RU2006297C1 - Method of rolling of specified curvature strip products - Google Patents

Abstract

FIELD: rolling of metal. SUBSTANCE: curvature of rolled strip is controlled by displacement of rollers relative each other along their generatrices an amount defined by a mathematical expression proceeding from geometrical, deformational and speed parameters of rolling process, with larger displacement values corresponding to lower curvature radius of the strip, and vice versa. EFFECT: improved rolling process. 2 dwg

Description

 The invention relates to the processing of metals by pressure in the field of ferrous metallurgy and is intended for the manufacture of products with a given curvature such as flat disks.

 A known method of rolling wedge-shaped profiles, including rolling in rolls with a conical barrel and holding the workpiece from lateral displacement and curvature at the entrance to the rolls, in which the rolls are set at an angle to each other with the intersection of their axes from the smaller diameter of the rolls, and the workpiece with the same the sides are crimped to a greater extent than the opposite [1].

 A distinctive feature of this method is that large reductions are set on the edge of the strip facing the intersection point of the roll axes, and when the wedge and compression of the strip change, the position of the rolling axis along the roll barrels is adjusted.

 The disadvantage of this method is the impossibility of changing the parameters of the deformation process without changing the geometry of the tool and the dimensions of the workpiece.

 Closest to the invention is a method of rolling wedge-shaped profiles, comprising crimping the workpiece in conical rolls with intersecting axes of rotation, larger along the edge facing the intersection point of the axes of the rolls, and applying a supporting force with the roller to the less crimped edge of the strip, in which the sickle shape is affected by a change the speed of the roller creating a supporting force, while its speed is increased with rib bending of the strip towards a less compressed edge and reduced with rib bending of the strip in sec a side of a more compressed edge facing the intersection point of the roll axes [2].

 The main distinguishing feature of this method is the additional mechanical effect on the crescent shape of the strip from the side of the less compressible edge by changing the speed of the roller, which provides a backing force on the strip.

 The main disadvantage of the prototype is the complexity of the equipment for its implementation in low productivity.

 The purpose of the invention is to increase productivity by increasing yield and reducing the complexity of manufacturing by reducing additional editing operations.

This is achieved by the fact that in the method of rolling strip products of a given curvature, including compression of a workpiece of strip products of a given curvature, including compression of a workpiece in rolls with conical barrels installed with the intersection of their axes from the side of the small bases of the cones, the rolls are installed with mutual displacement along the forming barrels on a value which, depending on a given radius of curvature of the strip, is determined from the expression
H = [2l _cf · b ₁ · Δh · ω (1-K _vsr )] / [ρ (V _1п -V _2п )], where l _cf is the length of the arc of the product along its midline;
b _l - product width;
Δh - compression of the workpiece;
ρ is the radius of curvature of the product;
ω is the angular velocity of rotation of the rolls;
v _1p is the speed of the outer edge of the product in the plane of exit from the deformation zone;
v _2p is the speed of the inner edge of the product in the plane of exit from the deformation zone;
To _bav - the ratio of the diameters of the opposite rolls along the midline of the product (K _bav ≅ 1), and the amount of displacement is increased to reduce the radius of curvature of the strip and reduced to increase it.

 In FIG. 1 shows a deformation zone of a rectangular strip with conical rolls with intersecting axes of rotation, a transverse section; in FIG. 2 - the same plan.

The inventive method is as follows. Work rolls 1 and 2 with conical barrels are installed at an angle φ _{1 to} each other so that the axis of the work rolls 1 and 2 are mutually intersected from the side of the small bases of the cones of the roll barrels. The work rolls have the same geometric dimensions, that is, the diameters of the large bases of the cones of both opposed work rolls are equal to each other; the angles of the cones of the roll barrels are equal to each other and the angle of their taper φ ₂ is equal to the angle φ _{1 of the} inclination of the axes of the work rolls relative to each other.

 It is possible to use a set of work rolls with different geometric dimensions. With the indicated geometric dimensions of the rolls and their mutual angular installation, the gauge is formed by parallel generators of the cones of the work rolls, i.e., the rectangular billet is uniformly crimped in width, which is the most convenient rolling case for considering the deformation mechanism in the conical rolls of strip products of a given curvature.

The deformation zone abcd (Fig. 2) is limited at the input cd by the plane N, and at the exit ab, by the plane M. The position of the plane N of the input of the workpiece 3 to the deformation zone is determined by the formula tgβ = (l ₁ -l ₂ ) / b ₀ , where l ₁ and l ₂ - respectively, the length of the deformation zone along the left 4 and right 5 edges of the workpiece 3; b _o - the width of the strip (blank) in the plane of the entrance cd to the deformation zone.

