热变形和加速冷却对低碳微合金钢组织的影响

利用Gleeble-1500热模拟实验机研究了热变形和加速冷却工艺对3种低碳微合金钢组织演变的影响，结果表明，在再结晶或未再结晶温区实施1道次变形的晶粒细化效果不如2道次形次的效果明显，在再结晶和再结晶温区实施4道次变形可以得到更细的组织，配合较高的冷却速度可以形成部分针状铁素体组织。随着冷却速度的提高，组织变得更细，并且针状铁素体的数量增加。在相近的变形和冷却条件下，碳、锰含量较高的试样具有更细的组织。

Effect of Hot Deformation and Accelerated Cooling on Microstructure of Low Carbon Microalloyed Steel

On a Gleeble 1500 hot simulator, the effect of hot deformation and accelerated cooling on the microstructural characteristics of low carbon microalloyed steels were investigated by means of compression tests. The results showed that the grain refinement of single pass reduction in recrystallization or unrecrystallization temperature range is weaker than that of two pass reductions in recrystallization or unrecrystallization temperature ranges. Alternatively, four pass deformation in recrystallization or unrecrystallization temperature ranges could result in rather fine microstructure, and when coupled with moderately high cooling rate, partially acicular ferrite microstructure could be obtained. With the increase of cooling rate, the microstructure become finer and the content of acicular ferrite is increased. Under the similar deformation and cooling conditions, the specimens with relatively high C and Mn contents possess finer microstructure.