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Leading steel casting research has been a cornerstone of SFSA for more than a century. The Society’s portfolio of research programs is devoted exclusively to steel castings. Topics are influenced by the various research committees and research is conducted at leading universities with experts in areas like modeling, melting, heat treat, and material development.

SFSA members have exclusive access to research results through the steel casting wiki, technical meetings and the annual T&O conference.

Digital Innovative Design for Reliable Casting Performance

The Digital Innovative Design for Reliable Casting Performance (DID) program is to develop a set of design tools that allow modern engineers to design castings confidently and elegantly. This set of design tools, based on comprehensive property measurements, will allow engineers to create cast parts that are reliable, high performance, and cost efficient for critical DoD and commercial applications.

The program aims to develop two design methodologies:

  • Codes based on design allowables
  • Model-based Process and Performance Design

The DID research projects are:

  • NDT Development and Evaluation of Variability and Reliability, Iowa State University – Frank Peters and David Eisenmann
    • To support developing the design methodologies proposed, it is important to develop new NDT standards tied to performance. Current NDT methods and standards for commercial work are based on visual comparisons of workmanship standards. Experimental testing will be done to establish correlations between the NDT methods used to evaluate a casting and the resultant mechanical performance. Magnetic Particle Inspection (MPI) or Magnetic Testing (MT) and Phased Array Ultrasonic Inspection (PAUT) will be evaluated. Another ISU research on developing digital visual inspection method, funded under AMC’s Innovative Casting Technologies, will be leveraged to tie performance to casting surface conditions.
  • Solidification and Performance Modeling, University of Iowa – Christoph Beckermann
    • Casting solidification modeling will be integrated to performance analysis tools. This effort will enable the casting process solidification modeling results to predict local material and quality design properties to allow the component geometry to be digitally tailored to meet the performance requirements. Modeling and evaluation will be done on common cast steels and DoD alloys such as AF96 and FeMnAl.
  • Material Characterization and NDT Development, University of Alabama at Birmingham – Robin Foley and John Griffin
    • The development of digital tools for computer modeling assessment of local design properties that are reliable will be impossible without experiments to validate the underlying assumptions in the process. Analysis of fracture surface of tested specimens and microstructural characterization of samples that are representative of the casting process will be conducted. This characterization will support the development of quantitative NDT and establishing its correlation with performance. Common cast steels and DoD alloys such as AF96, HY, and FeMnAl will be characterized.
  • Design & Code Standards, University of Alabama – Charles Monroe
    • UAB is working to further understand the failure limits of steel castings using the historic design codes and standards, as well as developing a relationship between a measured indication’s size and shape and a flaw as treated by fracture mechanics. This relationship will allow fracture mechanics to be used to predict the expected load at which a steel casting with an indication of a certain size will fail. This will then allow UA to compare the predicted failure limit to the allowable load indicated by the standards to understand if fracture mechanics provides a more reasonable lower bound for load-bearing capability of steel castings.
  • Lower Bound Properties of Cast Steels, University of Iowa – Christoph Beckermann and Richard Hardin
    • SFSA has collected an extensive amount of mechanical property data for common cast steel grades. Using the same statistical approach used by MMPDS, A and B design allowables will be calculated to determine the design capability of common cast steels.
  • Indications and Fatigue Life, Iowa State University – Frank Peters
    • ISU is studying the theory that features such as inclusions and porosity limit the fatigue life of a cast steel component regardless of the surface roughness. To demonstrate this, ISU is running fatigue tests of as-cast and machined samples of both carbon steel (WCB in normalized condition) and low alloy steel (8630 in quenched and tempered condition) after thorough surface and radiographic inspection. The outcome of this work will provide the background for considering the actual (or statistically likely) crack-initiating feature during a fatigue analysis rather than using the historical approach surface finish-based curve adjustments.
  • Building Construction Component Design and Testing, University of Arizona – Robert Fleischmann
    • Structural testing of cast components will be done to show that steel castings can be used as structural components. The effect of different quality factors on the performance of steel castings will be evaluated. Cast prototypes will be welded to hollow structural steels to demonstrate that castings can be welded to standard structural components. A design guide for designers will also be developed to make the use of steel castings less complicated.
  • Welding of Cast Steels, Lehigh University – John DuPont
    • Welding is a part of the production of steel castings; however, there is some misconception that this is done to “repair” the casting. This research aims to demonstrate that welds on castings do not degrade the quality and performance of the casting.
       
