UA125517U - RENTAL CONDITION - Google Patents

Abstract

The rolling mill contains consecutively arranged quarto cages with conical rolls, where the conical work rolls are mutually inverted. In each cage, the axes of the tapered working and supporting rolls are arranged horizontally. Angle (slope of the barrel cone of each working and support rolls is determined by the dependence: (= arctg (0,15 (R / L), where L is the length of the working roll barrel, mm; R is the minimum radius of the working roll barrel, mm. Each conical support roll the quarto mounted in the cage is reciprocally rotated relative to the contacting conical working roll In each subsequent mill stand, the set of conical working and supporting rolls is set reciprocally rotated relative to the set of rolls installed in the previous quarto cage.

Description

The useful model belongs to metallurgical engineering, namely to rolling equipment, and can be used in rolling cages of headquarters hot rolling mills.

A well-known technical solution (patent ShA45429, МПК В218В 31/00) is taken as an analogue, in which conical rolls with a variable profile of the forming barrel of the roll are used, and the convexity of the barrel of one working roll is shifted relative to the vertical axis of the working roll by a distance

SL -0.05-0.25, where (C is the displacement of the top; I is the length of the roll barrel), and relative to the top of the other working roll, it is shifted by a distance of 2C/I -0.1-0.5.

With this placement of the tops of the barrels of the working rolls, their diameter difference does not exceed 0.3-0.4 mm. Such a small difference in the diameters of the barrels of the working rolls corresponds to the angle of inclination of the cone approximately В x 0.000057. With such a small value of the angle of inclination of the cone, the coefficient of kinematic asymmetry (Ka) will not exceed the value of 1.001, which is almost not reflected in the hot rolling process, and the rolling process will take place similarly to symmetrical rolling in traditional cylindrical rolls.

Therefore, the analogue solution has a number of disadvantages: during rolling in working rolls, which are almost indistinguishable from smooth cylindrical rolling rolls, a pronounced anisotropy of mechanical properties is manifested in hot-rolled stock (different mechanical properties depending on the coincidence of the stock/sheet axis and the rolling axis), which negatively affects on its stamping and does not allow the use of such a hot-rolled staff for obtaining products by the method of deep drawing or bending.

The roll profile is designed for rolling hot-rolled bars with a width close to the minimum value. Therefore, this roll barrel profile will work well in a width range not exceeding 2/3 of the length of the roll barrel.

So, for example, the 1700 hot rolling mill of the Ilyich MMK (Mariupol) manufactures hot-rolled bars with a width of 900-1600 mm with a barrel length of 1700 mm. A similar solution will work well when rolling hot-rolled bars no wider than 1700x2/32:1135 mm.

Also, for example, the MMK "MMK" (Magnitogorsk) hot-rolling plant 2500 produces hot-rolled bars with a width of 1000-2350 mm. And the solution - the analog will work well, respectively, for a headquarters no wider than 2500x2/31670 mm.

Thus, when rolling wide bars, the extreme sections will fall out of the regulation zone and, accordingly, flatness will decrease, anisotropy and thickness variation of wide hot-rolled bars will increase, especially in the extreme areas, that is, the quality of hot-rolled bars will suffer. Expanding the operating range of the analog solution leads to an increase in the barrel length of rolling rolls by approximately 1.3-1.5 times, which creates problems with placing these rolls in existing rolling mills.

The above-mentioned shortcomings of the analogue are eliminated by another well-known technical solution, the construction of a rolling mill with conical rolls (patent KL 29823, МПК В218В 1/00), taken as a prototype, containing conical working rolls, cushions with bearing assemblies, a spindle with roller couplings, a gear cage with a motor clutch, the electric motor of the main drive and the rolling cage directly. At the same time, the conical rolls of this rolling mill stand are located in relation to each other, mutually inverted and at an angle to the horizontal surface.

