RU48285U1 - SHEET ROLLING QUARTO CART - Google Patents

Abstract

The utility model relates to the processing of metals by pressure and can be used on sheet mills for hot and cold rolling. The technical task of the proposed utility model is to increase the resistance of the backup rolls of sheet rolling stands of the quarto due to the equalization of roll pressures. The essence of the utility model is that in a sheet rolling mill quarto equipped with a system for regulating the profile of the strips by axial movement of convex-concave work rolls, the profiling of the backup rolls is made in accordance with the dependence: where z _O is the ordinate of the profile of the back roll barrel, mm; a - amplitude (half of the total convexity - concavity of the profile of the backup roll), mm; L is the length of the barrel of the backup roll, mm; x - coordinate along the length of the roll of the backup roll, mm, and the profiling of the work rolls according to the equation: Z _P = (a ₁ -0.0015a) x + a ₂ x ² + a ₃ x ³ + a ₄ x ⁴ + a ₅ x ⁵ where z _P is the ordinate of the profile of the barrel of the work roll, mm; а ₁ , а ₂ , а ₃ , а ₄ , a ₅ - polynomial coefficients obtained empirically; and - the amplitude (half of the total convexity - concavity) of the profile of the backup roll, mm; x - coordinate along the length of the barrel of the work roll, mm

Description

The utility model relates to the processing of metals by pressure and can be used on sheet mills for hot and cold rolling.

Known sheet rolling stand quarto (roll unit), in which the extreme sections of the backup rolls are made on a quadratic parabola, and the transitional sections of the work rolls from the barrel to the ends are made with a radius of 0.04-0.08 diameter of the working roll (A.S. No. 1405925 )

The disadvantage of this stand is the uneven distribution of the roll pressure due to the mutual discrepancy between the barrels forming the working and backup rolls, which negatively affects the stability of the latter.

The closest analogue is the quarto sheet rolling stand (VTI 101-P-HL 5-505-2002. Production of cold rolled strips on a two-stand reversing mill in LPC-5 of OJSC MMK), equipped with a system for regulating the profile of the strips by axial sliding of convex-concave work rolls, in which the work rolls have a profile described by a polynomial, and the backup rolls are cylindrical with bevels of 100 mm.

The disadvantage of this stand is also the uneven distribution of the roll pressure due to the mutual discrepancy between the barrels forming the working and backup rolls, which negatively affects the stability of the latter. Calculations performed using a mathematical model show that this unevenness is from 30% to 90% along the length of the barrel from the maximum. The latter is confirmed by the wear data of the backup rolls.

The technical task of the proposed utility model is to increase the resistance of the backup rolls of sheet rolling stands of the quarto due to the equalization of roll pressures.

The solution to this problem is achieved by the fact that in a sheet rolling stand a quarto equipped with a system for regulating the profile of the axial stripes

by moving convex-concave work rolls, the profiling of the backup rolls is made in accordance with the dependence:

where z _O is the ordinate of the profile of the back roll barrel, mm;

a - amplitude (half of the total convexity - concavity of the profile of the backup roll), mm;

L is the length of the barrel of the backup roll, mm;

x is the coordinate along the length of the roll of the backup roll, mm, and the profiling of the work rolls according to the equation:

Z _P = (a ₁ -0.0015a) x + a ₂ x ² + a ₃ x ³ + a ₄ x ⁴ + a ₅ x ⁵ ,

where z _P is the ordinate of the profile of the barrel of the work roll, mm;

a ₁ , a ₂ , a ₃ , a ₄ , a ₅ - polynomial coefficients obtained empirically;

and - the amplitude (half of the total convexity - concavity) of the profile of the backup roll, mm;

x - coordinate along the length of the barrel of the work roll, mm

Figure 1 presents the General scheme of sheet rolling stand quarto with rolls with the proposed profiling. Figure 2 shows the wear curve of the backup roll of a two-stand reversing mill of OJSC MMK with the existing and proposed profiling.

