Hot Rolling Stability Analysis For GH33 Superalloy Based On DMM And FEM

GH33 alloy are widely applied to such components serving in high temperature as turbine blades,turbine disks,and aircraft due to its good mechanical processing performance,high strength at 700-750 ~oC and excellent oxidation resistance at 900 ~oC.As the main production method of superalloy round rod,the hot continuous rolling has the characteristics of high production efficiency,technology and quality controllability.However,due to the temperature and deformation rate sensitivity of this type of alloy,its hot tandem rolling stability requires in-depth analysis.In this paper,GH33 alloy is chosen as the research object,the true stress-true strain curve of this alloy is obtained based on the compression experiments.Based on the data in these curves,the flow stress model is regressed and the three-dimensional plastic processing map is constructed.Finite element analysis model,to carry out numerical simulation analysis of the temperature,equivalent strain and equivalent strain rate of the rolling products under different rolling process parameters;the obtained temperature-strain-strain rate spatial trajectory of the typical node of the rolling products,the reasonable rolling process is determined by the stability of the space trajectory in the three-dimensional plastic processing map.The details are as follows:(1)The uniaxial compression single-pass experiment of the cylinder was performed on the Geeble-3500 thermal simulation test machine to obtain the stress-strain curve of the GH33 alloy,and the flow stress model of the GH33 alloy during hot rolling was constructed.(2)A two-pass experiment of cylindrical uniaxial compression was performed on a Geeble-3500 thermal simulation test machine to construct a softening rate model due to recrystallization.(3)Based on the dynamic material model(DMM),construct a three-dimensional plastic processing map of the alloy to determine the rolling process parameters of the alloy's stable deformation and dynamic recrystallization.(4)Based on the rigid-plastic finite element method,the finite element model of the hot continuous rolling process of GH33 alloy round steel was constructed using the MSC.Marc finite element analysis software.The variation law of the typical node equivalent strain,equivalent strain rate and temperature of the rolling stock during the twelve pass rolling process are analyzed.(5)Based on the spatial trajectory of temperature-strain-strain rate of the central node of the round steel obtained by finite element analysis,the reasonable rolling process is determined by the stability of the space trajectory in the three-dimensional plastic processing map.