Numerical Simulation Of Heat Treatment And Deformation Prediction Of Complex Surface On ZG06Cr13Ni4Mo Stainless Steel Casting

Due to the complex shape of the large sculptured surface and the influence of different stress and thermal stress in the process of heat treatment,the deformation and residual stress in different positions are difficult to be predicted.It is difficult to characterize the residual stress,which makes the high residual stress region face the potential danger of serious stress corrosion.The numerical simulation technique can be used to predict the deformation and residual stress of large sculptured blade,but it is a complex process involving the interaction between phase change,temperature and deformation.it is of great significance to guide the manufacture of components by breaking through the bottleneck of numerical simulation technique,analyzing distribution regularities of deformation and residual stress under the heat treatment.For this,the research measures correlation parameters of ZG06Cr13Ni4 Mo,such as TTT diagram,to establish an intercoupling model among microstructure,deformation and temperature.Using “SP+NR+MIX” to solve the difficulty of non-convergence in numerical simulation.innovatively taking the influence of gravity on deformation and residual stress into consideration as well as the relations among correlation parameters.The research regards specimen and turbine blade as simulation target to analyze,the result shows that the equivalent stress,reverted austenite content and hardness value of cube specimen based on finite element simulation are basically constant with measurement value.Since the model is more accurate on predicting deformation and residual stress values of wedge shaped specimen,the heat treatment process of a typical X-type blade is predicted by the model,the result shows that the distribution of equivalent stress on the surface of the blade is extremely uneven,the equivalent stress of central part is the largest while the equivalent stress of the outlet of blade is the smallest.The prediction result of the deformation of the typical X-type blade shows that the deformation of the blade is extremely uneven,the largest deformation is on the place that is near to outlet and band,it's about 23mm;getting flat is a tendency of blade.The prediction accuracy of the deformation distribution and value of the blade of Bai Shan hydropower station have been verified.The finite element model which is established in the research can accurately predict the heat treatment process of blades and predict the deformation and equivalent stress during welding and annealing of ZG06Cr13Ni4 Mo runner.