Finite element method is the most powerful tool for development and optimization of the metal forming processes. Analysis of titanium alloy critical parts should include the prediction of microstructure since their mechanical and technological properties essentially depend on the type and parameters of the microstructure. The technological process of parts production for aerospace applications is multi-operational and consists of deformation, heating and cooling stages. Therefore, it is necessary to simulate the microstructure evolution to obtain high quality parts. In presented paper FE simulation coupled with microstructure evolution during hot forging of TC11 titanium alloy has been performed by QForm FEM code. Constitutive relationships, friction conditions and microstructure evolution model have been established using the experiments. The kinetics of phase transformations has been described by the Johnson-Mehl-Avrami-Kolmogorov (JMAK) phenomenological model. The approach is illustrated by industrial case study that proved its practical applicability and economic advantages for technology development of titanium alloy critical parts.
Hot Metal Gas Forming (HMGF) is a coupled process of gas forming and quenching of tubes. This process allows to obtain complex and accurate geometry due to the elimination of springback and high mechanical properties due to the formation of martensite, as a result, the weight of the parts can be reduced. HMGF is widely used in the aerospace and automotive industries to make critical parts from high hardenability steels such as 22MnB5. A typical hot stamped component has 1000 MPa yield stress and 1500 MPa ultimate tensile strength. The main challenge of HMGF process is a significant material thinning and cracking due to the biaxial tension stress state. The paper proposes a preforming method for increasing the forming limits of HMGF by the cold upset bulging of tubes by means of the additional volume of material in the deformation zone. This method allows to obtain one or several waves in the cross section of the tube, which helps to increase the minimum workpiece wall thickness after the forming process by more than 40% and to reduce a probability of the crack formation.
One of the most promising methods for manufacture of axially symmetric parts such as disks or hollow shafts of gas turbine engines is local deformation using cold rolling. Physical and mathematical modeling can be quite effective for designing this class of equipment and process operations. This article presents the methodology and results of physical and mathematical finite element modeling of local deformation of parts such as a tapered cylinder fabricated from chromium steel alloy grade 11H11N2V2МF-Sh. Chemical elements in the alloy are designated by the letters which stand for: H -Chromium, N -Nickel, V -tungsten, M -molybdenum, F -vanadium, Sh -electroslag remelting. According to GOST 5632-72 (Russian standard), this type of nickel-chromium alloy consists of about 11 % of chromium, 1.5-2 % of tungsten and nickel, up to 1 % of molybdenum and vanadium, and 0.11 % of carbon, hundredths of one percent of phosphorus and sulfur. It is heat-resistant high-grade steel, which is used for the manufacture of parts operating unloaded at 900-1000 °C. The purpose of the paper is to analyze the process energy-power parameters and possible fracture of parts during deformation.
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