热轧带钢层流冷却过程温度场研究

 建立了热轧带钢层流冷却过程中温度场的三维有限元模型,对3 mm厚带钢轧后冷却过程带钢温度场进行模拟计算,得出卷取温度比现场测量值低9.5 ℃,相对误差为1.42%,验证了模型和假设的合理性。研究了上喷嘴直径对带钢温度的影响,带钢上表面宽度方向上存在2种不同的冷却区域：位于喷嘴正下方层流冷却过程中交替经过冲击区和平流区的区域和位于两喷嘴之间层流冷却过程中只经过平流区的区域,这造成带钢宽度方向上温度分布不均匀。计算结果表明,喷水量保持不变的情况下,存在一个最佳喷嘴直径,使带钢宽度方向上温度分布更均匀。喷水速度保持不变,增加喷嘴的直径有利于带钢宽度上方温度均匀,但增加了喷水量,降低了带钢的卷取温度。     

卷取带钢速度测量系统的开发

卷取温度（CT）精度是冷却过程控制的核心,而卷取带钢速度是作为热轧带钢CT控制的重要参数。结合某热轧厂CT控制系统的改造,提出了一种卷取带钢速度测量系统。该系统能精确测量卷取带钢的速度,为提高带钢尾部CT的控制精度提供有力保证。     

宝钢三热轧带钢卷取温度控制改善方法的研究与实践

层流冷却是热轧的一道重要工序,其控制精度对带钢物理性能具有重要影响。在宝钢三热轧实际生产中发现部分带钢尾部卷取温度单向偏高或偏低,引起质量损失。质量损失的主要成因在于基于带钢中间坯测量值计算的带钢理论长度与实际值偏差过大,导致带钢运行图预报不准。通过采用特定传感信号对带钢长度及运行图进行修正,达到了理想效果。     

热轧带钢层流冷却控制系统

为了提高莱钢1500mm热连轧卷取温度的控制精度,对原基础自动化控制系统进行改造,增加了带Smith预估器的反馈控制和轧机抛钢后的冷却水前馈控制;同时增加了过程自动化控制系统,包括预设定计算、修正设定计算和自学习计算模块。系统改造后,带钢卷取温度控制不稳定的现象基本消除,实现了带钢的冷却模式、卷取温度和冷却速率的精确控制,提高了带钢的质量。     

济钢1700mm热轧层流冷却系统改造

针对济钢1700mm热连轧生产线原层流冷却卷取温度控制系统中存在的不足和弊端,通过采用数学模型,开发多种冷却策略,修正带钢速度变化,抛钢后处理,采用反馈控制,开发模型维护工具等措施对层流冷去系统进行改造。系统改造后稳定可靠,卷取温度命中率有了较大幅度的提高。     

Development of Cooling Process Control Technique in Hot Strip Mill

Therearethreemajordifferencesbetweenthenewlydevelopedhotstripcoolingsystemandthecon ventionalsystem .Firstly ,newtemperaturemathemat icalmodelisdevelopedwithmoreaccurateconsidera tionsontemperaturedependenceoftheheattransfercoefficient,phasetransformation…     

宝钢三热轧层流冷却过程控制系统研究与开发

热带钢轧制的卷取温度对带钢的质量有着重要作用.新建的三热轧层流冷却控制系统由宝钢自主开发,L2级进行完全动态控制(三菱L1级仅负责执行L2设定结果,不作任何动态控制).该系统具有实时控制性强、模型计算精度高、自学习后精度爬坡快等优点.相比2050mm产线,新增的冷却速率控制、带钢分段冷却、反馈PID模糊控制等技术,满足了高强钢和硅钢高品质冷却的要求.     

Effects of Technological Parameters on Microstructures and Properties of Low Cost Hot Rolled Dual-Phase Steel on CSP Line

The effects of technological parameters on microstructures and properties of low cost hot rolled dual-phase steel was researched by design different finish rolling temperature,mid cooling temperature between laminar cooling and UFC (ultra fast cooling) and stable UFC rate on the same gauge strips with the same chemistry composition during the manufacture process.It is the key for controlling coil temperature to control finish rolling temperature and mid cooling temperature between laminar cooling and UFC that based on stable UFC rate precondition.The lower finish rolling temperature,with mid cooling temperature between laminar cooling and UFC,the better to form martensite is.The foundation of developing the similar productions on the similar product line was supplied.It is good to technological advancement of developing high affixation value production as hot rolled DP steel,TRIP steel etc.in CSP line.     

