SU1659144A1 - Set of sheet mill rolls - Google Patents

Description

The invention relates to rolling equipment, in particular to rolls for rolling strips and sheets in hot and cold conditions. The purpose of the invention is to reduce the power parameters of rolling by improving the capture of lubricant while maintaining the centering of the strip. To do this, on the surfaces of the work rolls made areas with greater and lesser roughness. The slope of the line of protrusions and depressions in areas with greater roughness is 10-56 ° to the vertical axis, which helps to improve the delivery of lubricant to the deformation zone. 2 ill., 1 tab.

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The invention relates to rolling equipment, in particular to rolls for rolling strips and sheets in hot and cold conditions.

The purpose of the invention is to reduce the power parameters of rolling by improving the conditions for gripping lubricant while maintaining the centering of the strip.

Figure 1 shows the roller set with the reference and working sensors; Fig.2 Guofil forming rolls.

Nafig.1 shows the support roll 1, the work roll 2, the roll section 3 with a lower roughness, the lines of depressions and protrusions on which are concentrically around the circumference, the roll section 4 with greater roughness, the lines of depressions and protrusions on which are at an angle of 10-56 ° to the vertical axis of the rolls.

The invention consists in the following. The power and force parameters of rolling essentially depend not only on the size of the microroughness of the roll surface, but also on the direction of the lines of depressions and protrusions on the roll surface, since this factor determines the conditions of capture by the rolls or strip of technological lubricant. When concentrating the lines of hollows and protrusions (99 = 0 °) on the roll surface when grinding it with an abrasive wheel, the conditions for gripping the process lubricant to the deformation zone are the worst and the flow resistance of the metal along the rolling direction is minimal, since the ridges on the roll surface are circumferentially . If the lines of the protrusions and depressions are parallel to the axis of the roll (<р = 90 °), then the conditions for gripping the lubricant

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best at any height microroughness. However, the resistance to metal flow in the deformation zone is maximum due to the perpendicular arrangement of the ridges relative to the direction of rolling. This causes an increase in the energy-power parameters of rolling as compared with rolling at <p = 0 °. Both variants of the surface microrelief do not ensure the centering of the rolls and the strip along the rolling axis.

Thus, there is an optimal type of microrelief of the surface of the rolls, which ensures the reduction of energy-power rolling parameters in comparison with the prototype and centering the rolls and the strip along the rolling axis.

In accordance with experimental data is optimal angle microrelief ridges equal <p = 10-56 °, and the difference Ive radii ί? Ι and K of the roll in areas with different roughness is 3-20 _and K

Roll set with such a micro-profile works as follows.

After installation in the cage, the process of rolling the strips begins. The arrangement at an inclination to the axis of the trough of the microrelief is filled with technological grease, which is plentifully supplied to the rolls, and together with this roll section the grease enters the deformation zone. Since the protrusions of the microrelief interfere with the release of the lubricant from the deformation zone, the thickness of its layer is increased compared with rolling on rolls with. φ. = 0 °, and this provides an increase in the share of forces of fluid friction and a corresponding decrease in the share of forces of dry (boundary) friction. This leads to a general decrease in the friction forces on the contact surface and a decrease in the power and force parameters of rolling (force and moment of rolling) compared to rolling at φ = 0 ° and compared to rolling on the prototype.

A microrelief φ = 15-50 ° is imprinted on the rolled strip, the depressions of which are filled with technological lubricant already hardened in the deformation zone. This circumstance, as well as an increase in the volume on the strip, ensures a corresponding decrease in the power parameters in the subsequent stand due to a decrease in the friction forces and the friction coefficient.

Due to the noted features of the proposed microrelief, the supply of technological lubricant and the contact area between the working and support rolls is improved, and this causes a decrease in strength

friction on the roll contact, reducing torque and rolling power.

The presence of alternating sections with ^> = 0 ° and φ> 0 ° and differing from each other by radii Ρι and B (Fig.2) allows fixing the strip along the rolling axis due to its pinching between the work rolls. The value ΔΒ = Κι - B is determined by the stand in which the roll set is installed. In the stand 1 of the continuous cold rolling mill, rolls with ΔΒ = 0.030.05 mm can be installed, and in intermediate stands (stands 2, 3) with ΔΚ = 0.01–0.02 mm, the use of work rolls with Δ В = 0.01 -0.04 mm is due to the closure of traces from the boundaries of one site to another. Moreover, the smaller the subsequent deformation of the strip, the smaller should be the height Δκ, Therefore, in the stands 1 Δ 1 = 0.03-0.05 mm, and in stands 2 and 3 ΔΒ = 0.01-0.02 mm. If the diameters of the work rolls of the strip (sheet) mills are within O = 400-1200 mm, then the relative height of the section with inclined ridges of the microrelief is strip (sheet) hot rolling mills, the first stand of cold rolling mills ΔΒ / Κ = (0.03 - 0.05) / (200-600) = 0.000050,00025, finishing stands for hot or cold rolling mills for strips going to the subsequent processing ΔΒ / Β = (0.010.02) / (200-600) = 0.000033 -0,0001.

Thus, when rolling in rolls with ΔΕ / Β = 0.000033-0,00025, with subsequent reductions of the strip in the stands of hot rolling mills, the boundaries between sections with different surface relief are rolled up. Such a relief is made on the work and support rolls, on one pair or on two pairs of rolls of a four-roll stand.

