Effect of roller die drawing on structure, texture and other properties of high carbon steel wires

Abstract

In the work the effect of application of roller dies in process of drawing of high carbon steel wires for their structure, texture, residual stresses, surface roughness and mechanical properties has been investigated. Among structural features alignment of cementite lamellae to the wire axis by means of SEM and Pericolor 1500 has been quantitatively determined. Degree of cementite lamellae fracture in colonies parallel to wire axis has been estimated by Langford method. Obtained results were compared with those structural features for conventionally and hydrodynamically drawn wires. It has been found that degree of alignment of cementite lamellae in wires drawn in roller dies was smaller than in wires drawn conventionally and hydrodynamically but in the case of fracture degree the opposite result was noticed. Residual stresses were determined by electrochemical reversal pickling in water solution of sulphuric acid. A significant drop of longitudinal residual stresses in surface layer of wires drawn in roller die has been observed as compared to those stresses for conventionally and hydrodynamically drawn wires. Surface roughness of wires was measured with FORM TALYSURF profilographometer. It has been proved thad roller die drawing has formed very smooth surface with much smaller longitudinal and circumferential roghness parameters that for surface of wires drawn conventionally and hydrodynamically. In the work the tensile, yield and fatigue strength of tested wires were determined. It has been concluded that roller die drawing has many advantages as compared to conventional process and should be implemented in wire industry for larger scale.