Research and Development Trend of Shape Control for Cold Rolling Strip

Shape is an important quality index of cold rolling strip. Up to now, many problems in the shape control domain have not been solved satisfactorily, and a review on the research progress in the shape control domain can help to seek new breakthrough directions. In the past 10 years, researches and applications of shape control models, shape control means, shape detection technology, and shape con- trol system have achieved significant progress. In the aspect of shape control models, the researches in the past improve the accuracy, speed and robustness of the models. The intelligentization of shape control models should be strengthened in the future. In the aspect of the shape control means, the researches in the past focus on the roll opti- mization, mill type selection, process optimization, local strip shape control, edge drop control, and so on. In the future, more attention should be paid to the coordination control of both strip shape and other quality indexes, and the refinement of control objective should be strengthened. In the aspects of shape detection technology and shape control system, some new types of shape detection meters and shape control systems are developed and have successfully indus- trial applications. In the future, the standardization of shape detection technology and shape control system should be promoted to solve the problem of compatibility. In general,the four expected development trends of shape control for cold roiling strip in the future are intelligentization, coordi- nation, refinement, and standardization. The proposed research provides new breakthrough directions for improv- ing shape quality.

Opti mization and Model of Laminar Cooling Control Systemfor Hot Strip Mills

The structure of laminar cooling control system for hot rolling was introduced and the control mode, cooling strategy, segment tracking and model recalculation were analyzed. The parameters of air/water cooling models were optimized by regressing the data gathering in situ, and satisfactory effect was obtained. The coiling temperature can be controlled within ±15℃.

Flatness Control Based on Dynamic Effective Matrix for Cold Strip Mills

Steel strips are the main of steel products and flatness is an important quality indicator of steel strips. Flatness control is the key and highly difficult technique of strip mills. The bottle-neck restricting the improvement of flatness control techniques is that the research on flatness theories and control mathematic models is not in accordance with the requirement of technique developments. To build a simple, rapid and accurate explicit formulation control model has become an urgent need for the development of flatness control technique. This paper puts forward the conception of dynamic effective matrix based on the effective matrix method for flatness control proposed by the authors under the consideration of the influence of the change of parameters in roiling processes on the effective matrix, and the concept is validated by industrial productions. Three methods of the effective matrix generation are induced： the calculation method based on the flatness prediction model; the calculation method based on the data excavation in rolling processes and the direct calculation method based on the network model. A fuzzy neural network effective matrix model is built based on the clusters, and then the network structure is optimized and the high-speed-calculation problem of the dynamic effective matrix is solved. The flatness control scheme for cold strip mills is proposed based on the dynamic effective matrix. On stand 5 of the 1 220 mm five-stand 4-high cold strip tandem mill, the industrial experiment with the control methods of tilting roll and bending roll is done by the control scheme of the static effective matrix and the dynamic effective matrix, respectively. The experiment result proves that the control effect of the dynamic effective matrix is much better than that of the static effective matrix. This paper proposes a new idea and method for the dynamic flatness control in the rolling processes of cold strip mills and develops the theory and model of the flatness control effective matrix method.

Monitor automatic gauge control strategy with a Smith predictor for steel strip rolling

The simplified transfer function diagram block for a monitor automatic gauge control （Mon-AGC） system of strip steel rolling process was investigated. The new notion of strip sample length was given. In this way, the delay time varying with the rolling speed was evaded. After a Smith predictor was used to monitor the AGC system, the control laws were deduced for both proportional and integral regulators. The control strategies showed that by choosing the controller parameter P=∞ for both control algo- rithms each regulator could compensate the whole strip gage error in the first control step. The result shows that the integral algo- rithm is more controllable for the system regulating process and has a better steady-state precision than the proportional regulator. Compared with the traditional control strategy, the new control laws have a faster response speed and a hieher steadv-state precision.

