Charles A. Monroe
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- School: University of Alabama
- Campus: Birmingham
- Department: Engineering
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1720 2nd Ave S
Birmingham, AL - 35294 - Dates at University of Alabama: -
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Biography
University of Alabama Birmingham - Engineering
Associate Professor at University of Alabama at Birmingham
Higher Education
Charlie
Monroe
Birmingham, Alabama
My interest is in solving hard problems of manufacturing processing. These problems may involve simulations / experiments, material structure / process, deterministic / chaotic results, etc. The key is to find the unsolved mysteries of science of the everyday world.
Specifically my background is in multiphase thermal stress and solidification simulation and experimentation. My goal is to research new ways to improve manufacturing process design through simulation. This requires computer tool improvement, people-to-people networking, and increase of our understanding of the governing physics of the process.
Experience
Penn State University
Student Researcher
Worked to assess the dimensional variability of steel castings. Also, surveyed and explored the Advanced Oxidants process for wet reclamation of clay for the green sand process.
University of Iowa
Research Assistant
Topic: "Solidification and mechanical modeling of hot tear formation in steel castings"
Research Project with University of Northern Iowa from 2005 - 2007 where I prepared and poured test castings for the evaluation of the hot tear models.
Research project with Caterpillar from 2004 - 2007 where I developed and transferred simulation technology to predict hot tears using ABAQUS finite element simulation.
Research project with MAGMAsoft from 2004 - 2007 where I developed and transferred simulation technology to predict hot tears using casting simulation.Ashland
Engineering Co-op
Completed engineering analysis using Arena-Flow core-blowing simulation software for prediction of sand flow. Also, measured chemically bonded sand properties in the lab.
University of Alabama at Birmingham
Assistant Professor, Department of Material Science and Engineering
Executing research, advising students, writing proposals, and teaching classes
University of Alabama at Birmingham
Associate Professor, Department of Material Science and Engineering
Charles worked at University of Alabama at Birmingham as a Associate Professor, Department of Material Science and Engineering
Caterpillar Inc.
Senior Research Engineer
Quickly resolving quality and manufacturing issues with casting designs using simulation and experience. Working with many casting designs, materials, and processes from Large Mining Trucks, Track Type, Engines, Lower Powertrain, Transmission, Air Systems, and Business Construction business units. Typical feedback included working with designers to improve manufacture, with foundries to aid in rigging design for prototypes and production, and diagnosing current process improvements.
Caterpillar Inc.
6 Sigma Black Belt
Managed teams to execute quality improvements and develop research vision
Education
Penn State University
BS
Mechanical Engineering
Graduated with Honors in Mechanical Engineering with a thesis entitled "Minimizing Entropy Production Due to Conduction in a Heat Exchanger for a Thermoacoustic Refrigerator"Penn State University
Student Researcher
Worked to assess the dimensional variability of steel castings. Also, surveyed and explored the Advanced Oxidants process for wet reclamation of clay for the green sand process.University of Iowa
MS
Mechanical Engineering
Graduated with a thesis entitled "Development of a Hot Tear Indicator for Use in Casting Simulation"University of Iowa
PhD
Mechanical Engineering
Graduated with a thesis entitled "A modeling and experimental study of deformation and hot tearing in steel"University of Iowa
Research Assistant
Topic: "Solidification and mechanical modeling of hot tear formation in steel castings" Research Project with University of Northern Iowa from 2005 - 2007 where I prepared and poured test castings for the evaluation of the hot tear models. Research project with Caterpillar from 2004 - 2007 where I developed and transferred simulation technology to predict hot tears using ABAQUS finite element simulation. Research project with MAGMAsoft from 2004 - 2007 where I developed and transferred simulation technology to predict hot tears using casting simulation.
Publications
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Filling Thin Wall Steel Castings
Steel Founders Society of America Technical and Operators Conference
Castings with thinner walls are attractive to reduce weight and improve performance especially in moving equipment. Making castings thinner in wall sections runs the risk of failing to fill the casting, poor surface finish or cold shuts and laps. Using non-dimensional analysis, the important parameters of thin wall filling are evaluated for cast steel. A new model based on a one dimensional heat transfer analysis is developed to predict the flow life and length before freezing. This model shows good agreement to steel fluidity spirals and the trend compares well to an industrial survey. The model may also be extended to other materials and filling circumstances. Using this model in casting simulation shows promise to predict the hard to fill areas of complex thin wall castings. The model can also be used to evaluate gating systems to improve filling patterns.
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Filling Thin Wall Steel Castings
Steel Founders Society of America Technical and Operators Conference
Castings with thinner walls are attractive to reduce weight and improve performance especially in moving equipment. Making castings thinner in wall sections runs the risk of failing to fill the casting, poor surface finish or cold shuts and laps. Using non-dimensional analysis, the important parameters of thin wall filling are evaluated for cast steel. A new model based on a one dimensional heat transfer analysis is developed to predict the flow life and length before freezing. This model shows good agreement to steel fluidity spirals and the trend compares well to an industrial survey. The model may also be extended to other materials and filling circumstances. Using this model in casting simulation shows promise to predict the hard to fill areas of complex thin wall castings. The model can also be used to evaluate gating systems to improve filling patterns.
