EFFECTS OF THE RECASTING ON THE PHYSICAL PROPERTIES OF Ni-Cr BASED ALLOY FOR FUSED PORCELAIN

도재소부용(陶材燒付用) Ni-Cr 합금(合金)의 재주조(再鑄造)가 물리적(物理的) 성질(性質)에 미치는 영향(影響)에 관(關)한 연구(硏究)

Some physical properties of Ni-Cr based alloy for porcelain veneering were compared after repeated casting without the addition of any new alloy. The specimen were cast in a centrifugal caster with an oxygen-propane torch at optimum temperature. The obtained results were as follows: 1. The yield strength and hardness of the second generation were no significant differences compared with first generation but the yield strength and hardness of the third generation slightly decrased. 2. The ultimate tensile strength and elongation appeared to decrease slightly in second, third generations. 3. The tensile fractured facets of the first generation specimen were normal in all specimen, but in the second generation there were six tensile specimen out of ten, in the third there were four tensile specimen out of ten.