Study and application of crown feedback control in hot strip rolling

Crown feedback control is one part of the automatic shape control （ASC） system. On the basis of large simulation researches conducted, a linear crown feedback control model was put forward and applied in actual strip rolling. According to its successful op- eration in the ASP 1700 hot strip mill of Angang Group for one year and also from the statistical results of several crown measurements, it can be definitely said that this control model is highly effective and shows stable performance. The control effectiveness of different gauges of strips with the feedback control is found to increase by 10%-30% compared with that without feedback control.

Element Tracking Strategies for Hot Strip Laminar Cooling Control

Feedforward control is the core to control function in the cooling process of hot strip. One of the most important tasks in feedforward control is to determine the arrival time of the strip at various locations on the runout table for effective control. Based on the principles of element tracking and tracking strategies for variable rolling speed and constant rolling speed, a simple diagonal tracking method for an existing hot strip mill was proposed and tested. The test results show that the proposed strategies are effective for improving tracking control.

PROFILE AND FLATNESS CONTROL SYSTEM IN 1700mm HOT STRIP MILLS OF ANSTEEL

Varying contact-length backup roll and linearly variable crown work roll are provided for improving the mill performance of profile and flatness control. Integrated with theses technologies, relevant profile and flatness control models are developed for hot strip mills on the basis of large amount of finite element calculation. These models include shape setup control model in process control system, bending force feedforward control model, crown feedback control model and flatness feedback control model in basis automation system. Such a profile and flatness control system with full functions is applied in 1 700 mm industrial hot strip mills of Ansteel. Large amount of production data shows that the crown precision with the tolerance of±18 μm is over 90%, the strip percentage which the actual flatness is within ±25 I-unit surpasses 96%, and general roll consume is reduced by 28% by using the profile and fiatness control system. In addition, schedule-free rolling is realized.

Key techniques of automatic gauge control and profile control for aluminium strip and foil

Such characteristics of aluminium strip and foil as soft and thin gauge make tension control one of the key techniques for automation gauge control(AGC). To avoid the disadvantage of traditional mathematical control method which is unfitful for nonlinear hysteresis, the technique for tension AGC fuzzy control was developed and thickness deviation more than 3% of product thickness was achieved consequently in 1 350 mm cold rolling mill of aluminium strip and foil. Additionally, because the gauge of aluminium strip and foil is thin, stage-cooling roll method becomes a key technique for profile control. So stage-cooling roll intelligent control method is developed and pre-coated aluminum foil with good profile less than 10 I (the relative differences in elongation of 0.01%) is produced using the profile control system in 1 400 mm cold rolling mill of aluminium strip and foil.

Application of Cooling Water in Controlled Runout Table Cooling on Hot Strip Mill

The controlled runout table cooling is essential in determining the final mechanical properties and flatness of steel strip.The heat of a hot steel strip is mainly extracted by cooling water during runout.In order to study the heat transfer by water jet impingement boiling during runout,apilot facility was constructed at the University of British Columbia.On this pilot facility,the water jet impingement tests were carried out under various cooling conditions to investigate the effect of processing parameters,such as cooling water temperature,water jet impingement velocity,initial strip temperature,water flow rate,water nozzle diameter and array of water nozzles,on the heat transfer of heated strip.The results obtained contribute to the optimization of cooling water during runout.

Application of Fuzzy Logic Controller to Level Control of Twin-Roll Strip Casting

An intelligent fuzzy-PID controller consisting of fuzzy logic controller and PID controller was developed to control the molten steel level of twin-roll strip caster.Additionally,a feedforward differential PID controller was used for stopper position control in order to avoid differential kick.It is proved by simulation that the proposed intelligent controller is able to obtain zero steady state error asymptotically and the control system is robust due to its fuggy behavior of the controller.

Designing of Hot Strip Rolling Mill Control System

Aimed at the complex demand of hot strip rolling mill in practicing, the configuration of the coiler and the technological process is analyzed. The arithmetic of coiling tension and the control process is introduced. The frame of the tension adjusting system is given. The coiler control system hardware is designed. The system is designed scientifically with steady control and meets demand of the market.