Simulation of Hot Tearing and Distortion during Casting of Steel: Comparison with Experiments
Steel Founders Society of America Technical and Operators Conference
Hot tears are defects that occur during solidification of a casting that is subjected to mechanical restraints. Several key factors are known to aggravate the hot tearing of cast steel. These factors include: increasing the duration of a hot spot without increasing the feeding, increasing the strain, and increasing the solidification range through alloying elements. The effects of these factors have been evaluated during solidification through the use of a T-section test casting. The T-section test castings provide measurements of distortion and stresses during solidification and during further cooling of the casting. The results confirm previous findings and provide new data for analysis and comparison for accurate hot tear prediction.
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Filling Thin Wall Steel Castings
Steel Founders Society of America Technical and Operators Conference
Castings with thinner walls are attractive to reduce weight and improve performance especially in moving equipment. Making castings thinner in wall sections runs the risk of failing to fill the casting, poor surface finish or cold shuts and laps. Using non-dimensional analysis, the important parameters of thin wall filling are evaluated for cast steel. A new model based on a one dimensional heat transfer analysis is developed to predict the flow life and length before freezing. This model shows good agreement to steel fluidity spirals and the trend compares well to an industrial survey. The model may also be extended to other materials and filling circumstances. Using this model in casting simulation shows promise to predict the hard to fill areas of complex thin wall castings. The model can also be used to evaluate gating systems to improve filling patterns.
Simulation of Hot Tearing and Distortion during Casting of Steel: Comparison with Experiments
Steel Founders Society of America Technical and Operators Conference
Hot tears are defects that occur during solidification of a casting that is subjected to mechanical restraints. Several key factors are known to aggravate the hot tearing of cast steel. These factors include: increasing the duration of a hot spot without increasing the feeding, increasing the strain, and increasing the solidification range through alloying elements. The effects of these factors have been evaluated during solidification through the use of a T-section test casting. The T-section test castings provide measurements of distortion and stresses during solidification and during further cooling of the casting. The results confirm previous findings and provide new data for analysis and comparison for accurate hot tear prediction.
Prediction of Aluminum Nitride embrittlement in heavy section steel castings
International Journal of Metalcasting
Aluminum Nitride (AIN) embrittlement is a problem in heavier section (>4″) steel castings. AIN precipitates at higher residual aluminum and nitrogen levels and slow cooling rates. In load critical components, the formation of AIN will embrittle the casting, reducing the impact strength and ductility of the steel. The precipitation diagram for AIN from Hannerz is reviewed and his more accurate equation plotted. In addition, this information is matched to simulated cooling curves in slab castings to plot maximum aluminum content against section size to avoid embrittlement. However, these rules of thumb can be misleading in analyzing geometries without final rigging or production information like the sand properties. The most important information in predicting AIN is the cooling rates in the production setting. Therefore, the equations are incorporated into casting simulation software to use the simulated cooling curves to locate embrittled volumes. Two example castings serve to show the use of the AIN embrittlement indicator. This prediction will help to avoid AIN embrittlement in the design of heavy section steel castings and rigging.
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Filling Thin Wall Steel Castings
Steel Founders Society of America Technical and Operators Conference
Castings with thinner walls are attractive to reduce weight and improve performance especially in moving equipment. Making castings thinner in wall sections runs the risk of failing to fill the casting, poor surface finish or cold shuts and laps. Using non-dimensional analysis, the important parameters of thin wall filling are evaluated for cast steel. A new model based on a one dimensional heat transfer analysis is developed to predict the flow life and length before freezing. This model shows good agreement to steel fluidity spirals and the trend compares well to an industrial survey. The model may also be extended to other materials and filling circumstances. Using this model in casting simulation shows promise to predict the hard to fill areas of complex thin wall castings. The model can also be used to evaluate gating systems to improve filling patterns.
Simulation of Hot Tearing and Distortion during Casting of Steel: Comparison with Experiments
Steel Founders Society of America Technical and Operators Conference
Hot tears are defects that occur during solidification of a casting that is subjected to mechanical restraints. Several key factors are known to aggravate the hot tearing of cast steel. These factors include: increasing the duration of a hot spot without increasing the feeding, increasing the strain, and increasing the solidification range through alloying elements. The effects of these factors have been evaluated during solidification through the use of a T-section test casting. The T-section test castings provide measurements of distortion and stresses during solidification and during further cooling of the casting. The results confirm previous findings and provide new data for analysis and comparison for accurate hot tear prediction.
Prediction of Aluminum Nitride embrittlement in heavy section steel castings
International Journal of Metalcasting
Aluminum Nitride (AIN) embrittlement is a problem in heavier section (>4″) steel castings. AIN precipitates at higher residual aluminum and nitrogen levels and slow cooling rates. In load critical components, the formation of AIN will embrittle the casting, reducing the impact strength and ductility of the steel. The precipitation diagram for AIN from Hannerz is reviewed and his more accurate equation plotted. In addition, this information is matched to simulated cooling curves in slab castings to plot maximum aluminum content against section size to avoid embrittlement. However, these rules of thumb can be misleading in analyzing geometries without final rigging or production information like the sand properties. The most important information in predicting AIN is the cooling rates in the production setting. Therefore, the equations are incorporated into casting simulation software to use the simulated cooling curves to locate embrittled volumes. Two example castings serve to show the use of the AIN embrittlement indicator. This prediction will help to avoid AIN embrittlement in the design of heavy section steel castings and rigging.
