The surface of Fe-3% C-2% Si alloy was rapidly melted and solidified using cw 250 W CO2 laser. The absorptivity of the alloy was estimated by comparing the values of melt depth and width of spot-melted specimens to those by FEM analysis. The determined value of absorbtivity was 50%. The relation between secondary arm spacing and average cooling rate calculated for spot-melted specimens was obtained. Using the relation, average cooling rates of scan-melted specimens were estimated to be 2×105 K·s-1 at maximum.
