شبيه سازي فرآيند آهنگري پره توربين از جنس سوپر آلياژ پايه نيكل

چكيده انگليسي :

Simulation of the forging process of a gas turbine blade of nickel based super alloy Mohamadreza Nayebsadeghi Reza sadeghi747@yahoo com 2010 10 3 School of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Mehran Moradi Email moradi@cc iut ac ir Abstract Gas turbine blade requires high geometrical precision and mechanical properties including high strength creep low cycle fatigue crack initiation and crack propagation characteristics due to its difficult working conditions In addition conventional forging process could not gain special mechanical properties for turbine blade of nickel based super alloy some special care should be taken Forging process of gas turbine blade requires advanced tools for design and analysis of forging process due to the sensitivity of the properties of the material to process conditions and complexity of the shape product In recent years finite element method has been extensively employed to research blade forging process providing helpful information of several process parameters as material flow stress strain strain rate temperature histories during the deformation process and forging force For nickel based alloy 718 until now Park et al 2001 presented the two step forging process with a technique for heat treatment and lubrication and controlled microstructures Na et al 2003 carried out 3D simulation of microstructures for nickel based alloy 718 blades forging using 3D finite element method In this paper the two step forging process with the heat treatment during process is designed to manufacture nickel based alloy 718 turbine blades 3D finite element analysis of this thermomechanical processing of the gas turbine blade is carried out and the thermomechanical results of the simulation is discussed by using of microstructure analysis results of nickel based alloy 718 forging process On the bases of finite element results the practical forging process is recommended It is considered that the forging process is hot the material under the forging process follows an elasto viscoplastic path in stress strain plane and its properties are isotropic and homogenous The flow rule has been followed the Prandtle Reuss s rule and Von mises yield criteria has been prevailed 8 node 3 D element for blade modeling and 4 node 2 D element for die modeling has been used Contact condition has been defined by using of penalty formulation For plastic deformation on billet trivial incremental displacement method has been used All of the deformation stages from initial cylindrical billet to the final simple shaped blade has been designed and simulated Then the thermomechanical results of the simulation such as the material flow load strain temperature has been obtained and discussed At the end as a validation of the simulation results the load in the preforming process by using of the analytic method has been calculated and also the flow behavior of nickel based alloy 718 was presented elsewhere 12 has been compared to as those in the simulation Key Words Gas turbine blade Forging process Nickel based super alloy Elastic viscoplastic

نايب صادقي، محمدرضا

شبيه سازي فرآيند آهنگري پره توربين از جنس سوپر آلياژ پايه نيكل

پره توربين گاز , الاستيك - ويسكوپلاستيك