SU1731314A1 - Sheet rolling stand roll set - Google Patents

Abstract

The invention relates to the processing of metals by pressure and is used, in particular, during cold rolling. The aim of the invention is to improve the quality of finished steel by reducing the non-uniformity of wear along the length of the barrel. In the set of work rolls, the roughness on the rolls is made with damped cosine curves with a period of 0.002-0.03 and with attenuation to the middle and edges of the rolls. The maximum difference in the roughness of the corresponding sections on the one and the other rolls is made at a distance of 0.05, ... 0.4 times the length of the roll barrel from the edges of the rolls. The ratio of two adjacent roughness amplitudes to each other is 1.1 ... 200. The largest roughness along the length of the barrel is 2.5-1000 times smaller than the smallest. 1 tab., 3 Il.

Description

The invention relates to sheet rolling, in particular to cold rolling mills.

The aim of the invention is to improve the quality of finished steel by reducing the uneven wear of the rolls along the length of the barrel.

Figure 1 shows a characteristic plot of the distribution of normal contact stresses across the width at the contact of the rolled metal with the work roll; Figures 2 and 3 show the law of roughness variation along the length of the barrel on one of the work rolls, where a is the distance from the edges of the roll to the maximum difference in roughness on the corresponding roll areas; L is the length of the roll barrel; Рmax - the maximum roughness value; RMHH - the minimum amount of roughness; Ri, R2 - the values of two adjacent roughness amplitudes; T is a period equal to 0.002 ... 0.05 of the length of the roll barrel; Ri / R2 1.1 ... 200; RMBKC / RMMH 2.5 ... 1000.

The maximum difference in roughness of the corresponding roll areas should be made at a distance not exceeding 0.4 of the roll barrel length from the edges of the rolls, since an increase in this distance leads to a decrease in contact voltage, but not at the peak, but closer to the middle of the barrel roll. A decrease in this distance of less than 0.05 in the length of the roll barrel leads to a decrease in pressure also not at the peak, but closer to the edge of the roll, which leads to uneven wear of the rolls.

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Increasing the ratio of two adjacent roughness amplitudes of more than 200 leads to instability of the rolling process or even loss of flatness, while reducing this ratio to less than 1.1 leads to the fact that the pressure peaks are not smoothed and the unevenness of roll wear is not reduced.

The device works as follows.

For rolling strips and sheets, a set of work rolls is installed in the quarto stand, the roughness on one of which varies as shown in Fig. 2. Extremes of the same sign on the other roll are displaced relative to the corresponding extremes on the first roll by the length of the barrel by half the period, i.e. the maximum roughness on one roll corresponds to the minimum on the other and vice versa, which means that an asymmetrical rolling process is created with different asymmetry values across the width of the rolled metal. This leads to a general reduction in rolling force, and the greatest decrease in pressure is observed at the point of maximum difference in roughness of the respective sections on one and the other rolls, performed at a distance of 0.05 .., 0.4 times the length of the roll barrel from the edges of the rolls.

Thus, the uneven distribution of contact stresses across the width of the rolled metal is reduced, which entails a reduction in the uneven wear of the barrel and an increase in the quality of finished rolled products.

Mill 300 uses ground work rolls with a barrel diameter of 100 mm and a length of 300 mm. Rough variable

wadiness along the roll barrel was obtained by electrosparking polished rolls. The width of the rolled strips varied from 100 mm to 250 mm.

The table shows the parameters and ratios of the roughness of the rolls, which were used in 12 sets during rolling on the mill.

As a result of the application of the invention, the non-uniformity of rolls wear along the barrel length is reduced by 16 ... 20%, as a result of which the rejection of sheets and strips into the second grade is reduced.

Claims (1)

Claim set of working rolls of sheet rolling stands, mainly for cold rolling, whose barrels are made with a roughness varying parallel to them. forming according to a harmonic law with an equal period within 0.002-0.05 of the length of the roll barrel, the extremums of one mark on the barrel of one roll are offset relative to the extremes of roughness along the barrel length of the other roll by half the period, and the largest roughness of the barrel exceeds the smallest by 2, 5-1000 times, characterized in that, in order to improve the quality of finished rolled products by reducing the uneven wear of rolls along the length of the barrel, the roughness is made along cosines that attenuate towards the middle and edges of the roll barrels, and the maximum difference in roughness in the corresponding sections of the roll was made at a distance of 0.05-0.4 in the length of the rolls from its edges, and the ratio of two adjacent amplitudes of the roughness is 1.1–200. I i i i: i i i I i - ES HSSJ: SISiJ. RMUKC RMUH Fig 1 fv: 2 ShGZ R