IN SITU MELT TEMPERATURE ANALYSIS DURING HIGH PRESSURE GAS ATOMIZATION OF LIQUID METALS

Abstract

Imaging of the melt plume during high pressure gas atomization (HPGA) using consumer digital single lens reflex (DSLR) equipment provides useful information about the process. Color imaging and high spatial resolution can be a useful adjunct to the more widely reported imaging using specialist high frame rate cameras. With knowledge of the camera's color response curves, the ratio of the signals in the red, green, and blue channels can be used to make spatially resolved temperature estimates of the material within the melt plume. Moreover, by combining these temperature estimates, which depend only upon intensity ratios, with the actual intensity of the optical signal, we propose that it is possible to obtain estimates of the relative surface area of the melt within the plume. This in turn can be related to the local melt fragmentation rate within the atomization plume.