Effects of controlled rolling and controlled cooling on the structure and cold brittleness resistance of low carbon steel plates

Abstract

  This paper studies the effects of controlling rolling process parameters (austenitizing temperature, pass reduction rate and final rolling temperature) on the average diameter of ferrite grains and brittle transition temperature after rolling of low carbon steel plates and their interrelationships. . The test results show that the final rolling temperature plays a major role in the rolling process parameters, determining the average diameter of ferrite grains after rolling, the brittle transition temperature and the impact toughness at -40°C; the final rolling at about 800°C has the best effect. . The test results of the effects of post-rolling rapid cooling time and cooling rate on the microstructure and brittle transition temperature of low carbon steel plates show that extending the rapid cooling time and accelerating cooling have complex effects on the post-rolling microstructure: increasing the Widmanstatten structure level; The amount of decomposed pearlite increases; the pearlite is degraded and refined. Such complex structural changes have a complex impact on the brittle transition temperature. Several mechanisms of pearlite degradation in low carbon steel are proposed.