CSP低碳钢薄板连铸坯的连续冷却转变及显微组织细化

Continuous Cooling Transformation and Microstructure of Low Carbon Steel Thin Slab Made by CSP Line

在 Gleeble- 15 0 0热 /力模拟机上测试了用 CSP技术生产的低碳钢薄板连铸坯变形后的连续冷却转变曲线 ,并分析了组织演变规律。低碳钢薄板连铸坯的连续冷却相变转变温度较低 ,且随冷速的提高而降低 ,其 γ+α两相区的温度范围较宽 ,都在 15 0℃以上。相变后的最终组织为大量铁素体加部分珠光体。冷速较低时 ,铁素体晶粒呈多边形 ;冷速高时 ,晶粒多呈尖角形。随着冷速的提高 ,铁素体晶粒尺寸减小。在本实验变形条件下 ,当冷速达到 15℃ / s时 ,细化的铁素体晶粒尺寸趋于一个极限值 ,约为

The transformation of low carbon steel thin slab made by CSP line during continuous cooling was simulated on Gleeble 1500 thermomechanical simulator, and the evolving rule of microstructure was analyzed. The phase transition temperature during continuous cooling is lower, and is decreased with the increase of cooling rate. The temperature range of dual phase region ( γ+α ) is wider, more than 150 ℃. The microstructure after phase transformation consists of ferrite mainly and some pearlites. The ferrite shape is polygon when the cooling rate is low, it becomes of acicular features while the cooling rate increases. The ferrite size is decreased with the increase of cooling rate, and reaches a limit of about 8 μm when the cooling rate is 15 ℃/s.