Papers by Keyword: Hot Strip Mill

Abstract: The production of hot-rolled sheets of high-strength and wear-resistant special structural steels by direct quenching from the rolling heat is a cost effective and energy-saving alternative to traditional production via downstream quenching the previously cut-to-length plates. Reaching the required strength and toughness parameters in combination with best flatness of the sheets requires strict compliance with the pre-set rolling and cooling conditions over the entire strip width. Using two high-strength low-alloyed steels, plant trials have been carried out to study the effect of the cooling conditions and the coiling temperature on mechanical properties, impact toughness and flatness of cut-to-length sheets made of hot-rolled strip. The results showed that by applying optimized cooling pattern and low coiling temperatures, high-strength steel sheets with outstanding mechanical properties and good flatness can be produced.

Abstract: This thesis studies and develops an agent-based on-line monitoring and diagnosis system. In order to make production line automation, yield high production rate, and enhance the ability of market competition, an effective way is to ensure facilities running smoothly and to reduce the manpower monitoring. Meanwhile in order to reduce the cost of development and enhance the feature of reuse, we use a communication interface to integrate and interact information among developed softwares. Through this system, users may easily monitor and diagnose the machines on production lines through user interfaces, Consequently, it is of greatly help to lower the cost of personnel and enhance the ability of market competition .

Abstract: The hot rolled strip thickness accuracy sometimes can not be guaranteed after a long time for waiting for slabs or other reasons. The reason is when rolling, the rollgap adaptive model has considered the thermal expansion of the roll. So when rolling is restarted, thermal expansion of the rolls must be cleared in order to accurately calculate the setup rollgap value. The finite element software ANSYS is used to calculate the temperature field and thermal expansion amount of the rolls in the rolling process. Application results show that this method can improve the accuracy of strip thickness.

Abstract: Aimed at the main factors of hot rolled strip steel product width fluctuation, rolled piece is put forward to plasticity coefficient and entrance width as the input variables of feedforward AWC control algorithm.Expounds a kind of optimization of plasticity coefficient Q feedforward AWC control system principle and plasticity coefficient Q of linear prediction algorithm.Field application shows that the Q prediction feedforward AWC has significant effect on inhibition of hot rolled strip width deviation.

Abstract: Thickness model adaption plays a important role in obtaining strip with high thickness precision. In order to improve the thickness precision, a complete thickness model adaption system has been designed for every specific model used in the setup system including gap position model, temperature model, rolling force model. Snapshot data and stretch equation are used to adapt gap position. Forced convection coefficient is selected as adaption parameter. A deformation resistance-based fitting quadratic curve is proposed in rolling force adaption, it can be inherited to any other thick range class and a quick thickness adaption method is introduced. Application results show that this adaptive system is with high accuracy, quick adaption and high stability.

Abstract: The accuracy of roll force model and the rationality of roll fore adaptive model play a key role in obtaining the thickness of strip with high precision. The roll force model has been established. It includes the elastic flattened roller model and deformation resistance model considering the chemical composition of strip. A deformation resistance-based fitting curve is proposed in rolling force adaption, it can be inherited to any other thick range class. Application results show that the rolling force model and its adaptation are with high prediction accuracy and it has improved the strip thickness accuracy.

Abstract: This paper has researched traditional algorithms. The defects had been pointed out and proved. According to this, setup calculation algorithm was optimized. Considering strip transverse flow and creep deformation, natural output profile was defined. Practical applications in domestic 1500 hot strip mill show that the setup calculation strategy achieved good effect and enhanced the profile and flatness precision

Abstract: In order to improve the thickness precision, the model adaption method is of great concern which is a necessary component in the thickness control system. The sample concept is first taken into the model adaption in hot tandem mill, from which the learning coefficients are updated by a series of samples. Comparing to the single sample in traditional method, the new method can consider the variance in the length direction. And the source data is more comprehensive, the robustness is increased with flexible proportion coefficients. The thickness precision in stable production process is enhanced to 35μm. On-line result shows practical value and on-line application prospect.

Abstract: in this paper, the author used method of Two-dimensional finite difference to establish a model of temperature in hot rolled steels in finishing stands, and used explicit difference method to solve the difference model. The model was optimized by correct parameters through particle swarm optimization combining with measure data. It has been verified that the deviation of the models prediction and real data keeps between ±10°C.

Abstract: Work roll temperature prediction model is an important part of shape control system in hot strip mill. This article performs work roll mesh generation, and establishes difference equations of each lattice point using two-dimensional alternating difference method. Then, the work roll temperature distribution at any time is acquired after solving equations with chasing method. The model established in this article has high stability, fast solving speed and high operation precision. The results, compared with the measured data, indicate that the model has high reliability and meets the demand of strip quality in hot rolling.