Cu-Ni-Zn 15-20 Alloy - Particular Qualities of Alloying and Crystallization Parameters

Abstract

The article is devoted to the study of Cu-Ni-Zn ternary alloy properties. German silver is applied in the instrument making industry, shipbuilding industry, and medical tool production. Furthermore, German silver is extensively used for domestic goods and costume jewelry. It is known that the aluminum and tin additions improve the Cu-Ni-Zn alloy flowing and casting mold fillability. It is a matter for the figurine and thin section casting production. That is why, using the experiment planning method we have studied the effect of Al and Sn alloyage and crystallization temperature on structure, casting characteristics and the casting characteristics of German silver. The study was realized by casting samples which were produced with lost wax method. Aluminum microadditives (0.4 %) have a positive impact on the casting mold fillability and improve markedly surface quality of casting samples. Tin leading into melt (about 4 %) ensure the marked growth of yield strength (by 65...70 %), while the elongation is maintained. The role of the mold temperature has a lesser impact on the yield strength. The mold temperature reduction from 550 °C to 450 °C leads to the grain size decrease and the little yield strength increase. Moreover, the surface condition measurement shows that aluminum and tin additions greatly reduce the castings surface roughness.