The results show that higher Nb content is favorable for obtaining acicular ferrite(AF).Accelerated cooling promotes AF transformation,and refines lath size of AF.

• 结果表明,铌含量高有利于在极低的冷却速率下获得针状铁素体组织,提高冷却速率则能进一步促进针状铁素体转变,并使铁素体板条得到细化。