Prediction of hot tear formation in a magnesium alloy permanent mold casting
International Journal of Metalcasting
A viscoplastic deformation model considering material damage is used to predict hot tear evolution in AZ91D magnesium alloy castings. The simulation model calculates the solid deformation and ductile damage. The viscoplastic constitutive theory accounts for temperature dependent properties and includes creep and isotropic hardening. The mechanical properties are estimated from data found in the literature. Ductile damage theory is used to find mechanically induced voiding, and hot tears are expected in regions of extensive damage. Simulations are performed for a test casting consisting of a 260 mm (10.2 in) long horizontal bar connected to a vertical sprue on one side and an anchoring flange on the other. The contraction of the horizontal bar is restrained during solidification and hot tears nucleate at the junction between the horizontal bar and the vertical sprue. The hot tearing severity is manipulated by adjusting the initial mold temperature from 140°C (284°F) to 380°C (716°F). For the simulation, a trial-and-error method is used to determine the mold-metal interfacial heat transfer coefficient from experimental thermocouple results. The simulation results suggest that the predicted damage is in agreement with the hot tears observed in the experimental castings, both in terms of location and severity. The simulation results also confirm the observed decrease in hot tear susceptibility with increasing mold temperature. These results suggest that the proposed viscoplastic model with damage shows promise for predicting hot tearing.
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Filling Thin Wall Steel Castings
Steel Founders Society of America Technical and Operators Conference
Castings with thinner walls are attractive to reduce weight and improve performance especially in moving equipment. Making castings thinner in wall sections runs the risk of failing to fill the casting, poor surface finish or cold shuts and laps. Using non-dimensional analysis, the important parameters of thin wall filling are evaluated for cast steel. A new model based on a one dimensional heat transfer analysis is developed to predict the flow life and length before freezing. This model shows good agreement to steel fluidity spirals and the trend compares well to an industrial survey. The model may also be extended to other materials and filling circumstances. Using this model in casting simulation shows promise to predict the hard to fill areas of complex thin wall castings. The model can also be used to evaluate gating systems to improve filling patterns.
Simulation of Hot Tearing and Distortion during Casting of Steel: Comparison with Experiments
Steel Founders Society of America Technical and Operators Conference
Hot tears are defects that occur during solidification of a casting that is subjected to mechanical restraints. Several key factors are known to aggravate the hot tearing of cast steel. These factors include: increasing the duration of a hot spot without increasing the feeding, increasing the strain, and increasing the solidification range through alloying elements. The effects of these factors have been evaluated during solidification through the use of a T-section test casting. The T-section test castings provide measurements of distortion and stresses during solidification and during further cooling of the casting. The results confirm previous findings and provide new data for analysis and comparison for accurate hot tear prediction.
Prediction of Aluminum Nitride embrittlement in heavy section steel castings
International Journal of Metalcasting
Aluminum Nitride (AIN) embrittlement is a problem in heavier section (>4″) steel castings. AIN precipitates at higher residual aluminum and nitrogen levels and slow cooling rates. In load critical components, the formation of AIN will embrittle the casting, reducing the impact strength and ductility of the steel. The precipitation diagram for AIN from Hannerz is reviewed and his more accurate equation plotted. In addition, this information is matched to simulated cooling curves in slab castings to plot maximum aluminum content against section size to avoid embrittlement. However, these rules of thumb can be misleading in analyzing geometries without final rigging or production information like the sand properties. The most important information in predicting AIN is the cooling rates in the production setting. Therefore, the equations are incorporated into casting simulation software to use the simulated cooling curves to locate embrittled volumes. Two example castings serve to show the use of the AIN embrittlement indicator. This prediction will help to avoid AIN embrittlement in the design of heavy section steel castings and rigging.
Prediction of hot tear formation in a magnesium alloy permanent mold casting
International Journal of Metalcasting
A viscoplastic deformation model considering material damage is used to predict hot tear evolution in AZ91D magnesium alloy castings. The simulation model calculates the solid deformation and ductile damage. The viscoplastic constitutive theory accounts for temperature dependent properties and includes creep and isotropic hardening. The mechanical properties are estimated from data found in the literature. Ductile damage theory is used to find mechanically induced voiding, and hot tears are expected in regions of extensive damage. Simulations are performed for a test casting consisting of a 260 mm (10.2 in) long horizontal bar connected to a vertical sprue on one side and an anchoring flange on the other. The contraction of the horizontal bar is restrained during solidification and hot tears nucleate at the junction between the horizontal bar and the vertical sprue. The hot tearing severity is manipulated by adjusting the initial mold temperature from 140°C (284°F) to 380°C (716°F). For the simulation, a trial-and-error method is used to determine the mold-metal interfacial heat transfer coefficient from experimental thermocouple results. The simulation results suggest that the predicted damage is in agreement with the hot tears observed in the experimental castings, both in terms of location and severity. The simulation results also confirm the observed decrease in hot tear susceptibility with increasing mold temperature. These results suggest that the proposed viscoplastic model with damage shows promise for predicting hot tearing.
