High-Strength Cast Iron Castings Produced by Engineered Cooling (14-15#03) Phase 2

The possibility of development of high-strength ductile iron castings in the as-cast condition by applying an engineered cooling was investigated for three processes: cast into massive sand molds, cast into thin shell molds and continuously cast bars. A bench-scale cooling device that included fine spray wide angle nozzles that are operated by computer-controlled solenoid valves was used. The temperature of the casting was monitored by an infrared pyrometer. Engineered cooling was applied to castings shaken out early from a sand mold, through a thin shell mold without shakeout, and directly on the surface of continuously cast bars. The computational fluid dynamic (CFD) simulation models were developed for these cases, and the process parameters were experimentally investigated for different casting geometries: plates, bars, box-type castings with internal cores and turbochargers. The results of several experimental heats with cooling parameter variations are illustrated by microstructures and tensile tests performed on samples taken from the experimental castings. The possible strengthening level and process limitations are discussed.