RU2356664C1 - Method of restorative function of banded forming roll - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention is provided for increasing of durability, reduction of consumption of banded forming roll, expenditure for rollers and effectiveness increase of rolling mill on sheet mills. Method includes roller withdrawal from exploitation and mounting of devices of circular and axial fixation of tyre on the axis of roller. After rollers commissioning, beginning from the first transposition, it is controlled appearance of circular and axial shift tyre, and at detection axial deflection roller is remove from the exploitation, herewith support butt end, project out of limits of landing surface of axis, it is treated on roll-turning machine up to primary dimensions of its form surface, and tyre fixation facility on the axis of circular and axial displacement it is installed by circumference coupling of end surface of tyre and axis.

EFFECT: providing of full manufacture of resource of hardened labor surface layer band.

6 dwg

Description

The invention relates to rolling production, mainly to restore the operability of the bandaged backup rolls of sheet rolling mills.

The use of banding is an effective way to increase the durability and production of rolls (the number of rolled metal during the full life of the product), reduce the consumption of rolls and the cost of their purchase. At the same time, one of the drawbacks of bandaged rolls is a rather high probability of longitudinal axial displacement of the bandage relative to the axis of the roll. The shift occurs mainly due to insufficient tightness of the bandage on the axis of the roll during its manufacture or asymmetric distribution of tensile stresses from the tightness relative to the central cross section of the bandage.

When axial displacement of the bandage occurs, it occurs in one direction and does not stop during the operation of the roll. Upon reaching a certain amount of displacement, the bandage abuts against the roll bearing cover with its end face, and further operation of the roll becomes impossible due to subsequent destruction of the bearing or breakage of the roll. The roll is decommissioned, as a rule, long before the resource is fully depleted of the hardened working surface layer of the bandage. The bandage must be replaced or the roll together with the bandage is sent to scrap. This leads to an increase in the consumption of rolls, the cost of their acquisition and reduce the efficiency of rolling production.

Existing methods for restoring the operability of bandaged rolling rolls are based on replacing the bandages with repeated use of the axles after they have developed their full life or after the bandages have failed for other reasons, including axial displacement. Moreover, the percentage of rolls output for this reason reaches 30% [Polukhin P.I., Nikolaev V.A., Polukhin V.P. et al. Strength of rolling rolls. Alma-Ata: Science, 1984, pp. 90-104]. To eliminate the axial displacement of the bandages in the manufacture of rolls, various types of end brace fasteners are used on the axis of the roll (ibid., Pp. 100-101). However, in most cases, bandage rolls are used in practice, in which the bandage with an axis is connected by guaranteed interference without the use of end mounts. In this case, with the axial displacement of the bandages, the rolls are subject to restoration of operability only with the replacement of the bandages with new ones or decommissioned into scrap metal.

A known method of restoring the functionality of bandaged rolling rolls (analogue), including decommissioning the rolls, dismantling the bandages and re-forging them for use in rolls of a different size [USSR Author's Certificate No. 1658474, IPC VB 28/02, 1995].

The disadvantage of this method is the need to dismantle the bandage and the inability to continue using it with axial displacement after repeated reforging in rolls of the same size. In addition, the method is characterized by high complexity, high energy consumption and cost comparable to the cost of new integral rolls.

The closest technical solution (prototype) is a method of restoring the functionality of bandaged backup rolls, which can be implemented using bandaged rolls with means of circumferential and axial fixation of the bandage on the axis of the roll according to US patent No. 4813258, B21B 21/01, B21B 29/00. In accordance with this patent, the bandage is installed on the roll axis with an interference fit at half the length of the seating surface and is fixed on the roll axis from circumferential displacement by a prismatic key, from the axial one with a collar on the neck of the roll axis and bolts that attract the band end to the collar. The second half of the length of the landing surface of the axis is conical with a gradually decreasing diameter.

Unlike the analogue in the prototype, when the axial displacement of the bandage, the roll can be restored while maintaining this bandage. However, to restore the roll’s working capacity, it is necessary to remove the bandage from the axis, cut new keyways on the seat surfaces of the bandage and axis, threaded holes in the end of the bandage for bolts, and re-attach with a turn of the bandage on the axis.

When using this method, grinding of the bearing surfaces of the axis and the band is required, which leads to a significant reduction in the interference fit and an increase in the load on the bolts of the axial fastening of the band, the band strength is significantly reduced due to cutting an additional keyway, and the laboriousness of restoring the rolls significantly increases, which makes it economically inappropriate in comparison with the usual reuse of axles and replaceable new bandages.

The technical result of the invention is to increase the service life, reduce the consumption of bandaged rolls, the cost of rolls and increase the efficiency of rolling production by ensuring the full development of the resource of the hardened working surface layer of bandages.

The technical result is achieved by the fact that after putting the bandaged rolls into operation, starting from the first transshipment, the appearance of the circumferential and axial displacement of the bandage along the axis of the roll is controlled and, when a bias is detected, the roll is taken out of operation, the end face of the bandage protruding beyond the landing surface of the axis is machined fixation tools are installed to the nominal dimensions of its initial curved surface like that of a new roll and along the mating circumference of the end surfaces of the brace and axis and bandage on the axis from the circumferential and axial displacement.

The invention is illustrated by drawings, which depict the following.

Figure 1 - bandaged roll with a longitudinal displacement of the bandage relative to the axis until recovery.

Figure 2 - bandaged roll with a machined end face of the bandage from the exit side beyond the landing surface of the axis.

Figure 3 is a fragment of the axial section of the roll after processing the end face of the bandage and making blind holes for dowels.

Figure 4 - bandaged roll after recovery.

Figure 5 is a view along arrow "A" in figure 4.

