Papers by Author: Zhi Jie Jiao

Abstract: Pilot hot rolling mill is developed with perfect measuring devices and automation system. The hot rolling experimental studies of the plate and strip can be done on this mill. Automation system for this pilot mill is composed with Basic Automation System (BAS), Process Control System (PCS) and Human Machine Interface system (HMI). PC server is used as the PCS hardware, and Microsoft software is used as the operation system and developing software. With the coordination of the functions such as date communication, process tracking, data management, and model calculation, the PCS software function is realized. The effect on the model calculation accuracy with the pilot mill using condition was analyzed. This pilot hot rolling mill gets a lot of application. The practical application shows that the PCS’s setup has a high precision.

Abstract: According to the requirement to the pilot mill for the cold rolling process research work, new type pilot reverse cold rolling mill is designed. Computer control system, including primary automation system, process automation system and human machine interface (HMI) system, is developed for this mill. Technological control function such as electric position control, hydraulic tension control, automatic gauge control (AGC), and process control functions such as model setup calculation, process tracking, actual data treatment are realized. This new type pilot cold rolling mill has been used successfully in several iron steel companies.

Abstract: Pilot cold rolling mill is the important tool for the cold rolling process researching and new steel grade development. According to the design of the new type direct pulling pilot cold rolling mill, based on the mass flow constant principle, strip exit thickness indirect measurement method is studied. During rolling, strip entry and exit speed can be calculated accurately according to the measured value of two sides’ clamps movement. Data filtering treatment is adopted and program flow chart is designed. Based on the material entry thickness measured manually, exit thickness of all passes can be measured indirectly. This thickness indirect measurement method has been applied successfully on the new type pilot cold rolling mill, and the measurement results show that this method has a good accuracy.

Abstract: For cold rolling process, the theoretical Bland-Ford-Hill model and Hitchcock model are used for the rolling force and roll flatten radius calculation. Friction coefficient and deformation resistance are calculated with empirical regression models. From rolling force model, the recalculation model for the friction coefficient and deformation resistance can be derived. After rolling, with actual measured data, friction coefficient and deformation resistance can be recalculated, and model parameter can be got by regression method. The practical application verifies that the accuracy of rolling force calculation model is good.

Abstract: High strength steels, such as austenitic stainless steel, Transformation Induced Plasticity (TRIP) steel and silicon steel, have significant work hardening during cold rolling, which in turn induces a quickly increased rolling force. Tension plays a very important role in the reduction of the rolling force. However, coiler tension control system used in the classic experimental rolling mill requires long-scale strip, which cannot be satisfied for most experimental cases. To overcome this drawback, a new pilot rolling mill has been developed. The horizontally located hydraulic cylinders and clamps have been used to apply tension to the rolled short-scale strip. With this rolling mill, the austenitic stainless steel strip, TRIP steel strip and other high strength strips have been studied.

Abstract: Rolling force model is the core of all the mathematical models of plate for rolling process, but the accuracy of traditional rolling force model is not high enough in application, so in this study the rolling force model of plate is researched and improved. The effects of different physical conditions on resistance of deformation are decoupled, and the formula acquired is practical. While the composition, Nb is used to calculate residual strain. At the same time, the self-learning method, which is based on the thickness layer is applied. The on-line application results show that the predictive error between force model calculated and measured can be controlled at less than 9% and 80% of the passes can be controlled within 5%.

Abstract: Rolling force is the most important technical parameter for the tandem cold mill. In this paper, the precise models and calculation process for the rolling force are introduced. The rolling force model is based on the Bland-Ford and Hill theory, and the roll flatten radius is calculated with the Hitchcok’s formula. The deformation resistance of the strip is calculated with the model, whose parameters are decided according to the steel grade. The friction coefficient model is built according to rolling speed and rolled length of the roll. The rolling force and the roll flatten radius are calculated with the iterative method. These models are used for online process control of one five-stand tandem cold mill. Comparing the calculation result and the actual data, the precision of the rolling force calculation is high.