国产热轧型钢伸缩缝在沪宁高速公路上的应用

沪宁高速公路(上海段)全线桥梁采用国产热轧型钢伸缩缝装置,成功地解决了伸缩缝的跳车、振动问题,增强了高速行车的舒适感和连续感,对国产型钢伸缩缝的推广使用,具有重要的意义。

化学成份和加热温度制度对18-8型奥氏体热轧不锈带钢表面质量的影响

在18-8型奥氏体不锈钢热带轧制过程中常常由于α相的大量存在而出现结疤和边裂缺陷。就作为α相含量主要影响因素的化学成份和加热温度制度对18-8型奥氏体热轧不锈钢表面质量的影响进行了研究,为合理地制定加热工工艺,提高热轧带钢表面质量提供了必要的理论依据。

加热炉供热系统优化的数学模型研究

本文首先建立了加热炉内钢坯加热过程的数学模型，根据变化的轧制生产情况，即可得出钢坯的准确温度分布，通过建立在给定条件下尽可能地提高加热质量、降低燃耗和钢坯氧化烧损的优化加热模型和加热炉区域热平衡模型，结合钢坯加热过程数学模型，应明分割技术采用FORTRAN编程计算出了加热炉最佳供热的Q－P模型。在现场实验数据的基础上，结合操作经验与理论计算，制定相应的待轧策略．这些研究结果可进一步用于加热炉的计算机控制系统的开发。

浅析热轧不锈钢纵剪切口断面水波纹解决办法

公称厚度5 mm热轧不锈钢卷材纵剪加工时成品切口断面断裂层会出现凹凸不平的水波纹缺陷,严重影响下游工艺焊接可靠性和扁钢外观质量。为消除该缺陷,分别采取不同参数进行试验,研究了重刀量、侧间隙、产线速度、侧间隙和产线速度双因素对纵剪成品切口断面水波纹缺陷的影响。研究表明,增大圆盘刀侧间隙至18%,同时产线速度降低至25~30 m/min时,可以很好地避免切口断面水波纹缺陷的产生,为消除该缺陷供了参考方案。

Multi-objective optimization for draft scheduling of hot strip mill

A multi-objective optimization model for draft scheduling of hot strip mill was presented, rolling power minimizing, rolling force ratio distribution and good strip shape as the objective functions. A multi-objective differential evolution algorithm based on decomposition （MODE/D）. The two-objective and three-objective optimization experiments were performed respectively to demonstrate the optimal solutions of trade-off. The simulation results show that MODE/D can obtain a good Pareto-optimal front, which suggests a series of alternative solutions to draft scheduling. The extreme Pareto solutions are found feasible and the centres of the Pareto fronts give a good compromise. The conflict exists between each two ones of three objectives. The final optimal solution is selected from the Pareto-optimal front by the importance of objectives, and it can achieve a better performance in all objective dimensions than the empirical solutions. Finally, the practical application cases confirm the feasibility of the multi-objective approach, and the optimal solutions can gain a better rolling stability than the empirical solutions, and strip flatness decreases from （0± 63） IU to （0±45） IU in industrial production.

Mathematic modeling on flexible cooling system in hot strip mill

A novel cooling system combining ultra fast cooling rigs with laminar cooling devices was investigated.Based on the different cooling mechanisms,a serial of mathematic models were established to describe the relationship between water flow and spraying pressure and the relationship between water spraying heat flux and layout of nozzles installed on the top and bottom cooling headers.Model parameters were validated by measured data.Heat transfer models including air convection model,heat radiation model and water cooling capacity model were detailedly introduced.In addition,effects on cooling capacity by water temperature and different valve patterns were also presented.Finally,the comparison results from UFC used or not have been provided with respect to temperature evolution and mechanical properties of Q235B steel grade with thickness of 7.8 mm.Since online application of the sophisticated CTC process control system based on these models,run-out table cooling control system has been running stably and reliably to produce resource-saving,low-cost steels with smaller grain size.

