Determination of Particular Relative Reduction in Cold Rolling of Thin and Extra Thin Strips to Implement the Process with the Least Force

Abstract

Introduction. It has been theoretically established and experimentally confirmed that the elastic deformations of rolls and strips in cold rolling have a significant and, in the case of thin rod rolling, a crucial effect on all process parameters.Problem Statement. The influence of the elastic-plastic interaction of a thin strip with rolls, the tension, the temperature and rate of deformation, and the strength of strip material shall be taken into account for developing a modern theory of longitudinal cold rolling.Purpose. Modeling and forecasting the parameters of cold rolling of thin and extra thin strips.Materials and Methods. To solve this problem, the conditions of rolling strips made of 08kp steel with different degrees of preliminary metal hardening, which reflected the features and regularities of hardening the strip material in the multicellular state line, have been modeled. The partial relative reductions vary within 0.02—0.35,with the initial data corresponding to the most characteristic conditions of cold rolling of thin and extra thin steel strips on operating mills taken.Results. The quantitative data on the influence of the strip thickness, at the entrance to the deformation zone, partial and preliminary relative reduction during cold rolling on the process conditions with the least force. For the first time, the conditions and range of partial relative reductions for the cold rolling process of thin and extra thin strips with the least force have been determined. It has been established that in the case of cold rolling of thin and extra thin strips made of unriveted and pre-hardened steel, varying partial relative reductions within the rangefrom 0.1 to 0.30—0.35 provides the realization of process with the least force.Conclusions. The implementation of cold rolling process with the least force is advantageous in terms of energy saving and manufacturability, as it allows reducing the specific consumption of electricity and expanding the range of cold rolling mills for smaller thicknesses of rolling strips and indicates the need to determine conditionsfor such a process.

Influence of emulsols type on energy-power consumption and surface contamination at DC01 steel cold rolling on the continuous four-stand mill

“…At the same time, researchers [15] note that during their one-time evaluations, a more effective emulsol than "Quakerol 671" was not found for the conditions of 1700 CRS of OJSC "AMT". Electricity consumption during rolling depends not only on the type of emulsion used, but also on many factors: on the setting of inter-stand tension [1,16], the realized stress-strain state of the material [16,17], rheological properties of steels [18], efficiency of intermediate recrystallization annealing [19] and other methods of processing rolled steel [20], structural features of the rolling stock and its working and conductive elements [21], technological state and obsolescence of electrical equipment designs [22]. Indicators of power quality [23], which depends on the efficiency and stability of workshop converters and transformers [24], have a significant influence on the stability of the electrical equipment of heavy-loaded machines, and, as a rule, the controllability of rolling mills.…”

“…Four-high mills are used for production of cold-rolled sheets and strips 0.6-2.5 mm thick and 1300-1800 mm wide as finished products from 3-8 mm thick hot-rolled steel in coils weighing 25-50 tons. High energy consumption in such mills is due to the presence of a barrel 1500-2000 mm with a diameter of working rolls 500-550 mm and reserve 1300-1500 mm for the transfer of torque [1]. Rolling speedat least 5-12 m/s, productivity -from 0.6-0.8 million tons per year [2].…”