This solution eliminates such disadvantages of the analogue as anisotropy of mechanical properties in the hot-rolled stock, which improves the situation with the production of hot-rolled products by deep drawing or bending methods, that is, the quality indicators of the finished hot-rolled stock are increased.

However, the disadvantages of the prototype are: a violation of the flatness of the hot-rolled staff when rolling in conical rolls, because a significant kinematic asymmetry occurs. Because the working rolls have an inverted conical shape with an angle of inclination B-10", then with a width of the hot-rolled staff B-1000 mm, the difference in diameters (AB) of the lower and upper rolling rolls can be of the order of АЮ-2x Input4(107)-350 mm.

Based on the fact that the diameter of the working roll (0) of the headquarters state is of the order of

Orab-600-1200 mm, then the coefficient of kinematic asymmetry (Ka) when rolling a hot-rolled bar with a width equal to B-1000 mm will be Ka-1-A4AB/0-1-350/(600-1200) хз 1.29-1.60 . At such a value of the coefficient of kinematic asymmetry, the metal bends to the side of the roll at a lower speed (in our case, with a smaller diameter). Therefore, from one edge of the rolling rolls, the hot-rolled staff will bend in one direction, for example, up, and from the opposite edge of the rolls in the opposite direction - down. Thus, at the exit from such a pair of conical rolls, the hot-rolled staff (sheet) will have the shape of a "propeller".

With a large angle of inclination of the cone (in the B-107 prototype), problems arise in the bearing units, because they are loaded, in addition to significant radial loads, 60 also by significant axial loads arising during the rolling process due to the inclination.

In addition, the larger angle of the cone creates problems with the profile of the support roll barrel for the quarto type cages, because the axial loads will push the support rolls out of the rolling cage.

The useful model is based on the task of improving the quality of hot-rolled bars on a rolling mill by improving their flatness and reducing the anisotropy of mechanical properties.

The task is solved by preventing the barrel of the working roll from shifting relative to the barrel of the support and optimizing the kinematic asymmetry to create additional shear deformations in order to work out the structure of the hot-rolled stock and eliminate the "propeller" twisting effect in the hot-rolled stock.

To achieve the above result on a rolling mill containing consecutively arranged quarto cages with conical rolls, where the conical working rolls are mutually inverted, according to a useful model, in each cage the axes of the conical working and support rolls are horizontal, and the angle B of the cone of the barrel of each of the working and support rolls is determined depending on:

V-agsyu (0.15xV), where

Y - length of the barrel of the working roll, mm;

B is the minimum radius of the barrel of the working roll, mm, in addition, each conical support roll installed in the quarto cage is mutually inverted relative to the contacting conical working roll, and in each subsequent state cage a set of conical working and support rolls is installed mutually inverted relative to the set of rolls installed in the previous cages quarto.

As a result of the comparative analysis of the proposed rolling mill with the prototype, it was established that they have the following general characteristics: - consecutively arranged quarto cages with conical rolls; - conical working rolls are located opposite each other; and also: distinguishing features: - in each cage, the axes of the conical working and support rolls are located horizontally; - the angle B of the cone of the barrel of each working and support roll is determined depending on:

V-agsyu (0.15xV), where

Ko) Y - length of the barrel of the working roll, mm;

B - the minimum radius of the barrel of the working roll, mm, - each conical support roll is installed in the cage of the quarto, mutually inverted relative to the contacting conical working roll; - in each subsequent state cage, a set of conical working and support rolls is installed in reverse order relative to the set of rolls installed in the previous quarto cage.

Thus, the proposed rolling mill has a new design of nodes and parts, new connections of nodes and parts, as well as a new arrangement of them relative to each other.

There is a cause and effect relationship between distinctive features and the technical result that is achieved.

