【作者】 刘钊；

【导师】 余驰斌；

【作者基本信息】 武汉科技大学 ， 材料加工工程， 2010， 硕士

【摘要】 随着钢铁行业的发展,连铸坯热装热送及“热送直轧”技术的应用程度已成为衡量钢铁生产技术水平的新指标,连铸坯热送热装具有提高生产率、降低能耗和减少铸坯氧化烧损的作用,生产实践表明,在热装温度为600℃、热装比50%时,热轧加热炉的生产率可提高约30%、节约能耗约20%。然而,由于对钢种特性认识的不足,随着铸坯热送率的升高,产品缺陷暴露的种类逐渐增多,严重时难以修复、甚至报废,造成巨大的经济损失。本文以武钢二热轧的热装热送工艺为研究对象,通过综合考虑材料热物性参数随温度的非线性变化、热传导系数及对流换热系数等边界条件,采用有限单元法,借助大型有限元分析软件ANSYS,利用VB建立ANSYS的二次开发,对铸坯的温度场应力场进行研究。通过VB建立的ANSYS二次开发界面,输入相应的参数,模拟出所需要的温度场应力场。对比了在空冷和堆冷的情况下铸坯的温度场和应力场,利用等效热容法处理相变潜热对温度场的影响。得出了在单独空冷和堆冷两种情况下表面应力的变化曲线。通过在现场用红外测温仪测出单独冷却时的温度场,和模拟值基本吻合,验证了建立模型的正确性和方法采用的正确性；通过现场采样进行热模拟实验,测出选取钢种的抗拉强度极限和断面收缩率以及通过膨胀仪测出其膨胀曲线,对比发现,在单独空冷的情况下其表面应力超过了抗拉极限,而在堆冷时表面应力没有超过抗拉极限。在加热阶段,通过对模拟进行简化处理,模拟出在不同的中心温度和表面温度组合时的应力情况,从而得出在何种表面温度与中心温度组合时才不会出现裂纹。更多还原

【Abstract】 With the development of steel industry, continuous casting-hot charge rolling and"hot send direct rolling" technology have become the new target level to measure level of iron and steel production technologies, billet hot charging has increased productivity, reduced energy consumption and reduce the role of oxidation loss slab production.Practice indicates that the temperature in hot charge of 600℃, hot charge than 50%, hot rolling heating furnace productivity increased by about 30%, reduce energy consumption by about 20%. However, because of the shortage knowledge of steel properties,with the rate increased in continuous casting-hot charge rolling, product defect gradually increased including serious, or even scrapped problem, causing huge economic losses.In this paper, in study with hot charge rolling process of The second hot rolling plant in WISCO, With comprehensive consideration of thermal properties of nonlinear parameters, Thermal conductivity and convection heat transfer coefficient change with temperature, use large finite element analysis software ANSYS, and Using VB to establish the secondary development interface of ANSYS to simulate the stress field and temperature field of the slab.VB created secondary development interface of ANSYS, enter the appropriate parameters needed to simulate the temperature field, stress field. Comparison temperature and stress fields of slab Air cooling and the slab heap cooling, using the Equivalent heat capacity method to treat latent heat effect on the temperature field. Obtained in a separate air-cooled, and heaps of cold stress in both cases the surface of the curve. Through measured the temperature the site with infrared thermometer on slab of separate air cooling, and it basic equal to simulated results, Verify the validity of the model and methods to establish the correctness of using; through on-site sampling to thermal Simulation simulation experiment, measured selected steel kind ultimate tensile strength and area reduction rates and measured by dilatometer curve of its expansion, contrast found in the separate case of air cooling the surface stress exceeds the tensile limit, and in the heap cooling surface of the tensile stress does not exceed the limit.In the heating stage, to simplify handling of simulation, to simulate the stress conditions at different core temperature and at different surface temperature combination so as to arrive at what combination of surface temperature and core temperature when the cracks is not appear.更多还原