Structure formation in wire

Abstract

The microstructure formed in the surface layer of industrially produced steel 70 wire rod (diameter 5.5 mm), wire (diameter 4.2 mm), and thin brass-plated steel 70 wire (diameter 0.933–1.75 mm) is studied. Local surface sections with turbulent structure are identified by means of transmission and scanning electron microscopy and microhardness measurements. Those sections are associated with shear stress forming additional rotary deformation modes. With increase in the deformation, a gradient in the microhardness appears. The hardness is greatest at the surface in sections with anomalous structure. The dynamics of dislocational structure in metal with deformation is investigated. The formation of pearlite colonies in high-carbon steel is studied. The results may be used in determining the limiting deformability of wire rod and wire on drawing.