Development of a hot tear indicator for steel castings
Materials Science and Engineering A
A hot tear indicator based on the physics of solidification and deformation is presented. This indicator is derived using available data from computer simulation of solidification and solid deformation. Hot tears form when the mushy zone is starved of liquid feeding and deformed in tension. The unfed tensile deformation causes a small additional porosity. A physical model based on a mass balance is developed to find the additional porosity formed. This additional porosity or porosity due to solid deformation (PSD) is a locator for initiation sites for hot tears in the casting, not a full tear predictor. Simulation results for various “T”-shaped steel castings show good agreement with previous experimental findings. Reducing the strain in the casting and increasing the feeding of the section are found to decrease the hot tear tendency.
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Filling Thin Wall Steel Castings
Steel Founders Society of America Technical and Operators Conference
Castings with thinner walls are attractive to reduce weight and improve performance especially in moving equipment. Making castings thinner in wall sections runs the risk of failing to fill the casting, poor surface finish or cold shuts and laps. Using non-dimensional analysis, the important parameters of thin wall filling are evaluated for cast steel. A new model based on a one dimensional heat transfer analysis is developed to predict the flow life and length before freezing. This model shows good agreement to steel fluidity spirals and the trend compares well to an industrial survey. The model may also be extended to other materials and filling circumstances. Using this model in casting simulation shows promise to predict the hard to fill areas of complex thin wall castings. The model can also be used to evaluate gating systems to improve filling patterns.
Simulation of Hot Tearing and Distortion during Casting of Steel: Comparison with Experiments
Steel Founders Society of America Technical and Operators Conference
Hot tears are defects that occur during solidification of a casting that is subjected to mechanical restraints. Several key factors are known to aggravate the hot tearing of cast steel. These factors include: increasing the duration of a hot spot without increasing the feeding, increasing the strain, and increasing the solidification range through alloying elements. The effects of these factors have been evaluated during solidification through the use of a T-section test casting. The T-section test castings provide measurements of distortion and stresses during solidification and during further cooling of the casting. The results confirm previous findings and provide new data for analysis and comparison for accurate hot tear prediction.
Prediction of Aluminum Nitride embrittlement in heavy section steel castings
International Journal of Metalcasting
Aluminum Nitride (AIN) embrittlement is a problem in heavier section (>4″) steel castings. AIN precipitates at higher residual aluminum and nitrogen levels and slow cooling rates. In load critical components, the formation of AIN will embrittle the casting, reducing the impact strength and ductility of the steel. The precipitation diagram for AIN from Hannerz is reviewed and his more accurate equation plotted. In addition, this information is matched to simulated cooling curves in slab castings to plot maximum aluminum content against section size to avoid embrittlement. However, these rules of thumb can be misleading in analyzing geometries without final rigging or production information like the sand properties. The most important information in predicting AIN is the cooling rates in the production setting. Therefore, the equations are incorporated into casting simulation software to use the simulated cooling curves to locate embrittled volumes. Two example castings serve to show the use of the AIN embrittlement indicator. This prediction will help to avoid AIN embrittlement in the design of heavy section steel castings and rigging.
Prediction of hot tear formation in a magnesium alloy permanent mold casting
International Journal of Metalcasting
A viscoplastic deformation model considering material damage is used to predict hot tear evolution in AZ91D magnesium alloy castings. The simulation model calculates the solid deformation and ductile damage. The viscoplastic constitutive theory accounts for temperature dependent properties and includes creep and isotropic hardening. The mechanical properties are estimated from data found in the literature. Ductile damage theory is used to find mechanically induced voiding, and hot tears are expected in regions of extensive damage. Simulations are performed for a test casting consisting of a 260 mm (10.2 in) long horizontal bar connected to a vertical sprue on one side and an anchoring flange on the other. The contraction of the horizontal bar is restrained during solidification and hot tears nucleate at the junction between the horizontal bar and the vertical sprue. The hot tearing severity is manipulated by adjusting the initial mold temperature from 140°C (284°F) to 380°C (716°F). For the simulation, a trial-and-error method is used to determine the mold-metal interfacial heat transfer coefficient from experimental thermocouple results. The simulation results suggest that the predicted damage is in agreement with the hot tears observed in the experimental castings, both in terms of location and severity. The simulation results also confirm the observed decrease in hot tear susceptibility with increasing mold temperature. These results suggest that the proposed viscoplastic model with damage shows promise for predicting hot tearing.
Development of a hot tear indicator for steel castings
Materials Science and Engineering A
A hot tear indicator based on the physics of solidification and deformation is presented. This indicator is derived using available data from computer simulation of solidification and solid deformation. Hot tears form when the mushy zone is starved of liquid feeding and deformed in tension. The unfed tensile deformation causes a small additional porosity. A physical model based on a mass balance is developed to find the additional porosity formed. This additional porosity or porosity due to solid deformation (PSD) is a locator for initiation sites for hot tears in the casting, not a full tear predictor. Simulation results for various “T”-shaped steel castings show good agreement with previous experimental findings. Reducing the strain in the casting and increasing the feeding of the section are found to decrease the hot tear tendency.
A geometric algorithm for automatic riser determination and shrinkage identification in directionally solidifying castings
IOP Conference Series: Materials Science and Engineering vol 84
A geometric approach for analysis of castings is outlined and contrasted with physics-based simulations. The approach uses a linear-time algorithm to create an implicit geometry representation known as a distance field. Local maxima are extracted from the distance field using heuristic search logic to determine isolated heavy sections and hotspots. Unsound sections are determined by combining hotspot results with regions of constant distance-field value. Possible uses of the algorithm as an augmentation for application of physics-based solvers is explored. The algorithm is compared against a commercially available simulation software package.
