薄板连铸连轧CSP工艺缓冲性能的研究：直通式辊底炉传热模型及其数值分析

ＣＳＰ工艺是薄板连铸连轧的主要生产工艺之一,直通式辊底炉在ＣＳＰ工艺中起到加热、均薄板和缓冲作用,是十分重要的热工设备。     

连铸坯热装炉改善钢的组织性能

连铸坯热装炉改善钢的组织性能鞠幼华鞍钢钢研所我国连铸工业的发展与国际发达国家有许多不同之处，随着连铸坯短流程直送热装工艺的推广应用与连铸连轧新工艺的开发，将形成连铸坯冷装、温装、热装、在线补热直接轧制和薄板坯连铸连轧等多种工艺。装炉坯温（表面形心温度...     

CSP薄板坯连铸连轧热过程的数值模拟

细致研究了CSP工艺中连铸，均热保温缓冲及其连轧过程对板坯/轧板传热的影响，建立了薄板生产热过程中板坯/轧板温度变化规律的二维非稳态数学模型，通过较精确研究连铸过程中坯壳-结晶器交界面传热，均热热保温过程辐射换热及其连轧过程中轧板-轧辊交界面传热模型，确定板坯/轧板在CSP过程中的复杂边界条件，模型计算结果与邯钢CSP生产线板坯实例数据相吻合。     

薄板坯连铸连轧CSP工艺缓冲性能的研究--直通式辊底炉传热模型及其数值分析

CSP工艺是薄板坯连铸连轧的主要生产工艺之一,直通式辊底炉在CSP工艺中起到加热、均热薄板坯和缓冲作用,是十分重要的热工设备.建立了描述直通式辊底炉炉内换热的长炉模型,应用预解区域法解算其辐射换热,提出了新的"显式"迭代法,对直通式辊底炉的设计和操作参数的影响进行了数值分析.     

等离子体技术在连铸中间包上的应用

介绍了等离子技术在国内外连铸中间罐加热中的应用情况。重点阐述了唐钢应用此技术的效果及研究情况，提出了对应用此技术的看法。     

骨盆骨折并发动脉血栓形成一例

建立了连铸板坯直接热装加热数学模型,并用有限差分法进行求解,获得了各期加热温度分布及加热时间,此模型可用于连铸铸板坯直接热装加热制度的确定。     

特殊钢生产技术的发展及对内燃机零件用钢选择的思考

机电产品大量使用各种特殊钢。随着特殊钢的冶炼、铸坯、成型技术发展,不同铸坯方式的结晶学特征以及最终材料的质量,发生了显著的变化。对铸锭-开坯-轧(锻)制成材与连铸连轧成材的工艺特点和钢材的质量进行比较,对钢材的选择提出一些应考虑的问题。     

等离子体技术连铸中间包上的应用

介绍了等离子技术在国外连铸中间罐加热中的应用情况。重点阐述了唐钢应用此技术的效果及研究情况、提出了对应用此技术的看法。     

枝晶尺度溶质再分配对连续铸造凝固过程的影响

阐述了凝固微细尺度结构上的溶质再分配与宏现尺度传热传质现泉之问的关联，总结比较了多种徽现健析模型，并针对反向凝固工艺和传统的薄板坯连铸连轧(CSP)工艺的传热传质现泉进行了数值模拟，与实验数据进行对比分析。结果表明，微细尺度固—液相界面上的溶质再分配对凝固宏观传输过程的影响不可忽略。     

基于仿真的连铸坯电磁感应加热过程温度控制研究

热连轧生产线连铸坯电磁感应加热过程中,采用常规电压控制曲线难以实现目标温度控制。首先对连铸坯电磁感应加热机理分析,确定连铸坯温升因素,建立基于BP神经网络温度预测模型,并利用此预测模型仿真探究各种情况的加热效果。最终在实际生产中验证、调整电压控制曲线,达到温度控制精度要求。     

轧钢加热炉温度均匀性和氧化烧损的优化

某1 700线加热炉经过5年多的生产实践,存在沿板坯长度方向温度均匀性较差和氧化烧损率偏高的问题。通过出钢端斜炉底改造、更换高温区的耐热滑块、均衡南北供热负荷、合理控制炉压、调整空燃比等方案的实施,使得板坯沿长度方向温差降到30℃以下,板坯的氧化烧损率降到0.95%,很大程度上提高了加热炉的技术水平和加热质量。     

A numerical analysis of slab heating characteristics in a walking beam type reheating furnace

Numerical analysis of slab heating characteristics in a reheating furnace has been accomplished using FLUENT, a commercial software. The phenomena in the furnace are periodically transient because the slabs are transported toward a rolling mill with every time interval controlled. Unsteady calculation has been performed to obtain a periodically transient solution. A User-Defined Function (UDF) program has been developed to process the movement of slabs because FLUENT cannot handle the movement using its default functions. When the mean temperature of a slab emitted to the rolling mill does not change, calculation is considered to have converged and is stopped. This convergence criterion is appropriate for achieving an analytical solution. With the boundary and initial conditions given, over 55 new slabs are inserted to get a converged solution. Skid posts and beams are included in the calculation because they disturb radiation heat transfer from hot combustion gas to the slabs. This article examines what the slabs experience in the furnace before they are emitted to the rolling mill and whether a slab emitted to the rolling mill satisfies the required slab conditions, such as target temperature and skid severity.     