Dynamic matrix predictive control for a hydraulic looper system in hot strip mills

Controlling the looper height and strip tension is important in hot strip mills because these variables affect both the strip quality and strip threading. Many researchers have proposed and applied a variety of control schemes for this problem, but the increasingly strict market demand for strip quality requires further improvements. This work describes a dynamic matrix predictive control(DMC) strategy that realizes the optimal control of a hydraulic looper multivariable system. Simulation experiments for a traditional controller and the proposed DMC controller were conducted using MATLAB/Simulink software. The simulation results show that both controllers acquire good control effects with model matching. However, when the model is mismatched, the traditional controller produces an overshoot of 32.4% and a rising time of up to 2120.2 ms, which is unacceptable in a hydraulic looper system. The DMC controller restricts the overshoot to less than 0.08%, and the rising time is less than 48.6 ms in all cases.

Extrinsic Risk Factors for Women Breast Cancer in Gaza Strip, Palestine: Associations and Interactions in a Case-Control Study

Background: Worldwide, breast cancer (BC) is the most frequently diagnosed neoplastic disease in women around menopause that is the leading cause of DALYs, because it causes a significant reduction of these women’s ability to function normally in everyday life. Methods: The present hospital-based case-control study was carried out between January and August 2018 using a structured questionnaire on 105 breast cancer women and 210 controls who are clinically free from breast cancer. Data about the study cases were collected in the oncology day-care clinics of the two main hospitals in Gaza strip “Al-Shifa and European Gaza hospitals”. Univariate logistic regression and multivariate logistic regression analyses were employed to identify the significant factors associated with BC. Results: Multivariate logistic regression analyses with adjustment for all confounders revealed that woman with BMI more than or equal 30 kg/m2 are under risk of getting BC 2.9 times greater than those having BMI less than 29 kg/m2 (AOR = 2.895;95% CI: 1.305 - 6.423). Analysis of risk according to reaching menopause showed that the estimated AOR was greater among those reached menopause (3.137, 95% CI 1.824 - 5.395) than among those that did not reach menopause. The risk of developing BC in the case of a history of incidence of BC in the family was more than two times higher (AOR = 2.632, 95% CI 1.528 - 4.535) than in case of the history of a free family of BC. Conclusion: In this context, the above-mentioned risk factors must be taken into consideration in BC management processes in the Gaza strip.

NUMERICAL SIMULATION OF MOLTEN POOL AND CONTROL STRATEGY OF KISS POINT IN A TWIN-ROLL STRIP CASTING PROCESS

Coupled turbulent flow, temperature fields of the twin-roll casting strip process were simulated by three-dimensional finite element method. Based on the heat balance calculation and using inverse methods between the simulations and real experiments, the relational models among casting speed, location, and coefficient of heat transfer between molten metal and rolls in different regions are given. In the simulation, the calculated surface temperatures are in good agreement with the measured values. An on-line model of kiss point is derived by simulations and the geometry of molten pool, corresponding control strategy is also proposed.

Measurement and AFPS control of molten steel level in strip casting

The measurement and control of the molten steel level are studied, which affect the quality of strip surface in strip casting. A system of molten steel measurement with a CCD (Charge Coupled Devices) sensor is designed, real-time measured data are given and its precision is analyzed. The level fluctuation model is derived, and an adaptive fuzzy-PID controller with supervisory control (AFPS) is proposed. The stability of the system is proved using Lyapunov theorem, and the simulation results are given when the model, the casting speed and the roll gap change. It is suggested that this kind of coupled nonlinear and time varying system is stable and robust using the designed AFPS controller.

