Effects of crystallography and dispersibility of plate pearlite in wire rod to the structure and properties of the wire

Steels of pearlitic grade are natural composites which, on their micro-structural levels, consist of cementite and ferrite plates with their conjugated grids having orientation bonds with the both, the austenite and between each other. The major type of cementite and ferrite grids' conjugation is described by the Isaychev's ratio: (103)c || (110)f and (010)c || (1l1)f, which results in forming of the coinciding nodes grid, which, therefore, leads to low-power interphase boundaries of Z13 type. Increasing of perlite's dispersibility results in increasing of the specific area of the interphase boundaries between cementite and ferrite. This, in turn, leads to the number of specific boundaries. The width of cementite plates decreases, and, therefore, the drawing ability of carbon steels is increased. In the course of cold deforming, the mechanical hardening of wire rod made of carbon steel takes place along with re-orienting of pearlite colonies to the axis of drawing at the angle which depends of the deformation degree. Continuous increasing of tensile strength and dropping of plasticity (reduction of cross-section area, number of kinks and twists) in the course of drawing of patented high-carbon steel with its deformation degree over 78 % can be explained by partial destruction of cementite plates resulting in blocking of ferrite plates' dislocations by carbon.