 A change in the angle of the strip task in the work rolls is accompanied (in known solutions) by a change in the working width of the strip entering the work rolls. In order to exclude this fact, which leads to a change in the geometric dimensions of the cross section of the product emerging from the work rolls, which requires additional calibration calculations, process adjustment and ultimately increases the complexity of manufacturing products, the angle of the workpiece in the rolls is assumed to be constant for each particular product, calculated according to the above formula and does not change during the rolling process.

Upon receipt of strip products of a given curvature, for example, screw spirals, friction clutch disks (their blanks) for the engineering industry by deformation of the initial blank in conical rolls with intersecting rotation axes, the radius of curvature ρ of the product exiting the rolls can vary over a wide range , and in the direction of decrease depending on the angle φ ₁ , the inclination of the axes of the work rolls with respect to each other, on the angle φ _{2 of the} taper of the work rolls, as well as on friction conditions at the strip-shaft contact ki, the uniformity of the mechanical properties of the deformable material, the accuracy of the geometric dimensions of the deformable workpiece, etc.

 The multifunctional dependence of the process of obtaining products of a given curvature in conical rolls does not allow, in a known manner, to provide a technological process for producing products with exact geometric dimensions.

 Therefore, when the radius of curvature ρ of the strip (product) leaving the rolls 1 and 2 changes, due to, for example, the above reasons, the work rolls are shifted along the generatrix barrels of the synchronous in opposite directions by N. by means of special mechanisms (not shown).

 At the initial moment of rolling the product, when a part of the product comes out of the rolls, sufficient to measure its curvature using known devices, for example contact messdozas interacting with the strip leaving the rolls, and by the magnitude of the mass dose delivered to the control system of the mechanism for moving the barrels of work rolls, by means of the mentioned mechanisms, the work rolls are moved in the desired direction.

 So when increasing the radius of curvature of the product from the given dimensions, the work rolls are shifted in the direction of increasing the magnitude of the displacement H of the work rolls, and in the case of a decrease in the radius of curvature of the product in the direction of decreasing the magnitude of the displacement H of the work rolls.

 In the initial position of the work rolls, the critical line ef is located at an angle γ to the plane of the product exit from the work rolls.

When moving the work rolls, the critical line ef (Fig. 2) will change its position and rotate around point 0 by a certain angle and, for example, will take the position b ^l f ^l . In this case, a change in the ratio of advance zones from the side of the inner 4 and outer 5 edges of the product, i.e., the lead zone, for example, from the outer edge of the product will increase and will have a value of bf ^l , and the advance zone ed from the side of the inner 4 edge of the product will decrease and will have the value e ^l a, on the basis of which the speed v _{1p of} metal from the side of the outer 5 edge of the product will increase, and the speed v _{2p of} metal from the side of the inner 4 edge will decrease and the radius of curvature ρ emerging from the rolls of the product will be to shrink.

выходящего из валков изделия с помощью изменения положения валков вдоль их бочек.Thus, the operational regulation of the curvature K =

emerging from the rolls of the product by changing the position of the rolls along their barrels.

On a laboratory mill SPKN-110M tapered work rolls (diameter of the greater base of the barrels of the rolls 110 mm) set with the intersection of axes angled ³⁰ ° rolled by the present method the workpiece flat disc (ring) with cross-sectional dimensions of 5 x 20 mm, with an average diameter 100 mm

 The speeds along the edges (inner 4 and outer 5) of the product emerging from the rolls were measured using contact speed meters.

 It should be noted that in the absence of a deviation of the radius of curvature of the product from a given speed difference along the lateral edges of the product is a constant value.

 As a mechanism for moving work rolls along its generators, a hydraulic system is used, consisting of hydraulic cylinders that are mounted on the shanks of the work rolls and kinematically connected to the work roll shafts, which, in turn, are mounted on the shafts of the work rolls using an axial key coupling movement along the shafts of the work rolls, hydraulic pump and control unit.

 When there is a deviation of the difference in the speeds of the products along its edges, the signal from the speed gauges enters the hydraulic system control unit and, according to the magnitude of the control signal, the work rolls are shifted towards each other by hydraulic cylinders in the required direction, due to either a decrease in the radius of curvature of the product or its increase from its specified dimensions.