国内铜板带发展现状与热轧技术的创新方向分析

文章论述了国内铜板带行业的发展现状,指出铜板带的热轧应分别从理论和技术,生产和工艺,设备设计制造,生产线配置和工程设计等方面进行基础性的研究和改进,并在工程项目的实践中不断创新。

铁路工程长距离带状GNSS控制网高精度解算

铁路工程控制网三网合一,采用GNSS卫星导航定位基准站(CORS)方式建网是发展的趋势,但其长距离、带状布设的控制网要确保高精度且连续均匀,具有一定的难度。针对长距离带状控制网的特点,分析影响GNSS控制网解算的影响因素,引入IGS站点坐标的松弛约束,筛选出优化解算策略:融合多星座卫星观测数据,基于电离层约束模型求解宽巷模糊度,当控制网的基线长度小于100 km时,对流层延迟采用站间差分改正、电离层延迟采用差分或模型改正,并结合环境条件顾及其他负荷改正。实际铁路工程带状控制网解算测试表明,优化策略控制网处理精度相较于常规策略在Y和Z方向上提升2~5 mm。通过对复杂地形环境下长距离带状控制网的解算质量分析,进一步表明该策略可优化铁路工程长距离带状控制网高精度解算性能。

某超长条结构件柔性工装平台结构设计与实现

针对某超长条结构件加工过程中由于使用传统工装夹具造成的工艺准备时间长、工装数量多、材料浪费严重等问题,开展一种柔性工装平台的研究。该工装平台采用多个可旋转夹臂替代传统夹具进行夹持,在工件外形变化时,可通过更换夹臂长度、按压角度等保持良好夹持效果,满足柔性工装的需求。对该工装平台结构进行设计,对关键参数进行建模和校核,通过样机对工装效果进行验证。结果表明,该工装平台在加工相同工件的情况下,可节省约3%的零件材料,缩短310 min工艺准备时间,同时由于该工装平台采用了新型柔性固持方案,还提高了加工连续性,避免由于工艺变化造成大量的夹具浪费,为超长条结构件的加工提供了一种新的工装固持方案。

Ti微合金化400 MPa级光伏支架用钢的开发

详细介绍了山西建龙1500生产线试制400 MPa级光伏支架用热轧钢带的成分设计、工艺路线以及产品质量情况。生产实践表明,按照设计的成分和工艺生产的光伏支架用热轧带钢的组织为铁素体+少量珠光体,拉伸性能和冷弯性能优异,能够满足用户的使用要求。

植草带宽度对蜘蛛和步甲群落动态及比邻玉米田害虫发生的影响

农田边界植草带是农田系统各斑块间生物物种迁移和群落演替、物质和能量交换的主要区域,对维持农业生物多样性及提高农田生产力具有重要意义。基于作物-害虫-天敌互作有机整体对植草带宽度的响应,选取不同宽度植草带(2 m、4 m、6 m)及其比邻农田并以对应宽度作物边界作为对照,采用地表陷阱法对蜘蛛和步甲进行取样调查,探究植草带宽度对蜘蛛和步甲种群结构、迁移扩散规律以及对农田害虫控制潜力的影响。结果表明:植草带内蜘蛛和步甲个体数均显著高于对照条带,4 m、6 m植草带的蜘蛛和步甲多度显著高于2 m植草带,且物种丰富度和多度显著高于其对照条带。此外,不同宽度植草带蜘蛛和步甲群落存在较高的异质性,蜘蛛和步甲群落结构差异显著;在4 m和6 m植草带及其比邻玉米田内,蜘蛛和步甲多度在植草带和植草带与比邻玉米田交界处显著高于农田内部,且随距离的增加,蜘蛛物种多度呈显著降低趋势,植草带宽度和距离共同决定蜘蛛和步甲的空间分布;Monte Carlo检验结果表明,植草带宽度、植被Margalef指数对农田中蜘蛛和步甲群落结构的影响均达到显著水平,蜘蛛主要优势科和步甲主要优势种主要分布在6 m植草带比邻玉米田内;4 m、6 m植草带比邻的玉米田中蜘蛛和步甲对玉米害虫的益害比显著高于2 m植草带比邻的玉米田,且4 m、6 m植草带显著增加了玉米籽粒的百粒重及比邻农田的玉米总产量。本研究对植草带涵养捕食性天敌预防害虫发生的最适宽度进行探索,综合考虑植草带耕地占用、天敌涵养和生物控害潜力等因素,确定4 m宽度植草带是具有推广价值的农田边界模式。