铝带连续铸轧温度场有限元仿真

研究了铸轧过程中各相关主要工艺因素对铸轧辊-板系统温度场的影响,建立了铸轧辊-板系统传热规律的基本方程,揭示了铝带双辊铸轧过程中铸轧辊-板系统温度场的变化规律和传热的基本规律,为制定双辊铸轧工艺打下了基础。     

双辊板带铸轧凝固过程的数值模拟

根据双辊板带铸轧工艺中金属熔池内的传热特点,建立了笛卡尔坐标系下的传热数学模型,并利用有限差分法对其凝固过程进行了数学求解,从而对双辊板带铸轧凝固过程的传热特点及其影响因素进行总结,并对其加工工艺提出了一些见解,最后将该方法的求解结果和文献中的结果进行了对比。通过本方法的研究,为控制带钢铸轧的凝固过程提供了理论基础。     

不锈钢薄带铸轧过程中的流动特性

采用有限元法模拟了双辊铸轧不锈钢过程的流热耦合问题,分析了铸轧速度对熔池内流场、温度场遥影响以及流场与温度场之间的相互关系,给出了大过程中熔池与铸轧辊之间的热流密度变化趋势及帮轧速度的变化规律,并比较了模拟与试验的结果;给出了薄带表面温度在铸轧过程中的变化及其随铸轧速度变化的趋势。     

工艺因素对铝双辊铸轧凝固过程的影响

利用铝双辊铸轧过程传热数学模型,系统分析了辊套材料、浇注温度等工艺因素对铝双辊铸轧过程凝固速率的影响及进一步提高铸轧机生产能力的途径,建立了钢和铜合金2种辊套材料的凝固壳厚度随时间变化的计算公式。     

IAD法在双辊铸轧薄带温度场数值模拟中的应用

双辊铸轧薄带过程中的凝固传热现象十分复杂。用交替方向隐式插分法通过VB语言计算了薄带坯的动态温度场,进而模拟了薄带坯的凝固传热过程,对实际生产有重要的参考价值。     

双辊薄带钢铸轧过程的流场温度场耦合数值模拟

采用有限元法模拟了双辊铸轧不锈钢过程的流热耦合问题;分析了铸轧速度对熔池内流场,、温度场的影响以及流民温度场与温度场之间的相互影响,给出了凝固过程中熔池与铸轧辊之间的热流密度变化趋势及随铸连的变化规律,并把此模拟的结果与试验的结果相比较,吻合较好;通过熔池内温度场及温度梯度分析了熔池内凝固的发展及其对热流密度变化的影响。此     

双辊液态铸轧中铸辊温度场的数值解析及热疲劳问题的分析

通过双辊液态铸轧中铸辊二维温度场数值计算，研究了多种工艺参数对铸辊温度场及热疲劳寿命的影响规律，其结论对提高铸辊寿命具有指导意义。     

铝合金连续铸轧过程直接热-力耦合数值模拟研究

基于大型有限元模拟软件MSC.Marc建立了连续铸轧过程的热-力耦合模型,应用材料流变本构模型和辊/板界面接触热导模型,对铝合金的连续铸轧过程进行了二维的直接热-力耦合数值模拟,分析了连续铸轧过程中辊套及板坯的温度场、应力场的分布规律,研究了不同的铸轧工艺下的板坯温度场、应力场变化的规律。研究发现：在铸轧过程中,辊套的温度分布、应力分布均存在所谓的＂集肤效应＂,板坯在铸轧区内的应力场与板坯物性因素、几何因素及温度、铸轧工艺等有密切的联系,仿真的结果与大量的工业现象相符,在一定程度上可以为实际生产提供技术指导。     

双辊铸轧工艺温度场和流场耦合的数值模拟

 双辊铸轧过程中熔池内金属的流动状态及温度分布直接影响着铸轧过程的稳定性与铸带产品的质量。针对实验室双辊铸轧试验的特点,采用三维有限元法模拟了双辊铸轧过程的热流耦合问题,利用热平衡计算、铸轧实验和模拟相结合的反向方法分段建立了凝固过程中凝壳与铸辊之间热传导系数与铸轧速度、熔池位置之间的关系模型,并分析不同工艺条件下熔池内凝固变化的情况。     

双辊铸轧薄带钢温度场的有限元分析

针对实验室现有的实验设备条件,建立了双辊铸轧薄带钢过程的有限元数学模型,通过程序开发对熔池内的温度场进行了模拟;给出了各工艺参数对凝固终点位置及铸带表面温度的影响规律,为铸轧过程的分析和控制提供了理论依据.     

Simple model for thermal calculation in twin-roll strip casting process

The numerical model for the solidification process of metal in the twin-roll type strip caster is presented in this paper. In the model the temperature change as well as the eliminating process of latent heat is calculated along the stream lines obtained by a comparatively simple velocity field. The calculations are carried out on the strip casting of type 304 stainless steel under various casting parameters. The results so obtained show a good fit to the experimental ones, and suggest that the control of the height of molten pool is of importance to the establishment of the optimal operation.     