Rolling temperature 950 ^о С, compression of the workpiece Δh - 2 mm; the friction coefficient f = 0.3, the workpiece material is steel 08KP, the strip thickness at the exit from the rolls h ₁ = 3 mm, the angular velocity of the rolls ω = 6.28 s ^-1 ; the radii of both rolls along the edges of the strip when rolling without bias R _b1 = R _b1 ^' = 38 mm; R _b2 = R _b2 ^' = 27.5 mm.

 Given the geometry of the rolls and strip, as well as the deformation parameters, a strip product with a given radius of curvature ρ = 50.7 mm is obtained as follows.

At the beginning, the radius of curvature of the product is determined by calculating at given initial data for this particular case according to the formula
ρ = [V _in1 (1 + i ₁ ) + V _in2 · (1 + i ₂ ) · b ₁ ] / [V _in1 (1 + i ₁ ) -V _in2 (1 + i ₂ ) · 2], where v _b1 and v _b2 are the speeds of the work rolls, respectively, along the right (at point b, Fig. 2) edge of the strip and the left edge of the strip (at point a, Fig. 2);
i ₁ and i ₂ - advances respectively on the right and left edges of the strip.

When rolling in rolls without offset, the speed of the right edge of the product is v _1p = 258.6 mm / s, the speed of the strip along the left edge of the product at the exit of the rolls is v _2p = 179.26 mm / s.

 From the calculation according to the above formula it follows that the radius of curvature of the product is ρ = 55.2 mm, which is 4.5 mm more than the specified value.

 To obtain the product of the required radius of curvature, the displacement of the rolls is determined according to the dependence given in the claims. From the calculation it follows that the rolls must be displaced by 15 mm.

The ratio of the radii of the rolls when the roll displacement 15 mm is K _ave = 26.5 mm / 38 mm = 0.72368; K _lion = 17 mm / 275 mm = 0.61818.

When rolling rolls in an offset 15 mm speed right edges of the article v _1P = 218.93 mm / s; speed along the left edge of the product v _2n = 146.849 mm / s.

 Thus, the specified radius of curvature of the strip product is obtained when the rolls are displaced by 15 mm and is ρ = 50.7 mm.

 The shift of the rolls along its generators leads to a change in the radius of curvature of the product due to the redistribution of friction forces in the deformation zone, which are determined by the position of the critical line in the deformation zone, dividing it into advance and lag zones.

 The proposed technical solution can be used to obtain long and shaped profiles, especially asymmetric.

 The increase in productivity is achieved by reducing the preparatory time of the technological process on the basis of the proposed method, since to change the magnitude of the curvature of the deformable profile, the operation of the working stand is not necessary, in particular the dismantling of the gear system providing kinematic connection between the work rolls and the supporting roller, and the installation of a new gear set with the required gear ratio.

 In addition, the implementation of the proposed method does not require expensive equipment for controlling the rotation speeds of the work rolls, as is necessary in the case of an individual drive of the work rolls and the supporting roller of the prototype.

 A more surgical intervention in the deformation process, which involves the proposed method, also reduces the complexity of manufacturing products with a given curvature by reducing additional straightening (bending) operations, which is achieved by changing the position of the rolls along their barrels.

 The proposed technical solution allows to increase productivity compared to the prototype 4 times by increasing the yield by 75% and reducing additional operations at subsequent stages of product processing by 5. . . 8 times by increasing the accuracy of the geometric dimensions of the products. (56) 1. USSR author's certificate N 995919, cl. B 21 B 1/08, 1983.

 2. USSR author's certificate N 995921, cl. B 21 B 1/08, 1983.

Claims (1)

METHOD FOR ROLLING STRIPS OF A TURNED CURVITY, comprising compressing a workpiece in rolls with conical barrels installed with the intersection of their axes from the side of the small bases of the cones, characterized in that the rolls are set with mutual offset along the forming barrels by an amount H, which, depending on the specified radius of curvature stripes are determined from the expression
H =

where l _cf - the length of the arc of the product along its midline;
b ₁ is the width of the product;
Δh - compression of the workpiece;
ρ is the radius of curvature of the product;
ω is the angular velocity of rotation of the rolls;
V _1p - the speed of the outer edge of the product in the plane of exit from the deformation zone;
V _2p - the speed of the inner edge of the product in the plane of exit from the deformation zone;
K _{century average} - the ratio of the diameters of the opposite rolls along the midline of the product (K _{century average} ≅ 1),
moreover, the amount of displacement is increased to reduce the radius of curvature of the strip and reduced to increase it.

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