METHOD FOR SELECTING DOSE OF MICROBALLS FOR SHOT BLASTING TO PROVIDE SURFACE PLASTIC DEFORMATION OF ALLOY STEEL PART TO ACTIVATE SURFACE BEFORE NITRIDING Russian patent published in 2023 - IPC C23C8/26 C23C8/36 

FIELD: shot blasting.

SUBSTANCE: method for selecting a dose of microbeads for shot blasting, which provides surface plastic deformation of an alloy steel part to activate the surface of the said part before nitriding. Flat specimens of alloy steel for tensile testing of the same shape and dimensions with a thickness equal to the thickness of the specified nitrided layer are used. Shot blasting of the mentioned samples is carried out while increasing the dose of microballs for the said shot blasting with an increment of 20 g/cm² for each subsequent sample used to plot the dependence of tensile strength of the nitrided sample with preliminary activation by surface plastic deformation on the dose of microballs for the said shot blasting. The studied range of doses of microballs for the said shot blasting is selected from the minimum possible dose of microballs for shot blasting providing surface plastic deformation with formation of an ultra-fine-grained structure of the said sample, to a dose of microballs for shot blasting providing surface plastic deformation with softening of the said sample. Then, through nitriding is carried out over the entire thickness of the mentioned samples, tensile strength of each of the said samples is determined and, based on the obtained maximum value of tensile strength, a dose of microballs is selected for shot blasting which provides surface plastic deformation to activate the surface of the mentioned part before nitriding.

EFFECT: quality and wear resistance of the nitrided layer are improved by selecting the optimal mode of surface plastic deformation before nitriding.

4 cl, 1 dwg, 1 tbl, 1 ex