Study On Laser Cladding Modification Technology Based On W₆Mo₅Cr₄V₂ High-speed Steel Cutter

The W₆Mo₅Cr₄V₂ high-speed steel cutter which is usually applied to the cutting tool market as the research in this article,selecting the WC/Co composite ceramic powder of high hardness,good high temperature performance,the cladding modifying experiments are done on the cutter substrate surface by using fiber lasers and related auxiliary equipment,the aim is to increase the machinability including hardness and red hardness of high-speed steel surface.Investigate and explore the influence of different process parameters on the cladding layer macroscopic appearance to reduce the data range of process parameters in early experiment,it can provide a certain basis for the tool modification study.Firstly,single-channel cladding orthogonal experiment and range analysis are done.Exploring the relation of cladding forming basic parameters?laser power,powder feeding voltage and scanning speed?on the macroscopic appearance,microhardness and microscopic structure.Experiment results show that the average microhardness of the cladding layer are influenced by the powder feeding voltage and the laser power.When the laser power is 1.1k W,the powder feeding voltage is 14 V,the average microhardness of cladding layer is about 1.52 times of the cutter substrate,and the cladding layer and the substrate achieve a better metallurgical bone,the crack only appear at the left and right boundaries,the pores appear in the range about 0.25 mm from the top of the cladding layer.Combining polynomial regression and orthogonal experiment,equation of powder feeding voltage,laser power and average microhardness can be obtained.Through this equation,average microhardness can be predicted and controlled.Secondly,according to the above experiment conclusions,to explore the influence of scanning speed on cutter cladding at optimum microhardness parameter range.The result show that the slow scanning speed can easily cause the warp deformation of the substrate,the deformed shape is “saddle shape”,when the scanning speed is 3mm/s,the amount of warp deformation of the substrate can be well controlled.In the cladding process,the heat accumulation in the initial position of the cladding direction is the least,and the diffusion is carried out along the cladding direction,and it affects the surrounding organization.Refer to microscopic structure and cladding height,determine the optimal process parameters are laser power 1.1k W,powder feeding voltage 14 V,scanning speed 3mm/s.Then the microscopic structure and properties of the cladding layer under the optimum parameters are analyzed.The result show that the main phase are Fe₃W₃ C,WC,W₂ C,M₆C hard phase and gap carbide.The highest microhardness appears in the sub-surface range about 0.4mm from the top of the cladding layer,which is 1.64 times of the substrate.The red hardness of the cladding layer is more than 60 HRC at the temperature reaches 600?,the red hardness of the cladding layer still meet more than 50 HRC at the temperature reaches 1000?,which is close to the red hardness of hard alloy.Last,practical cladding and machining verification are carried out on ordinary highspeed steel turning tool,the precast groove cladding process is determined by experimental study,the special flip fixture for laser cladding is designed to solve the difference of turning tool cutting edge inclination.The high-speed steel turning tool after laser cladding strengthening has better cutting performance than ordinary high-speed steel turning tool,the laser strengthening turning tool can complete the cutting of quench Cr12 Mo V steel,which the hardness reaches 68?70HRC,the laser strengthening turning tool is also applicable to the high speed cutting requirements over 100m/min.Using laser cladding modification technology to cladding WC/Co composite powder on ordinary high-speed steel cutter can effectively improve the cutting performance and practicability of high-speed steel cutter,which has a certain value of application and popularization in the field of tool reinforcement and modification.