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Filling Thin Wall Steel Castings
Steel Founders Society of America Technical and Operators Conference
Castings with thinner walls are attractive to reduce weight and improve performance especially in moving equipment. Making castings thinner in wall sections runs the risk of failing to fill the casting, poor surface finish or cold shuts and laps. Using non-dimensional analysis, the important parameters of thin wall filling are evaluated for cast steel. A new model based on a one dimensional heat transfer analysis is developed to predict the flow life and length before freezing. This model shows good agreement to steel fluidity spirals and the trend compares well to an industrial survey. The model may also be extended to other materials and filling circumstances. Using this model in casting simulation shows promise to predict the hard to fill areas of complex thin wall castings. The model can also be used to evaluate gating systems to improve filling patterns.
Simulation of Hot Tearing and Distortion during Casting of Steel: Comparison with Experiments
Steel Founders Society of America Technical and Operators Conference
Hot tears are defects that occur during solidification of a casting that is subjected to mechanical restraints. Several key factors are known to aggravate the hot tearing of cast steel. These factors include: increasing the duration of a hot spot without increasing the feeding, increasing the strain, and increasing the solidification range through alloying elements. The effects of these factors have been evaluated during solidification through the use of a T-section test casting. The T-section test castings provide measurements of distortion and stresses during solidification and during further cooling of the casting. The results confirm previous findings and provide new data for analysis and comparison for accurate hot tear prediction.
Prediction of Aluminum Nitride embrittlement in heavy section steel castings
International Journal of Metalcasting
Aluminum Nitride (AIN) embrittlement is a problem in heavier section (>4″) steel castings. AIN precipitates at higher residual aluminum and nitrogen levels and slow cooling rates. In load critical components, the formation of AIN will embrittle the casting, reducing the impact strength and ductility of the steel. The precipitation diagram for AIN from Hannerz is reviewed and his more accurate equation plotted. In addition, this information is matched to simulated cooling curves in slab castings to plot maximum aluminum content against section size to avoid embrittlement. However, these rules of thumb can be misleading in analyzing geometries without final rigging or production information like the sand properties. The most important information in predicting AIN is the cooling rates in the production setting. Therefore, the equations are incorporated into casting simulation software to use the simulated cooling curves to locate embrittled volumes. Two example castings serve to show the use of the AIN embrittlement indicator. This prediction will help to avoid AIN embrittlement in the design of heavy section steel castings and rigging.
Prediction of hot tear formation in a magnesium alloy permanent mold casting
International Journal of Metalcasting
A viscoplastic deformation model considering material damage is used to predict hot tear evolution in AZ91D magnesium alloy castings. The simulation model calculates the solid deformation and ductile damage. The viscoplastic constitutive theory accounts for temperature dependent properties and includes creep and isotropic hardening. The mechanical properties are estimated from data found in the literature. Ductile damage theory is used to find mechanically induced voiding, and hot tears are expected in regions of extensive damage. Simulations are performed for a test casting consisting of a 260 mm (10.2 in) long horizontal bar connected to a vertical sprue on one side and an anchoring flange on the other. The contraction of the horizontal bar is restrained during solidification and hot tears nucleate at the junction between the horizontal bar and the vertical sprue. The hot tearing severity is manipulated by adjusting the initial mold temperature from 140°C (284°F) to 380°C (716°F). For the simulation, a trial-and-error method is used to determine the mold-metal interfacial heat transfer coefficient from experimental thermocouple results. The simulation results suggest that the predicted damage is in agreement with the hot tears observed in the experimental castings, both in terms of location and severity. The simulation results also confirm the observed decrease in hot tear susceptibility with increasing mold temperature. These results suggest that the proposed viscoplastic model with damage shows promise for predicting hot tearing.
Development of a hot tear indicator for steel castings
Materials Science and Engineering A
A hot tear indicator based on the physics of solidification and deformation is presented. This indicator is derived using available data from computer simulation of solidification and solid deformation. Hot tears form when the mushy zone is starved of liquid feeding and deformed in tension. The unfed tensile deformation causes a small additional porosity. A physical model based on a mass balance is developed to find the additional porosity formed. This additional porosity or porosity due to solid deformation (PSD) is a locator for initiation sites for hot tears in the casting, not a full tear predictor. Simulation results for various “T”-shaped steel castings show good agreement with previous experimental findings. Reducing the strain in the casting and increasing the feeding of the section are found to decrease the hot tear tendency.
A geometric algorithm for automatic riser determination and shrinkage identification in directionally solidifying castings
IOP Conference Series: Materials Science and Engineering vol 84
A geometric approach for analysis of castings is outlined and contrasted with physics-based simulations. The approach uses a linear-time algorithm to create an implicit geometry representation known as a distance field. Local maxima are extracted from the distance field using heuristic search logic to determine isolated heavy sections and hotspots. Unsound sections are determined by combining hotspot results with regions of constant distance-field value. Possible uses of the algorithm as an augmentation for application of physics-based solvers is explored. The algorithm is compared against a commercially available simulation software package.
