薄板坯连铸连轧工艺生产的Nb、Ti复合微合金化热轧带钢的强化机制  

STRENGTHENING MECHANISM OF Nb AND Ti COMPLEX MICROALLOYED STRIP STEEL PRODUCED BY THIN SLAB CASTING AND DIRECT ROLLING PROCESS

作　　者：王瑞珍[1] 章洪涛[1] 

机构地区：[1]钢铁研究总院结构材料研究所,北京100081

出　　处：《金属学报》2007年第10期1082-1090,共9页Acta Metallurgica Sinica

摘　　要：对具有高、低屈服强度的薄板坯连铸连轧工艺生产的Nb、Ti复合微合金化钢的热轧板进行了组织分析,研究了强化机制.组织分析表明,板卷均为铁素体组织.但具有高屈服强度的板卷铁素体呈现出非多边形特征,位错密度较高,晶粒明显小于低屈服强度的板卷.两类板卷中的复合型星形析出物较多,平均尺寸140—150 nm,消耗了钢中50%的Nb.强化机制研究表明,铁素体晶粒细化强化是主要强化机制,占总屈服强度的(43—46)%;两类板卷的析出强化效果微弱,只占总屈服强度的(4—6)%.位错强化与晶粒细化强化是板卷具有高屈服强度的原因.The Nb and Ti complex microalloyed steels with two strengths were produced by thin slab casting and direct rolling （TSCR） process. The microstructural analyses show that both coils mainly consist of ferrites and have the same precipitation characters. The ferrites in the coil with higher yield strength present non-ploygonal morphology, finer grain size and higher dislocation density. A large number of complex star-like precipitates exist in both coils, which have the average sizes of 153-142 nm and account for about 50% of the total Nb content. Ferrite grain refinement strengthening is the predominant mechanism and contributes （43-46）% to total yield strength. Precipitation strengthening effect is very weak and only contributes （4-6）% to total yield strength. Dislocation strengthening and grain refinement strengthening make coil possess higher yield strength.

关 键 词：薄板坯连铸连轧工艺 热轧带钢 强化机制 微合金化 显微组织 析出 

分 类 号：TG142.1[一般工业技术—材料科学与工程]