To efficiently produce an Ni-Ti alloy having an objective compsn. with high precision by adding metallic Ti to metallic Ni melted in a crucible with specified inside diameter obtd. by stamping a calcia granulated body contg. a specified amt. of CaO onto the inside of a refractory vessel to a specified thickness.
A high purity calcia granulated body contg. CaO such as electromelted calcia by ≥93 wt.% is stamped onto the inside of a refractory vessel so as to regulate the thickness to ≥30 mm and the inside diameter to ≥50% the outside diameter without using a binder to obtain a crucible increased in the frequency of services without generating cracking. As the calcia granulated body, a calcia melted clinker with 2 to 8 mm particle size composed of 30 to 80 wt.% coarse particle content, and the balance fine particle content is preferably used. This crucible is charged with metallic Ni, which is melted in a high frequency vacuum furnace, and to the melted Ni, a prescribed amt. of metallic Ti is added to melt so as to be divided for plural times. In this way, the high quality Ni-Ti alloy having the objective compsn. of, by weight, ≤0.02% C, ≤0.002% Mg and Ni+Ti>99.3% can be melted at a low cost.
YAMAUCHI TAKASHI
SAWASHIGE KOSUKE
