Flexible lubrication concept. The future of cold rolling lubrication

Abstract

For cold rolling systems, in particular for tandem mills that are the major form of the process, conventional lubrication processes appear to have reached their limits. This paper proposes a new advanced lubrication concept called flexible lubrication which adjusts the friction levels at the three process time scales: the rolling campaign, the local scale (coil to coil), and the transient stages within two coils. The proposed approach is expected to increase roll campaign length, energy saving, mill capacity, and flexibility of production programming while at the same time avoiding the detrimental effects created by uncontrolled friction variations such as sudden increases in rolling force and chattering. Showing the conventional lubrication limits through a deep production analysis, this paper is then concerned with the study of the flexible lubrication concept at the laboratory scale and finally, initial results obtained in the first industrial application of this procedure are also reported.

Plate-out efficiency related to oil-in-water emulsions supply conditions on cold rolling strip

“…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.…”

“…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.…”

Study of the boundary friction of high-strength steel during the cold rolling

“…The rolling force significantly depends on the friction coefficient between the work rolls and strips, and lubrication systems can effectively reduce the friction coefficient and rolling load. [3][4][5] However, when the friction coefficient becomes significantly low, skidding occurs between the work rolls and rolled strips, particularly HSS strips. 6,7 The skidding occurs when the circumferential speed of the work roll V R greater than the speed of the strip at the exit of the rolling bite V o .…”

“…The rolling force significantly depends on the friction coefficient between the work rolls and strips, and lubrication systems can effectively reduce the friction coefficient and rolling load. 3–5…”

Guaranteed cost control design for descriptor systems with time-varying delays

“…Due to the evolution of the technology, the specifications required for the steel sheets continuously change asking for thinner sheets with an increased performance assessment (mainly hardness, but also flatness...) [18]. In order to accomplish this objective one needs to adopt new control strategies aiming at: reaching the required specifications of the steel sheets; taking into account the complex interactions inside the system; reducing the energy cost of the rolling process and finally being ready for the further introduction of new actuators such as flexible lubrication [19], [20].…”