RU2040348C1 - Three-roll stand of helocal rolling mill - Google Patents

Abstract

FIELD: rolled tube production. SUBSTANCE: three-roll stand has the frame with the cover, three working rolls, arranged along a circle and mutually spaced by an angle, equal to 120 degrees, and mounted on rotary drums. One of the drums is mounted in a window of the cover. Two other drums are arranged in turnings between the frame and the cover. The stand also has screw-down mechanisms for lengthwise motion of the rotary drums, two mechanical screwdown units of the drum with the working roll and a drive unit for their motion. Both mechanical screwdown units are mounted for moving the drums with working rolls, arranged in the turnings between the frame and the cover. The drive of these screw-down units are mounted on the frame. Sleeves are also mounted in the frame oif the stand with use of bearings assemblies. Nuts of the screw-down mechanisms are mounted inside of the sleeves. Double-arm levers are secured to ends of the sleeves. The arms of the levers extend at both sides of the stand. One of the arm is jointly connected with the drive unit. A stroke limiting stopper is mounted opposite to the other arm. The drive units and the stroke limiting stoppers are mounted in the frame. EFFECT: enhanced structure of the stand. 1 cl, 9 dwg

Description

 The invention relates to pipe rolling production and relates to the improvement of a three-roll mill stand for cross-helical rolling of pipes on a mandrel with a ratio of diameter to pipe wall thickness of up to 11 and more than 11.

 The aim of the invention is to increase the yield of rolled products, reducing dynamic loads in the stand and simplifying its maintenance.

Known working stand Kosovalkovaya mill (ed. St. N 519234, class B 21 b 13/12), containing the frame with a lid, three workers arranged in a circle through 120 ^{about the} roll, mounted on rotary drums, one of which is placed in the opening of the lid and the other two in the bores between the bed and the lid, push mechanisms for the longitudinal movement of the rotary drums and stoppers for each drum. The cage is equipped with a caliber dilution device during the rolling process, made in the form of a power cylinder pivotally connecting the bed and the cover, equipped with an adjustable stop.

 A disadvantage of the known design is the violation of the integrity of the cage when changing the caliber during the rolling process and, as a result, a decrease in the quality of the rental. In addition, when rolling at high speeds, there are sufficiently long end sections of the pipe having a thickened shape, which go to waste.

 Another disadvantage is the high complexity of the crate during transshipment due to the need to disconnect the power cylinder inlets and the adjustable stop connecting the bed and the cover when folding the cover.

The closest to the proposed is a three-roll stand helical rolling [1] comprising a frame with cover, three working arranged in a circle 120 ^on the roll mounted on the rotary drums, one of which is placed in the opening cover, and the other two in the bores between the frame and a lid, push mechanisms for the longitudinal movement of rotary drums and a caliber dilution mechanism during rolling, made in the form of a hydromechanical push device of a drum with a work roll placed in the cover of the bed and of driving the upper roll in the rolling process.

 A disadvantage of the known design of a three-roll stand of helical rolling is that when rolling at high speeds, there are sufficiently long end sections of the pipe having a thickened wall, which reduces the yield of rolled products. In addition, during the operation of the caliber breeding mechanism, significant dynamic loads arise, leading to a violation of the integrity of the cage body and a deterioration in the quality of the rental.

 Another disadvantage of the known design is the increased complexity of the maintenance of the mill during transshipment.

 The aim of the invention is to increase the yield of rolled products, reducing dynamic loads and simplifying stand maintenance, simplifying the handling of drums with work rolls.

The goal is achieved by the fact that a three-roll stand of cross-helical rolling, containing a bed with a cover, three workers arranged in a circle through 120 ^{about the} roll, mounted on rotary drums, one of which is placed in the opening of the cover, and the other two in the bores between the frame and the cover, push mechanisms for the longitudinal movement of rotary drums, made in the form of electric drive screws, passed through nuts placed one in the lid, two others in the bed, a mechanical drum press device with a work roll and ivod its movement, it is provided with additional mechanical pusher drum with working roll drive and its movement, both mechanical pressing devices are installed to move the drums with working rolls arranged in bores between the frame and the cover, and drive devices mounted on the frame.

