Rolling Stands Research Articles

Effects of physical properties and operating parameters on soybean flaking

AbstractThe soybean crushing industry aims at attaining greater oil extraction by optimizing flake thickness. This involves modifying the physical and viscoelastic properties of cracked soybeans and adjusting operational settings of the flaking roll stands. Vibratory feeders distributed 20–32% fewer cracked soybeans at the roll ends and 12% fewer cracks at the center. This increased the variability in roll wear and flake thickness along the length of the rolls. The flow rate distribution produced by rotary feeders was more uniform. Vibratory feeders produced a uniform particle size distribution of cracks (diameter range 2.71–2.76 mm) along the length of the rolls. At constant roll pressure, the increased flow rate of cracks increased the flake thickness and power consumption. While roll stands were operating at their rated flow capacity, the desired flake thickness range (0.25–0.38 mm) could not be obtained by merely increasing the roll pressure, because it caused hot spots in the rolls. Modifications of the metallurgical properties of the rolls and the viscoelastic properties of the soybeans are possible means of reducing flake thickness. During six plant visits, 73.2% of the sampled flakes were thicker than the maximum desired value (0.38 mm). This may be costing the U.S. soybean milling industry an annual loss in oil revenues of S7–16 million.

Stabilization of Strip Tension between Rolling Stands by Decentralized Control System

This paper presents decentralized control application for stabilization of strip tension in Hot Strip Finishing Mill. Hot Strip Mill, in particular, thickness deviation at head-end and tail-end becomes more serious problem. In order to stabilize strip tension, feedforward decentralized control system has been proposed with the high performance of automatic gage control system. This control method has been confirmed effectiveness by simulations and applying in hot strip mill has shown thickness improvement.

Modeling the microstructural changes during hot tandem rolling of AA5XXX aluminum alloys: Part III. Overall model development and validation

Part III of this article presents the overall mathematical development for the microstructural and textural evolution during industrial hot tandem rolling of AA5182 and AA5052 alloys and validation of the mathematical model, by comparison to both industrial data and information from the literature. The model consists of a plasticity module to simulate the temperature and deformation in the roll bite and an interstand module to characterize the changing microstructure, texture, and temperature in the strip between the rolling stands. The plasticity module was developed using a commercial finite-element package, DEFORM, a two-dimensional transient Lagrangian model which couples the thermal and deformation phenomena and is able to predict the temperature, strain rate, and strain distribution in the strip at any position in the roll bite. The interstand module incorporates semiempirical equations, developed in this study, which quantify the microstructural (percent recrystallization and recrystallized grain size) and textural changes in the strip between the rolling stands. The interstand model also includes a temperature module to predict the through-thickness temperature distribution in the strip based on one-dimensional heat conduction. Validation of the model against industrial data indicated that it gave reasonable predictions for the temperature, grain size, and volume fraction of some of the deformation texture components after recrystallization was completed. However, the model overestimated the mill loads in the last stands for both the AA5182 and AA5052 alloys and underestimated the amount of cube ({100}〈uvw〉) and S ({123}〈634〉) texture in the recrystallized strip.

Endless rolling technology for No. 3 hot strip mill at Chiba Works of Kawasaki Steel

Fully continuous finishing rolling, so-called “endless hot strip rolling”, has started in operation for the first time in the world. This unique technology realizes finishing rolling under an uninterrupted tension between rolling stands. As a result, product quality, productivity, and stability of rolling were improved. In addition, ultra-thin strip, like 1.0 mm thickness, has been produced without trouble.

A hybrid neural-network/mathematical prediction model for tandem cold mill

In tandem cold mill, a strip is flattened by stands of rolls to a desired thickness. At Pohang Iron and Steel Company (POSCO) in Pohang, Korea, precalculation determines the mill settings before a strip actually enters the mill and is done by an outdated mathematical model. A corrective neural network model is proposed to impoove the accuracy of the roll force prediction. The network is fed not only the usual mathematical model's input but also a set of additional inputs such as the chemical composition of the coil, its coiling temperature and the aggregated amount of processed strips of each roll. The network was trained using a standard backpropagation with 4,944 process data collected at POSCO from March 1995 through December 1995, then was tested on the unseen 1,586 data from February 1996 through April 1996. The combined model reduced the prediction error by 33.88% on average.

