Design and control of cooling rate for improving the strength of gray cast irons

The quality of gray cast iron was enhanced by controlling the cooling rate of cast iron in the manufacturing process. We have investigated the structures and properties of the gray cast irons obtained the control of the cooling rate with different mold wall thickness. The cast iron specimens were made by controlling the cooling rate in the solidification process. The mold was cylindrical in shape and made of sand. The process of the heat transfer of the materials was investigated. The heat transfer rate was considered as the radial thickness of the mold wall. The X-ray diffraction (XRD) technique was used to identify the phase and optical microscope used to study the microstructure. Optical emission spectroscopy was employed to examine the constituent of the specimens. Three gray cast irons with the mold wall thickness of 0.7, 1.5 and 2.8 inches, respectively, were casted and tested for tensile strength. The results showed that the specimens made of 1.5 inch radial mold thickness yielded the highest tensile strength.