低炭素鋼における大過冷却現出のための溶湯処理法の開発

抄録

High undercooling up to 98 K has been obtained by a cycle of melting and freezing. A specimen of 0.23 wt% carbon steel weighing 1.5 kg was melted in a fused alumina crucible set in a tammann furnace and it was kept at 1 893 K. Then, the granular mish metal (REM) of 18 g, which corresponds to the quantity of 1.2 wt% to the weight of the melt, was intermittently injected into the melt with Ar gas through a mulite tube which had been immersed into the melt, followed by cooling to 1 853 K. In order to promote the reaction among molten metal, mulite tube and REM, the molten metal was intermittently stirred while being kept at that temperature and then cooled in the furnace.