of casting skin in CGI, evaluating its effect on selected mechanical properties, and developing the methodology for its complete elimination. The results of this research will be of immediate applicability to the industry without major capital investment.


The research strategy is designed to develop the knowledge required to improve and ultimately eliminate skin quality of CGI castings and to generate data on its impact on the static mechanical and fatigue properties of CGI, as well as on the efficiency of shot blasting in improving these properties. Ad- ditionally, the study may help in the definition of the minimum thickness of the layer that must be removed by machining to avoid negative skin quality effects. The research will capitalize on the experience in the characterization of casting skin ac- cumulated in the Virtual Solidification and Casting Laboratory (VisionCast) at OSU.


The success of this investigation will rely on the completion of extensive experimental work that will provide critical data


International Journal of Metalcasting/Summer 10


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