Study On Abrasion Resistance Of High Speed Steel Cutting Tools Surface By Laser Shock Peening

High speed steel tool is the key foundation piece, as commonly used in machining. It often fails due to wear in the cutting process. Therefore, adopting an appropriate technology is crucial to guarantee the stability of cutting force, surface quality of workpiece, dimensional accuracy of workpiece, tool life and good wear resistance. In this paper, the technology of laser shock peening(LSP) was used to process the W9 steel. The influence of process parameters on surface properties were discussed by the combination of experimental and numerical methods. Then, the differences in friction properties were analyzed after Laser Shock Peening on high speed steel surface, and the cutting performance of high speed steel tool was studied. Main tasks are as follows:(1) The principle and pressure model of LSP were introduced. The influence mechanism of LSP on surface quality, microstructure and mechanical performance of material were discussed. Tool wear mechanism and theory about effect of laser processing parameters on friction and wear were described.(2) After laser single shock peening on W9 steel with different energy and impact times, the surface morphology, residual stress, nano-hardness, modulus of elasticity and microstructure were tested. As the laser energy and impact times increased, surface plastic deformations, residual stress, hardness, elastic modulus and depth of grain refining are increased. But, amplitude increased is decreases with the bigger impact times. At the same time, the surface morphology and residual stress were characterized by using ABAQUS software to simulate the process of laser shock peening. Results show that simulation results are in good agreement with the experimental results, which validates the correctness of numerical simulation model.(3) Experiment of multi laser shock peening on surface was conducted based on box-benhken design. Then friction and wear experiment were carried out. It found that coefficient of friction and mass wear increased with the increases of laser energy and horizontal overlapping rate. When the longitudinal spacing increased, the coefficient of friction and mass decrease first and then increase. Cutting performances of LSPed tool and untreated tool were compared in cutting tests under different cutting parameters. It found that cutting forces of two tools gradually increased with the increase of cut depth, feed and cutting speed. But, cutting force of LSPed tool is less than the untreated tool and has better resistance to abrasion in all parameters. Life of LSPed tool increased by 40% with cutting parameters of f=0.08 mm/r, vc=30 r/min and ap=0.8 mm based on blunt benchmark of VB=0.4mm. Tool life tests of LSPed tools under different laser parameters were conducted. The results show that the larger laser energy and overlapping rate could increase the service life of tool. Untreated tool mainly is adhesive wear and abrasive wear, while abrasive wear phenomena of LSPed tool is not obvious due to the large hardness. And the bonding material on rake face is reduced, only the adhesion phenomenon obviously exists in the knifepoint position.