Work

The manuscript is dedicated to the question of technological parameters influence on the structure and properties of pure titanium and its alloys castings during electron-beam skull melting with electromagnetic stirring. In this work the technological features of the EBSM with EMS method and its influence on the formation of the structural parameters and mechanical properties of three main structural groups cast titanium alloys have been researched. The correlation analysis of the relationship between technological parameters of melting process and alloys structure and properties have been done. The results were described by usingmathematical models. The task of titanium and its alloys melting modes multi-criteria optimization was solved, which makes it possible to simulate the process, ensuring production of titanium castings with predetermined structural parameters and hardness. It was found that the factors affecting the structural parameters and mechanical properties of titanium alloys castings of different structural groups are various, with the most significant impact for all the alloys has an alloying rate, casting weight, melting capacity before discharge and time of the metal filling in the mold. It is shown that the commercial titanium alloys, produced by EBSM with EMS method have strength properties at or above with similar alloys in other conditions. The plasticity of alloys containing β-phase is lower than required, due to the formation on the grain boundaries of the primary grain α-phase areas. Solving of this is possible by using a heat treatment and / or by increasing the metal crystallization speed in the mold.