Due to the fact that in each cage, the axes of the conical working and support rolls are located horizontally, and the angle B of the cone of the barrel of each working and support roll is determined by the dependence:

V-agsyu (0.15xV), where

Y - length of the barrel of the working roll, mm;

B - the minimum radius of the barrel of the working roll, mm, the optimal angle of inclination of the cone of the barrel of the working roll is determined, which does not exceed the value of the friction angle, which prevents the shift of the barrel of the working roll relative to the barrel of the support roll, ensures the optimal effect of kinematic and geometric asymmetry when rolling hot-rolled bars, and This means that the quality of hot-rolled bars and sheets increases due to the reduction of anisotropy of mechanical properties and improvement of flatness.

Due to the fact that each conical support roll is installed in the quarto cage in a mutually inverted manner relative to the contacting conical work roll, optimal contact between the work and support rolls is ensured, as well as a fairly high hardness of the roll system, which affects the quality of the hot-rolled stock.

Placing a set of conical working and support rolls installed in each subsequent stand cage in reverse relative to the set of rolls installed in the previous quarto stand will allow to ensure the centering of the roll along the rolling axis, and will significantly improve the quality of the staff due to the reduction of wedgeness and sickleness.

Exclusion of at least one of them from the above set of distinguishing features does not ensure 60 the achievement of the technical result.

The claimed technical solution is not known from the prior art and is therefore novel. The technical solution that is claimed is industrially applied, because its technological and technical implementation does not present difficulties, in the conditions of PJSC "NKM3" a sketch-technical project of working cages of the finishing group of state 2500 h.p. PJSC "MMK".

A useful model is explained by drawings that show:

Fig. 1 Rolling mill (type of quarto cage with conical rolls).

Fig. 2 Section AA in fig. 1.

Fig. From Place B in fig. 1.

The rolling mill is represented by a group of consecutive quarto rolling cages 1, which contain a bed 2, in which the upper and lower working rolls 3,4 with conical barrels 5,6 are installed, which, respectively, rest on the conical barrels 7,8 of the support rolls (Fig. 1) . In each cage, the axes of the conical working and support rolls are located horizontally.

During the rolling process, the hot metal 9 is fed between the conical barrels 5,6 of the work rolls 3,4, which are individually rotated using the spindles 10 and the gear cage 11 from the electric motor 12 through the motor coupling 13. Because the hot metal 9 is deformed in thickness between two conical barrels 5, working rolls 3,4, the process of asymmetric rolling is ensured, during which intensive shear deformations occur in the longitudinal direction of the staffs, which positively affect the quality of rolling, elimination of anisotropy of mechanical properties.

In the sequential group of rolling cages 1 (Fig. 1, Fig. 2), for example, in the finishing group of the wide-bar condition, the metal 9 enters the working rolls 3, 4 with conical barrels 5, 6, and in the process of hot rolling, intense shear deformations occur, which metal 9 can move from the rolling axis 14 either to the transshipment side or to the drive side.

In order to improve the centering of the metal 9 along the rolling axis 14, it is suggested that a set of conical working rolls 3,4 be installed in each subsequent rolling cage 1 in reverse order of the set of conical working rolls 3,4 installed in the previous rolling cage quarto 1 (Fig. 2).

Such an alternation of taper directions will allow to neutralize the one-sided shift of metal 9 from the rolling axis 14, because the first rolling cage quarto 1 in the sequence will shift metal 9 in

From one side, and the next rolling cage 1 will tend to move the metal 9 in the opposite direction. Thus, the installation of a sequential group of rolling cages 1 with conical working 3,4 and support rolls with conical barrels 7,8 will ensure the centering of the metal 9 along the rolling axis 14.

All this increases the quality of the hot-rolled stock, that is, the anisotropy of the mechanical properties decreases, the flatness increases, the transverse profile improves, and thanks to the reduction of sickle-likeness, the loss on the edge will be reduced, which means that the yield of suitable material will increase.

All these positive effects are possible only if the flatness of the metal 9 will not be disturbed in the process of asymmetric rolling, i.e. there will be no bending in one direction or another.

