Effect of Microstructure and Microtexture on the Mechanical Properties of Small-Strain Cold-Drawn Pearlite Steel Wires

Abstract

The effect of microstructure and microtexture on the mechanical properties of small-strain (e < 0.8) cold-drawn pearlitic steel wires was investigated by scanning electron microscopy, transmission electron microscopy and electron backscatter diffraction. A quantitative statistical analysis of the measured parameters of interlamellar spacing indicated a slight decrease during the testing and a relatively high deviation from the calculated values. Calculations on the dislocation density increased from approximately $$ 4.25\; \times \; 10^{14} \;{\text{m}}^{ - 2} $$ at e = 0 to approximately $$ 4.33 \times 10^{15} \;{\text{m}}^{ - 2} $$ and then to $$ 5.81 \times 10^{15} \;{\text{m}}^{ - 2} $$ with increasing cold-drawing strain. As calculated using the misorientation angle across the dislocation boundaries and the dislocation boundary area per unit volume, the dislocation density generally increased consistently. Under these conditions, a microstructure tends to form through the deflection of pearlitic colonies, consequently affecting the crack propagation path and improving the yield and tensile strengths.