热轧钢带连续热镀锌生产实践研究

热轧钢带连续热镀锌生产是钢带生产的重要环节,热轧钢带连续热镀锌生产技术水平的高低直接影响着钢带质量,这一理念产生于70年代的日本,此技术的应用大大提高了钢带连续镀锌生产效率。但是在长期发展过程中这一技术也遇到了一系列问题,解决这些问题是提高热轧钢带连续热镀锌水平的关键。本文将重点探讨热轧钢连续热镀锌的生产。

唐钢连续热镀锌钢带企业标准及其保证措施

介绍了唐钢连续热镀锌钢带企业标准的主要内容及标准执行的主要保证措施。

基于热轧钢带连续热镀锌的研究

本文从镀锌生产线的工艺及主要设备介绍出发,对这种连续热镀锌生产工艺的产品性能从镀层质量、力学性能以及镀层的附着性与传统工艺进行比较说明,然后以具体的热轧钢带连续热镀锌生产线的实际案例对该工艺流程作相应的阐述,指出了当前热轧钢带连续热镀锌生产中存在的不足并进行了必要的问题分析,希望能为钢铁企业提高生产效率与生产质量提供一定的参考,从而推动我国的工业化进程。

连续热镀锌钢带钝化膜耐腐蚀性

针对发往南方潮湿多雨地区的镀锌卷易生"白锈"这一缺陷,采用中性盐雾实验研究了钝化膜厚度对连续热镀锌钢带耐腐蚀性能的影响。结果表明:随着钝化膜厚度的增加,连续热镀锌钢板的腐蚀白绣面积的比例呈逐渐降低趋势,连续热镀锌钢板的腐蚀电位逐渐增加,表明其耐盐雾腐蚀性能越来越强,在钝化膜厚度为55 mg/m2时,满足镀锌板中性盐雾试验所要求的72小时后白锈面积不超过5%,可保证产品质量、降低生产成本。

结构用热镀锌钢带的生产实践

采用LF精炼、ASP连铸连轧、可逆式冷轧、美钢联法连续热浸镀锌的工艺路线,通过合理设计钢的成分以及合理的轧制、热镀锌工艺,开发了结构用热镀锌钢带。实物质量检验表明,产品的力学性能、锌层组织及锌层附着性都达到标准要求,得到用户的认可,为更高强度结构镀锌板的开发提供了参考。

济钢年产20万吨钢带连续热镀锌机组自动化系统总体配置

介绍了镀锌机组的自动化系统总体配置，并分别对基础自动化系统、电气传动系统、连续退火炉控制系统及整个系统的通信网络进行阐述，对系统的性能指标及FM458控制模块进行了重点说明。

Control and application of cooling path after rolling for hot strip based on ultra fast cooling

Hot rolled strip requires diverse and flexible control of cooling path in order to take full advantages of strengthening mechanisms such as fine grain strengthening, precipitation strengthening, and transformation strengthening, adapting to the development of advanced steel materials and the requirement of reduction-manufacturing. Ultra fast cooling can achieve a great range of cooling rate, which provides the means that the hardened austenite obtained in high temperature region can keep at different dynamic transformation temperatures. Meanwhile, through the rational allocation of the UFC （ultra fast cooling） and LFC （laminar flow cooling）, more flexible cooling path control and cooling strategy of hot rolled strip are obtained. Temperature distribution and control strategies under different cooling paths based on UFC are investigated. The process control temperature can be limited within 18 ℃, and the mechanical properties of the steels get a great leap forward due to the cooling paths and strategies, which can decrease costs and create great economic benefits for the iron and steel enterprises.

Advanced run-out table cooling technology based on ultra fast cooling and laminar cooling in hot strip mill

In order to meet the severe requirements of market and reduce production costs of high quality steels,advanced run-out table cooling based on ultra fast cooling(UFC) and laminar cooling(LC) was proposed and applied to industrial production.Cooling mechanism of UFC and LC was introduced first,and then the control system and control models were described.By using UFC and LC,low-cost Q345B strips had been produced in a large scale,and industrial trials of producing low-cost dual phase strips were completed successfully.Application results show that the ultra fast cooling is uniform along the strip width and length,and does not affect the flatness of strips.The run-out table cooling system runs stably with a high precision,and makes it possible for the user to develop more high quality steels with low costs.

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.

Simulation-based multi-objective optimization for roll shifting strategy in hot strip mill

A simulation-based multi-objective optimization approach for roll shifting strategy in hot strip mills was presented. Firstly, the effect of roll shifting strategy on wear contour was investigated by mtmerical simulation, and two evaluation indexes including edge smoothness and body smoothness of wear contours were introduced. Secondly, the edge smoothness average and body smoothness average of all the strips in a rolling campaign were selected as objective functions, and shifting control parameters as decision variables, the multi-objective method of MODE/D as the optimizer, and then a simulation-based multi-objective optimization model for roll shifting strategy was built. The experimental result shows that MODE/D can obtain a good Pareto-optimal front, which suggests a series of alternative solutions to roll shifting strategy. Moreover, the conflicting relationship between two objectives can also be found, which indicates another advantage of multi-objective optimization. Finally, industrial test confirms the feasibility of the multi-objective approach for roll shifting strategy, and it can improve strip profile and extend same width rolling miles of a rolling campaign from 35 km to 70 km.

