Input Data Influence on FEM Simulation of Steam Turbine Blades Materials Hot Forming

Abstract

Computer simulation/optimization is widely applied to hot forming processes nowadays. A crucial point of any kind of computer simulation is the input data. There are implemented in all FEM codes some basic material database, but usually for limited materials and material states. As the input data decide about the output results quality, it is always necessary to pay attention, what are the simulation inputs. The best solution, but not always possible, is direct measurement of materials parameters for considered material and state. As this is in some cases not possible, materials data are searched in alternative ways. One possibility is survey of published data in literature. A reliability of published data is difficult to assess, as there are usually not available sufficient information about the material investigated in publications. Other possibility how to obtain material data nowadays is utilization of programs predicting material behavior on the basis of chemical composition. One of currently available software for material properties prediction is JMatPro. The program is able to calculate a broad range of properties and behavior with the use of established thermodynamics models on the basis of chemical composition and the initial state of the considered material state. There can be for example determined thermophysical and physical properties (from room temperature to the liquid state), time-temperature-transformation/ continuous-cooling transformation diagrams, stress/strain diagrams, proof and tensile stress, hardness, coarsening of γ and γ , and creep. The current paper is dealing with the simulation of hot forming of steam blade made of Ti-based alloy. As an input material data used for FEM simulation are conventionally measured data and data obtained from JMatPro. With the use of both material data sets, a sample component forming is simulated. The results obtained from both simulations are subsequently compared with the results obtained from physical forming of the sample component. Performance of both simulations is discussed here, taking into account results of physical forming results.