【作者】 刘强；

【导师】 陈登福；

【作者基本信息】 重庆大学 ， 冶金工程， 2011， 硕士

【摘要】 H型钢主要应用于桥梁、重型设备、高层建筑的建设方面,有减轻构件重量等优点。异型坯用于轧制H型钢不但可以减少轧制道次,降低能耗和投资建设成本,而且可以大幅提高生产效率。但在异型坯的连铸过程中,由于其断面几何形状复杂,加之均匀冷却难以实现,因而裂纹敏感性较方坯、板坯则大大增加,其裂纹缺陷主要表现在腹板和内缘处的表面裂纹、翼缘顶端角部的内裂、腹板厚度1/2处的中心裂纹。因此对异型坯铸机的结构参数和连铸过程的工艺参数的优化设计提出更高要求。本文针对某钢厂新建异型坯连铸机,建立了异型坯连铸过程铸坯二维凝固传热数学模型。以变间距网格划分方法离散模型区域,并运用有限差分法离散传热微分方程。考虑到异型坯横断面冷却水流不均情况,建立了喷淋水水流密度分布模型,模型可将测试的平板水流密度分布转化为异型坯横向水流密度分布,使模型可以用于优化异型坯喷嘴布置。于此同时模型考虑了异型坯宽面内弧、宽面外弧及窄面的喷嘴排列不同的情况,模型更接近于实际情况,使得模型准确性更高。应用Visual Basic 6.0程序设计语言,开发了异型坯连铸二次冷却通用仿真软件,软件集成了异型坯连铸过程的凝固传热仿真和数据后处理等功能,为异型坯铸机的结构参数和连铸过程的工艺参数优化设计提供了依据。应用所开发的异型坯连铸过程二冷仿真软件,结合异型坯冶金准则的要求,对所研究连铸机的喷嘴布置和二冷制度进行优化设计。分析了现有喷嘴布置所存在的问题,提出了两种优化喷嘴布置的方案。并以Q235钢为例,说明了异型坯连铸过程二冷制度的确定过程,并给出了常拉速下Q235钢异型坯连铸过程的温度变化情况,对比了不同拉速对异型坯的温度场分布、坯壳厚度生长、特征点温度变化的影响。更多还原

【Abstract】 H-shaped steel is mainly used in bridges, heavy equipment, and high-rise building construction. There are advantages to reduce component weight and so on. For rolling H-shaped steel used beam blank can reduce rolling pass, reducing energy consumption and investment, construction costs, and can significantly increase productivity. However, in beam blank continuous casting process, because of its cross-section geometry of the complex, coupled with difficult to achieve uniform cooling, and thus Beam blank crack more sensitive than billet, slab. The cracks and defects mainly in the inner edge of the web surface cracks, the inner flange of the top corner crack, web thickness 1/2 the center of the crack. Therefore, optimize the design the structure of beam blank casting machine casting process parameters and process parameters is demands.In this paper, contrary to a new beam blank continuous casting machine, established a two-dimensional beam blank continuous casting solidification process of heat transfer mathematical model. Mesh spacing with Variable grid spacing method to discrete model and the used finite difference method to discrete the heat equation. Taking into account the cooling water flow unevenly shaped cross-section billet, establishing a spray of water flow density distribution model, the model can test the water density distribution into a flat-shaped billet flow transverse density distribution.The model can be used to optimize the layout of the nozzle. At the same time the model takes into account a wide area within the arc-shaped blank, wide and narrow plane surface of the nozzle arc discharge different situations, the model closer to reality, making the model with higher accuracy.Application of Visual Basic 6.0 programming language, developed a common secondary cooling beam blank continuous casting simulation software, the software integrates beam blank continuous casting process of solidification and heat transfer simulation and data processing functions for the beam blank casting machine parameters and structures continuous casting process parameters to optimize the design process was provided.Applications developed secondary cooling beam blank continuous casting process simulation software, combined with the beam blank Metallurgical requirements of the guidelines, optimized the design of the secondary cooling system and the continuous casting machine nozzle layout. Analysis the problem of the existing layout of nozzle, proposed two optimization programs for the nozzle layout. Illustrated design the secondary cooling system of beam blank continuous casting process by Q235 steel. Given the temperature changed of Q235 steel under constant casting speed in beam blank continuous casting process. Contrast the temperature distributions, the growth of solidified shell thickness and the feature point temperature changingunder different casting speeds.更多还原