For this purpose, it is proposed to perform the angle of inclination of the cone of barrel B on barrels 5.6 of the working and barrels 7.8 of the support rolls according to dependence (1):

B-agsio (0.15xAL), (1) where

B - angle of inclination of the cone of the barrel of the working roll, g;

Y - length of the barrel of the working roll, mm;

B - the minimum radius of the barrel of the working roll, mm.

In this case, the upper working roll C is made with one taper direction on its barrel 5, and the lower working roll 4 is made with the reverse taper direction, i.e. with the opposite inclination (Fig. 3).

Therefore, a working gap will be formed between the two barrels 5,6 of the working rolls 3,4, which will be located at an angle B to the horizontal surface. But considering that this angle B is not large, on the order of 1.37-2.6", it does not lead to complications either with gripping or with rolling of the hot-rolled staff with conical barrels 5.6 working rolls 3.4.

It is well known that during hot rolling of thick rolls (bars, sheets) there is a so-called "critical" pressing Ekrit?, in which the inconsistency of the speeds of the working rolls Am has no effect on the vertical bending of the roll ("point of insensitivity"),

If the value of the relative compression per pass exceeds the "critical" value, the bending of the front end of the roll occurs to the side of the roll with a greater circumferential speed. Then the value of the misalignment of the speeds of the working rolls Dm should be set inversely proportional to the radius of curvature of the front part of the roll from the range 0.1-2.0 95, and the larger Am, the smaller the radius of curvature and, accordingly, the "steeper" the bend of the front end of the roll.

If the value of the relative compression per pass is less than "critical", then the bend of the front end of the roll can be directed to the side of the roll, which rotates both at a higher and at a lower circumferential speed. It depends on the magnitude of the discrepancy between the speeds of the working rolls, if it is insignificant 0.1-2.0 956, the rolling bend is directed to the side of the roll with a lower speed, and if it is significant, that is, it is within the range of 2.01-15 95, the rolling bend is directed to the side of the roll with at a higher speed.

This ambiguous behavior of the front end of the roll is due to the different degree of frictional asymmetry of the upper and lower arc of contact between the metal and the rolls. As a result of this field of metal movement speeds at the exit from the hearth, the deformations are different. At the same time, in the case of a less intensive mismatch of the speeds of the working rolls, the effectiveness of the speed field is directed to the side of the roll with a lower speed. In the case of a more intensive inconsistency of the speeds of the working rolls, the effectiveness of the speed field is directed, on the contrary, to the side of the roll with a higher speed.

From the above, it follows that the rolling bend will occur to the side of the roll with a smaller diameter, in asymmetric rolling with a speed mismatch of 2.01-15 Fo, the rolling bend will be directed to the side of the roll with a higher speed.

Thus, the difference in the diameters of the working rolls ensures the bending of the roll to the side of the roll smaller in diameter, and the selection of the diameter for the larger roll in accordance with the decision ensures the creation of a kinematic asymmetry of a certain calculated level, which is no more than 15 95.

All this allows you to bend the roll 9 to the side of the roll rotating at a higher speed, that is, in our case, to the side of the roll with a larger diameter.

All this makes it possible to ensure in the process of asymmetric hot rolling that the roll bends upwards and at the same time bends the same roll downwards, that is, the horizontality of the roll is maintained.

З At the contact of two conical barrels 5,6 of the working 3,4 and conical barrels 7,8 of the support rolls, axial forces arise, directed both along the radii of the conical surfaces and along the barrels 5,6 of the working rolls 3,4 and the barrels 7,8 of the support rolls (Fig. 1, Fig. 3).

In the process of hot rolling in the rolling cage quarto 1, the deformed metal 9 resists and generates a rolling force, which is divided into a radially directed force P and an axial force Eos. The radially directed forces P are received by the bearing units of the pillows and locked in the frames 2 of the rolling cage quarto 1. The axial forces Ros are directed along the barrels 5,6 and push the working 3,4 or support rolls 7,8 out of the rolling cage quarto 1 (Fig. 1).

