SU1570806A1 - Method of rolling - Google Patents

Abstract

The invention relates to rolling production, specifically to the production of blanks on roughing cages of sheet mills. The purpose of the invention is to increase the productivity of the process by the intensity of the reduction mode. The method is carried out in rough rollers, the roughness of which has extremes along the circumference of the barrel of the working rolls in the form of a chevron with an inclination to the axis of rotation of the rolls at an angle of ϕ (hail), and the width S (m) of sections with different height of roughness within ϕRCOS * 98F / 5≤S≤ϕRCOSϕ, where R is the roll radius, m. During the rolling process, different areas of different asperities are alternated on one relative other roll, so that a periodic antiphase replacement of the contact area on one roll with m the maximum height of asperities to the minimum, and on the other roll, on the contrary, from the minimum to the maximum. The system of rolls - rolled stock during rolling turns into a harmonic oscillator, which excites harmonic self-oscillations in the distribution of the relative magnitude of plastic deformation between the upper and lower surfaces of the crimped blank. This makes it possible to increase the reduction in skip by 2.6-9.1% and increase the productivity of the rolling stand due to the intensification of reductions by 1.5-2%. 3 dw., 2 tabl.

Description

The invention relates to rolling production, in particular to the production of blanks on roughing cages of sheet mills.

The purpose of the invention is to increase the productivity of the process by intensifying the reduction mode.

Figure 1 shows the rolling pattern of the strip in rolls with a variable roughness along the diameter of the barrels with the antiphase orientation of the minimum i

Noah and maximum roughness on the lower and upper rolls; 2 - the same, with the change of the positions of the lower and upper rolls relative to the sections with the maximum and minimum roughness in figure 3 - the mutual orientation of the working surfaces of the upper and lower rolls in the implementation of the proposed method.

The essence of the proposed method lies in the fact that rolls for romrom ix passes are obtained in roller committees having varying roughness around the perimeter of their chevron barrels, and when crimping the workpiece along its length, different irregularities of workability alternate on the surface of one roll relative to the other in such a way that, during the rolling process, JQ periodically antiphase replaces the contact area on one roll with the maximum height of asperities at the minimum, and at the other eoborot, with minimal to maximum fj nougat. Such a periodic replacement of the roughness in the zone of the deformation zone leads to harmonic self-oscillations of the power parameters of the rolling process, 20

The system of rolls - rolled billet turns into a harmonic oscillator, which excites harmonic self-oscillations in the distribution of the relative amount of plastic deformation between the upper and lower surfaces of the crimped in the deformation zone of the billet. Due to a periodic change in the direction of the rolling axis of sections with different height of irregularities on the surface of the roll barrels in the contact zone with the metal, such interaction of the rolls with the metal is achieved, in which symmetrically oriented sections of opposite extremes of the microroughnesses from both rolls relative to the axis of rolling alternate during rotation of the rolls. friend of the harmonic law, and with them harmoniously. To what law does the degree of plastic deformation of the metal of the crimped workpiece change in the zones contacting with the rolls?

To implement the method used.

four

Rolling rolls with alternating on the working surface areas of different height of asperities are inclined, which are inclined to the axis of the rolls at an angle cp, and the pyrin of the areas R is determined in accordance with the radius for each of the rolls within:

3

cos / 5 ё S Ј 7R cos if (I), (1),

- width of asperity sections, m,

- roll radius, m; - the angle of inclination of asperities to the roll axis, deg.

Due to this, the load on the rolls is balanced and shocks in the drive are prevented, since the total contact area of the working surfaces of both rolls with the workpiece in areas with higher irregularities and smaller ones in the deformation zone varies slightly.

During rolling, when the rollers rotate, the interfaces between sections with different height of irregularities move along the axes of the rolls along a helix, which in turn affects the increase in broadening, reduction and stretching of the workpiece in one pass through the roll gap due to acceleration metal crimped workpiece in width.