加热炉钢坯加热质量的数值模拟研究

处理不同入炉温度的钢坯需采用合理的加热时间和工艺,针对此问题,采用数值模拟的方法研究人炉温度分别为200,400,600,700℃的钢坯最佳加热时间和加热质量。通过利用Fluent流体计算软件建立了钢坯非稳态导热模型和氧化烧损模型,模拟结果表明：在相同的加热工艺下,钢坯人炉温度为27℃,炉内停留时间为180min时,位于预热段的第5块钢坯表面受到的辐射热流最大,达到92kW／m^2,出炉钢坯氧化率为1．419％;钢坯入炉温度为200℃时,合理的炉内停留时间为150min,出炉温度达到1183℃,出炉钢坯氧化率为1．307％。     

板坯质量在线诊断分析系统的研究与开发

针对板坯表面裂纹和内部裂纹两大类质量缺陷,基于凝固传热仿真、应力应变计算及连铸相关冶金工艺理论分析,并结合浇铸异常事件专家知识库方法,开发了CISDI板坯质量在线诊断分析数学模型及其应用软件CISDI_SQDS ONLINE R2011,其中引入裂纹生成指数来作为质量评级的参考理论指标,并在其计算过程中耦合考虑了与浇铸冶金准则密切相关的质量损失因子和异常事件对应的调节因子,实现了理论解析与专家系统的有机结合,为板坯质量的预测和控制提供了重要的理论工具,以期在板坯连铸生产中得以有效的推广应用。     

Research on a 3D Temperature Field Model of a Slab with Oxide Layer Growth

Slab heating plays an important role in the production of iron and steel materials. However, it is a very complex process involving physical and chemical change. In this study, we built a numerical heat transfer model to predict the three‐dimensional transient temperature field of a slab based on the implicit finite difference method. The model takes the growth of the oxide layer into account, as well as the impact on heat transfer. Slab temperature and oxide layer thickness were calculated in each step. The model considers three kinds of boundary conditions. It displays the temperature variation of each part of the slab in the furnace at all time, the heating curve, and the growth in the thickness curve of the oxide layer. This model can be used to control heating time, optimize the heating curve, and improve production efficiency, thereby reducing cost. The model is also useful for calculation of rolling force, as well as the control of carbon isolation and product microstructure.     

板坯加热炉内加热特性的数值分析

以某公司热轧厂常规与双蓄热烧嘴组合供热的板坯加热炉为研究对象,建立该加热炉炉内流动、传热、燃烧和板坯运动吸热过程的三维物理数学模型,运用CFD仿真技术对其进行详细的数值计算,得到炉内稳态的速度场和温度场分布规律、板坯的升温曲线以及板坯温度分布均匀性,计算结果与"黑匣子"实验测量数据吻合良好。本文给出的板坯加热特性计算方法为研究加热炉新工艺、优化板坯加热温度制度提供了科学依据。     

Research of two-phase density wave instability in reactor core channels with rolling motion

In this study, two-phase density wave instability in parallel-twin rectangular channels was investigated with axially nonuniform heat profiles in the reactor core combined with static and rolling conditions. A parallel-channel thermal-hydraulic model was built using the method of two-phase homogeneous flow developed in previous work, while the drift-flux approach for void fraction and profile-fit model for subcooled boiling were implemented. Although the rolling condition was chosen as the typical motion in this work, the additional force caused by the motion with six degrees of freedom was derived. The theoretical analysis was performed based on the method of small power perturbation for parallel-twin rectangular channels. The flow oscillation caused by rolling was studied for different system parameters, including inlet resistance, exit resistance, pressure, and axial heating profile. The influence on flow instability of rolling parameters such as period, amplitude, and distance between channels was analyzed. The results showed that it would destabilize the system if a larger additional force was generated by rolling parameters. The influence of different axial heat profiles on flow instability was also studied under inlet-peaked, cosine-shape, and outlet-peaked heat fluxes. The coupling effect of rolling motion and axial nonuniform heating was finally studied. The stability boundaries under different conditions were compared to the inherent boundary under the static condition with uniform heating. The results indicated that the influence of nonuniform heating was more evident and should be paid more attention to.     

提高不锈钢板坯表面质量的生产实践

为进一步改善立式板坯连铸机的不锈钢铸坯表面质量,通过对全流程钢水洁净度集成控制、采用优质合适的结晶器保护渣、稳定的结晶器工况、改善设备功能精度、振动参数优化等措施,使其板坯连铸机铸坯质量得以稳定提升,304卷板无修磨比例大幅提高,从9％达到78.2％,修磨损失率降至0.3％的水平,全钢种修磨损失率降至1.01％,同时轧后废品率也大幅度降低,降幅达50％,经济效益十分明显.