【作者】 董长征；

【导师】 朱苗勇；

【作者基本信息】 东北大学 ， 钢铁冶金， 2008， 硕士

【摘要】 本文对大方坯连铸动态轻压下压下过程进行分析,建立了描述大方坯压下过程的压下模型并利用有限元计算软件MSC.MARC对其求解计算,研究了压下过程中铸坯内部应力/应变分布规律,并对该过程中的压下率进行分析。本文的主要研究内容和取得主要成果如下：1.连铸大方坯自然热收缩的数值分析研究。热收缩值是动态轻压下在线控制模型中的一个重要参数。通过加载铸坯的实时温度场分布,对铸坯连铸过程进行热力耦合计算,获得了铸坯在整个过程的热收缩量。结果表明：拉速对铸坯的热收缩影响较大,随着拉速升高,铸坯上同一位置处的自然热收缩量越来越小,而过热度和钢种对铸坯的自然热收缩的影响则很小。2.大方坯应力/应变的数值分析。对大方坯连铸过程进行数值模拟计算,获得铸坯内部及表面的应力/应变分布。研究表明：应力/应变在拉矫辊与铸坯接触处最大,并由铸坯表面向铸坯中心依次减小。3.大方坯压下率数值分析研究。结合某厂板坯和方坯实际铸机条件,对铸坯轻压下过程进行三维有限元数值模拟计算,获得了不同压下量、钢种、拉速下压下率的变化规律。研究结果表明：方坯的压下率均沿拉坯方向近似线性减少；方坯的平均压下率与拉速呈线性减少关系；钢种对方坯压下率的影响小。4.大方坯压下模型的在线应用研究。对拉矫辊的压下过程进行分析研究,根据连铸生产过程中拉速、凝固终点等条件的变化实现压下量的动态分配和动态压下；编制压下模型在线控制程序,将压下参数在大方坯连铸生产中动态实现。热试和投产半年内的大方坯质量表明轻压下的实施达到了预期的效果。更多还原

【Abstract】 In this paper, soft reduction process of dynamic soft reduction was analyzed, by using finite element analysis software MSC.MARC, and the distribution of stress/strain inside the bloom as well as reduction gradient was investigated.The main research work and corresponding results as follows:1. Numerical analysis of CC Bloom natural shrinking. The shrinking volume is an important parameter of bloom which was calculated during the whole CC process. The real-time temperature distribution of bloom was loaded, and the thermal coupling calculation was proceeded in the bloom continuous casting process. The shrinking volume of bloom was calculated during the whole CC process. The result shows that:As the casting speed increases, the shrinking volume becomes smaller, the casting speed has much greater effect on the bloom shrinking, and the effect of overheating on the natural shrinking of bloom becomes smaller.2. Numerical analysis of the bloom stress/strain.By using the numerical simulation on bloom continuous casting process, we obtained the distribution of stress/strain inside the bloom. The result shows that:the stress/strain in straightening roller that contacting with the bloom is the largest, and reducing from the surface to the centre of bloom in turn.3. Numerical analysis of the bloom reduction rate. With the actual conditions of slab bloom in a factory, a three-dimensional finite element numerical calculation was made in the process of bloom soft reduction, and the range and laws of reduction rate were obtained under various reduction volume, steel and casting speed. The research shows that:The reduction rate of bloom is approximately linearly reduction along the casting direction. The average reduction rate of bloom has a linear reduction relationship with the casting speed. The kind of steel has small influence on the reduction rate of bloom.4. The online application research of Bloom soft reduction model. The research as well as analysis was done in the process of roll reduction. According to the change of casting speed, solidification end point and other parameters in the process of continuous casting production,the dynamic allocation and dynamic pressure of reduction volume were achieved. The reduction parameters were dynamic achieved at the manufacture of bloom continuous casting by establishing control procedures.After heat test and put into production for six months, the quality of the bloom shows that the implementation of soft reduction achieved the expected effect.更多还原