HARDENED LAYER QUALITY EVALUATION AT SURFACE PLASTIC DEFORMATION BY ROLLERS OF DIFFERENT DESIGNS

Abstract

The PURPOSE of the paper is to study the influence of deformation kinematics on the quality characteristics of the hardened part surface layer including roughness, residual stresses, mechanical hardening depth, hardness and microhardness. METHODS. The characteristics of the surface layer of hardened parts have been experimentally determined using modern equipment: a profilograph-profilometer Form Talysurf i200, a hardness tester HBRV 187.5, a microhardness meter PMT-3, a device Xstress 3000 G3/G3R, a metallographic microscope MET-2. RESULTS AND THEIR DISCUSSION. The experimental studies allowed to find out that surface plastic deformation by a two-radius roller has a number of advantages in the quality of the hardened layer as compared with a single radius roller. For example, surface roughness decreases by 3-3.5 times, surface layer hardness increases by 6-8%, residual compressive stresses in the surface layer increase by 1.2-1.5 times. CONCLUSIONS. The results of experimental studies allow to choose the method of hardening in order to obtain specified quality characteristics of the surface layer of machine parts. The obtained results can serve the basis for the development of combined methods of surface plastic deformation ensuring high quality of the surface layer by a number of parameters.