Abstract: The effect of finishing rolling temperature (880 〜935℃) on the actual grain size of hot rolled medium carbon boron steel 40B has been studied. With start rolling at 990 〜1010℃ , the different finishing rolling temperatures are achieved by controlling the rolling rhythm of round steel. It is verified that decreasing finishing rolling temperature is beneficial to improve the actual grain size Φ32 mm hot rolled medium carbon boron steel. Through experimental production and analysis of the longitudinal metallographic structure in the radius 1/2 of the head, middle and tail of round steel, it is found that the actual grain size of hot rolled medium carbon boron steel is the smallest and uniform as the finishing rolling temperature is in the range of 880 〜890℃.

摘要： 研究了终轧温度(880～935℃)对热轧中碳含硼钢40B实际晶粒度的影响。在开轧温度990～1010℃的情况下,通过控制圆钢轧制节奏,实现不同的终轧温度,得出终轧温度降低有利于改善Φ32mm热轧中碳含硼钢的实际晶粒度。通过试验生产实践,并分析圆钢头、中、尾部1/2半径区域的纵向金相组织,发现当终轧温度在880～890℃时,热轧中碳含硼钢40B的实际晶粒度最细小且均匀。