Prediction of hot tear defects in steel castings using a damage based model
Proceedings from the 12th International Conference on Modeling of Casting, Welding, and Advanced Solidification Processes
Caterpillar has been collaborating with suppliers to analyze steel castings for the tendency to form hot tears using a newly developed damage-based model. The implementation and application of the damage-based hot tear model is presented. The implementation is through an uncoupled simulation of the solidification and deformation problems using commercial software with a user-defined constitutive model. However, the liquid feeding and shrinkage porosity information is coupled to the solid deformation constitutive model to calculate the material damage. Hot tears should then initiate at locations where significant damage is predicted. Two industrial case studies are presented that demonstrate the effectiveness of the hot tear model at predicting the locations where hot tears form. Good correlation with indications on castings is observed. Using this new model and collaborating with foundries, part geometry can be modified or casting process changes can be identified before designs are finalized and production begins, reducing the likelihood of hot tear issues occurring.
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Filling Thin Wall Steel Castings
Steel Founders Society of America Technical and Operators Conference
Castings with thinner walls are attractive to reduce weight and improve performance especially in moving equipment. Making castings thinner in wall sections runs the risk of failing to fill the casting, poor surface finish or cold shuts and laps. Using non-dimensional analysis, the important parameters of thin wall filling are evaluated for cast steel. A new model based on a one dimensional heat transfer analysis is developed to predict the flow life and length before freezing. This model shows good agreement to steel fluidity spirals and the trend compares well to an industrial survey. The model may also be extended to other materials and filling circumstances. Using this model in casting simulation shows promise to predict the hard to fill areas of complex thin wall castings. The model can also be used to evaluate gating systems to improve filling patterns.
Simulation of Hot Tearing and Distortion during Casting of Steel: Comparison with Experiments
Steel Founders Society of America Technical and Operators Conference
Hot tears are defects that occur during solidification of a casting that is subjected to mechanical restraints. Several key factors are known to aggravate the hot tearing of cast steel. These factors include: increasing the duration of a hot spot without increasing the feeding, increasing the strain, and increasing the solidification range through alloying elements. The effects of these factors have been evaluated during solidification through the use of a T-section test casting. The T-section test castings provide measurements of distortion and stresses during solidification and during further cooling of the casting. The results confirm previous findings and provide new data for analysis and comparison for accurate hot tear prediction.
Prediction of Aluminum Nitride embrittlement in heavy section steel castings
International Journal of Metalcasting
Aluminum Nitride (AIN) embrittlement is a problem in heavier section (>4″) steel castings. AIN precipitates at higher residual aluminum and nitrogen levels and slow cooling rates. In load critical components, the formation of AIN will embrittle the casting, reducing the impact strength and ductility of the steel. The precipitation diagram for AIN from Hannerz is reviewed and his more accurate equation plotted. In addition, this information is matched to simulated cooling curves in slab castings to plot maximum aluminum content against section size to avoid embrittlement. However, these rules of thumb can be misleading in analyzing geometries without final rigging or production information like the sand properties. The most important information in predicting AIN is the cooling rates in the production setting. Therefore, the equations are incorporated into casting simulation software to use the simulated cooling curves to locate embrittled volumes. Two example castings serve to show the use of the AIN embrittlement indicator. This prediction will help to avoid AIN embrittlement in the design of heavy section steel castings and rigging.
Prediction of hot tear formation in a magnesium alloy permanent mold casting
International Journal of Metalcasting
A viscoplastic deformation model considering material damage is used to predict hot tear evolution in AZ91D magnesium alloy castings. The simulation model calculates the solid deformation and ductile damage. The viscoplastic constitutive theory accounts for temperature dependent properties and includes creep and isotropic hardening. The mechanical properties are estimated from data found in the literature. Ductile damage theory is used to find mechanically induced voiding, and hot tears are expected in regions of extensive damage. Simulations are performed for a test casting consisting of a 260 mm (10.2 in) long horizontal bar connected to a vertical sprue on one side and an anchoring flange on the other. The contraction of the horizontal bar is restrained during solidification and hot tears nucleate at the junction between the horizontal bar and the vertical sprue. The hot tearing severity is manipulated by adjusting the initial mold temperature from 140°C (284°F) to 380°C (716°F). For the simulation, a trial-and-error method is used to determine the mold-metal interfacial heat transfer coefficient from experimental thermocouple results. The simulation results suggest that the predicted damage is in agreement with the hot tears observed in the experimental castings, both in terms of location and severity. The simulation results also confirm the observed decrease in hot tear susceptibility with increasing mold temperature. These results suggest that the proposed viscoplastic model with damage shows promise for predicting hot tearing.
Development of a hot tear indicator for steel castings
Materials Science and Engineering A
A hot tear indicator based on the physics of solidification and deformation is presented. This indicator is derived using available data from computer simulation of solidification and solid deformation. Hot tears form when the mushy zone is starved of liquid feeding and deformed in tension. The unfed tensile deformation causes a small additional porosity. A physical model based on a mass balance is developed to find the additional porosity formed. This additional porosity or porosity due to solid deformation (PSD) is a locator for initiation sites for hot tears in the casting, not a full tear predictor. Simulation results for various “T”-shaped steel castings show good agreement with previous experimental findings. Reducing the strain in the casting and increasing the feeding of the section are found to decrease the hot tear tendency.
