The Ni-base superalloys are used in the aircraft industry for the production of aero engine most stressed parts, turbine blades or turbine discs. Quality of aero jet engine components has a significant influence on the overall lifetime of a jet engine as itself as well as the whole airplane. From this reason a dendrite arm spacing, grain size, morphology, number and value of γ' - phase are very important structural characteristics for blade or discs lifetime prediction. The methods of quantitative metallography are very often used for evaluation of structural characteristics mentioned above. The high-temperature effect on structural characteristics and application of quantitative methods evaluation are presented in this paper. The two different groups of Ni-base alloys have been used as experimental material: cast alloys ZhS6K and IN713LC, which are used for small turbine blades production and wrought alloys EI 698VD and EI 929, which are used for turbine disc production. Selected alloys have been evaluated in the starting stage and after applied heattreatment at 850°C for 24 hrs. This applied heat-treatment causes structural changes in all alloys groups. In cast alloy dendritic structure is degraded and gamma prime average size has grown what has a negative influence on turbine blade creep rupture life. Wrought alloys show partially grain boundary melting and grain size changed due to recrystallization what causes mechanical properties decreasing - ultimate tensile strength mainly.
In the paper numerical analysis of closed-die forging process of turbine disc to fix blades was presented. Forging technologies which take into account conventional and isothermal boundary conditions were analysed. Forging processes were lead as one stage or as two stages - with initial upsetting. In the analysis additional influence of lubrication conditions on the process parameters was taken into account.
PL
W artykule przedstawiono analizę numeryczną alternatywnych sposobów kucia tarczy turbiny do mocowania łopatek. Przeanalizowano technologie kucia z uwzględnieniem warunków konwencjonalnych i izotermicznych. Proces prowadzono jako jednozabiegowy lub dwuzabiegowy - ze wstępnym spęczeniem. W analizie uwzględniono dodatkowo wpływ warunków smarowania na parametry procesu.
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