The influence of the High Drawing Speed on Mechanical-Technological Properties of High Carbon Steel Wires
In this work the influence of the drawing speed on mechanical-technological properties of high carbon steel wires has been assessed. The drawing process of ϕ5.5 mm wires to the final wire of ϕ1.6 mm was conducted in 11 passes, in industrial conditions, by means of a modern Koch multi-die drawing machine. The drawing speeds in the last passes were: 5, 10, 15 and 20 m/s. For ϕ1.6 mm wires the investigation of mechanical-technological properties has been carried out, in which yield strength, tensile strength, uniform and total elongation, reduction of area, the number of twists and the number of bends were determined. On the basis of numerical analyses wire drawing process, the influence of the drawing speed on effective strain has been determined. The investigations have shown the essential influence of high drawing speed on mechanical-technological properties of high carbon steel wires. In the case of the wires drawn with speed 20 m/s the increase by 15% their strength properties and the decrease of plasticity properties about 25% have been noted. It has been shown that the increase of strength properties in wires drawn with high drawing speed is related to the occurrence in their bigger effective strain. The data of investigations prove the negative influence of high drawing speed on technological properties. The wires drawn with 20 m/s do not comply with the internal standard connected with torsional strength of wire, and despite having high strength properties, they cannot be used as the material for ropes, tyre cords or springs. The obtained data investigation can be applied in wire industry while implementing the new technologies of high speed drawing process of high carbon steel wires.