The purpose of this study is to clarify the effects on the mechanical properties of two Ni-Cr base alloys for porcelain veneering in relation to the casting method by testing the specimen in three different ways.
The specimen were cast in a centrifugal caster with an Oxygen-propane torch at optimum and 100℃ overheated temperature, and also with an argon arc melting vacuum and pressure casting machine.
The results obtained were as follows:
1. The yield strength and Ultimate tensile strength after casting were higher in the optimum temperature than in the overheated specimen. Whereas, the overheated and argon arc casting were similar.
2. When the specimen were heat-treated by a porcelain firing cycle the yield strength and ultimate tensile strength were decreased in all three cases. But those of the argon arc casting were the highest with the optimum temperature casting following and the overheated casting being last.
3. The elongation after casting was the highest in the argon are casting, lower in the optimum temperature casting and lowest in the overheated casting.
4. When the specimen were heat-treated by a porcelain firing cycle, the elongation was increased more in the argon arc casting than in the optimum temperature casting, but the overheated temperature casting was unchanged.
5. The hardness after casting was the same in all three cases. However, when the specimen were heat-treated the hardness decreased.