V-N微合金化CSP带钢中的析出物研究

利用Gleeble 1500D热力模拟实验机,在实验室模拟了V-N微合金化CSP钢带的生产过程.实验结果显示,在连铸初期,TiN基本全部从钢中析出,而随着铸坯温度的降低,V开始以TiN为核心或单独形核析出,在铸坯均热后,大部分单独形核的V(C,N)趋于溶解,未溶解的则开始长大,而以TiN为核心的(Ti,V)(C,N)中的V部分溶解于钢中,V在粒子中的含量减少.在CSP连轧中,V(C,N)不断从钢中析出,全部析出物起阻碍奥氏体晶粒长大的作用,而含V颗粒还促进铁素体的形核,提高奥氏体/铁素体相变比率,细化最终的铁素体组织.

Study on Precipitates of V- N Microalloyed CSP Steel

A Gleeble 1500D simulation machine is applied to simulate the production process of V-N microalloyed CSP steel strip in laboratory.The results show that almost all Ti of the steel precipitates as TiN in the incipient period of continuous casting.With the temperature decreasing of casting slab,V starts to precipitate with TiN as nucleation core or nucleate and grow up independently.After soaking,most of the independently-nucleated V(C,N) tends to dissolve,and the undissolved V(C,N) starts to grow up,meanwhile the V in(Ti,V)(C,N) dissolve partially and the V content in these particles reduces.During the tandem rolling process,the V(C,N) precipitates from the steel again,which plays a role of preventing austenite grain from growing up and facilitates ferrite nucleation.This increases austenite/ferrite transformation ratio and fines ferrite grain size eventually.