The investigation of forces' component during frictional hardening of cylindrical surfaces of machine parts

Abstract

Friction treatment refers to methods of surface hardening (strengthening) using highly concentrated energy sources. After processing in the surface layers of the parts a hardened (reinforced) white layer with a nanocrystal-line structure is formed. Friction treatment of the cylindrical surfaces of the samples was performed on an upgrad-ed lathe (model 16K20), on which instead of a tool-post was installed a special device for autonomous tool drive. A metal disk made of steel 45 is used as a tool. Mineral oil with active additives containing polymers was used as a technological medium in the process of friction treatment. A special dynamometer was developed to study the components of the force that occurs in the contact area of the tool-part during the frictional hardening of the cy-lindrical surfaces of the parts. The immovable elastic elements of the dynamometer are fixed on conical holes in the rear headstock and spindle. To make rotation impossible of the elastic element in the spindle, it is mounted in the adapter bushing through the bearings. Studies have shown that the modes of friction treatment significantly affect the normal Py and the tangential component Pz of the force that occurs in the contact area of the tool-part. The increasing of the part’s rotational velocity slightly affects into magnitude of the force components that occurs in the contact area of the tool-part during processing with the longitudinal feed S = 0.3 mm/rev and the depth of pressing the tool into the workpiece t = 0.1 mm. When increase the depth of pressing the tool into the workpiece from 0.1 to 0.3 mm and part’s rotational velocity equal n = 40 rpm, the normal force component Py increased from 380 N to 690 N, and the tangential component Pz – from 28 N to 47 N. And in that the same time increasing the part’s rotational velocity to 125 rpm leads to an increase the normal component Py from 510 N to 1160 N, and the tangential component Pz – from 38 N to 69 N.