Thus, the greater the angle of inclination of the VD, the greater the force of pushing out the Ros working 3,4 or support 7,8 rolls from the rolling cage quarto 1, which are perceived by the latches of the support rolls 7,8. Therefore, in this decision, it is proposed that these forces do not exceed the resulting friction forces Well, which exactly compensate for these additional axial forces (Fig. 1).

It is known that the friction forces Et are defined as the product of the normal (directed along the normal) component of the rolling force P by the friction coefficient y. The coefficient of friction is -0.1 for two steel ground (polished) surfaces in contact. Based on the fact that on large-scale hot rolling mills, technological lubrication systems of either working rolls C and 4 or support rolls 7 and 8 are actively implemented, which reduce rolling forces due to the redistribution of stresses in the deformation center, and also have other positive effects, then the coefficient of friction will be reduced to Y-0.05.

Noting that the friction coefficient Yi is related to the friction angle ah by the following

IF the ratio is -id(c05)-0.05, then in order to guarantee the prevention of the negative effect of pushing out the rolls (the appearance of axial forces acting along the axis of the rolls), which occurs at any angle of inclination of the VD, it is necessary to ensure that the angle of inclination of the cone of the VD was less than the minimum friction angle a.

Thus, when axial forces occur that push the working 3,4 or support 7,8 rolls out of the rolling cage 1, oppositely directed frictional forces H. immediately appear, which prevent the pushing out and prevent axial displacement of the rolls, provided that the angle the slope of the cone B will be less than the minimum friction angle ah (Fig. 1).

Thus, to prevent ejection, it is necessary to ensure the condition: ag»r, (d)

where at is the minimum friction angle,

B - the angle of inclination of the cone of the barrel.

Thus (at) (B), (3)

Substituting d(at)-0.05 and expression (1) into expression (3) we have:

O,OBoshchd(agsid(0.15 x V / I), (4) where

Y - length of the barrel of the working roll, mm;

B - the minimum radius of the barrel of the working roll, mm.

The analysis of the diameters of the working rolls and the length of their barrel showed that for the operating wide-scale hot rolling mills (state in 2000 of OJSC "NLMK", state of 1700 of PJSC "MMK named after Ilyich", state of 2500 of PJSC "MMK", as of 2000, PJSC "MMK", as of 1680 as of PJSC "Zaporizhstal", as of 1800 as of "AMEN" and others) in draft and finishing cages of the V/I ratio. is 0.15-0.30.

By substituting these values for V/. in expression (4), we have that 0.0550.15x(0.15-0.30); 0.0550.0225-0.0450, that is, the condition is fulfilled.

Thus, the angle of inclination of the cone B, according to the proposed solution, will always be less than the minimum angle of friction at, that is, the additional forces of the axles, which arose from the angle of inclination and push the rolls out of the cage, will be less than the frictional forces E. that prevent them.

Thus, the performance of the rolling mill, according to the formula of the useful model, due to the optimization of the parameters of asymmetric rolling, will increase the quality of the hot-rolled stock and improve its flatness and anisotropy of the mechanical properties of the metal.

Claims (1)

USEFUL MODEL FORMULA 30 A rolling mill containing sequentially arranged quarto cages with conical rolls, where the conical working rolls are mutually inverted, which differs in that in each cage the axes of the conical working and support rolls are horizontal, and the angle of inclination of the barrel cone of each working and the support rolls is determined by the dependence: p-agsid(0.15x I), where 35 I is the length of the barrel of the working roll, mm; B - the minimum radius of the barrel of the working roll, mm, in addition, each conical support roll is installed in the quarto cage in a mutually inverted relation to the contacting conical working roll, and in each subsequent cage, a set of conical working and support rolls is installed in a mutually inverted relation to the 40 set of rolls, established in the previous cage quarto.