The effect of microstructural characteristics of pearlite on the mechanical properties of hypereutectoid steel

The relationship between mechanical properties and microstructural characteristics of pearlite was investigated using various heat treatments on a hypereutectoid steel. The materials were reheated between 900 and 1200 °C and these microstructures were then subjected to isothermal transformation at temperatures of 550, 580 and 620 °C. For the hypereutectoid steel, the mean value of the interlamellar spacing was observed to increase with increasing reheat and transformation temperatures. Examination of the mechanical properties of the resulting pearlitic microstructures indicated that the strength was related primarily to the interlamellar spacing by a Hall-Petch type relationship, while the ductility was dependent also on the prior-austenite grain size and pearlite colony size.