| The steam turbine blade is one of the most critical core components in the steam turbine system.It converts kinetic energy into mechanical energy under the working conditions of high temperature,high pressure and high-speed steam flow.It is easy to be damaged during continuous operation for a long time.Serious consequences are not uncommon.The manufacturing cost of blades is high,and as a remanufacturing technology,laser cladding has outstanding advantages,saving energy and environmental protection,and obtaining coatings with good performance.It is widely used in repairing damaged parts and upgrading performance.research is of great significance.This paper takes the steam turbine blade as the research object,and takes the repair and protection of the blade as the engineering background of the specific application.In view of the complex metallurgical bonding phenomenon in the laser cladding process,based on the life and death element technology of ANSYS finite element analysis,the parametric design language is used.(APDL)completed the creation of Gaussian heat source and established the thermomechanical coupling numerical model of laser cladding of steam turbine blades in combination with Workbench software,and adjusted the combination of laser process parameters to analyze the influence of temperature field and stress field in the model cladding process.By selecting nodes and paths in the temperature field and stress field of the model,it is found that the heating process of laser cladding is close to a straight line,and the cooling stage is gradually slow;there is obvious stress concentration at the connection between the cladding layer and the substrate.The process of laser cladding of steam turbine blades is analyzed,and the control variable method is used to take one of them as the variable and other parameters remain unchanged to carry out a single-channel cladding test.The results of the test and data simulation are compared and analyzed.The cladding process parameters of the steam turbine blade are optimized by the morphology and deformation degree to verify the reliability of the simulation model;the microstructure and performance of the cladding layer are analyzed based on the optimized laser process parameters,and the quality of the cladding layer is further evaluated by the combination of macro and micro.,analyze and determine the best combination of process parameters: the laser power is 1600 W,the scanning speed is 8mm/s,and the powder feeding rate is 1.6r/min.The effect of adding tungsten carbide to Ni60 on the quality of the cladding layer was explored.Based on the optimal process parameters,Ni60,Ni60+15% tungsten carbide and Ni60+25% tungsten carbide were prepared by multiple cladding on a 2Cr13 stainless steel substrate.For the cladding layer,the microstructure observation,XRD phase analysis and microhardness test of the cladding layer were carried out by using the super-depth microscope.The analysis shows that the cladding layer is well combined with the matrix and has a fine structure;the main precipitation components of the cladding layer include WC,Ni-Cr-Fe,γ-Ni and Fe Cr;the hardness of the matrix material 2Cr13 stainless steel is 220 HV and Ni60 melting The average hardness of the cladding is much higher than that of the substrate by about615.56 HV,and the hardness of the Ni60+25%WC coating section is 23.2% higher than the average hardness of the Ni60+15%WC coating,which verifies that the selected cladding process is reliable. |
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