结晶器漏钢预报系统的原理分析

通过对粘结漏钢产生的原因及粘结时坯壳的特征 ,结晶器漏钢预报系统的原理进行分析 ,得出发生粘结漏钢必须满足三个必要条件 ,并得出发生漏钢预报后铸坯拉出结晶器不漏钢应满足的条件     

结晶器漏钢预报系统的原理分析

通过粘结漏钢产生的原因及粘结时坯壳的特征,对结晶器漏钢预报系统的原理进行分析.得出发生粘结漏钢必须满足三个必要条件,并得出发生漏钢预报后铸坯拉出结晶器不漏钢应满足的条件.     

板坯漏钢机理及基于热电偶检测的漏钢预报技术研究

通过粘结漏钢、裂纹漏钢(纵裂、角裂)及异物卷入漏钢发生的原因,产生的机理及漏钢发生的部位,坯壳特征等因素的研究与分析,建立一种可预报粘结、裂纹及异物卷入漏钢的新型板坯漏钢预报系统.     

板坯连铸粘结漏钢坯壳特征及结晶器铜板温度变化研究

为了研究板坯粘结漏钢的机理和预防粘结漏钢的发生,分析了粘结漏钢后凝固坯壳的厚度、裂纹形貌和表面振痕等特点,建立了初生凝固坯壳受力的数学模型,研究了正常生产及粘结漏钢前后结晶器热电偶温度变化规律.总结出粘结漏钢坯壳的典型特征,确立了保护渣性质、拉速、振动参数等对粘结的作用,得到粘结的热电偶温度变化特征,为漏钢预报系统的优化提供参考.     

高碳钢小方坯粘结漏钢形成原因分析与控制

针对某厂高碳钢小方坯粘接漏钢发生率高的问题,通过观察高碳钢漏钢坯壳组织形貌,分析其在结晶器中运动规律,研究了粘结漏钢的形成机理。结合现场连铸生产过程参数和保护渣使用情况的调查,弄清了造成该钢种粘结漏钢的主要原因。凝固坯壳在二次弯月面附近发生粘结,在结晶器上下振动过程中粘结处坯壳发生拉断、重接和再拉断,漏钢破裂处随之逐渐下行,直至结晶器出口处发生漏钢。调查分析发现,保护渣润滑性能不良、结晶器液面波动大、过热度和拉速不合适是该钢厂高碳钢小方坯粘结漏钢的形成原因。采用可行的控制措施后,高碳钢小方坯粘结漏钢发生率从8.4%降低到1.5%。     

连铸结晶器内粘结漏钢的形成机理及对策

连铸结晶器内钢液弯月面在连铸生产中起着至关重要的作用，本文结合钢液弯月面的行为对粘结漏钢的形成进行了详细地分析，介绍了一种新的粘结漏钢形成机理，认为钢液弯月面的破损是粘结漏钢发生的直接起因，此外，还在该机理的基础上，探讨了防止粘结漏钢的对策。     

大板坯连铸粘结漏钢浅析

介绍了大板坯连铸粘结漏钢的发生机理和和主要特点;结合邯钢三炼钢厂生产实践,分析了工艺、操作和设备等因素对粘结漏钢的影响;提出了降低粘结漏钢次数的主要措施。措施实施后取得较好效果。     

连铸结晶器漏钢预警系统算法研究

连铸是把液态钢浇铸、冷凝和切割变成铸坯的过程,高温钢液通过结晶器浇铸成型。如果钢液在结晶器内发生粘结,继续高速拉坯将导致漏钢事故,给安全生产带来巨大的风险。连铸结晶器漏钢预警系统作为预防漏钢的智能系统,能够通过精密的算法及时侦测到钢液粘结,通过降低浇铸速度增加凝固时间,使粘结处坯壳补强,从而避免浇铸漏钢事故发生。系统功能是基于算法实现的,所以,对结晶器漏钢预警系统算法的研究显得十分重要。     

基于温度比波形识别的BP神经网络漏钢预报模型

通过对粘结漏钢过程的研究,提出了一种温度比波形,该波形可以反映粘结发生时热点的传播过程,弥补了以往漏钢预报模型只能通过延迟检查对热点传播过程进行监控的不足.利用BP神经网络对温度比波形和粘结发生时的两种典型温度模式进行识别,建立漏钢预报模型.将该模型应用于板坯连铸漏钢预报中,并用某厂的现场数据对该模型进行测试,测试结果表明该模型能有效地进行漏钢预报.     

板坯连铸机粘结漏钢的原因分析及解决措施

为了减少大板坯连铸机粘结及粘结漏钢的发生,对结晶器保护渣的消耗量、保护渣液渣层厚度及粘结的受力机理进行了研究和分析,认为保护渣消耗量低及保护渣液渣层厚度不够时容易产生粘结和粘结漏钢。通过采集现场的参数进行理论计算并与实际生产值进行对比,结果表明,保护渣的消耗量控制在0.4～0.6 kg/m2、保护渣液渣层厚度控制在10mm以上后,未发生粘结漏钢事故,且粘结发生次数降低了60%。     

连铸结晶器黏结漏钢的可视化及其识别方法

基于现场实测热电偶温度数据,将结晶器铜板温度及其变化速率进行2维可视化。综合考虑黏结形成和发展过程中结晶器铜板温度随时间的变化和空间传播行为,借助计算机图像处理中的8连通区域标记和边界跟踪算法,提取了异常区域的结晶器铜板温度、位置、时间等信息,计算了结晶器铜板温度变化速率的均值、最大值、区域的面积、宽度、高度及其纵向和横向移动速率特征,对实际浇铸过程中多例漏钢样本的共性特征进行了统计和归纳。结果表明,结晶器铜板温度变化速率、几何特征与传播速率能够作为黏结漏钢在线预报的重要判据,为提高漏钢预报系统准确率提供参考,减少漏钢事故,同时为结晶器可视化、智能化监控技术开发提供方法和依据。     

