Effect of Surface Roughness and Surface Material of Substrate on Initial Solidification Structure of 18Cr-8Ni Stainless Steel

The effects of casting conditions as surface roughness and surface materials of the substrate, and pouring temperature on the solidification behavior and the structure of rapidly solidified 18Cr-8Ni stainless steel droplet samples have been studied. On the onset of the solidification, undercooling phenomena is observed. The undercooling linearly depends on the cooling rate, but does not on the casting conditions. Initial solidification length increases, and primary arm spacing and surface grain size decreases with increasing cooling rate. With very small cooling rate, solidification morphlogy changes from cell to dendrite. It presumably shows the change in the primary phase in the initial solidification.