Study On Laser Repair Technology Of Cold Stamping Die Edge Based On Cr12MoV

The cold work die steel Cr12MoV has good hardenability,wear resistance and high hardness.It is widely used in the production of cold punching dies with high wear resistance requirements and high impact load.After the cold stamping die works for a period of time,due to the relative squeeze friction between the die and the plate,the blade edge of the die will appear wear and deformation,which is the main reason for the failure of the cold stamping die.Choose nickel-based self-fusible powder with good wettability,wear resistance and corrosion resistance mixed with high hardness and wear resistance tungsten carbide ceramic powder as the repair material for the edge of the cold punching die.Using laser cladding technology can Effectively repair the wear area of the mold,improve the overall performance of the mold,and extend its service life.Through on-site inspections in the enterprise,to understand the actual punching process and master the technical requirements of cold-punching die performance,lay the foundation for the development of laser repair failure mold research.In the early stage of the project,it was concluded by collating the data accumulated in the laboratory and querying relevant references to summarize the approximate process parameter range of cladding WC/Ni alloy powder on the surface of Cr12MoV cold-working die steel.Orthogonal experiments are carried out in this range.Through the mutual verification of range analysis and analysis of variance,the main factors affecting the height and width of the cladding layer and the depth of the molten pool are analyzed and summarized.The ratio of the laser energy density to the surface density of the powder is used as the evaluation index.Combined with the analysis of the cross-section morphology of the cladding layer,a reasonable range of ratios was determined,and the better process parameters were initially formulated.According to the performance requirements of cold-punching die,the hardness,bonding strength,red hardness and wear resistance of the cladding layer prepared by combining different parameters are tested.Scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray diffraction(XRD)and other characterization methods were used to analyze the macroscopic morphology,microstructure and phase composition of the cladding layer.And analyze the change law of its organization and performance,find the best cladding parameters that can repair the cold punching die,and prepare for the actual repair of the die edge.The repair process using the laser head perpendicular to the ground(horizontal plane)needs to first find the range of defocus amount that meets the performance of the mold to determine the angle of the mold edge pretreatment bevel.In order to reduce the number of cladding tests,a simulation model of laser cladding was established by using the life and death unit technology to simulate the effect of different defocus amounts during the laser cladding process.The effect of defocus on the quality of the prepared cladding layer was further elaborated by using an inverted metallographic microscope to observe the corresponding cladding experiments.The two cladding processes perpendicular to the ground and the surface of the substrate were compared,and WC/Ni cladding layers were prepared on the substrate surface at different inclined angles.According to the average hardness of the cladding layer and the measured data of the processed plate,the numerical analysis model is established,and the wear accumulation method is used to solve it.After obtaining the expected service life,the fiber laser and rotary fixture are used to repair the punch and the repaired punch is involved in the actual punching process to verify the feasibility of laser repairing the cold punching mold and the reliability of the finite element simulation model.