连铸二冷区铸坯表面温度的连续测量

本文介绍一个连铸二冷区铸坯表面温度测量系统的测量方法和实际应用情况。     

连铸二冷区的夹辊与铸坯间传热研究

本文采用一种新的差分格式对夹辊导热微分方程进行了差分化,建立了夹辊与铸坯间的传热数学模型。使用模型在计算机上模拟计算获得了夹辊与铸坯间的传热计算式。公式表明,夹辊与铸坯间的传热和铸坯表面温度、拉速及铸坯接触部分的夹辊弧长所对应的接触角度有关。     

攀钢板坯连铸二冷区铸坯表面温度连续测试工艺研究

阐述了ＣＩＴ－Ｍ型红外测温线性化传感器连续测温的工艺特点，并对攀钢板坯连铸的典型钢种进行了不同拉速条件下的连续测试。为今后开展攀钢板坯连铸二冷动态控制奠定了基础。     

连铸二冷区铸坯表面温度测量

介绍了ＣＩＴ－Ｍ型红外辐射测温系统的工艺特点,利用该系统实测了板坯连铸的典型钢种在不同拉速条件下的铸坯表面温度。分析了拉速和冷却强度对铸坯表面温度的影响,为攀钢板坯连铸二冷配水制度的优化提供了依据。     

小方坯连铸过程二冷区水量的优化

对于目前连铸生产中优质高产的要求,运用控制容积方法建立小方坯连铸冷却热传导模型,将钢的高温性能和现场生产实际相结合,提出通过控制连铸冷却过程的分段温升温降来优化二冷区的冷却水量.在此基础上对于连铸过程不可微相变问题运用粒子群优化方法建立连铸二冷区水量优化模型.该模型通过合理分配各段水量,有效降低热应力,能够较好地指导现场生产.     

连铸二冷工艺优化与铸坯角部裂纹控制研究

通过研究连铸二冷的作用及原理,分析和阐述了二次冷却工艺可能会出现的缺陷和问题,研究了如何优化提升连铸二冷工艺促进铸坯质量,从而连铸机的生产量也会大大增加.同时对二冷系统进行水质优化也会很大程度上减少铸坯裂纹的出现.     

大方坯连铸二冷区凝固坯壳厚度测试

应用"射钉法"测试了攀钢2#大方坯连铸典型钢种在工作拉速下凝固末端附近的凝固坯壳厚度,获得了凝固坯壳厚度、凝固末端位置与连铸拉速和冷却强度的关系,为优化连铸工艺,控制连铸坯凝固终点位置和制定合理的轻压下工艺制度提供了重要依据.     

不同条件下铸坯表面传热系数的变化

连铸二冷制度设置是否合理与铸坯质量有很大关系,铸坯传热系数直接影响二冷制度的制定。本文在实验测定的基础上研究了不同水流密度、不同气体水比条件下传热系数与铸坯表面温度之间的关系,分析了其形成机理。     

不锈钢板坯连铸温度场及二冷配水优化的研究

采用有限元法编制了计算不锈钢板坯在连铸时凝固过程温度场及坯壳的生长随时间的变化。将计算结果与实测结果进行了比较 ,得出影响铸坯温度场和凝固末端位置的主要因素是拉速和二冷配水 ,而过热度影响较小     

Application of Hot Strength and Ductility Test to Optimization of Secondary Cooling System in Billet Continuous Casting Process

By means of Gleeble-1500 dynamic thermomechanical simulator, the continuous casting process for HRB335C steel was simulated using solidifying method and hot ductility and strength of the steel were determined. The test results indicate that there are three temperature regions of brittleness for HRB335C billet in the temperature range from 700 ℃ to solidification point; the first temperature region of brittleness is 1 300 ℃ to solidification point of the billet, the second temperature region of brittleness is 1 200-- 1 000 ℃, and the third temperature region of brittleness is 700-850 ℃ ; the steel is plastic at 850--1 000 ℃. The cracking sensitivity was studied in the different temperature zones of the brittleness for steel HRB335C and the target surface temperature curve for the secondary cooling is determined. With optimized process, the mathematical model of the steady temperature field with two-dimensional heat transfer for 150 mm×150 mm HRB335C steel billet was established to optimize the secondary cooling process. The conic relation of water distribution between secondary cooling water flux and casting speed is regressed. Keeping the surface temperature of billet before the straightening point above 1 000 ℃, the results of billet test indicate that there is free central shrinkage cavity. The billet defect is decreased greatly, and the quality of billet is obviously improved.     