A geometric algorithm for automatic riser determination and shrinkage identification in directionally solidifying castings
IOP Conference Series: Materials Science and Engineering vol 84
A geometric approach for analysis of castings is outlined and contrasted with physics-based simulations. The approach uses a linear-time algorithm to create an implicit geometry representation known as a distance field. Local maxima are extracted from the distance field using heuristic search logic to determine isolated heavy sections and hotspots. Unsound sections are determined by combining hotspot results with regions of constant distance-field value. Possible uses of the algorithm as an augmentation for application of physics-based solvers is explored. The algorithm is compared against a commercially available simulation software package.
Prediction of hot tear defects in steel castings using a damage based model
Proceedings from the 12th International Conference on Modeling of Casting, Welding, and Advanced Solidification Processes
Caterpillar has been collaborating with suppliers to analyze steel castings for the tendency to form hot tears using a newly developed damage-based model. The implementation and application of the damage-based hot tear model is presented. The implementation is through an uncoupled simulation of the solidification and deformation problems using commercial software with a user-defined constitutive model. However, the liquid feeding and shrinkage porosity information is coupled to the solid deformation constitutive model to calculate the material damage. Hot tears should then initiate at locations where significant damage is predicted. Two industrial case studies are presented that demonstrate the effectiveness of the hot tear model at predicting the locations where hot tears form. Good correlation with indications on castings is observed. Using this new model and collaborating with foundries, part geometry can be modified or casting process changes can be identified before designs are finalized and production begins, reducing the likelihood of hot tear issues occurring.
Simulation of deformation and hot tear formation using a visco-plastic model with damage
Proceedings from the 12th International Conference on Modeling of Casting, Welding, and Advanced Solidification Processes
A three-phase model is presented that predicts solid deformation and damage as well as melt pressure, feeding flow and shrinkage porosity during metal casting. A visco-plastic constitutive theory with damage is used to model the solid deformation. Damage created by mechanically induced voiding is used as a hot tear indicator. The absence of liquid feeding determines when damage starts to form. The model has been implemented in general-purpose simulation codes. Novel steel casting experiments have been designed and performed which measure the deformation and force from solidification to shakeout. The measured and predicted deformations show generally good agreement with the simulation results. Furthermore, the damage predictions show good correspondence with hot tear indications on a radiograph of the test casting.
Simulation of stresses during casting of binary magnesium-aluminum alloys
Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
A viscoplastic stress model is used to predict contraction forces measured during casting of two binary Mg-Al alloys. Force measurements from castings that did not hot tear, together with estimates from data found in the literature, are used to obtain the high-temperature mechanical properties needed in the stress model. In the absence of hot tearing, the simulation results show reasonably good agreement with the measurements. It is found that coherency of the semisolid mush starts at a solid fraction of about 0.5 and that the maximum tensile strength for the Mg-1 and 9 wt pct Al alloys at their final solidification temperatures is 1.5 and 4 MPa, respectively. In the presence of hot tearing, the measured stresses are generally overpredicted, which is attributed to the lack of a fracture model for the mush. Based on the comparison of measured and predicted stresses, it is also shown that coupling of the stress model to feeding flow and macrosegregation calculations is needed in order to accurately predict stresses in the presence of hot tearing.
Filling Thin Wall Steel Castings
Steel Founders Society of America Technical and Operators Conference
Castings with thinner walls are attractive to reduce weight and improve performance especially in moving equipment. Making castings thinner in wall sections runs the risk of failing to fill the casting, poor surface finish or cold shuts and laps. Using non-dimensional analysis, the important parameters of thin wall filling are evaluated for cast steel. A new model based on a one dimensional heat transfer analysis is developed to predict the flow life and length before freezing. This model shows good agreement to steel fluidity spirals and the trend compares well to an industrial survey. The model may also be extended to other materials and filling circumstances. Using this model in casting simulation shows promise to predict the hard to fill areas of complex thin wall castings. The model can also be used to evaluate gating systems to improve filling patterns.
Simulation of Hot Tearing and Distortion during Casting of Steel: Comparison with Experiments
Steel Founders Society of America Technical and Operators Conference
Hot tears are defects that occur during solidification of a casting that is subjected to mechanical restraints. Several key factors are known to aggravate the hot tearing of cast steel. These factors include: increasing the duration of a hot spot without increasing the feeding, increasing the strain, and increasing the solidification range through alloying elements. The effects of these factors have been evaluated during solidification through the use of a T-section test casting. The T-section test castings provide measurements of distortion and stresses during solidification and during further cooling of the casting. The results confirm previous findings and provide new data for analysis and comparison for accurate hot tear prediction.
Prediction of Aluminum Nitride embrittlement in heavy section steel castings
International Journal of Metalcasting
Aluminum Nitride (AIN) embrittlement is a problem in heavier section (>4″) steel castings. AIN precipitates at higher residual aluminum and nitrogen levels and slow cooling rates. In load critical components, the formation of AIN will embrittle the casting, reducing the impact strength and ductility of the steel. The precipitation diagram for AIN from Hannerz is reviewed and his more accurate equation plotted. In addition, this information is matched to simulated cooling curves in slab castings to plot maximum aluminum content against section size to avoid embrittlement. However, these rules of thumb can be misleading in analyzing geometries without final rigging or production information like the sand properties. The most important information in predicting AIN is the cooling rates in the production setting. Therefore, the equations are incorporated into casting simulation software to use the simulated cooling curves to locate embrittled volumes. Two example castings serve to show the use of the AIN embrittlement indicator. This prediction will help to avoid AIN embrittlement in the design of heavy section steel castings and rigging.