The proposed orientation of the roughness extremes on one roll relative to the other during rolling of the blanks is provided by the regulated ratio of the angular speeds of rotation of the rolls:

W

to FY777 +)

- / 9)

Uz. -KN./ "h

where GO,, COj are the angular rotational speeds of the rolls, 1 / s; R I, RЈ - roll radii, m;

DL - compression of the workpiece in rolls per pass, m; Sts, S2 width of asperities on rolls, m / C - the angle of inclination of asperities to roll axes, deg.

Primer p. The method was carried out on a duo-850 roughing stand with an upper work roll diameter of 830 mm and a lower 850 mm working surface of which had a variable roughness with different micro irregularities made in the form of a chevron at an angle to the roll barrel forming 45 (to the axis of rotation of the roll) 45. Having a difference in diameters of 2.35% when rotating at the same angular velocity, the rolls have the same difference in circumferential speeds.

The circumferential speed of the lower roll is 2.35% more than the circumferential speed of the upper. Therefore, in order to ensure that the rough section of one roll opposite the smooth section of another roll in the deformation zone, with synchronous rotation, the width of alternating sections on the upper roll should be 2.35% less than the bottom roll.

By dividing the circumference of the rolls along the perimeter into ten equal parts with arc lengths supported by a central angle of 36 °, the width of the sections for each of the rolls is determined through diameters.

For the upper work roll with a barrel diameter d (830 mm, the width of the alternating irregularities of microroughness is mm, and for the lower roll with a barrel diameter of d% 850 mm, the width of the microroughnesses is mm. Having a difference in the values of the lengths of arcs, formed by micro-irregularities, is 2.35%.

Rolled billet with the original thickness of mm for eight passes to the final thickness of mm.

Specific data on the amount of compression for the pass, the angle of capture in comparison with the method of the prototype are given in Table 1.

The ratio of the angular velocities of the rolls corresponded to the expression (2) -and are shown in Table 2.

The working surface of the rolls, having a minimum height of asperities, are considered 1 relatively smooth, and the areas of the working surface of the rolls that have microscopic irregularities with a maximum height are roughened in comparison with the smooth ones.

The billet metal, which is drawn into the roll roll gap by the rough section of one roll due to friction forces, spreads relatively freely when squeezed over the smooth surface of the other roll, thereby unloading the deformation zone,

a l Q

1570806 6

reduction of rolling effort on rolls of the rolling moment, which allows to increase the amount of skipping per pass by 2.6-9.1% and in comparison with the method of the prototype to reduce the number of passes by one (8 passes instead of 9), increasing the productivity of the duo rolling stand -850 at 1.5-2%.

Claims (1)

Invention Formula The rolling method, which includes compression of the workpiece with regulated angular speeds of rolls with a mutual orientation of the working surfaces of their barrels, on which roughness in the form of chevrons is performed, with sequential alternation of sections with the highest and smallest asperities, characterized by the fact that process performance, rolling is carried out with a misalignment of the angular velocities of the rolls, at which sections of barrels with opposite extreme points of roughness are introduced into the deformation zone vatosti with the greatest height to present their communication on one roll and the lowest on the other roll, the ratio of speeds roll angles s are determined from the relationship 35 Ј11 Uj where C0 (, C02 - the angular velocity of the rolls, 1 / s; 1C, RЈ - radii of roll points, m; u h - the absolute reduction of the workpiece, m; Cf - the angle of the rough area to the axis of the roll, hail, S. and S is the width of asperity sections on the upper and lower rolls, m, and S, (, cos tf / 5 - 7 R, coslf); ft R2-cos - ft R2coscf). Table 1 The parameters of the rolling sheet billet thickness of 145 mm 23 mm thickness table 2 The change in the ratio of the angular velocity of the rolls and reductions by passes in the proposed method of rolling AT WUB.1 Well 0 Csj tr I