Zhong Zhao

Application of Approximation Full-Load Distribution Method to Pass Scheduling on Plate Mill With Hydro-Bending System

The influence of positive bending system on plate crown control was researched. The approximation fullload distribution method for pass scheduling was put forward. This method can not only make full use of the mill capacity with decreased pass number, but also give quality product of excellent flatness.

Analysis of Process Control Model of Plate MAS Rolling

Using the identification quantity to identify the long ear disfigurement was brought up, and by calculation, it can be found that identification quantity should be set as the quantity of long ear disfigurement of the position which is about 0.2 times of plate width to the plate border. Conception of plate head tiny cell was brought up, and the long ear disfigurement was uncoupled into the product of elongation percentage and length of tiny cell. On the basis of prediction of long ear disfigurement, process control model of MAS rolling was built up, and application indicates that it can fit the on-line production and eliminate the long ear disfigurement commendably.

Effect of Processing Condition on Texture and Drawability of a Ferritic Rolled and Annealed Interstitial-Free Steel

The processing conditions of the texture formation and deep drawability of a Ti-IF steel strip hot-rolled in ferritic region and subsequently annealed were investigated. The r-value increases with the decrease of reheating temperature, and finish rolling temperature and the increase of reductions in ferritic region. For lubricated ferritic rolling and annealing, the r-value is raised up to 1.75, and elongation rate is over 50% at the finish rolling temperature of 650 °C, which is suitable for DDQ grade products. However, the r-value is below 1.0 in the case of unlubricated rolling. The X-ray diffraction was used to analyze the textural characteristic of samples. For samples subjected to lubricated rolling and annealing, the strong {111}//ND recrystallization texture is distributed homogeneously along the thickness direction, and the intensity of {110} recrystallization texture is very low even in surface. However, for unlubricated samples, the {111} texture is distributed inhomogeneously and is weak along the thickness direction, and {110}//ND recrystallization texture is strong, which deteriorates the formability.

Calculation of Taper Rolling Time in Plan View Pattern Control Process

The forward slip model with adhesion was used to derive the formula of calculating taper rolling time. The relation between the rolling time and the taper length and the relation between the rolling time and the taper thickness can be obtained. The numerical solution for this formula was used on-site. According to the simulation result, the roll gap value should be changed linearly with rolling time.

Gauge-meter model building based on the effect of elastic deformation of rolls in a plate mill

Abstract The calculation error of the gauge-meter model will affect the gap setting precision and the self-learn precision of rolling force. The precision of the gauge-meter model is strongly influenced by plate width, working roll radius, backup roll radius, working roll crown, backup roll crown, and rolling force. The influence rules are hard to get by measuring. Taking a conventional 4-h plate mill as the research subject, these influences were transferred into the calculation of roll deflection and flattening deformation. To calculate these deformations, the theory of the influence function method was adopted. By modifying the traditional gauge-meter model, a novel model of the effect of roll elastic deformation on the gap setting was built by data fitting. By this model, it was convenient to analyze the variation caused by the rolling condition. Combining the elastic deformation model of rolls with the kiss-rolls method, a gauge-meter model was put forward for plate thickness prediction. The prediction precision of thickness was greatly improved by the new gauge-meter model.

Research and Improvement on the Rolling Force Model of Plate

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%.

Influence Factors on Finishing Temperature of Plate Rolling

Based on the character of plate rolling, the temperature model was developed by considering the influence of radiation, convection, water descaling, and roll conductivity and deformation energy. The factors affect the finishing temperature of the plate were analyzed, including the holding time during control rolling, rolling speed, slab temperature and pass number. Holding time, rolling speed and slab temperature have significant influence on finishing temperature, and pass number has great influence on finishing temperature of thick plate, but has little on finishing temperature of media plate.

Gap Setting Model and Application in Plate Rolling Process

According to the characteristic of plate rolling process and the on-line applications, the non-homogeneous wear and thermal expansion of rollers, the elastic recovery and thermal expansion of work pieces, the variation of oil film thickness and the zero point deviation, which influence the precision of gap setting model, are analyzed. Based on the results of analysis, a high-precision gap setting model is proposed, and a zero point correction method is developed, in order to avoid overshoot, damp coefficient, which is affected by the thickness of work piece and zero point deviation are considered, is introduced. On-line applications indicate that the gap setting model improves the precision of gap setting and laid a good foundation of further improvement of thickness accuracy.