板条马氏体大变形轧制工艺的晶粒细化机制  

Grain-Refining Mechanism of Severe Rolling to Lath Martensite

作　　者：赵新[1] 荆天辅[1] 高聿为[1] 王威[1] 周继锋[1] 

机构地区：[1]燕山大学材料科学与工程学院,河北秦皇岛066004

出　　处：《钢铁研究学报》2004年第6期69-73,共5页Journal of Iron and Steel Research

基　　金：国家自然科学基金资助项目(钢铁联合基金50271060;50371074);河北省自然科学基金资助项目(503291)

摘　　要：分析了采用板条马氏体大变形轧制工艺制备超细晶钢板时的显微组织演变过程及其晶粒细化机制。结果表明,该工艺包含3个具有不同晶粒细化机制的工艺过程:①轧前预淬火+回火使原始奥氏体晶粒分裂为均匀细小的板条马氏体,板条晶内部含有大量吸附着碳原子的位错;②大变形轧制细化、破碎板条马氏体,并进一步增加了组织中的位错密度;③在轧后再结晶退火时,基体中的高密度位错提供了超常的驱动力,使再结晶晶核尺寸小于1μm,400℃和500℃退火后钢板的晶粒尺寸分别为52nm和316nm。The microstructure evolution and grain-refining mechanism of the process, severe rolling of lath martensite, was studied. The result shows that the mechanism is composed of three steps: ① subdivision of austenite grains into homogeneous and tiny martensite laths with plenty of dislocations with C atoms absorbed during quenching and tempering before severe rolling; ② thinning and damage of martensite laths and increase of dislocation density in laths during severe rolling; ③ recrystallization driven by ultra-high density of dislocations in matrix, making the nucleus size less than 1 μm. The grain size of steel sheet annealed at 400 ℃ and 500 ℃ was 52 nm and 316 nm respectively.

关 键 词：大塑性变形 板条马氏体 热处理 晶粒细化 低碳钢 

分 类 号：TG336[金属学及工艺—金属压力加工]