 In addition, the cage is equipped with cups mounted in the frame by means of bearing bearings, fixing them in the axial direction, inside of which are installed the nuts of the pressure mechanisms placed in the frame, and levers mounted on the ends of the glasses, made in the form of a beam, one arm of which is pivotally connected to the drive of the pressure devices, and the other is installed above the stop-stroke limiter, while the drives and stop-limiters are mounted on the bed on opposite sides of the stand.

 Such a constructive implementation of a three-roll stand of cross-helical rolling provides a reduction in the breeding time of the caliber, since when the caliber is re-sized to the same size by two mechanical pressing devices, the work rolls need to be moved almost two times less than when the single roll is retracted, which ensures less vertical movement of the workpiece along compared with the movement of one upper roll, while the movement coincides with the direction of gravity acting on the rolled workpiece, and enshaet additional dynamic loads in the cage at a dilution gauge in the rolling process. Moreover, the indicated reduction in caliber dilution time leads to a corresponding reduction in the transition section from the normal pipe wall to the thickened one. The difference in metal volumes between the transition section of a larger length and the transition section of a shorter length goes into the useful volume of the pipe with a normal wall, i.e. accordingly, the pipe length increases by this value, and the yield of rolled products increases. The placement of the drives on the bed excludes the operations of disconnecting-connecting the inlets to the cylinders when removing the cover from the bed, facilitating the maintenance of the stand.

 Such a constructive implementation of a three-roll stand of cross-helical rolling allows to significantly simplify the transshipment due to the fact that all the elements of the pressure devices are mounted in the frame (the stand element is stationary during transshipment). There are no connections between the elements of the pressure devices and the drums, which must be disconnected-connected when transshipment of the cage drums.

 Since the regulation of the caliber solution is carried out directly by the pressure screws of the two lower mechanisms for the longitudinal movement of the drums by turning the nuts through which they are passed, by turning these nuts installed in the glasses by means of bearing bearings mounted in the stand frame and by making levers fixed to the glasses with two shoulders, and the withdrawal of the shoulders of the levers on both sides of the stand, this provides the ability to place the actuators of the pressure devices (power cylinders) and the stop-limiters of their stroke along e sides of the crate on the bed.

 Figure 1 shows the proposed stand; figure 2 view a in figure 1; in FIG. 3 view B in figure 2; figure 4 section BB in figure 2; in Fig. 5, section G-G in Fig. 1; in FIG. 6 caliber breeding scheme with one upper rolls; Fig.7 diagram of the breeding caliber of the two lower rolls; on Fig the rear end of the pipe obtained by breeding the caliber with one upper roll; Fig.9 is the same, two lower rolls.

The three-roll stand of cross-helical rolling comprises a frame 1 with a cover 2, three workers arranged in a circle through 120 ^{about a} roll 3, 4, 5, mounted on rotary drums 6, one of which is placed in the opening of the cover 2, and the other two in the bores between the frame 1 and cover 2, push mechanisms for the longitudinal movement of rotary drums, made in the form of pressure screws 7 with electric drive 8, based on the heel supports 9 of the drums. The pressure screws are passed through the nuts 10, 11. The nut 10 is mounted motionless in the cover. And the nut 11 is mounted in the cups 12, which by means of bearing bearings 13 are placed in the frame 1, fixing the cups 12 with the nuts 11 in the axial direction. The crate has two mechanical pressure devices 14 with a drive 15 and stop stops 16. Both mechanical pressure devices 14 are installed to move the drums with work rolls located in the bores between the bed and the cover. To the ends of the glasses 12 fixed two-arm levers 17, made in the form of a beam. The shoulders of the levers are brought out on both sides of the crate. One shoulder is pivotally mounted with a drive 15 (power cylinder), and opposite to the other a stop stop 16 of the stroke is installed. Moreover, the actuators 15 and the stop stops 16 of the stroke are mounted on a bed. The pressure screws of the lower drums 6 move freely in the splines of the gearboxes 18.

 Three-roll stand transverse helical rolling works as follows.