The manufacture of the proposed relief on the work and support rolls ensures the centering of the work roll relative to the reference roll without the use of special tools, improves the performance characteristics of the bearing rolls, and improves the productivity of the rolling mill.

Rolling rolls are manufactured as follows.

A swath, for example with a diameter of ϋ = 500 mm, is mounted on a roller grinder and is machined in the following mode

Roll speed, rpm p _in

= 50-60

The speed of rotation of the abrasive wheel

Rev / min _to -600-70.0

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Longitudinal speed of the circle, m / min ν _κ = 1.0

The amount of lateral feed circle, mm (5 = 0.005-0.05

The load on the motor drive abrasive wheel, And I = 50-60.

When the grinding mode is used, a monotonous polished surface is obtained with a concentric arrangement of the lines of depressions and protrusions (ridges) around the roll circumference and the microroughness of its surface with P _a −0.8-1.2 μm.

After obtaining the required profile, the roll is processed in the following mode. ·

Roll rotation speed, rpm n _{and a} = • 2-11

The speed of rotation of the abrasive wheel, rpm n _k = 600-700

Longitudinal speed of movement of a circle, m / min ν _κ = 2-3

The amount of lateral feed circle, mm (5 = 0.01-0.05

The load on the motor drive abrasive wheel, A 1 = 70-115

When grinding in this mode in the first pass of the circle, remove the roll layer on the section (belt) equal to the width of the circle along the spiral line. When the circle is reversed, the belt is spirally rolled onto rolls with the same processing characteristics. This method of grinding provides the relief of the roll shown in figure 1, and the microroughness of the roll in this area is equal to E _a ~ 1.5-3.5 μm.

For greater roughness, use large values of <5ι. The angle φ of the inclination of the ridges depends on the velocities n _in and ν _κ . To obtain the angle of inclination φ = 10 °, it is necessary to obtain Pv ^ U rpm and ν _κ «> 2.0 m / min. Decreasing η _β and increasing ν _κ allows increasing the angle φ. So, for r _»a = 2 r / min and ν _κ = 3 m / min was prepared roll relief angle φ = 60 °. In this case, several even passages are performed with an abrasive wheel to create the desired relief on the roll.

The roller set will be tested on a laboratory mill with a diameter of work rolls Οι = 70 mm and a diameter of support rolls = 100 mm. On experienced work rolls perform surface relief with the slope of the lines of projections and depressions with an angle φ = 1065 °. the difference in diameters ΔΕ / Ε = = 0.000021-0,00035. The width of the sections with inclined ridges is 22 mm, the length of the roll barrel is 1_ = 300 mm, the thickness of the aluminum strips is A = 1.2 mm, and the width is 195 mm. Rolled strip at a speed of 0.21 m / s from cutting oil emulsol T. microroughness rolls at station 3 _and is equal to E * 1.1 m, and the area 4 Ea'Y.EB microns During experiments measured rolling force value which compared with the values obtained by rolling on the work rolls of the prototype with a width of the notched area "22 mm and roughness of the section B _a ~ 1.08 and Ya'Y.Eb micron.

Experimental data presented in the table,

From the table it follows that when rolling in rolls of the prototype (experiment 1) due to the presence of sections with a notched surface, the rolling force has a maximum value equal to P = 84.4 kN. When rolling in rolls with an inclined arrangement of crests, the force decreases, and the degree of its decrease depends on the angle φ of the inclination of the crests. At φ = 6 °, the force is P = 79.7 kN (experiment 2), which is 6.0% less than in experiment 1. However, insufficient inclination of the ridges does not ensure effective delivery of technological lubricant to the deformation zone and, at the same time, reduction of friction forces and rolling. Increasing the angle to <£> = 10 ° significantly reduces the rolling force (experiment 3) and a further increase in the angle to φ = 56 ° ensures a gradual decrease in the force P to 64.9 kN, i.e. by 23.5% (experiment 9). This decrease is due to the improvement of the conditions for the capture of technological lubricant in the deformation zone.

At φ = 65 °, the rolling force increases to P = 76.2 kN (experiment 10), which is caused by the manifestation of the protrusions (crests) of the microrelief, which have a retarding effect on the metal sliding along the deformation zone, and an increase in friction and rolling forces. Under these rolling conditions, the resistance to flow of the metal from the microrelief affects the power parameters to a greater extent than the increase in the thickness of the lubricant layer.

Thus, when rolling in rolls with φ <10 °, the rolling force decreases as compared with the prototype because of poor lubricant pickup conditions, with φ>

> 56 ° rolling force increases compared with rolling when y? = 10-56 ° due to increased resistance to the flow of metal from the crests of the microrelief. The best is the microrelief with φ = 10-56 °.

Rolled poles with the obtained microrelief rolled in a smooth polished rolls. It has been established that for the complete elimination of the microrelief with Δ Е / Е = 0.0001, the relative reduction within £ = 0.1-0.3 is sufficient.

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Thus, the rolls provide a reduction in rolling force in the range of 17.1 - 23.5% (on average 20.8%), which contributes to a proportional reduction in power consumption.

Claims (1)

Claim A set of rolls for the rolling stand of a sheet mill containing support and work rolls whose barrels are made with. alternating uneven and different 10 directional areas of micro-roughness formed by lines of protrusions and valleys, characterized in that, in order to reduce the power parameters of the roller by improving lubricant gripping conditions while maintaining centering of the strip, the lines of protrusions and valleys are located at an angle of 10--56 ° vertical axis rolls. 2