Study On The Influence Of Edge Passivation Technology Based On Cryogenic Treatment Process On The Life Of Spiral Groove Tap

Tap is a common cutting tool for internal thread tapping.The main failure forms of tap in the process of internal thread machining are wear and fracture.The tapping characteristics determine that the thread quality is affected by the tap accuracy,especially when cutting difficult materials,the machining quality and efficiency are difficult to guarantee.The wear resistance of tap is the main characteristic of its accuracy maintenance.Therefore,through the process research to improve the wear resistance of tap,the service life of tap can be improved and reference can be provided for the improvement of tap process.In this paper,the manufacturing process of M8 machine spiral groove tap for machining 304 stainless steel is taken as the research object.On the basis of conventional heat treatment process,cryogenic treatment and edge passivation process are introduced.Based on advantageedge FEM metal cutting simulation,the optimal passivation radius and cutting parameters are determined.Through tapping test,the influence law of different process treatments on the life of spiral groove tap is analyzed,and the optimal process of tap is determined.The main research contents and results of this paper are as follows:(1)Determination of heat treatment process route of tap.The tap material studied in this paper is W6Mo5Cr4V2 Al high-speed steel.On the premise of ensuring the hardness and impact toughness of the tap,the wear resistance of the tap is improved.Through the preliminary research of the research group,the optimal surface cryogenic treatment temperature is-160 ℃,the process route is: quenching temperature 1220 ℃,cryogenic temperature-160 ℃,tempering temperature550 ℃,the cooling and heating rate during cryogenic treatment is 1 ℃ / min,continuous cryogenic cooling for 3 times and thermal insulation for 6h each time,Tempering shall be conducted for 3 times continuously,and each time shall be kept warm for 1H.(2)Optimization of blunt radius and cutting parameters of spiral groove tap.Based on the tapping simulation of advantageedge FEM,the blunt circle radius of different cutting edges is set,and the tapping simulation test is carried out on 304 stainless steel.The entropy weight method is used to analyze the simulation data,and the optimal blunt circle radius is determined to be 20 μ m.The speed is 360 r / min.(3)Spiral groove tap edge passivation and tapping test.Based on the optimal cryogenic treatment process,the edge passivation treatment is carried out for the spiral groove tap.The relationship between the electrolytic parameters and the blunt circle radius of the tap edge is studied to obtain the spiral groove tap with the edge radius of 0.015 mm,0.02 mm and 0.025 mm.The tapping test is carried out.When the passivation radius is 0.02 mm,the service life of the spiral groove tap is the longest,which is 1.94 times that of the tap without cryogenic treatment and passivation treatment,which is consistent with the simulation data.