Авіаційно-космічна техніка та технологія (Aug 2019)
PRODUCTION OF FDM-PATTERNS VIA 3D-PRINTING FOR GAS TURBINE CASTINGS
Abstract
A study of the fuse deposited pattern and castings of gas turbine hot section, which was obtained with additive manufacturing, has been carried out in the present article. A pattern of the castings had been produced by selective laser sintering (SLS) process from the polystyrene powders according to developed in special program complex 3D-model. With involving of the obtained FDM-pattern via burned pattern casting process have been produced a parts of gas turbine hot section from nickel-base superalloy VKh4L-VI. The castings were investigated as in the as-cast state, thus and after inherent superalloy VKh4L-VI heat treatment with prior hot isostatic pressing (HIP). An analysis of the obtained FDM-pattern for the presence of surface defects and geometry compliance are provided, together with the macro- and microstructure study of obtained castings and evaluation of mechanical properties and stress rupture strength results. It was established that investigated patterns as precisely as possible reproduce dimensions accuracy of the parts, and castings had satisfactory surface cleanliness, roughness, dense and middle crystalline macrostructure. Micro-structure of castings material is typical for nickel-base superalloy VKh4L-VI in the as-cast state with carbides, carbonitrides and eutectic phase’s presence.HIP with subsequent heat treatment provides almost full micro porosity releases in the inner volumes of the metal and getting more uniform solid-state, almost full eutectic dissolving, and carbides dispersivity. Mechanical properties and stress rupture strength (rupture life) of the specimens produced by considered production processes meet the specification requirements. Application of HIP with subsequent heat treatment (homogenization and ageing) for specimen’s production provides slightly bigger indexes of mechanical properties at room temperature.Selective laser sintering application for FDM-patterns production made it possible to obtain qualitative castings with satisfactory microstructure, the acceptable level of the properties and realize traditional advantages inherent for both considered processes.
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