      Welding trials will also be done to demonstrate that castings are as weldable as other steel products and are suitable for structural applications. This research will support the current AWS D1.1 proposal to include carbon steel castings in the prequalified base metals. The mechanical properties of common cast carbon steels welded to similar mill grades will be evaluated.
  • Clean Steel, University of Iowa – Christoph Beckermann and Richard Hardin
    • Reoxidation inclusions, inclusions that form as a result of molten steel reacting with oxygen during pouring and filling, have been a major issue in steel casting quality. UI will be validating their model that predicts formation of reoxidation inclusions by pouring castings with different rigging systems. Castings will be evaluated using NDT methods and other material characterization methods. The predictive modeling tool is being developed under a different research program (see section on Innovative Casting Technologies). The capability to predict and control reox inclusions in different gating systems is critical in improving quality of castings.
  • Industry 4.0, Iowa State University – Frank Peters
    • ISU is developing manufacturing technologies that can be utilized in the job shop environment of steel foundries. The first demonstration is to develop robotic grinding of steel castings. The idea is to merge the strengths of humans and robots. The operator will identify and paint areas that need to be ground. The operator will then scan the marked casting. A software tool will be programmed to analyze these scanned data and plan a grind path. The robot then follows this plan and grinds. This process increases safety and efficiency without sacrificing quality and allows adaptability in job shop foundries. The other technologies that will be developed is robotic welding and robotic arc-air cutting.
  • Sand Mold Embedded IoT Sensors, University of Northern Iowa – Jerry Thiel
    • A major aspect of smart manufacturing is having big data to analyze in order to optimize processes. There are limited to no information on what happens in the mold during pouring and filling that foundries collect in a regular basis. Embedding sensors in sand mold would capture real-time conditions in the mold. Collecting data like gas evolution, temperature, pressure in the mold will allow foundries to monitor casting quality.
  • Sand Testing Gage R&R, University of Northern Iowa – Jerry Thiel
    • Mechanical properties of sand mold are used as an indicator of sand quality and integrity. Foundries typically perform tensile test using dog-bone shaped specimens to determine the tensile strength of their sand mold or sand core. This tensile test has poor reproducibility. UNI is investigating 3-point and 4-point bend testing to measure tensile strength. This evaluation is to support their development of temperature dependent mechanical properties of sand. This sand mold property data is important in improving accuracy of casting process simulations.
  • Monel, Lehigh University – John DuPont
    • The research conducted to develop Monel (Ni-Cu alloys) occurred quite some time ago at the International Nickel Company (INCO), and there has not been significant research conducted since that time to investigate potential improvements. Since that time, relatively new thermodynamic/kinetic simulation software and advanced microstructural characterization techniques have become available that would permit efficient optimization of Monel alloys for enhanced properties. The overall objective of this research is to use modern simulation and characterization tools to investigate the relationships betwen alloying elements, microstructure, manufacturability, and properties.
  • Process and Property Optimization of Cast and Rolled FeMnAl, Missouri University of Science and Technology – Laura Bartlett
    • Manganese steel, FeMnAl, offers excellent combinations of strength and toughness and low density; however, there are challenges, which are also common in making other manganese steels, in production of these alloys. These include melt cleanliness, large grain size, cracking during processing, and non-uniform response to heat treatment. This research will evaluate how to mitigate these issues and improve the manufacturability of this alloy. A next generation variant for cast FeMnAl and rolled FeMnAl will be developed. Collaborating with research being done in other universities, a FeMnAl best practices document will also be developed.
