R&D for Tomorrow’s Casting Supply Chain

An MCDP Staff Report

Industry research projects spur casting development and drive new applications.

People have been making useful items out of cast gray iron for centuries, and in 1966, the material accounted for more than three-quarters of total global casting production. But a new material was created in mid-century 1900 by researchers that opened new applications for the industry. Its usefulness as a strong, yielding material made its popularity so widespread that by 2016 it accounted for over one-quarter of total ferrous and nonferrous casting production.

The material, of course, is ductile iron, and it is a prime example of the impact research and development can have on an industry.

Government agencies, independent associations, universities and private sector businesses are working to push the metalcasting industry forward through research and development. These projects seek to improve manufacturing methods, diversify available materials, and create new applications.icme

The American Foundry Society (AFS) funds many research projects with allocated membership fees, with an active portfolio of close to 15 today.  These projects are selected and steered by volunteer-led committees and performed at properly equipped labs in foundries, colleges, and testing facilities.

AFS also collaborates with government agencies like the American Metalcasting Consortium and Defense Logistics Agency on research projects to advance casting engineering and design.

Following is a few of the current and recently completed projects that aim to find new and better ways to make quality castings as well as advance materials and processes to be used in new applications and markets.

Achieving Precise Low-Carbon Stainless Steel in Lost Foam
This project’s goal is to produce low-carbon stainless steel in the lost foam process. This steel casting market is primarily ruled by the sand and investment casting processes. Sand, while reasonably fast for delivery, especially in 3D-printed core and tool applications, is relatively imprecise compared to lost foam. Investment casting requires extensive machining of the casting and needs more weight for draft, stock, and molding dimensional issues. Investment casting, while precise, also has size and cost limitations. The research project will produce ASTM A351 CF8M stainless steel with 0.08% maximum carbon level in the lost foam process by understanding and implementing practices of bead selection, bead expansion, expanded bead density, permeability and fusion, coatings and their permeability, carbon-consuming additives, metal pouring rates and base composition and molding media refractoriness and permeability.

Improving Weld Repair in Aluminum 206 Sand Castings
Current practices to weld 206 alloy castings, particularly to repair through-wall defects or defect depths of greater than 0.25 in., result in unsatisfactory welds.

Both 206 and 2319 weld rods are typically used for repair welding of 206 castings. A recent project to determine the effect of weld repair on the static and dynamic properties of A206 sand castings did not successfully produce welds of the desired quality. The work determined that the major problem is the chemistry of the weld wire used to make the welds. The two alloys currently used by AFS foundries (A206 and 2319) either produce inconsistent weld quality (A206) or low ultimate tensile strength (2319).

To mitigate the effects of weld wire chemistry and other variables on weld repair quality, a research project is using a set of statistically designed experiments to optimize a weld alloy chemistry and the welding parameters necessary for the successful weld repair of A206 sand castings.

Optimizing Gray Cast Iron Strength
AFS-sponsored research has defined which manganese and sulfur concentrations produce the best properties as pertains to gray cast iron strength. The potential improvement in strength is sufficient to significantly improve the marketability of iron castings.

Refining Investment Casting
AFS-sponsored research has demonstrated the importance of firing parameters on the thermo-mechanical properties of investment shells. With this knowledge, foundries are one step closer to achieving shells that provide sufficient mechanical strength with fewer layers. This could translate into a marked reduction in operating costs.

Improving Steel Casting Quality
Continuing research seeks to address costly inclusion defects that plague steel casting production by exploring how various gating designs affect filling conditions and casting quality. At present, it is estimated that scrap and rework due to inclusion defects can account for as much as 16% of the manufacturing costs associated with steel casting production. This research has the potential to slash those costs by addressing turbulent filling conditions that cause unnecessary weld repair, low mechanical properties, and customer rejections.

Harnessing 3D Printing for the Lost Foam Casting Process
Continuing AFS-sponsored research seeks to harness the power of 3D printing to expand the marketability and viability of the lost foam casting process. Lost foam tooling is, in general, expensive, with long lead times associated with the complexity of tool designs. This research is attempting to address this by demonstrating production of tools for high-mix, low-volume production using 3D-printed aluminum. It is expected that this research will result in halving of both costs and tooling-related lead times, allowing foundries to enter new markets. 

Click here to see this story as it appears in the September/October 2019 issue of MCDP.

Casting Process and Alloy Assistance
The AFS website provides tools to assist casting design engineers in selecting the best casting process for a potential component and provides casting alloy property data on many commonly used alloys. The goal is to give design engineers, casting users, and purchasers relevant and accurate information on casting capabilities and properties, providing easily accessible and retrievable information from a single site. Alloy property data can be quickly exported to a spreadsheet or FEA tools. The casting alloy and process selector, Casting Alloy Data Search (CADS), is located at www.afsinc.org under the Designers & Buyers tab or can be accessed directly at: www.metalcastingvirtuallibrary.com/cads/cads.aspx.

Casting Source Directory
The Casting Source Directory is also available to the public on the AFS website. The site provides a directory of North American metalcasters in a single source. Potential casting buyers can search by metal, alloy, casting process, casting size (weight), and state to locate a casting provider that meets their needs. The Casting Source Directory is located on the AFS website under the Designers and Buyers tab or can be accessed directly at www.afsinc.org/metalcaster-directory.

CastingConnection is a private, professional, social network to connect, engage, and share critical industry information and best practices in real time. Through the Open Forum and sites devoted to special interest groups, AFS members gather to network via a comprehensive member directory and participate in focused discussion groups. AFS membership is open to any company and individual within the metalcasting supply chain, including equipment and service providers, foundries, and end-users. Visit https://castingconnection.afsinc.org.

Online Library
The AFS online library contains current and historical articles and research papers about the metalcasting industry, including topics on metallurgy, casting processes, and material property data. The digital library is open to all AFS members. With a simple-to-use search, members have access to relevant technical and research articles and reports from all AFS published sources.

Author and summary information is available for viewing, and full articles can be downloaded. All technical and management papers published in AFS Transactions, from the first edition (published in 1896) to the present, are available, as well as technical articles from all AFS magazines. Hundreds of members have already leveraged this resource, conducting thousands of searches that span topics ranging from iron inoculation to silica exposure to gating and riser design. The library is located at www.afsinc.org under the Innovation & Management tab.

AFS offers a program that provides metalcasting-specific training, information, and education for the industry supply chain in a web-based format for a single access fee. The e-Learning program gives subscribing organizations full access to online modules for formal staff training on a wide variety of metalcasting topics. Individual e-Learning modules also are available a la carte, including several focused on designing for casting. More information and a video demonstration are available at www.afsinc.org/e-learning.

Casting Design Training
The AFS Institute has partnered with the company NoRedesign.com to offer online education to support original equipment manufacturers and their design engineers. The partnership is formed expressly to support training for OEMs that will greatly enhance the design of components for the casting process. The training offers a suite 32 instructional videos walking the listener through each step of casting design and engineering, assisting design engineers to reduce final assembled component costs through effective design principles. With this methodology and training, users will avoid product launch delays, costly overruns, suboptimal components, and failed prototypes.

For more information, visit www.afsinc.org.