板坯连铸结晶器黏结及其传播行为

 基于国内某钢厂宽厚板坯连铸机,及黏结漏钢过程中结晶器铜板的实测温度样本,重点讨论了黏结的横向、纵向速度与角度等传播行为,分析和对比结晶器黏结的发展特征,及其随拉速和断面浇铸工艺的变化,为进一步认识宽厚板坯黏结漏钢的传播特性,以及热电偶优化布置与漏钢预报系统开发提供参考和依据。     

连铸粘结漏钢的结晶器温度变化及其传播行为

以国内某钢厂板坯连铸粘结漏钢的实测样本为基础,重点调查了铸坯粘结时结晶器热电偶温度变化,分析了粘结传播行为,讨论了现行热电偶布置合理性和漏钢预报模型的设计.研究结果表明:粘结时单个热电偶温度在时间上表现先升后降变化规律,且具有一定温度变化速率和持续时间,多行多列相邻热电偶温度变化在空间上表现粘结传播的"时滞性",具有典型性,同列热电偶温度变化表现"温度倒置"现象,但不具典型性;粘结纵向传播速度小于拉速,与拉速呈线性正相关,横向传播速度与拉速比为 0.91 ~ 1.91,存在较大不稳定性;从纵横向检测快慢和稳定性综合考虑,以纵向检测为主、横向检测为辅设计漏钢预报模型更为合适;现行热电偶布置较为合理.     

Recovery mechanism of the sticking-type breakout during continuous casting of steel

Sticking-type breakout is one of key factors which restrict the development of high-speed or wide-heavy plate continuous casting technology. In order to better heal and control the sticking-type breakout, this paper presents a comprehensive study for its recovery mechanism. First, according to force characteristics of solidified shell at mold exit, calculation method of safe shell thickness is proposed. Then, considering sticker propagation behaviour and safe shell thickness, a more practical recovery model of sticking-type breakout is established and verified by actual examples. The result shows the proposed recovery strategies avoid casting speed to be decreased too low or cast stop, thus save unnecessary operating time, and are better than original strategies. Furthermore, influencing factors of recovery behaviour are analyzed. The result shows hot spot location, operating casting speed, and mold oscillation frequency have a significant effect on minimum speed for the recovery and oscillation stoke has little influence on it.     

Break temperatures of mould fluxes and their relevance to continuous casting

Abstract

The break temperatures of mould fluxes are important since they help to control the horizontal heat transfer and lubrication between the steel shell and the mould, and consequently affect occurrences of longitudinal cracking and sticker breakout in continuous casting. Break temperatures T _br have been determined for both steady state and dynamic measurement of the viscosity, and equations relating T _br to chemical composition have been obtained for both cases. It has been found that T _br can be affected by (i) cooling rates and (ii) fluorine losses during the measurements.     

Continuous casting mould powder evaluation

Abstract

A continuous casting mould powder must satisfy various requirements including thermal insulation, chemical insulation, inclusion absorption, lubrication, and promotion of uniform heat transfer from the solidifying steel strand to the copper mould. The relative importance of these properties varies according to the type of steel cast, the prevailing casting conditions, and the end steel requirements. Development of mould powders at Corus UK Ltd involves plant based trials of different powders whose properties influence the above characteristics of which heat transfer is a major consideration. Particular use is made of mould thermal monitoring which, although primarily designed for sticker breakout detection, is now finding increasing use as an investigative tool in mould slag assessment. Both static and dynamic plant data are now available relating mould slag heat transfer performance to casting conditions and this paper describes some recent investigative work carried out by the Aluminium & Steel Casting Department of Teesside Technology Centre, Corus UK Ltd. The study shows that using a combination of plant based observation and laboratory analysis, a greater depth in understanding of mould powder performance can be realised, yielding important information for future powder development.     

Investigation of strand surface defects using mould instrumentation and modelling

Abstract

The surfaces of continuously cast steel blooms exhibit a variety of surface features and defects, which were investigated to reveal the interactions at the meniscus between the steel shell and interfacial flux layers that caused them. One such defect formed at periodic intervals along the surface of first and second blooms in a sequence. It was characterised by gradually deepening oscillation marks, followed immediately by longitudinal striations or 'glaciation marks'. In severe cases, deep depressions were clearly visible within the glaciated region. These defects were investigated through plant trials and both physical and mathematical modelling. The defects were found to exhibit a characteristic temperature history: temperature troughs that move down the mould at the casting speed. These defects may be monitored in much the same way as sticker breakouts, thereby allowing existing thermocouple based breakout detection systems to be modified to include a quality alarm. This study attributes these defects to high amplitude, low frequency, mould level fluctuations. A mechanism is proposed which ascribes the generation of these defects to the interaction of the meniscus with the slag rim at peaks in the mould level cycle. Installing an improved mould level control system eliminated the defects.     

优化鱼雷罐运行模式，减少粘罐量

从鱼雷罐生产运行数据着手，找出了影响鱼雷罐粘铁、粘渣的相关因素，并详细分析了各主要因素对鱼雷罐粘罐的影响程度；同时结合对鱼雷罐运行现状分析，提出了控制粘罐因素的目标参数。建立了系统工作方法及运行模式。     

酒钢板坯连铸漏钢成因分析及预防措施

对于酒钢4号、5号板坯连铸机的主要产品Q235及低合金钢的生产,近几年由于操作、设备等因素造成较高的漏钢率,给生产和设备造成极大危害.分析了漏钢的原因,在无漏钢预警系统的前提下制定了针对粘结漏钢与裂纹漏钢的预防措施,使板坯漏钢率显著下降.