Application of Ni-Mg-Ce Master Alloy Scrap for Inoculation of Copper-Nickel Alloys

Abstract

The problems of production of copper-nicckel alloys ingots by semicontinuous casting method are analysed. The requirement of grain size refinement in cast alloys macrostructure is shown. It is necessary to reduce the probability of hot cracks formation and increase the fabricability of cast bars during plastic working. The reasonability of fine fraction of Ni-Mg-Ce master alloy application for inoculation of copper-nickel alloys is established. The results of laboratory experiments on the study of master alloy quantity influence the structure and hardness of Cu-5Ni-1Fe, Cu-10Ni-1Fe-1Mn and Cu-30Ni-1Fe-1Mn copper-nickel alloys are presented. On the basis of industrial experiments it is revealed that inoculation of Cu-5Ni-Fe alloy ingots of diameter 200 mm by Ni-Mg-Ce master alloy leads to considerable reducing of macrograin size. It allows to improve mechanical properties of ingots and ensure their uniform distribution in cross section of ingots. It is established that residual magnesium content in alloy must be in range from 0,02 to 0,06 wt. %. The use of Ni- Mg-Ce master alloy makes it possible to increase the processability of copper-nickel alloys during plastic working and utilize the fine fraction master alloy scrap inevitably formed during its production.