6 - node I in figure 4.

A method of restoring the operability of bandaged rolling rolls includes controlling the appearance of axial displacement (sliding) of the band from the axis (hereinafter, axial displacement). Axial displacement can begin both immediately after the roll is put into operation, and during operation. Therefore, the control of the axial displacement of the bandage is carried out after commissioning the roll immediately after the first transshipment. Axial displacement is detected visually by the state of the joints of the curved end surfaces of the bandage and the axle seat on both sides of the roll after disassembling it with the bearings of the roll for regrinding or resurfacing for subsequent operation. It is impossible to detect axial displacement during the rolling process, since the ends of the brace and axes at the joints are closed by the rear covers of the roller bearings with lip seals.

With the appearance of axial displacement, the end face of the brace 1 on one side protrudes beyond the aisles of the landing surface of axis 2 by a certain amount of 6 (in Fig. 1 - on the right side), on the other (on the left side) it is pushed onto the landing surface by the same amount. During operation, if the roll is not withdrawn from it, the axial displacement of the band will continue in the same direction, and at a certain critical value δ, the band rests on the rear bearing cover, which can lead to destruction of the bearing or breakage of the roll. The axial displacement process does not occur instantly, for a sufficient time to be detected until a critical value of δ is reached.

When the axial displacement of the bandage is detected, the roll is decommissioned and goes directly to the restoration of performance.

Recovery occurs in the following order. On a roll-forming machine, the end face of the bandage, protruding beyond the landing area of the axis, is processed to the nominal (initial) size with the interface of its curved end surface with the curved surface of the end of the landing area of the axis (figure 2). The end surface of the bandage with the axis is usually made of a circular longitudinal section of radius R.

The opposite end of the bandage is not processed, since the detected value of the axial displacement is small and does not affect the performance of the bearing on the side of this end during subsequent operation of the roll. In this case, the length of the bandage during processing of the protruding end face decreases by the amount of the detected displacement δ. This displacement, due to its smallness, does not reduce the strength of the bandage. At the same time, the earlier the beginning of the axial displacement of the bandage is detected, the less metal removal during processing of the bandage end face, the recovery time of the roll, and the complexity of its mechanical processing. Therefore, the control of detecting axial displacement with this method begins immediately after the roll is put into operation.

After processing the end face of the mating bandage with the axis around the circumference of their mating set means fixing the bandage on the axis from the circumferential and axial displacement.

For circumferential and axial fixation of the bandage on the axis, various methods can be used. Studies of known methods have shown that one of the most reliable methods is fixing with dowels installed from the end of the brace along the circumference of its mating with the axis according to RF patent No. 2254184, IPC B21B 27/03, 2005. In accordance with this method, at an angle to the axis of the roll (figure 3) perform blind holes 3 passing through the body of the bandage and the body of the axis. In the bottom of the holes in the body of the axis, threaded holes 4 coaxial with them are cut. 4. In the blind holes, cylindrical dowels 5 with axial holes are installed, through which the dowels are bolted 6 with washers 7 to the roll axis 3. The bolts are screwed into the threaded holes, while the dowels and bolt heads with washers are placed in the blind holes so that they do not protrude beyond the curved mating end surfaces of the bandage and the axis of the roll. On this, the restoration of the functionality of the bandaged roll is completed, and the roll is ready for continued operation.

Blind holes 3 are made at an angle to the axis of the roll, passing through the body of the bandage and the body of the axis (Fig. 3). In the bottom of the holes in the body of the axis, threaded holes 4 coaxial with them are cut. 4. In the blind holes, cylindrical dowels 5 with axial holes are installed, through which the dowels are bolted 6 with washers 7 to the roll axis 3. The bolts are screwed into the threaded holes in the bottom of the blind holes, while the dowels and bolt heads with washers are placed in the blind holes so that they do not protrude beyond the curved mating end surfaces of the band and roll axis. On this, the restoration of the functionality of the bandaged roll is completed, and the roll is ready for continued operation.

After mechanical processing of the end face during the operation of the roll, the required distance between the end face of the bandage and the rear cover of the roll bearing is ensured, which ensures the normal operation of the roll and bearing after restoration of operability until the band resource is fully depleted.

The installation of fixing means is required only from the side of the processed end of the bandage, since after the installation of fixing means the axial displacement of the bandage in the opposite direction is impossible.

The practice and studies of the applicant have shown that axial displacement is usually preceded by a circumferential displacement of the bandage on the roll axis. Therefore, control of circumferential displacement is also important. The use of these fixation means eliminates the appearance of a circumferential displacement of the bandage, which increases the reliability and its axial fixation.

The application of the proposed method allows the operation of bandaged rolls after restoration to full use of the resource of the hardened working surface layer of bandages, since axial displacement of bandages is excluded during subsequent operation. This ensures an increase in service life, reduces the consumption of rolls and the cost of their acquisition. Due to the exclusion of axial displacements after the rolls are restored to serviceability, their bearing failures are reduced, roll breakdowns are reduced, emergency downtimes are reduced, the productivity of the rolling mill and the efficiency of the rolling production are increased.

Claims (1)

A method of restoring the functionality of bandaged rolling rolls, including decommissioning them and installing means of circumferential and axial fixation of the bandage on the roll axis, characterized in that, starting from the first transshipment after putting the rolls into operation, they control the appearance of circumferential and axial band offset along the roll axis, rolls are decommissioned when a circumferential and axial displacement of the band is detected, while the end of the band protruding beyond the seating surface of the axis is subjected to mechanical treatment Otke to its original dimensions of the curved surface, and means for securing the shroud to the axis of the circumferential and axial displacement circumferentially mounted mating shroud and the axis of the end surfaces.

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