Abstract: Provided herein is a heating apparatus for developing a latent impact mark. The heating apparatus includes: a sample treated with an amino acid reagent containing amino acids capable of reacting with a latent impact mark; a first heating plate having a plate shape, having a first steam hole in a lower surface thereof, the first steam hole allowing steam to be discharged therethrough, and capable of being heated to a predetermined temperature; a second heating plate having a plate shape, having a second steam hole in an upper surface thereof, the second steam hole allowing steam to be discharged therethrough, and capable of being heated to a predetermined temperature; and a connecting portion configured to connect the first heating plate to the second heating plate such that the first heating plate is rotatable with respect to the second heating plate.

Abstract: This invention provides a method and apparatus to produce metal or alloy ingots using spray casting with the features of easy manufacture of large diameter ingots and simultaneously their uniform microstructure due to followings. Firstly, spray deposition area on the top surface of the ingot can be enlarged by making use of multiple gas atomizers and also by controlling the their positions for the spray deposition. Secondly, at the same time, a mutually opposite-directional rotation between the gas atomizers and the catching plate provides a uniform deposition of sprayed droplets along the circumference-wise direction over the entire top surface of the ingot. In addition, a mutually opposite-directional reciprocation between the gas atomizer and the top surface of the ingot provides an enlargement of deposition area and an evenness of spray deposition along the radial direction on the top surface of the ingot.