热轧带钢横折缺陷的控制技术

来源期刊：钢铁2009年第5期

论文作者：李军

文章页码：68 - 71

关键词：热轧带钢； 横折缺陷； 上下屈服点应力差； 准针状铁素体组织

Key words：hot rolled strip； break marks； spike height； quasi-acicular ferrite

摘    要：根据上下屈服点应力差是产生横折的根本原因,采用"控制显微组织形态,降低上下屈服点应力差"来消除热轧带钢横折缺陷。结果表明:产生横折缺陷存在临界的上下屈服点应力差,准针状铁素体组织可降低上下屈服点应力差,并使其低于这个临界值,更为重要的是,准针状铁素体组织使控制横折缺陷的工艺难度大大降低;钢中碳含量高、奥氏体晶粒粗、加速冷却速度快、加速冷却开始和结束温度低,有利于获得准针状铁素体组织,最佳的加速冷却开始和结束温度分别为先共析铁素体和珠光体开始转变温度。该技术已在攀钢推广应用,效果显著。

Abstract: Based on spike height resulting in break marks,the new technique of eliminating break marks by getting microstructure of quasi-acicular ferrite in hot strip mill was applied.The results show as follows:(a)There is a critical spike height for producing break marks.By getting microstructure of quasi-acicular ferrite,spike height can be decreased below the critical point and it is more important to reduce remarkably the difficulty of controlling break marks;(b)Factors such as higher carbon content,coarser austenite grain,faster accelerated cooled rate,lower accelerated cooled start/end temperature can promote the formation of microstructure of quasi-acicular ferrite,and the optimal accelerated cooled start/end temperature are at which pro-eutectoid ferrite and pearlite start to form respectively.The new technique has been applied successfully at PZH Steel.