双辊薄带连续铸轧熔池内金属流动及传热特性的研究

本文建立了双辊式薄带连续铸轧熔池内二维传热流动数学模型，使用有限元计算方法实现了控制方程及边界条件的数值求解，计算结果揭示了熔池内的流场、凝固温度场的特点和规律。     

双辊连铸中工艺参数对薄带凝固晶粒的影响

以低碳钢为例对双辊连铸过程进行了微观模拟。研究了浇注温度、拉坯速度、冷却强度等工艺参数对带材结晶凝固晶粒度的影响,得出了不同工艺条件对铸轧带材晶粒度的影响规律以及最佳的模拟参数。通过实验结果与数值模拟结果的对比,验证了模拟结果的正确性,说明模拟结果对实际有一定的指导意义。     

Numerical Simulation of Filling Process During Twin-Roll Strip Casting

The modeling and controlling of flow and solidification of melt metal in the filling process is important for obtaining the optimal pool level and the formation of the solidified metal layer on the surface of twin-rolls during the twin-roll strip casting. The proper delivery system and processing parameters plays a key role to control flow characteristics in the initial filling stage of the twin-roll strip casting process. In this paper, a commercial CFD software was employed to simulate the transient fluid flow, heat transfer, and solidifications behaviors during the pouring stage of twin-roll strip casting process using different delivery systems. A 3D model was set up to solve the coupled set of governing differential equations for mass, momentum, and energy balance. The transient free-surface problem was treated with the volume of fluid approach, a k–? turbulence model was employed to handle the turbulence effect and an enthalpy method was used to predict phase change during solidification. The predicted results showed that a wedge-shaped delivery system might have a beneficial impact on the distribution of molten steel and solidification. The predicted surface profile agreed well with the measured values in water model.     

待定系数法确定双辊薄带铸轧中的边界热流

熔池与铸轧辊接触的边界热流是进行双辊薄带铸轧数值模拟研究的重点,通过铸轧过程中金属凝固机制和传热过程的研究,提出结晶辊和熔池接触的边界热流分布函数形式,利用凝固初始位置、薄带坯出坯厚度,再结合能量守恒原理进行求解,确定函数中的待定参数,避开传统方法需要求解坯壳和铸轧辊间气隙热阻的难题;通过施加所提出的边界热流函数对某试验铸轧辊温度场进行求解,结果与实测结果相吻合,这表明文中提出的边界热流分布函数形式与实际相符合。     

Control of the Molten Steel Level in the Top Side-Pouring Twin-Roll Casting Process Based on Fuzzy Rules Optimized by Particle Swarm Optimization Algorithm

Twin-roll strip casting is a near-net-shape casting technology that can produce thin steel strips directly from molten steel. Stably controlling the molten steel level is regarded as an important issue to ensure strip quality and casting process stability. As the control of the molten steel level is a time-varying, nonlinear, and multidisturbance complex system, it is difficult to establish an accurate process model for designing a model-based controller. Top side-pouring twin-roll casting is a new kind of twin-roll strip casting technology. This study introduces the control system of the top side-pouring twin-roll casting process. A fuzzy logic controller (FLC) with its fuzzy rules optimized by particle swarm optimization (PSO) is developed to regulate the molten steel level. Simulation results show that the performance of the FLC can be improved while its fuzzy rules are optimized by PSO. The objective function of PSO has a great influence on the optimization of the fuzzy rules. The top side-pouring twin-roll casting experiments are carried out using the FLC with its fuzzy rules optimized by PSO; the results show that strip quality and casting process stability are guaranteed.     

Crystallization Extent and Phase Constitution of Slag Films Taken from Continuous Casting Moulds for Stainless Steels

Slag film samples were taken from the mould wall after casting of stainless steel slabs of grade 304, 321, 409L and 430, which represent austenitic, ferritic and titanium stabilized stainless steels. The chemical compositions of the samples were analysed and their phases were identified using a combination of scanning electron microscope (SEM), energy dispersive X‐ray analysis (EDX) and X‐ray diffraction (XRD). Finally the crystallization ratio was determined by SEM. The results show that the chemical compositions of the films during casting differ from the original designed flux composition. Concerning the heat transfer in the mould, the film taken during casting of steel grade 304 showed the highest insulation ability whereas the film taken during casting of steel grade 409L had the lowest insulation ability. The films taken during casting of steel grades 321 and 430 showed average heat insulation abilities. The solidification conditions in the mould during casting of steel grades 304, 321, and 409L matched the solidification requirements of the corresponding steel grades. However, the basicity of the powder for steel grade 430 should be decreased a little in order to improve the lubrication function and counteract sticking tendencies. Perovskite crystals, which usually precipitate at relatively high temperature, were found in the film taken during casting of steel grade 321. This is harmful in view of the safety of the casting process and the surface quality of the slab.     

双辊薄带连铸生产取向硅钢的技术分析

 双辊薄带连铸工艺具有流程短、单位投资低、能耗低、劳动生产率高等特点,而取向硅钢被认为是双辊法连铸工艺中最具有发展前途的钢种之一。针对此介绍了双辊薄带连铸技术的工作原理及其研究现状,总结了目前国外双辊薄带连铸生产取向硅钢相关方面的专利,并分析了双辊薄带连铸生产取向硅钢与传统工艺在组织、织构以及抑制剂控制方面的差异性,指出该流程在生产取向硅钢方面具有独特的优势,其工业化应用将会对取向硅钢的生产和发展起到革命性的推动作用。