The invention belongs to the technical field of steel
surface modification heat treatment technology, and specifically relates to a steel surface composite
processing method using
plasma electrolytic carburization and then boro-
carbonization. The method comprises the following steps: (1) putting a steel sample into a
carburizing solution, taking the steel sample as the negative
electrode and a
graphite material as the positive
electrode, applying a
voltage of 220 to 400 V on two electrodes at a
room temperature, and carrying out a treatment for 3 to 5 minutes to obtain a carburization layer with a thickness of 15 to 90 [mu]m; (2) taking the sample which has been subjected to a carburization treatment as the negative
electrode, putting the sample into a boro-
carbonization solution, taking
graphite as the positive electrode, applying a
voltage of 200 to 500 V on two electrodes, carrying out a treatment for 10 to 30 minutes to obtain a boro-
carbonization layer with a thickness of 20 to 100 [mu]m. The
hardness of the obtained boro-carbonization layer can reach 1500 to 2400 HV, the
hardness is improved by 10 to 15 times, compared with the steel matrix, and moreover, the
wear resistant performance and durability are greatly improved. At the same time, the
friction coefficient and wear rate of the boro-carbonization layer are 1 / 5-1 / 8 and 1 / 21-1 / 25 of those of steel matrix. The friction and
wear resistant performance of steel is prominently improved by the
plasma electrolysis-boro-carbonization treatment. Furthermore, the technology does not need any
post treatment, and is simple, the deformation of workpiece is little, and the cost is reduced.