Papers by Keyword: Coiling Temperature

Abstract: Coiling temperature of hot rolled strip is one of the important parameters which affect performances of hot rolled strip. The control of coiling temperature is highly nonlinear and time-varying. Based on the laminar cooling control system of a hot rolling plant, a coiling temperature prediction model based on BP neural network was established. Many factors which affect coiling temperature control were taken into account, and the BP neural network was trained by actual production data. The simulation was carried out, which indicates that coiling temperature can be predicted precisely, and the BP neural network model has the prospect of online application.

Abstract: Coiling temperature, finish rolling temperature and running speed of ZSAC1 strip during U-type cooling and number of valves which had been turned on were analyzed in order to find out the reason of low coiling temperature at tail of ZSAC1 strip in U-type cooling process. Results of research showed that running speed of strip and finish rolling temperature were main factors affecting accuracy of coiling temperature. Coiling temperature decreased with the increase of running speed of strip. Coiling temperature fluctuation would occur at the same part of strip when finish rolling temperature increased or decreased. Holding rolling speed and rolling temperature of strip stably can improve accuracy of coiling temperature during downstream U-type cooling.

Abstract: The effects of coiling temperature and cold rolling reduction on planar anisotropy of Ti-alloyed low carbon steel were investigated. The results show that as the coiling temperature increases from 509°C to 633°C, the strength and elongation have little change, and the planar anisotropy trends to decrease. When coiling at 580°C to 640°C, the value of planar anisotropy index (△r) can be reduced to no more than 0.15. As the total cold rolling reduction increasing from 55% to 85%, the plastic strain ratio values (r-values) perpendicular to rolling direction increase firstly, then decrease; the change regulation of rolling direction is reverse, and the values of 45°direction nearly have no change. And the planar anisotropy can reach 0.07 as cold rolling at 75%.

Abstract: Hot strip cooling temperature and its cooling rate is get by strip cooling system and coiling temperature of hot rolled strip is an important parameter on its performance index. It presents laminar cooling system of the 700 mm hot strip mill and the mill rolling process is present, the laminar cooling system is analyzed on the rolling theory and techniques. The laminar cooling system and its problems are present. The improvement programs of laminar cooling system are present, The control system of laminar cooling system is present combining feed-forward main control and feed-backward self-learning control, and measuring instruments is reinstall and water valves is improved. It could be a reference for the similar mill units and new building rolling mills.

Abstract: Effect of coil temperature on the texture and microstructure evolution during cold rolling and annealing were investigated by OM, ODF and EBSD. The results indicate that the {223}<110> and {114}<110> textures appeared after cold rolling are inherited followed by annealing, whose intensities would be higher as the coil temperature decreased. Lower coil temperature could improve the uniformity of grain size and increase the fraction of low-angel grain boundaries as well as coincidence site lattice boundaries. And the {111}//ND texture is improved in the lower coil temperature cold and annealing steel sheet, which is beneficial for the deep-drawability.

Abstract: A systematic experimental investigation was conducted using lab processed low carbon 0.08C-2.0Mn-Cr-Mo steel microalloyed with Ti/Nb to evaluate the influence of initial hot-rolled microstructures on the kinetics of austenite formation and decomposition after cold-rolling and subsequent annealing. Coiling temperature as a major hot rolling parameter was used to obtain different types of hot-rolled microstructures. Dilatometer and continuous annealing simulator were employed for austenite formation studies and annealing simulations, respectively. It was found that the coiling temperature affects the processes occurring during heat treatment in continuous annealing lines of full hard material: ferrite recrystallization, austenite formation during continuous heating and austenite decomposition during cooling. A decrease in coiling temperature accelerates the recrystallization of ferrite and nucleation of austenite, which results in formation of refined ferrite-martensite structure. The effect of initial hot rolled structure on final mechanical properties after continuous annealing was also investigated.

Abstract: Run out table cooling equipment and coiling temperature control (CTC) system, especially mathematic models of a hot strip mill were introduced. Heat transfer models such as air convection model, heat radiation model and laminar cooling model, process control models such as segment tracking model, feedback control model, self-learning model and case-based reasoning model were detailed described. Since online application of the new CTC system, the laminar cooling control system has been running stably and reliably with a high precision of coiling temperature.

Abstract: The influence of the coiling temperature, ranging from 550 to 570°C, on the morphology and the phase composition of the oxide scale formed on the microalloyed low carbon steel for automobiles after hot strip rolling was investigated. Physicochemical characteristics of the oxide scales were examined and their formation mechanism was discussed. Thickness of the oxide scale is in the range of 8-11µm and decreases with a decrease of coiling temperature. The microstructure and phase composition, XRD analysis shows a large amount of magnetite (Fe₃O₄) and some sparse hematite (Fe₂O₃) exist on the surface of hot rolled strip when the coiling temperature reduces from 570 to 550°C. The coiling temperature substantially affects the internal microstructure and magnetite phase.

Abstract: Effects of steel composition and coiling temperature on textures of a series of high strength IF steels were studied. An intermediate coiling temperature (6200C), instead of a high coiling temperature (7100C), was found most beneficial for the steels containing moderate to high phosphorus content. On the other hand, high coiling temperature was found beneficial for the steels containing low amount of phosphorus.

Abstract: Hot rolled 260MPa grade high strength Nb-IF steel sheet was used to study the effect of coiling temperature and cold reduction ratio on the microstructures and mechanical properties. The experimental results showed that the recrystallization has finished. Under 650°Ccoiling temperature and 75% cold reduction ratio, and under 600°C or 700°C coiling temperature and 65% cold reduction ratio, the plastic strain ratio r value and the strain hardening exponent n value were reached the maximum, and respectively, the r value was approximate 1.8, the n value was approximate 0.26. That obtains optimally match of high strength and punching property.