N-Ti微合金化高强钢中的含Ti析出物

Precipitates containing titanium in a nitrogen and titanium micro-alloyed high strength steel

利用Gleebe1500热模拟试验机,对氮钛微合金化高强钢在薄板坯连铸连轧工艺下进行了热模拟试验,对模拟各工序下的Ti(C,N)析出物形貌进行观察和分析,并通过热力学、动力学分析了其析出的原因和条件,研究了Ti(C,N)析出物在热轧工艺中变化的全过程。研究表明:连铸过程中主要有直径200 nm的液析TiN;铸坯均热后有直径为50~100 nm的固析TiN,在原始奥氏体晶界和枝晶偏析带析出直径为100~200 nm的TiC;连轧后主要有形变诱导析出分布均匀、直径为10~30 nm的TiC;卷取后在铁素体中析出直径为6~15 nm弥散分布的TiC。

A Gleebe1500 thermal simulator was employed in simulation of the process of thin slab continuous casting and rolling of a N-Ti micro-alloyed high strength steel.The Ti(C,N) precipitation behavior of precipitates was observed and analyzed during the hot rolling.The conditions of precipitation process were investigated by thermodynamics and dynamics calculation,which provide important theoretical and technical support for the process of Ti micro-alloyed high strength steel.The results show that precipitation of TiN with size of 200 nm mainly occurs from liquid phase in the continuous casting process,TiN with size of 50-100 nm and TiC at original austenite grain boundary and dendrite segregation with size of 100-200 nm are precipitated during the casting soaking.Deformation induced precipitation of TiC with size of 10-30 nm and homogeneous distribution is observed after rolling,and dispersion TiC of 6-15 nm in ferrite is precipitated after coiling.