Before rolling, the work rolls 3, 4, 5 by push mechanisms of the longitudinal movement of the drums 6 are adjusted to the required caliber. The stop stops of the stroke of the pressure devices 14 are adjusted to the required value. The rod of the power cylinder 15 is in the initial position shown in FIG. In the work rolls 3, 4, 5, a tube blank on the mandrel is set and rolling is carried out. When the rear end of the workpiece approaches the rolls 3, 4, 5. The drives 15. The stems of the power cylinders (drives 15), pivotally mounted with the arms of the levers 17, turn them to a position until the second shoulders of the levers come in contact with the stops-stops 16 move. In this case, the glasses 12 with the nuts 11 fixedly mounted in them are rotated in the bearing bearings 13 in which they are mounted in the frame. In this case, the nuts 11 in the axial direction remain stationary, since the bearing bearings 13 fix them with the cups 12 in the axial direction relative to the bed 1. When the nuts 11 are turned, the pressure screws 7 of the lower drums 6 are axially moved, which move freely in the splines of the gearboxes 18. When this is the breeding of the lower drums with work rolls by a value of Δ ₂ . The caliber is then revealed by the value of d _to . To open the caliber according to the known scheme (Fig.6), one upper roll 3 by a value of d _k requires the movement of the drum located in the opening of the lid by a value of Δ ₁ . The value of Δ _{1 is} approximately 2 times greater than the value of Δ ₂ . But this movement, respectively, requires 2 times more time. At the same rolling speeds, the length of the transition section 19 of the pipe with a normal wall thickened according to the first scheme is equal to B, respectively, according to the second scheme, the length of the transition section 20 is A. It is approximately 2 times greater than A. The difference between the volumes of the transition sections V ₁ when rolling in the proposed stand goes into the useful volume of the pipe V ₂ with a normal wall thickness. In this case, the total length of the pipe increases by a value l corresponding to the volume V ₂ V ₁ , and in the pipe itself, its length with a normal wall thickness increases by a value L (Fig. 9), equal to the difference between B and A and plus the value l
LBA + l.

Thus, the yield increases. Moreover, the breeding of caliber rolls 4, 5 in the proposed stand determines the vertical movement of the pipe during the rolling process by an amount of X ₂ from top to bottom, i.e. in the direction of gravity. The value of X ₂ <X ₁ , where X _{1 the} magnitude of the movement of the pipe when breeding the caliber according to the known scheme (Fig.6), while the movement of X _{1 is} carried out in the opposite direction to gravity. Thus, in the proposed design, additional dynamic loads that occur during breeding of caliber during the rolling process are significantly lower.

 Before rolling the next pipe, the power cylinders (drives 15) return to their original position.

 When reloading drums with work rolls, the lid with the upper drum is removed from the crate. A drum with a work roll is freely removed from it. Two open lower drums with work rolls are removed from the open bed by a crane. At the same time, these drums freely come out of contact with the pressure screws 7. All these operations do not require disconnecting the elements of the drive mechanical pressure devices of the drums with work rolls, which greatly simplifies the maintenance of the stand.

 The proposed three-roll stand of cross-helical rolling in comparison with the known ones allows to increase the yield of rolled products, reduce dynamic loads and increase the durability of the stand.

 The device also allows to simplify the handling of drums with work rolls.

Claims (1)

THREE-SHAFT CELL OF A CROSS-SCREW ROLLING MILL, containing a bed with a lid, three rotary drums with work rolls arranged in a circle through 120 ^o , one of which is placed in the lid, and two others in the bores between the bed and the lid, push mechanisms for longitudinal movement of the rotary drums in in the form of electric pressure screws, passed through nuts placed respectively in the frame and cover, as well as additional mechanisms for the longitudinal movement of the lower drums with power cylinders, characterized in then each additional mechanism for the longitudinal movement of the drum with the work roll is made in the form of an enclosing pressure nut and fixed in the axial direction by means of bearing bearings of the glass, on the end of which a pivoting lever is fixed in the form of a rocker arm and a stop-limiter, while one arm of the rocker arm is pivotally connected to the power cylinder , and the other is installed with the possibility of interaction with the stop-limiter stroke.

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