  • Machining of FeMnAl, California Polytechnic State University – Pomona – Dika Handayani
    • Machining FeMnAl is challenging due to its high work hardening rate. Cal Poly-Pomona will develop best practices for turning FeMnAl. Using Design of Experiment, several factors such as feed rate, depth of cut, cutting speed, tool material, and coolant will be investigated.
  • Welding of FeMnAl, Lehigh University – John DuPont
    • The need to establish welding practices for FeMnAl is critical for its use in various applications. There is currently no matching welding filler material for FeMnAl. Lehigh will investigate the use of commercially available fillers. The effect of welding parameters on microstructure and properties and the need for a post weld heat treatment (PWHT) will also be evaluated.
  • AM Desert Sand, University of Northern Iowa – Jerry Thiel
    • The objective of Phase I of this project is to show a proof-of-concept of producing replacement parts for long-lead-time DoD critical components in-theater using 3D-printed desert sand. Phase II involves improving the integrity of the printed molds by critically examining recoater spreading speed, layer thickness and binder saturation.
  • Grain Refinement and Homogenization Using ECAP, Texas A&M – Ibrahim Karaman
    • Texas A&M has shown success in utilizing equal channel angular pressing (ECAP) to refine grain size to improve strength and impact toughness of AF96. ECAP preserves the cross-sectional area of a sample in between passes, allowing for multiple passes with different rotations to study multiple rotation combinations and the effect on grain size. The application of ECAP is being evaluated for FeMnAl and HY grades. They are also studying how to utilize ECAP to decrease segregation of manganese in FeMnAl by achieving a more homogenous precipitate distribution, which increases the dislocation density and leads to the higher strength and ductility combination.
  • Alternate Heat Treatment for Increased Toughness and Strength in HY-80, University of Maryland – Sreeramamurthy Ankem
    • The University of Maryland (UMD) has been focusing on creating alternative heat treatments for HY-80 to simultaneously increase toughness and strength through inter-critical heat treatments. Critical temperatures were determined by comparing literature studies with Calculation of Phase Diagrams (CALPHAD) modeling and experimental trials using Differential Scanning Calorimetry (DSC). The team at UMD has done extensive modeling predict mechanical properties of the inter-critical heat treatment, with proof of concept through studies in collaboration with Navy Carderock. They have also worked closely with Northwestern and provided two of the four heat recommendations for the composition optimization study.
  • Design and Qualification of Next-Generation Naval Hull Steel, QuesTek – Dana Frankel and Amit Behera
    • QuesTek has been utilizing its expertise in computational materials design and Accelerated Insertion of Materials (AIM) to design, model, test and qualify a next-generation high strength naval hull steel with higher strength, increased fatigue performance, and low magnetic permeability. They have worked with industry partners to produce three heats based on composition aims designed from their modeling capabilities. These prototype heats were used for forging studies, heat treatment and process optimization, and are now moving onto characterization of the heats for mechanical properties and microstructure analysis.
  • Alloy Design for Improved Weldability of HY-130, Lehigh University – John DuPont
    • Lehigh University studied the cracking susceptibility of HY-130 that renders the alloy nearly unweldable, and as a result, unusable for naval hull applications. They utilized thermodynamic modeling combined with Python and machine learning methods to investigate a large matrix of compositions for HY-130 that would minimize solidification temperature range and improve weldability while maintaining desirable levels of gamma prime precipitation and austenite stability.