Metallurgical Aspects of Ultra Fast Cooling in front of the Down‐Coiler

The Ultra Fast Cooling technology developed by CRM has been implemented on the hot strip mill of Carlam (Arcelor group), just in front of the down‐coilers (late UFC). The results have demonstrated the controllability of the system and the great efficiency (≥ 3.5 MWm^?2, 300°C/s on 4 mm thick strip) of the cooling unit. Increasing the cooling rate in a controllable way makes the production of high strength steels easier and cheaper. The combination of laminar and UFC technologies opens the way for new cooling schedules. Multiphase microstructures are therefore easily generated by controlling the intermediate temperature ‐ between laminar cooling and UFC ‐ and the coiling temperature.     

热轧带钢层流冷却计算机控制系统

从基础自动化、系统服务、过程自动化3个方面介绍了攀钢热轧带钢厂层流冷却计算机控制系统的设计，着重介绍了过程自动化中的样本微跟踪和一种改进的层冷热流密度参数回归求解方法以及系统模型调优。实际运行结果表明，国内自主开发的热轧带钢层流冷却计算机控制系统完全达到并超过了设计要求，具有较高的卷取温度控制精度。     

Modelling the Temperature Distribution along the Length of Strip during Hot Rolling Process

Hot strip rolling process includes four main stages, which are reheating process, roughing and finishing process, laminar‐cooling process, and coiling process respectively. Temperature is the most sensitive parameter and has direct effect on the microstructural evolution and further the mechanical properties, and the accurate control of temperature guarantees the quality of products and homogeneity of properties along the strip length. However, for the conventional hot strip rolling process, thermal history along the strip length is very complex, the related temperature variation concerns air cooling, water cooling, heat transmission by roll contact, heat generation by deformation and friction. Based on the actual hot strip mill, the thermal models are established in this paper to simulate the temperature distribution along the whole strip length from the reheating furnace exit to the down coiler. Different interface heat transmission coefficients are selected for the scale breaking and spray water‐cooling process, and a self‐learning algorithm is thus employed to improve the calculation accuracy. This model is characterized as simple and fast, and convenient for on‐line/off‐line prediction of temperature. Finally the simulated results are verified by the on‐line temperature detection at typical points such as roughing exit (RT2), finishing exit (FT7) and coiling position (CT).     

热轧带钢控制冷却技术的发展

新钢种开发和用户对板带产品质量越来越严格的要求使得轧后控制冷却得到高度重视,不但要求实现目标卷取温度控制,冷却速度控制还要求实现冷却路径控制和微观组织结构和性能控制.从冷却换热形式、数学模型、控制策略、质量控制思想四个方面阐述了控制冷却技术的发展.     

1780mm热连轧机带钢层流冷却自动控制系统开发及应用

层流冷却是控制带钢卷取温度的最重要手段。为了满足宁波钢铁有限公司1 780 mm热连轧机薄板生产线层流冷却工艺的控制要求,采用了由基础自动化控制系统和过程控制系统组成的两级计算机控制系统。介绍了层流冷却系统设备及自动控制系统结构。重点阐述了层流冷却基础自动化系统主要功能,包括层流冷却区域内带钢微跟踪、步序控制、卷取温度反馈控制以及速度前馈控制。运行结果表明,系统控制精度、响应速度均满足工艺要求。自系统投入运行以来,工作稳定,控制效果较好。     

Algorithm Design and Application of Laminar Cooling Feedback Control in Hot Strip Mill

 Abstract： Feedback control is one of the most important ways to improve coiling temperature control precision during laminar cooling process. Laminar cooling equipments of a hot strip mill and structure of the control system were introduced. Feedback control algorithm based on PI controller and that based on Smith predictor were designed and tested in a hot strip mill respectively. Practical application shows that the feedback control system based on PI controller plays a limited role in improving coiling temperature control precision. The feedback control system based on Smith predictor runs stable and reliable. When the measured coiling temperature deviates from the target value, it can be adjusted to the required range quickly and steadily by Smith predictor feedback control, which improves the coiling temperature control precision greatly, and qualities of hot rolled strips are improved significantly.     

