Surface layer characteristics due to slide diamond burnishing with a cylindrical-ended tool

The article presents an unconventional method of finishing shafts – slide burnishing with a cylindrical-ended tool whose axis is perpendicular to that of the worked shaft. The contact area of the tool with the workpiece and the tool force necessary for burnishing 42CrMo4 alloy steel shafts were calculated. The effect of burnishing parameters on the surface stereometric structure, the surface layer hardening and the distribution of final stresses was examined. Compared with grinding, a considerable improvement in surface condition indicators was found and it was possible to achieve a surface roughness, Sa of 0.05–0.18 μm. Surface microhardness increased by up to 29% and compressive stresses of up to a 400 MPa of the absolute value occurred in the surface layer. The effect of burnishing parameters on surface roughness, Sa and oscillatory bending strength were examined and the relevant mathematical models – multinominals of the second order that also allow for the interaction of input factors were obtained. Fatigue strength improved (compared to that of the ground workpieces) by 18%. It was found that those effects can be achieved without a lot of technological effort.