Acid-pickling plates and strips speed control system by microwave heating based on self-adaptive fuzzy PID algorithm

Double self-adaptive fuzzy PID algorithm-based control strategy was proposed to construct quasi-cascade control system to control the speed of the acid-pickling process of titanium plates and strips. It is very useful in overcoming non-linear dynamic behavior, uncertain and time-varying parameters, un-modeled dynamics, and couples between the automatic turbulence control (ATC) and the automatic acid temperature control (AATC) with varying parameters during the operation process. The quasi-cascade control system of inner and outer loop self-adaptive fuzzy PID controller was built, which could effectively control the pickling speed of plates and strips. The simulated results and real application indicate that the plates and strips acid pickling speed control system has good performances of adaptively tracking the parameter variations and anti-disturbances, which ensures the match of acid pickling temperature and turbulence of flowing with acid pickling speed, improving the surface quality of plates and strips acid pickling, and energy efficiency.

Numerical analysis of heat transfer intensity from twin slot vertical jet impingement on strip surface after hot rolling

The flow field and heat transfer of the strip surface due to the twin slot vertical jet impingement were investigated using the ANSYS FLUENT.The RNG k-ε model was carried out in the turbulent calculation.Systematic parametric research was conducted by varying the jet velocity of nozzle exit(V=5 m/s,7.5 m/s,10 m/s),the temperature of cooling water(T_w=280 K,300 K),the normalized spacing from the nozzle to the strip surface(H=10,15,20,33),and the normalized spacing from the nozzle to nozzle centerline(W=0,15,30).The velocity streamline of the flow domain and the general trend of the distribution of the local Nusselt number on the impingement surface of strip were obtained.The result indicate that,the average Nusselt number increases by about70%(90%) as the jet velocity is increased from 5 m/s to 7.5 m/s(from 7.5 m/s to 10 m/s),and T_w,Hand//have minimal effect on it.While the valley Nusselt number decreases by about 10%-43%with the increase of H and W.The functional relationship between the average Nusselt number and the systematic parameters is derived by the least square regression method.

热镀锌结构钢带S550GD+Z的连退模拟试验

通过对S550GD+Z热镀锌结构钢带的连续退火工艺研究,采用不添加贵金属的钢种成分体系下,探讨了不同退火均热温度与保温时间对其组织和性能的影响。结果表明,退火均热温度为605℃,保温时间为105~132 s时,试样的屈服强度≥570 MPa,抗拉强度≥600 MPa,伸长率A80≥10%,可满足S550GD+Z钢带的标准力学性能要求。

Artificial neural network prediction of mechanical properties of hot rolled low carbon steel strip

Conventionally, direct tensile tests are employed to measure mechanical properties of industrially pro- duced products. In mass production, the cost of sampling and labor is high, which leads to an increase of total pro- duction cost and a decrease of production efficiency. The main purpose of this paper is to develop an intelligent pro- gram based on artificial neural network （ANN） to predict the mechanical properties of a commercial grade hot rolled low carbon steel strip, SPHC. A neural network model was developed by using 7 x 5 x 1 back-propagation （BP） neural network structure to determine the multiple relationships among chemical composition, product pro- cess and mechanical properties. Industrial on-line application of the model indicated that prediction results were in good agreement with measured values. It showed that 99.2 % of the products＇ tensile strength was accurately pre- dicted within an error margin of ~ 10 %, compared to measured values. Based on the model, the effects of chemical composition and hot rolling process on mechanical properties were derived and the relative importance of each in- put parameter was evaluated by sensitivity analysis. All the results demonstrate that the developed ANN models are capable of accurate predictions under real-time industrial conditions. The developed model can be used to sub- stitute mechanical property measurement and therefore reduce cost of production. It can also be used to control and optimize mechanical properties of the investigated steel.

Making Use of the Eddy Currents Effect in the Examination of the Tribological Characteristics of Strip Rolling Mill Rolls

The key element in the proper performance of a rolling mill is the careful planning of the rolls operational conditions, since this factor constitutes the restricting element in the manufacturing process. In the article, a collection of operation and research steel strips hot-rolling mill information was presented, which was processed based on the advanced computer programmes for rolls grinders. The research outcomes were produced, presenting the application of eddy currents to detect materials flaws in metallurgical mill rolls.

一种新型的链条位置检测装置

文主要阐述了一种带接近开关的链条位置监测装置在人造板机器设备中的应用。该监测装置使用于中密度纤维板生产线的平压式连续压机上,可以检测到链毯链条的实际运行位置。通过检测到的链条位置,就能方便地知道链毯故障点在整个链毯的具体位置,使诊断链毯故障更容易,维护、维修更方便,减少了停机时间,更好地满足了生产工艺对生产连续性的要求。