热轧带钢超快冷模型及自适应控制系统的研究和开发

 超快冷技术是用新一代TMCP工艺理念开发低成本高性能钢铁材料的核心。热轧板带钢轧后工艺控制点温度的控制精度是保证带钢性能和质量的关键因素。基于前期开发的装备和工艺建立了超快冷自适应控制系统模型,并对模型的自适应功能进行了研究,旨在进一步提高轧后工艺控制点温度的控制精度。通过对模型结构的优化设计、模型自学习控制策略的研究及模型自学习系数加权平滑的处理,增强了模型自适应功能。该控制系统已经成功应用于热轧板带钢生产线。现场实践表明,该系统轧后工艺温度控制达到了较高的精度,为产品质量的提高及新产品的开发提供了有力的保证。     

基于面向对象技术的热轧卷取温度模型开发

以面向对象的视角审视热轧带钢轧后冷却过程涉及的轧件、辊道、集管、冷却介质与仪表5要素,对轧件在辊道的传热过程、冷却水量和温度的控制过程进行分析、分解并抽象成类。利用面向对象的方法对卷取温度控制(coiling trmperature control,简称CTC)模型的体系结构进行设计,结合模型的触发逻辑进行对象设计,利用C++语言开发面向对象的卷取温度模型。基于有限差分计算方法的模型设定时间满足在线快速计算的要求,模型具有良好的可移植性和可扩展性。现场应用表明,冷却控制系统运行稳定,模型设定准确,卷取温度控制效果良好。     

Improvement of Prediction Method for Strip Coiling Temperature

Thecoilingtemperatureisoneoftheimportanttechnologicalparametersaffectingthefinalmechani calpropertiesofstrip[1,2 ] .The purposeofcoilingtemperaturecontrolistomakestripcooltorequiredcoilingtemperaturefromhighertemperatureforap propriatemicrostructureandmechanicalproperty .Atpresent ,thecontrolmodelofcoilingtemperatureforBaosteel 2 0 5 0millisaself adaptingempiricalmodel.Thoughthecontrolissatisfactory ,theout of toleranceofcoilingtemperatureisstillobservedinproduction .Itwasconcludedbytheinvest…     

热轧带钢层流冷却自动控制系统开发与应用

结合现场情况介绍了热轧带钢层流冷却自动控制系统的设备及硬件配置,并从过程自动化和基础自动化两个方面介绍了该系统的功能和数学模型,其中数学模型主要包括空冷模型、水冷模型、自学习模型和前馈控制模型以及反馈控制模型。现场实际应用表明,带钢全长的95.93%的卷取温度可控制在目标值的±15 ℃之内。     

层流冷却中带钢温度分布模型的开发

在热轧带钢层冷却控制数学模型中，由于忽略带钢内部的热传导而使卷取温度控制不良，本文采用离线二维数模计算带钢沿厚度方向上的温度分布，在线控制中给予补偿，取得较好的效果。     

热轧窄带65Mn钢珠光体组织与性能的窄范围控制

为制定65Mn窄范围质量控制工艺参数,利用OM、SEM、拉伸试验机及洛氏硬度仪等,研究热轧窄带65Mn钢的终轧温度、终轧后冷速下以及卷取后冷速对珠光体组织及力学性能的影响。结果表明:在其他工艺参数相同的情况下,随着终轧温度的提高、终轧后冷却速率的减缓和卷取后冷却速率的加快,热轧窄带65Mn钢珠光体球团尺寸和片层间距不断增大、片层变厚、抗拉强度及硬度均逐渐降低,当终轧温度大于960℃、终轧后冷却速率小于5.58℃/s及卷取后冷却速率小于0.1℃/s时,其抗拉强度小于900 MPa。