Effects of Alloying Additions on the Liquid and Solid State Processing Characteristics of Machinable SAE 4120 Steel Grades

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9417437 Matlock This award is a "Tie" project between two Industry/University Cooperative Research Centers (I/UCRC) designed to evaluate the effects of alloy additions, added to enhance machinability of the steel, on the liquid and solid state processing characteristics of SAE 4120 alloy steel. The Industry/University Cooperative Research Center for Advanced Steel Processing and Products at Colorado School of Mines is determining the effects of alloying and solute segregation on the hot working behavior and final microstructures of the alloys. The Industry/University Cooperative Research Center for Iron and Steel Research at Carnegie Mellon University is evaluating the effects of these alloying additions in slag-metal interactions and solidification characteristics. The two efforts define independent yet collaborative studies of selected alloy additions, and the combined research creates a synergism in the understanding of machinable steels that would not be possible at either institution alone. Environmental and health concerns increase the urgency of replacing lead as an additive for enhanced machinability of steels. A number of chemical elements have potential substitutes for the lead, for example copper, niobium, bismuth, tellurium, and selenium. Some of these elements are known to adversely affect the hot shortness (a term that describes the deformability of the steel over a reasonable processing temperature), brittleness, segregation of alloying elements in the steel, solidification and casting processes, and the reaction of the steel melt with the refractory lining in the smelting furnace. Any utilization of these alloying elements as substitutes for toxic lead must be done in a manner to avoid any of the adverse situations above. Colorado School of Mines is investigating the properties of the steel and Carnegie Mellon University is investigating the melting, casting and solidification characteristics of the same experimental alloys. This c ombination of expertise addresses the complete scope of issues needed before these new alloys can become commercially viable. The Program Manager recommends Colorado School of Mines be awarded $75,000 for 36 months for this "Tie" project.