Abstract:Oil-in-water (O/W) emulsions are widely used in tandem cold rolling mills as coolants in order to reduce frictional forces and prevent heat scratches. Although the lubricating properties of O/W emulsions are determined by various factors, two particularly important ones are the amount of plate-out oil on the strip surface and the dynamic concentration mechanics of the emulsion at the inlet of roll bite, which has been a subject of much interest since the 1970s.As many studies have focused only on a single phen… Show more
“…Plate-out oil film formation on the vertical strip and the horizontal strip is reported by Fujita and Kimura, 14 and there is no difference between the vertical strip and the horizontal strip. Also, Fujita and Kimura 14 developed a new rolling simulator for evaluating the relationship between plate-out oil film and lubrication characteristics, and reported that the lubrication characteristics on cold rolling were transferred in the amount of plate-out oil film at about 500 mg/m 2 . Figure 5.Schematic view of apparatus used in plate-out experiments.…”
Section: Methodsmentioning
confidence: 68%
“…Azushima and Inakagi 12 proposed an estimation model for the oil film thickness using a new starvation model which considers the plate-out film on the roll and strip surfaces, and Guillaument et al 13 analyzed plate-out oil film formation after emulsion supply on the strip surface using CFD. Moreover, Fujita and Kimura 14 and Laugier et al 15 reported the influence of the plate-out oil film at the entry section of rolling on lubrication characteristics.…”
Section: Since 1980smentioning
confidence: 99%
“…13 analyzed plate-out oil film formation after emulsion supply on the strip surface using CFD. Moreover, Fujita and Kimura 14 and Laugier et al. 15 reported the influence of the plate-out oil film at the entry section of rolling on lubrication characteristics.…”
Oil-in-water emulsions are generally used in tandem cold rolling mills as lubricants, as they provide good lubricity and cooling performance. Lubricants are supplied by either a recirculation system or a direct application system. The dynamic concentration and the plate-out are known as the two main lubrication mechanisms, respectively, used in the two conventional lubrication applications. But it is difficult to realize direct control of the lubrication characteristics only using the dynamic concentration mechanism while the plate-out mechanism makes it possible. Therefore, this article is concerned with an experimental study of the efficiency of plate-out oil film formation, focusing on emulsion spraying conditions. Emulsion supply conditions are also examined in the plate-out test, which enables extremely rapid evaluation in a time equivalent to that in actual high-speed cold rolling. An air atomizing nozzle, which supplies a mixture of emulsion and air, was more efficient for plate-out oil film formation than the conventional flat nozzle, which only supplies emulsion. Air atomizing expands the space of the emulsion droplet and may prevent outflow of the plate-out oil film. The results of this research suggest that it is important to consider emulsion supply conditions as well as emulsion make-up conditions.
“…Plate-out oil film formation on the vertical strip and the horizontal strip is reported by Fujita and Kimura, 14 and there is no difference between the vertical strip and the horizontal strip. Also, Fujita and Kimura 14 developed a new rolling simulator for evaluating the relationship between plate-out oil film and lubrication characteristics, and reported that the lubrication characteristics on cold rolling were transferred in the amount of plate-out oil film at about 500 mg/m 2 . Figure 5.Schematic view of apparatus used in plate-out experiments.…”
Section: Methodsmentioning
confidence: 68%
“…Azushima and Inakagi 12 proposed an estimation model for the oil film thickness using a new starvation model which considers the plate-out film on the roll and strip surfaces, and Guillaument et al 13 analyzed plate-out oil film formation after emulsion supply on the strip surface using CFD. Moreover, Fujita and Kimura 14 and Laugier et al 15 reported the influence of the plate-out oil film at the entry section of rolling on lubrication characteristics.…”
Section: Since 1980smentioning
confidence: 99%
“…13 analyzed plate-out oil film formation after emulsion supply on the strip surface using CFD. Moreover, Fujita and Kimura 14 and Laugier et al. 15 reported the influence of the plate-out oil film at the entry section of rolling on lubrication characteristics.…”
Oil-in-water emulsions are generally used in tandem cold rolling mills as lubricants, as they provide good lubricity and cooling performance. Lubricants are supplied by either a recirculation system or a direct application system. The dynamic concentration and the plate-out are known as the two main lubrication mechanisms, respectively, used in the two conventional lubrication applications. But it is difficult to realize direct control of the lubrication characteristics only using the dynamic concentration mechanism while the plate-out mechanism makes it possible. Therefore, this article is concerned with an experimental study of the efficiency of plate-out oil film formation, focusing on emulsion spraying conditions. Emulsion supply conditions are also examined in the plate-out test, which enables extremely rapid evaluation in a time equivalent to that in actual high-speed cold rolling. An air atomizing nozzle, which supplies a mixture of emulsion and air, was more efficient for plate-out oil film formation than the conventional flat nozzle, which only supplies emulsion. Air atomizing expands the space of the emulsion droplet and may prevent outflow of the plate-out oil film. The results of this research suggest that it is important to consider emulsion supply conditions as well as emulsion make-up conditions.
“…The tandem rolling of stainless steels attains a relatively high rolling reduction rate, but large amounts of heat caused by friction and plastic deformation are generated. The high temperature causes the film to become thinner, 8,9) which increases the probability of incurring heat-streak defects. 10) Also, any roughness of the roll surface can give rise to defects.…”
In a tandem cold mill for stainless steel, an optimum reduction rate is necessary for each stand. A conventional mill set-up uses a lookup-table to optimize the rolling schedule. However, to reflecting all the input conditions and manual interventions on a model is difficult. In this paper, we propose a mill set-up model that can efficiently predict the reduction rate for each stand by considering various input conditions. The proposed prediction model has a multi-output tree structure with a smaller time complexity for easy interpretation. The key contribution to the proposed algorithm is variable selection. According to the results of an analysis of the time-complexity, the proposed algorithm is less time consuming and is capable of learning datasets with a large number of variables more efficiently than the single-output CART (classification and regression trees). To evaluate the performance of the proposed algorithm, we applied it to the rolling reduction rate of a tandem cold mill in POSCO. The proposed algorithm achieves a similar level of R-squared in only 18% of the computing time required for an existing single-output CART algorithm.
“…Many scholars have conducted numerous studies for emulsion rolling lubrication technology. Kimura and Fujita [1][2][3] established an estimation model of plate-out oil film after experimentally investigating the influences of plate-out time, emulsion flow, emulsion concentration, and oil droplet size on plate-out oil film formation characteristics through laboratory tests; then, these authors developed a hybrid lubrication system by combining recirculation and direct application systems. Azushima 4,5) proposed a numerical estimation method for oil film thickness during cold rolling by combining conventional starvation and plate-out models.…”
In double cold rolling process, rolling energy and oil consumption is normally controlled separately, thereby causing a high comprehensive cost. This study investigated a calculation model of plate-out oil film thickness on strip surface, oil film thickness in deformation zone, friction coefficient, bite angle, forward slip, rolling force, rolling power, rolling energy consumption, and rolling oil consumption. Subsequently, the effect of emulsion flow and concentration on rolling energy and oil consumption comprehensive cost was quantitatively analyzed. On this basis, an objective function of rolling energy and oil consumption comprehensive cost was proposed, and the corresponding comprehensive optimization control technology for rolling energy and oil consumption was developed. Through a field application of this technology, the reduction of rolling energy and oil comprehensive consumption cost was achieved by optimizing emulsion flow and concentration comprehensively. Thus, a significant economic benefit was created with further popularization and application values.
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