slide surface of the steel material although the foregoing embodiment uses glass beads as the peening elements and ejects them with air the invention is not limited to such features to make such cavities in the chromium plating layer it is also possible to use instead of glass beads the technique of first making depressions and projections by shots of steel balls ceramics or silica or by liquid honing and thereafter removing projections by polishing or super finishing while maintaining depressions next will be described a result of a test for confirming effects of the invention fig4 shows a result of measurement of loads causing seizure which were obtained by a falex method faville test the falex method uses a pair of test piece gripping blocks each having a straight groove of u shaped or v shaped cross sectional shape these test piece gripping blocks are arranged in mutually facing disposition with their grooves in mutually opposing relation a test piece cylindrical test pin is inserted into the space defined by the opposing grooves and gripped by the test piece gripping blocks which are caused to apply gradually increasing pressing forces to the test piece held between the grooves the test piece thus held and being applied with the pressing forces is forcibly rotated around its own longitudinal axis against the pressing force being applied thereto by the gripping blocks to rotate the test piece around its own axis a rotary driving hub is fitted coaxially on one end.