控制冷却改善连铸坯表面组织机理的研究  

Mechanism Study of Slab Surface Structure Improvement by Controlling Cooling Pattern

作　　者：赵新宇[1] 刘洋[1] 王海宝[1] 王文军[1] 邹扬[1] 秦丽晔[1] 甄新刚[2] 

机构地区：[1]首钢技术研究院 [2]秦皇岛首秦金属材料有限公司

出　　处：《首钢科技》2012年第6期1-6,共6页Shougang Science and Technology

摘　　要：以不同的冷却模式分别对直径为10mm的模拟连铸坯表面组织的试样进行冷却模拟，研究控制冷却对其组织形貌的影响。试验结果表明，传统冷却模式下，膜状先共析铁素体在晶界的过量析出、魏氏组织的形成和析出物在晶界的析出等行为会降低连铸坯表面的高温塑性，使连铸坯在弯曲和矫直过程中发生表面缺陷。控制冷却模式使析出物在晶界、晶内析出，成为再加热后冷却生成的铁素体形核的优先位置，从而减少膜状先共析铁素体在晶界的过量析出，均匀组织，细化晶粒。由于晶粒细化可以提高钢的高温塑性，使连铸坯在弯曲和矫直过程中抵抗更多应力，从而降低了连铸坯表面的裂纹敏感性，减少了表面横裂纹的发生率。The samples of diameter lOmm is made to simulate the structure of slab surface with different cooling patterns. Then the influence on microstructure morphology of controlled cooling pattern is studied. The experiment results are as follows： the behaviors of excessive precipitation of film-like ferrite along the austenite grain boundaries, the formation of widmanstatten structure and precipitation along the austenite boundaries under traditional cooling pattern can deteriorate the hot ductility of the slab, which causes surface defects during the process of bending and unbending. The precipitates create not only at austenite grain boundary but also inside the grain according to controlling cooling patterns, and the precipitates is the principal originated positions of the ferrites during the cooling stage after reheating. Therefore, the excessive film-like primary ferrite along the austenite grain boundaries is alleviated and grains refine and microstructures uniform. Grain refinement can promote the ductility of steel, and thus the slabs can resist more stress during the process of bending and unbending, the susceptivity of cracks of slab surface is reduced and the probability of transverse cracks is decreased.

关 键 词：连铸坯表面组织 表面横裂纹 传统冷却模式 控制冷却模式 

分 类 号：TG335.63[金属学及工艺—金属压力加工]