Reliable roll force prediction in cold mill using multiple neural networks

The cold rolling mill process in steel works uses stands of rolls to flatten a strip to a desired thickness. The accurate prediction of roll force is essential for product quality. Currently, a suboptimal mathematical model is used. We trained two multilayer perceptrons, one to directly predict the roll force and the other to compute a corrective coefficient to be multiplied to the prediction made by the mathematical model. Both networks were shown to improve the accuracy by 30-50%. Combining the two networks and the mathematical model results in systems with an improved reliability.

Mathematical model of the transfer of the excitation of vibration between adjacent rolling stands of a continuous group

In this study the bar is replaced by a system with a continuous distribution of mass. The mathematical description of this system should be an element of the model of continuous rolling mills and can be investigated only in conjunction with rolling mills.

Operational results with CCR cassette type compact rolling stands and super high load cantilever stands on bar and wire rod mills

The CCR Cassette Type Compact Rolling Stand is a design for extremely rapid programme change and allows a flexible production planning and, in conjunction with the high level of automation, the production of small order lots with high mill efficiency.Super High Load Cantilever Stands are used as rolling units for prefinishing or finishing blocks in wire rod mills. The design features predestinate this type of stand to roll high alloy steel grades and superalloys with high deformation resistance.

ＳＭＣロール成形法の開発研究 圧下量・ロール周速の影響

SMC (Sheet Molding Compound), which has such excellent characteristics as surface brilliance, formability and mechanical property, is usually formed by compression molding. This method has short cycle time of processing, but needs huge energy for forming because of formation of hydrostatic stress domain in the mold. So, roll forming is proposed for SMC so as to decrease the forming energy ay losing a formation of hydrostatic stress and to keep short cycle time.At first, the fundamental experiment is carried out to see the behavior of deformed material using a constant reduction on each forming condition. It is necessary to decrease the number of roll stand for making a compact roll forming system. But the condition for large reduction results in that the deformed material shows an instability behavior between roll stands. And, the condition for low reduction can improve the formability of the flange of channel shaped products.The tension brought in by the difference in driving speed makes material stable from the exit of one roll to the entrance of the next roll, and this tensile load affects the deformation of the materials. The result of this research is useful to decide the driving speed during reduction.

A simplified method for the simulation of cold-roll forming

A kinematical approach is proposed in this paper for predicting the optimal shape and the deformed length of a metal sheet during cold-roll forming, before the first roll stand. The middle surface of the sheet is described as a Coons patch depending on one geometrical parameter. A velocity field is then defined on this surface so that the plastic work rate depends only on this single geometrical parameter. Its minimization gives the optimal shape for a strain-hardening rigid-plastic material. This approach has been implemented on a workstation, and it allows a very fast simulation of the process. Moreover, this method can be extended to different shapes, and the whole process including several roll stands can also be calculated.

Trends in taking into account dynamic phenomena when designing and operating rolling stands

In this paper, the major factors leading to dynamic increase in the forces in a rolling stand are explored, both theoretically and experimentally. In particular, the effects of the following are examined: (i) the ratio of the bite time to the period of natural vibration of the rolling stand; (ii) the nature of the elastic characteristics of particular elements, including non-linearity associated with clearances and slacknesses; (iii) slip between the metal and the rolls. It is demonstrated that the increase in the forces arising from dynamic effects is of such magnitude as to constitute a hazard and that the rolling stand must be designed with due allowance for vibration effects.