SFSA also provides technical support to these American Metalcasting Consortium (AMC) research programs:

Innovative Casting Technologies

  • Digital Surface Inspection, Iowa State University – Frank Peters
    • Current standards for inspection of cast metal surfaces use qualitative methods leaving room for variation in interpretation of the standard. Standards used in the metal casting industry are the Alloy Casting Institute (ACI) Surface Indicator Scale, Manufacturer Standardization Society (MSS) SP-55 Visual Method, and American Society for Testing and Materials (ASTM) A802 that reference the Steel Castings Research and Trade Association (SCRATA) comparator plates. Some surface roughness inspection processes use the GAR Electroforming Cast Comparator C9. Other standards include ISO 11971 and BS EN 1370, which overviews SCRATA and BNIF, and ASTM A997 for investment castings. Digitizing the process will make the inspection more repeatable and reproducible and will help avoid confusion between the foundries and their customers. This will also help foundries verify visual inspection results internally or promote automation of the inspection qualification process. A quantitative visual inspection method with improved gage R&R could be leveraged to evaluate the effect of surface conditions on product performance.
  • Heavy Section Austenitic Stainless Steels, Lehigh University – John DuPont
    • Heat resistant austenitic stainless steels are capable of operating at high temperatures and are used in various applications. Depending on composition and section size (cooling rate), it can be difficult to achieve acceptable tensile properties in HH grade. The HK and HP grades are susceptible to cracking during welding and riser removal that has been attributed to carbide formation. This project will investigate the influence of composition on the formation of carbides, its type and morphology and their effects on mechanical properties and cracking susceptibility of these alloys. A neural network model will be developed that establishes the relationship between chemistry, microstructure, and tensile properties. This predictive capability will allow optimization of mechanical properties and improvement of manufacturability.
  • Intensive Quenching, Missouri University of Science and Technology – Laura Bartlett
    • Intensive quenching has been utilized in industrial settings to improve the formation of martensitic microstructures and improve the fatigue performance of steel. An additional benefit of intensive quenching is the elimination of size limitations from the dimensions of traditional quench tanks. Traditional methods of quenching also create the potential for quench cracking as a result of the compressive forces the steel is subjected to upon cooling. While intensive quenching is not a new technology, the goal of this project is to determine if intensive quenching is beneficial or detrimental to castings given possible inclusions, porosity, or surface roughness that may be present in castings and have the potential to act as stress risers.
  • Cost Modeling, University of Alabama – Charles Monroe
    • The ability to produce and deliver cast parts on time and with the required quality is thwarted by unexpected process complexities and associated manufacturing difficulties. A cost modeling software will be developed to predict process complexity and estimate variable costs. This project will identify possible manufacturing routes, improve the speed, quality, and predictability of production, and minimize the operation and sustainment costs through better reliability of replacement parts.
  • Modeling of Reoxidation Inclusions in Steel Castings, University of Iowa – Christoph Beckermann and Richard Hardin
    • Steel cleanliness still remains a major challenge in the steel industry. It was found that reoxidation inclusions are the major source of these inclusions. Reoxidation is the reaction of elements in liquid steel with oxygen after the molten steel has been deoxidized. Air entrainment during pouring is the main cause of reoxidation inclusions. SFSA’s Clean Steel program during the 1980’s and 1990’s has investigated the factors that affect air entrainment by conducting water modeling and several casting trials. University of Iowa (UI) is now developing a computational modeling tool that would predict the amount of air entrained during pouring and inclusion formation in steel castings. This modeling tool would help design and evaluate gating systems of steel castings.
  • Rapid Production Using Additive Manufacturing, University of Northern Iowa – Jerry Thiel
    • Rapid response and more suppliers are needed in the replacement of critical cast components for legacy weapons systems. Tooling including patterns and core boxes are often difficult to locate. New tooling for manufacturing cast metal parts is often expensive and requires significant lead-times. This project will enhance the use of AM in steel foundries by identifying the barriers and challenges with adoption of AM technologies. This project will also enhance the use of AM by improving surface finish of 3D printed sand mold castings and by developing 3D printing process for investment casting shells.
  • Workforce Development and Specifications Toolkit, SFSA
    • The steel casting industry has identified workforce development and customer education as key strategic initiatives. The objective of this project is to develop and maintain online tools that provide the essential skills and knowledge training to the next generation workforce, specification support to casting buyers and manufacturers, and to facilitate the transition of current and emerging steel technology development to Government and industry. Webinars on an extensive range of topics for foundry employees and for casting users will be presented. A web-based specification tool will also be developed and made available on the SFSA website where anyone can search and cross reference steel casting specifications or different steel grades.

Improves Forging Acquisition Manufacture and Materials (IFAMM)

  • Cast Preforms for Forging, University of Alabama at Birmingham – Robin Foley and John Griffin; University of Alabama – Charles Monroe
    • Many forgings have long lead times and high costs because the stock material required is unavailable or is poorly shaped to produce the final forging geometry. A cast preform utilizes the complex geometry of a casting combined with enhanced properties from the forging operation. This project will determine the forging reductions for cast steel preforms to realize the required properties of a forging. The objective is to reduce the reduction ratios while still meeting the required forging properties. Another application of this project is to further improve properties of some castings like ground engaging tools by forging critical areas of the castings. The use of cast preforms would expand the supply chain for low volume forged components since foundries can melt and cast in smaller batches.

Casting Solutions for Readiness (CSR)