The sheet rolling mill quarto has work rolls with the possibility of their axial movement to regulate the rolled profile and backup rolls profiled in accordance with the proposed dependencies (figure 1). In order to equalize the inter-roll pressure and, consequently, reduce the wear of the backup rolls, the profiling of the backup rolls is made in a cosine shape in accordance with the proposed relationship. However, such an adjustment of the backup rolls only causes the workers to skew in the horizontal plane. The latter negatively affects the durability of bearings. Therefore, it becomes necessary to adjust the profiling and work rolls. This is done by changing the polynomial

coefficient at x relative to the selected amplitude of the cosine of the backup roll a, namely, the coefficient at x is a ₁ -0.0015a.

In general, such profiling substantially equalizes the roll pressures, and thereby reduces wear. During the rolling process, the convex sections of the work rolls are in contact with the corresponding concave sections of the support, profiled according to the proposed dependence, and the concave sections are convex. Thereby, the roll pressures are equalized and, consequently, wear is reduced.

Example:

Two-stand reversive mill of OJSC MMK. The length of the backup roll barrel is 1750 mm.

The profiling of the backup rolls is cylindrical with bevels along the edges of the barrel (z _O = 0).

Profiling of work rolls is made according to:

Z _P = a ₁ x + a ₂ x ² + a ₃ x ³ + a ₄ x ⁴ + a ₅ x ⁵ ,

where z _P - the ordinate of the profile of the barrel of the work roll, mm,

x - coordinate along the length of the roll of the backup roll, mm,

a ₁ = 0.123261 · 10 ^-2 ;

a ₂ = -0.120973 · 10 ^-5 ;

a ₃ = 0.350647 · 10 ^-9 ;

a ₄ = 0;

a ₅ = 0;

These polynomial coefficients were obtained empirically for a given mill in accordance with its assortment.

As a result of this profiling, the wear of the backup rolls is uneven with a maximum corresponding to the convexity of the work roll (figure 2).

Using the mathematical model, the necessary value of the parameter a was determined for the proposed profiling of the backup rolls a = 0.07 mm. Thus:

Profiling was performed with edge bevels. In addition, in order to eliminate the skew of the work rolls, they corrected their profiling using the following polynomial coefficients:

Z _P = (a ₁ -0.0015a) x + a ₂ x ² + a ₃ x ³ + a ₄ x ⁴ + a ₅ x ⁵ ,

and ₁ = (0.123261 · 10 ^-2 -0.0015 · 0.07) = 0.112573 · 10 ^-2 ;

a ₂ = -0.120973 · 10 ^-5 ;

a ₃ = 0.350647 · 10 ^-9 ;

a ₄ = 0;

a ₅ = 0.

Those. the coefficients a ₂ -a ₅ left the same.

The result was a significant reduction in wear of the backup rolls by 30% from 0.27 mm to 0.18 mm, as well as a more uniform working pattern (figure 2).

Claims (1)

The quarto sheet rolling mill, equipped with a system for regulating the profile of the strips by axial sliding of convex-concave work rolls, characterized in that the profiling of the backup rolls is made in accordance with the dependence

where Z _o - the ordinate of the profile of the barrel of the backup roll, mm; α is the amplitude (half of the total convexity - concavity of the profile of the backup roll), mm; L is the length of the barrel of the backup roll, mm; x - coordinate along the length of the barrel of the backup roll, mm, and profiling work rolls according to the equation: Z _p = (α ₁ -0.0015α) x + α ₂ x ² + α ₃ x ³ + α ₄ x ⁴ + α ₅ x ⁵ , where Z _p - the ordinate of the profile of the barrel of the work roll, mm; α ₁ , α ₂ , α ₃ , α ₄ , α ₅ - polynomial coefficients obtained empirically; α - amplitude (half of the total convexity-concavity) of the profile backup roll, mm; x - coordinate along the length of the barrel of the work roll, mm