THE INFLUENCE OF CARBURIZATION PROCESS ON THE MICROSTRUCTURE AND PROPERTIES OF CYCLOIDAL GEARS
Using 20CrMoH steel as the raw material for the RV reducer cycloidal wheel,after two pre-treatment processes of quenching and isothermal normalization,the carbon content,microstructure,surface hardness,infiltration depth,and deformation of the heat-treated samples were studied using analysis methods such as direct reading spectrometer,optical microscope,Rockwell hardness tester,micro Vickers hardness tester,laser coordinate instrument,and Geomagic Quantify software under the carburizing temperature of 880 ℃,carburizing pressure of 1 500 Pa,holding time of 25 s,diffusion ratio of 1:5,and carburizing time of 45 min and 65 min,respectively.The results showed that the microstructure of the two pre-treatment cycloidal gears from the surface to the center after carburization was basically the same,with the same surface carbon content.The difference in Rockwell hardness between the surface and the depth of the carburization layer was 0.1 HRC and 0.007 mm,and the deformation was also basically the same.This indicates that these two different pre-treatment processes have a relatively small impact on the microstructure,mechanical properties,and deformation of the carburized cycloidal gears;When the carburization time was extended from 45 minutes to 65 minutes,the microstructure of the cycloidal wheel became more uniform,with a surface carbon content increase of 0.05%,a surface Rockwell hardness increase of 0.3 HRC,an increase in carburization depth of about 0.2 mm,and a decrease in deformation.This indicates that extending the carburization time will increase the surface carbon concentration,surface hardness,and carburization depth of the cycloidal wheel,while also making the microstructure more uniform and reducing the deformation.