Prediction of hot tear formation in a magnesium alloy permanent mold casting
International Journal of Metalcasting
A viscoplastic deformation model considering material damage is used to predict hot tear evolution in AZ91D magnesium alloy castings. The simulation model calculates the solid deformation and ductile damage. The viscoplastic constitutive theory accounts for temperature dependent properties and includes creep and isotropic hardening. The mechanical properties are estimated from data found in the literature. Ductile damage theory is used to find mechanically induced voiding, and hot tears are expected in regions of extensive damage. Simulations are performed for a test casting consisting of a 260 mm (10.2 in) long horizontal bar connected to a vertical sprue on one side and an anchoring flange on the other. The contraction of the horizontal bar is restrained during solidification and hot tears nucleate at the junction between the horizontal bar and the vertical sprue. The hot tearing severity is manipulated by adjusting the initial mold temperature from 140°C (284°F) to 380°C (716°F). For the simulation, a trial-and-error method is used to determine the mold-metal interfacial heat transfer coefficient from experimental thermocouple results. The simulation results suggest that the predicted damage is in agreement with the hot tears observed in the experimental castings, both in terms of location and severity. The simulation results also confirm the observed decrease in hot tear susceptibility with increasing mold temperature. These results suggest that the proposed viscoplastic model with damage shows promise for predicting hot tearing.
Development of a hot tear indicator for steel castings
Materials Science and Engineering A
A hot tear indicator based on the physics of solidification and deformation is presented. This indicator is derived using available data from computer simulation of solidification and solid deformation. Hot tears form when the mushy zone is starved of liquid feeding and deformed in tension. The unfed tensile deformation causes a small additional porosity. A physical model based on a mass balance is developed to find the additional porosity formed. This additional porosity or porosity due to solid deformation (PSD) is a locator for initiation sites for hot tears in the casting, not a full tear predictor. Simulation results for various “T”-shaped steel castings show good agreement with previous experimental findings. Reducing the strain in the casting and increasing the feeding of the section are found to decrease the hot tear tendency.
A geometric algorithm for automatic riser determination and shrinkage identification in directionally solidifying castings
IOP Conference Series: Materials Science and Engineering vol 84
A geometric approach for analysis of castings is outlined and contrasted with physics-based simulations. The approach uses a linear-time algorithm to create an implicit geometry representation known as a distance field. Local maxima are extracted from the distance field using heuristic search logic to determine isolated heavy sections and hotspots. Unsound sections are determined by combining hotspot results with regions of constant distance-field value. Possible uses of the algorithm as an augmentation for application of physics-based solvers is explored. The algorithm is compared against a commercially available simulation software package.
Prediction of hot tear defects in steel castings using a damage based model
Proceedings from the 12th International Conference on Modeling of Casting, Welding, and Advanced Solidification Processes
Caterpillar has been collaborating with suppliers to analyze steel castings for the tendency to form hot tears using a newly developed damage-based model. The implementation and application of the damage-based hot tear model is presented. The implementation is through an uncoupled simulation of the solidification and deformation problems using commercial software with a user-defined constitutive model. However, the liquid feeding and shrinkage porosity information is coupled to the solid deformation constitutive model to calculate the material damage. Hot tears should then initiate at locations where significant damage is predicted. Two industrial case studies are presented that demonstrate the effectiveness of the hot tear model at predicting the locations where hot tears form. Good correlation with indications on castings is observed. Using this new model and collaborating with foundries, part geometry can be modified or casting process changes can be identified before designs are finalized and production begins, reducing the likelihood of hot tear issues occurring.
Simulation of deformation and hot tear formation using a visco-plastic model with damage
Proceedings from the 12th International Conference on Modeling of Casting, Welding, and Advanced Solidification Processes
A three-phase model is presented that predicts solid deformation and damage as well as melt pressure, feeding flow and shrinkage porosity during metal casting. A visco-plastic constitutive theory with damage is used to model the solid deformation. Damage created by mechanically induced voiding is used as a hot tear indicator. The absence of liquid feeding determines when damage starts to form. The model has been implemented in general-purpose simulation codes. Novel steel casting experiments have been designed and performed which measure the deformation and force from solidification to shakeout. The measured and predicted deformations show generally good agreement with the simulation results. Furthermore, the damage predictions show good correspondence with hot tear indications on a radiograph of the test casting.
Observations of Microstructure and Properties in Cast Iron from Historical Experiments and Thermodynamic Modeling
2015 TMS Annual Meeting & Exhibition, Orlando, FL
Cast iron containing graphite morphologies including lamellar, vermicular, and spheroidal have been characterized over the last 100 years by experimental tests of physical and thermo-physical properties. A review of these heats of material gathered from papers published with data has been compared with a thermodynamic properties prediction code. The purpose of this work is to establish a baseline for cast iron properties with given chemistry, as a starting point for evaluating the affect of metal casting processing not included in thermodynamic modeling. These processing variables may include inoculation, cooling rate, kinetic effects currently not included in these models. Many of the established relationships can be seen as input from chemistry principally such as the decrease in ultimate strength with increasing carbon content. Further property prediction such as for nondestructive tests such as resonant frequency or ultrasonic velocity shows promise from these relationships.