METAL CASTING 
Project Fact Sheet 
YIELD IMPROVEMENT AND DEFECT REDUCTION IN 



 




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ENABLING PRODUCTION OF HIGHER QUALITY STEEL CASTINGS 
Most steel foundries must melt about twice as much steel as will be shipped as 
finished product. The additional metal is primarily present in risers, which provide 
feed metal that helps prevent holes or voids from forming inside the casting as it 
solidifies. This research is identifying techniques for decreasing the size and 
number of risers required to produce quality castings. It will also develop models 
to predict the formation, growth and motion of re-oxidation inclusions during the 
pouring of steel castings. 
The University of Iowa and industry partners will develop new feeding rules for 
high alloy steel castings by conducting a limited amount of high alloy casting 
trials, and then correlating the results of these trials with extensive casting 
simulation. The project will also look at unconventional yield improvement and 
defect reduction techniques, examining both riser pressurization and filling with a 
tilting mold. Optimizing the method for riser pressurization will reduce shrinkage 
porosity defects and increase yields in steel castings. Tilting the mold during 
filling will enable metal to flow smoothly into the cavity, creating less splashing 
and air entrainment. This will lessen the formation of troublesome re-oxidation 
inclusions that normally occur in castings created with a typical gravity pour 
through the sprue. Finally, this research will develop models to predict the 
formation of re-oxidation inclusions during the pouring of steel castings, the 
subsequent advection and buoyant movement of the inclusions, and their final 
characteristics and location in the solidified casting. This will result in substantial 
benefits to steel foundries, primarily due to the ability to redesign the metal 
delivery system to avoid inclusions before any castings are actually poured. 



	

 


 
Numerical simulation results for a steel valve indicate the presence of 
microporosity, as was found in the gasket. 
OFFICE OF INDUSTRIAL TECHNOLOGIES 
ENERGY EFFICIENCY AND RENEWABLE ENERGY • U.S. DEPARTMENT OF ENERGY

	

 
Goals: To develop techniques that will improve casting yield by 10% from current 
practices while maintaining quality, and to develop techniques that will improve 
yield by 25% on an optimized casting system. Specific objectives are to: 
• Develop new feeding rules for risering of high-alloy steel castings and provide 
the new rules to foundries through a new manual for risering of high alloy steel 
castings. 
• Develop yield improvement and defect reduction technologies for steel casting 
including (i) riser pressurization and (ii) filling with a tilting mold. 
• Develop a model for the prediction of re-oxidation inclusion formation during 
steel casting. 







 
• Research to date has established new feeding rules for the risering of carbon/ 
low-alloy steel castings. This work resulted in more consistent and widely 
applicable feeding rules that can improve casting yield by up to 10%. These 
low-alloy feeding rules have been published in a new risering manual for lowalloy 
steel castings. 
• Preliminary casting trials were performed at several foundries using high-alloy 
steel. These trials indicated that the presently available feeding rules for highalloy 
steel are overly conservative and too limited in scope. 
• In the current project, feeding rules for high-alloy steel will be developed 
through casting trials and computer simulation. Yield improvements with these 
new rules are expected to be of the same order as for the new low-alloy rules 
mentioned above. The new high-alloy rules will be written into a new risering 
manual for high-alloy steel castings. 
• Casting trials performed at Harrison Steel Castings investigated the external 
application of pressure, in the form of compressed argon, to the riser during 
solidification to improve the feeding of steel castings. This pilot study laid the 
groundwork for this portion of the project. Riser pressurization has been 
reported to increase feeding distances in the casting of low-carbon steel, cast 
irons, and aluminum alloys using both permanent and sand molds. With 
increased feeding distances, the occurrence of shrinkage defects is reduced 
and the casting yield is improved. 
• Unconventional and defect-reduction techniques will be developed through 
studies of riser pressurization and filling with a tilting mold. This will be 
conducted through various trials and simulations, using both simple shape 
castings and actual production castings. 
• After a thorough literature review, researchers will develop models to predict re- 
oxidation inclusion formation, growth and motion during steel casting. Results 
from the model will be tested through actual casting trials. 


	

 
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