受损H型钢梁力学性能静态应变时效影响研究

既有钢结构建筑受损待修复期间,钢材受静态应变时效影响,其材料性能发生显著变化,致使受损钢结构修复后整体受力性能改变。为研究静态应变时效对受损钢梁受弯力学性能的影响,设计了3根Q355B热轧H型钢梁,通过两阶段加载试验方法完成受损钢梁应变时效影响试验研究,并基于试验结果建立ABAQUS有限元分析模型。通过二次模型导入和材性重定义,实现钢材经应变时效影响前后的不同材料属性建模,完成受损钢梁应变时效影响的有限元模型建立及参数分析。研究结果表明:受损钢梁的受力性能由残余变形和钢材力学性能变化两者共同决定,当钢梁发生损伤程度较小时,钢材力学性能变化不显著,钢梁因残余变形而极限承载力降低;当钢梁损伤变形导致部分截面应变达到4.5%及以上时,不再适合修复后继续使用。

Analysis of strain variation in cross shear zone of plate during snake hot rolling

In order to study the distribution of equivalent and shear strain of aluminum alloy plate during snake hot rolling, several coupled thermo-mechanical finite element models(FEM) are established. Effects of speed ratio and offset distance on strain distribution of the plate are analyzed. The length of cross shear zone is defined to have a better understanding of the deformation characteristic in cross shear zone, which is the essential difference from symmetrical rolling in deformation zone. The results show that the equivalent strain and shear strain of lower part both increase with the increase of speed ratio, while the upper part decreases; the equivalent strain through the whole thickness decreases with ascending offset distance, while the shear strain of lower part increases. The length of cross shear zone quickly increases with ascending speed ratio and slightly decreases with ascending offset distance. The "positive" and "negative" cross shear zones are formed with the increase of speed ratio and offset distance, respectively. The value of the sensitivity coefficient of speed ratio is an order of magnitude bigger than the offset distance. However, the shear strain at center point increases with the ascending speed ratio and offset distance for different mechanism. As speed ratio increases, the asymmetry of the distribution of equivalent is becoming larger and the shear strain is generated in the same direction in cross shear zone. The FEM results agree well with experimental results.

Simulation, Power Quality Analysis and Improvements in a Hot Rolling Mill Using a STATCOM

This paper presents an analysis of the electric power flows in a hot rolling mill plant using a power quality analyzer and developing simulation models with Matlab-Simulink. The model inputs have been taken from process data by the process computer of the plant. Data from different rolling campaigns have been analysed. A STATCOM （static synchronous compensator） with a control strategy based on voltage oriented control with d-q coordinates is used as solution to improve the reactive compensation as well as to minimize the voltage fluctuations and sags effect. The overall electric model has been simulated with the STATCOM to check the improvement in the voltage stability and the consumption.

Establishment of wear model and life prediction of drum of hot rolling coiler

For the drum of hot rolling coiler is prone to be easily destroyed, the type of MMU-5G abrasion tester was applied to revealing the friction and wear behavior. The morphology observation by scanning electron microscope (SEM) demonstrates the wear mechanism of the drum, and the test data of the influence coefficient of the normal pressure, relative sliding speed and surface lubrication conditions acted on the linear rate of the wear could be obtained by the regression method. A calculation model, which considers the factors of the structure of the drum, coiling tension and coiling strip specifications, was established by the combination method to predict the wear life of the drum. Then the practical production data was applied into this model and the analysis result was in good accordance with that of actual production.

区别处理H型钢梁与工字钢梁稳定性条件

热轧H型钢是一种高效经济性型材,具有抗弯性能好、翼缘宽、侧向刚度大等优点。目前国内生产的H型钢有宽翼缘H型钢(HW),中翼缘H型钢(HM),窄翼缘H型钢(NH)和薄壁H型钢(HT)等,但GB50017—2003《钢结构设计规范》在描述保证梁的整体稳定性内容中,有关热轧H型钢的规定直接借用了轧制普通工字钢或三板焊接截面的相关条文,没有体现H型钢良好的截面特性对整体稳定性的贡献。为了使GB50017—2003能够更充分、准确地指导钢结构工程设计应用,区别处理H型钢梁与工字钢梁,了解和掌握适用于国产热轧H型钢的整体稳定控制条件是十分必要的。从梁整体稳定原理出发,依照现行GB 50017—2003提出的计算公式,通过专门的分析程序对H型钢梁整体稳定进行计算,结合重庆大学已经获得的研究工作结果,提出了更适合国产H型钢的整体稳定控制条件,可作为GB 50017—2003修订的依据,也可供工程应用实践参考。

河钢集团唐钢大型型钢产线产品开发及技术创新

针对大型型钢产线工艺布置及设备特点,河钢集团唐钢公司开发了30^(#)特大角钢及热轧U型钢板桩、电极扁钢等系列产品,主要介绍了系列新产品的化学成分及孔型设计;围绕大型型钢产品的特点,介绍了该产线的技术创新,如首台无级可变不等节距双支撑矫直机功能的优化,全液压式步进冷床功能的完善,型钢生产全流程综合管理系统的研发与应用,以及多项智能制造工艺模块的设计等等,并与国内外同类技术进行了对比,产线综合生产效率提高30%,大大降低了生产成本,提高了产品的市场竞争力。