A Study on the Variation of Tensile Strength and Hardness According to the Frequency of Reuse with Chrome-Cobalt Alloy Widely used in the Production of Partial Denture

국부의치 제작에 사용되는 Chrome Cobalt Alloy의 재주조 횟수에 따른 인장강도 및 경도 변화에 대한 실험적 연구

  • Chung, Kyung-Pung (Dept. of Dental Laboratory Technology, Won-Kwang Public Health Junior College)
  • 정경풍 (원광보건전문대학 치기공과)
  • Published : 1996.07.01

Abstract

This study is to measure and compare the hardness and tensile strength of each time after we recast seven times continually only with and metal alloy Chromium-Cobalt alloy used in the production of partial denture frame work. The result of the experiment were as follow; 1) The result of the hardness measurement The result of the first casting was $490.48{\pm}38.38$ and that of the second recasting was $455.18{\pm}35.61$ and form the third recasting. the result were $518.38{\pm}37.68$ and over. The change of the hardness difference between each recasting was as follow; The hardness difference between the first casting and the second recasting was $35.25{\pm}31.93$ and that between the second recasting and the third recasting was $63.20{\pm}54.02$. There was a statistically significant difference(P<0.01) in the above hardness, however, there was little difference on the whole. And after the third recasting, the hardness grew high a little bit. That is why low-melting metals such as Cr, Mn, Cu of alloy ingredient was evaporated or there was an effect of changes in metal crystal structure, I suppose. 2) The result of the tensile strength measurement. There was a statistically significant difference(P<0.01) between the first casting and the second, the fourth recasting, however. there was little difference in general.

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