Effect of cryogenic and electrolytic passivation treatment on wear resistance of M2 high-speed steel

Through cryogenic treatment and electrolytic passivation treatment of M2 high-speed steel (HSS), the effect of electrolytic passivation process parameters on the life of M2 HSS taps and the combined effect of cryogenic treatment and electrolytic passivation treatment on the wear resistance of the M2 HSS were investigated by using a scanning electron microscope (SEM) and energy-dispersive spectrometer (EDS). The results show that the life of M2 HSS tap after electrolytic passivation treatment increases most significantly under the theoretical edge radius; the functional relationship between the charge consumption (y) and the tap edge radius (x) is as follows: y = 8.135x - 48.842. The wear resistance of the sample after cryogenic and electrolytic passivation treatment is the highest, which is 1.52 times higher than those of the traditional heat treatment sample. This is due to the increase of the number of carbides on the surface of the specimens after cryogenic treatment; the distribution and size of carbides are relatively uniform; the average size of carbides is reduced by 60.4%. There is a carbon layer on the surface of the sample after passivation, which can effectively improve the wear condition. The size and number of carbides in the surface layer of the sample remain unchanged after passivation treatment, indicating that cryogenic treatment plays a key role in the performance of the material.