方坯二冷末端电磁搅拌参数的研究

结合南京钢铁股份有限公司电炉厂方坯连铸机的生产实际,用数学模型初步计算凝固末端的坯壳厚度,在二次冷却区末端对铸坯进行射钉实验,利用射钉结果对数学模型进行修正.通过一定拉速下、一定钢种的温度场的计算,找出液芯为φ35～φ55 mm的位置,确定将末端电磁搅拌器安装在距弯月面8 m处.调整电磁搅拌的电流和频率,在冷态状态下测试末端电磁搅拌器不同位置处的磁感应强度,并计算不同电流和频率下的电磁力大小,从测试及计算结果确定电流为550 A,频率为13 Hz时的参数为最佳搅拌参数.     

二冷喷淋强度对连铸坯凝固组织的影响

 推导了连铸过程中二冷喷淋强度与连铸参数之间的关系,比较了喷淋强度对2种断面连铸坯凝固组织的影响。结果表明,喷淋强度能更精确地反映铸坯凝固组织与冷却参数间的关系;铸坯表面的枝晶间距为20 μm左右,而中心区为200～350 μm;距表面相同距离,对角线区的枝晶比横向细小。喷淋强度相近时铸坯的凝固规律为：200 mm×200 mm断面中心区组织较细小,150 mm×150 mm断面近中心区组织较细小。从铸坯表面到中心整体上符合凝固曲线左侧规律,但断面大于200 mm×200 mm的连铸坯,中心和近中心区凝固时符合凝固曲线右侧规律。     

方坯连铸机二冷水动态控制

文中论述了方坯连铸机二冷段配水对铸坯质量的影响，提出了以钢种、铸坯断面、拉速等多种因素来自动调节二冷段配水量的控制方法，实现了有效地二冷水动态控制。     

16MnNb钢圆坯连铸二冷制度的研究

 以某钢厂圆坯连铸机为研究对象,建立了连铸坯凝固传热模型。在不同拉速下对280 mm断面圆坯二次冷却过程进行仿真优化,确定了16MnNb钢合适的二冷制度。根据仿真结果,在最小工作拉速(0.9 m/min)下,矫直点处铸坯内弧表面中心温度为947 ℃,有效避开了铸坯的二次低延性区。在最大工作拉速(1.2 m/min)下,铸坯出结晶器时,其凝固坯壳厚度为19 mm,二冷初期产生漏钢等质量问题的可能性较小。不同拉速下,横断面温度场分布均匀。经低倍检测发现,铸坯表面及内部质量良好,无裂纹、疏松、缩孔等质量缺陷。     

方坯连铸凝固过程冷却的最优化

建立了方坯连铸冷却最优化数学模型,用于确定最优二冷制度和最大拉速。应用分布参数系统最优化控制理论,对此最优化问题进行了分析求解。模型还应用于某厂方坯连铸,进行优化计算,证明模型是合理的。     

Dynamic Water Modeling and Application of Billet Continuous Casting

The continuous casting process is used for solidifying molten steel into semi-finished steel.The technology of secondary cooling is extremely important for output of the casting machine and billet quality.A dynamic water model was introduced,including solidification model in the secondary cooling,feedforward control strategy based on continuous temperature measurement in tundish,and feedback control strategy based on surface temperature measurement.The mathematical model of solidification process was developed according to the principle of solidification,and the solidification model was validated by measuring billet shell thickness through shooting nail and sulfur print.Primary water distribution was calculated by the solidification model according to procedure parameters,and it was adjusted by the other two control strategies online.The model was applied on some caster and billet quality was obviously improved,indicating that the dynamic water model is better than conventional ones.     

Compensation Control Model of Superheat and Cooling Water Temperature for Secondary Cooling of Continuous Casting

In this paper, a compensation control model of secondary cooling process of billet continuous casting for quality steel has been presented. The effects on the spray control of the various parameters such as steel superheat, casting speed, cooling water temperature and chemical component of steel were considered. The parameters of control model were determined to associate with the two‐dimensional heat transfer equation and solved by finite‐difference method. Effects of steel superheat and cooling water temperature on surface temperature, solidification structure and solidifying end point were discussed. Results indicate that steel superheat significantly affects solidification structure and solidifying end point but has a little effect on slab surface temperature. Moreover, secondary cooling water temperature affects surface temperature and solidifying end point but has a little effect on solidification structure. The surface temperature and solidifying end point can be maintain stabilized through applying the compensation control model when steel superheat and cooling water temperature vary. The models have been validated by industrial measurements. The results show that the simulations are in very good agreement with the real casting situation.