Vliv rychlosti tažení na únavové vlastnosti ocelových drátů pro lana

Abstract

This diploma thesis deals with the influence of the drawing speed of bare phosphated wire for steel ropes on material fatigue, the storage of plasticity and the rate of strengthening. C68DP wire grades with ultimate tensile stress 1 570 MPa and C86D2 wires with ultimate tensile stress 2 160 MPa were selected for this experiment. Wires of these grades were drawn at speeds of 6, 8 and 10 m/s. In a field experiment, wire samples were obtained after cold drawing. These specimens were used for fatigue testing on a Schenck PUL N machine, for tensile, bending and torsion testing. By analyzing the measured values, we have shown that to increase the strength values, the highest tested drawing speed of 10 m/s would be recommended. For higher fatigue resistance, the lowest tested speed of 6 m/s would be recommended. For both qualities C68DP and C86D2, the largest number of cycles to fracture and at the same time the smallest range of measured values were found at a speed of 6 m/s.