A roller roll guide for a semicontinuous medium shape mill

The 350 semicontinuous medium shape mill of our plant consists of 14 roll stands, of which stands IV, VII, XI, and XIII are with vertical rolls; stands I, IX, and X are independent; and the others are grouped in three continuous groups. The first continuous group includes stands II-V, the second XI-XIII, and the third XI-XIV. The maximum rolling speed in the finishing stand is 15 m/sec. The original billets (80-, I00-, 120-, 125-, 150-, and 160-mm squares) with lengths of 4-6 mm are heated in three three-zone continuous furnaces with a productivity up to 80 tons/h each.

本邦條鋼圧延技術め進歩

At the end of Pacific War, Japan had 8 units of blooming mills. During ten years since then new establishment of 4 mills and renovation of 1 plant were performed. Besides, bulk amount of fund was invested to the established blooming mills to improve the soaking pits and other accessories. Above all, the Chiba plant of Kawasaki Iron Mfg. Co. constructed a latest and largest blooming mill, in which majority of mechanical equipments had been imported from the United States. On the cotrary, the plant of Nippon Steel Tube Co. shows the most modern mill made of Japanese equipments. Majority of soaking pits had been improved_in Japan following instructions of Messrs. Fred N. Hays and James T. Macleod (Carnegie-Illinois Steel Co. ). As for the bloom-rolling stands, renovation of the millmotors and the motor-generator sets was performed by turns in respective plants. The quality of cast or forged rolls still remained an unsolved problem. No continuous mill for billets, however, had been constructed anew. Nevertheless, some improvements had been made in the ways of rolling such as utilization of diamond-squared calibers and roller guides. As for the finishing of billets, Yawata Iron & Steel Works had used since July 1952 a. hot-scarfing equipment (Lindé Co. ) with heat-resisting nozzles made in Japan.Moreover, in the field of bar sections rolling efforts had been made for recovery of devastated equipments, improvement in the quality, of products, reduction of consumption-unit of fuels and power and enhancement of the labor-productivity. In the continuous reheating furnaces, rationalization of the structure, amelioration of refractories and control-automation were performed. Heavy oil and high-pressure gas began to be utilized rationally instead of the traditional coal-combustion. As for the main motor, the chartacteristics were increase of output and magnification in the number of rotation and widening of the range of velocitychange. To meet recent demands in multiformed sections, some equipment was devised for a speediest resetting of rolls especially for the sake of heavy sections. In the new wire-rod mill at Hikari (Yawata Iron & Steel Co.). all-continuous equipment had been projected so that increase in the unit-weight of billets, increase in the finish-rolling speed, independent driving of each stand and utilization of vertical rolling stands were prospected for an enhanced production of products homogenous in quality and shape. In conclusion, the stress was laid on further improvement in the bar and section mills in Japan, although majority of the rationalization fund in the postwar Japan had been invested to amelioration of the plate or sheet mills.

Power requirements for rolling high-carbon steel of small section

The tests in this paper were taken from a 9-in. merchant mill, a plan of which is shown in Fig. 1. The mill consists of seven stands of three-high rolls and one finishing stand of two-high rolls driven by a two-speed two-phase, 60-cycle, 2200-volt induction motor of squirrel-cage rotor construction, connected to the mill by means of a 42-in. three-ply belt. The ratings of the motor are 600 h. p. at 600 rev. per min. (synchronous speed) and 450 h. p. 450 rev. per min. The pulley reduction gives a mill-speed of one-half these values.

Power Requirements for Rolling High-Carbon Steel of Small Section

The tests in this paper were taken from a 9-in. merchant mill, a plan of which is shown in Fig. 1. The mill consists of seven stands of three-high rolls and one finishing stand of two-high rolls driven by a two-speed two-phase, 60-cycle, 2200-volt induction motor of squirrel-cage rotor construction, connected to the mill by means of a 42-in. three-ply belt. The ratings of the motor are 600 h. p. at 600 rev. per min. (synchronous speed) and 450 h. p. 450 rev. per min. The pulley reduction gives a mill-speed of one-half these values.