November 27, 2022


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What’s a rolling mill bearing?

Rolling mill bearings are used within the rolling business, this is, rolling of non-ferrous metals, ferrous metals and non-metallic merchandise. It’s used for bearings on the roll diameter of the calender roll and at the drum. Generally four-row cylindrical curler bearings are used to resist radial quite a bit, and thrust curler or thrust ball bearings and radial angular touch ball or radial curler bearings are used to resist axial quite a bit. At the present, oil and gasoline lubrication or oil mist lubrication and grease are most commonly used for lubrication and cooling.

Influencing components and preventive measures of rolling mill bearings

1.1 Meeting high quality

(1) The lifetime of the bearing is inseparable from the design of the bearing seat. If the bearing seat is wrongly designed and manufactured, it is going to reason asymmetric bearing drive and cut back the bearing lifestyles. The bearing seat will have to be self-aligning to steer clear of eccentric loading of the bearing because of the burning and deflection of the roll.

(2) Whether or not the dimensions, geometry, accuracy grade, and tolerance vary of spare portions associated with the bearing are in keeping with the design.

(3) Whether or not the smoothness and hardness of the touch floor matched with the bearing are throughout the specified vary, whether or not all clearances and interference suits meet the design necessities, and many others.


1.2 Set up of interior and outer jacket

1.2.1 Set up of interior sleeve

The internal sleeve and the roll neck of the four-row cylindrical curler bearing will have to be an interference are compatible. All through set up, the temperature will have to be heated to 80-90 °C, and the temperature will have to now not exceed 100 °C. Another way, the bearing ring raceway and rolling parts will probably be simply annealed, which can impact the hardness and resistance.

Abrasiveness, leading to diminished bearing lifestyles and untimely failure. When the use of the heating solution to set up the bearing, the bearing will have to be briefly got rid of from the oil after the oil temperature reaches the required temperature for 10 mins, and put in at the shaft whilst it’s nonetheless scorching. If important, just a little power will also be carried out to the tip face of the bearing interior ring with the set up software, which makes it more straightforward to put in.

After the bearing is put in at the shaft, the interior ring should be pressed in an instant till it cools. It’s in most cases heated with induction warmers or oil, and the usage of torches is illegal. When the interior sleeve is put in at the roll neck, it’s in shut touch with the water maintaining ring to forestall the water maintaining ring from shifting.


1.2.2 Set up of the jacket

The outer sleeve of the four-row cylindrical curler bearing is a transition are compatible with the interior hollow of the bearing seat. When assembling, evenly force the entire consisting of the jacket, rollers and cage into the bearing seat with a copper rod, and connect the tip duvet towards the interior facet.

When putting in the outer casing, take note of the markings at the finish face and the tip face of the cage. It can’t be put in in opposite. It will have to be put in within the order of the preliminary state when the bearing is unpacked to forestall the bearing from burning because of asymmetric drive at the rollers.

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When putting in the bearing, the bearing will have to be positioned horizontally. After the bearing is put in, its drive vary will have to be marked for key inspection when the curler is changed.


1.3 Correct meeting of bearing seals

Bearing seals will also be thought to be to make use of abnormal fluororubber skeleton seals, which aren’t most effective affordable, but in addition can reach excellent effects with affordable use. When the rolling mill is in a horizontal state, the lip of the shaft sealing ring within the static labyrinth on either side should be put in towards the out of doors of the bearing, which will successfully save you the splashing of cooling water and oxide scale; when the rolling mill is in a vertical state, the interior of the labyrinth at the transmission facet The lip of the sealing ring is put in in opposition to the interior of the bearing, which will successfully save you the overflow of lubricating oil because of the downward gravity; the lip of the sealing ring within the labyrinth at the non-transmission facet could also be put in in opposition to the out of doors of the bearing, which will successfully save you the splashing of cooling water.


1.4 Cheap choice of bearing grease

For the reason that frequently used grease for bearings is abnormal 3#MoS2 lithium-based grease, it has the disadvantages of excessive viscosity, low penetration, excessive temperature resistance and excessive velocity resistance.

Additionally, it’s simple to reason unusual put on and burn out of the bearing because of the hardening of the grease and the failure to lubricate the bearing in most cases. In view of those disadvantages that aren’t conducive to the usage of bearings, it is suggested to make use of excessive power lithium complicated grease in attention of the above components.


1.5 Inspection of bearings

1.5.1 Inspection of bearings right through operation

Consistent with the necessities of the bearing use surroundings, the bearing will have to be incessantly listened to, seen and measured. Listening is to make use of the required device to stand the radial housing of the bearing axial finish duvet and bearing seat, and pay attention carefully to the opposite finish to peer if there’s any affect sound and mechanical friction sound right through the operation of the bearing; statement is to watch the working surroundings, set up place, vibration deviation Take a look at whether or not there’s a dangerous surroundings; the dimension is to make use of a thermometer and a vibration meter to quantitatively discover the bearing seat.

In the course of the above strategies, it may be decided whether or not the bearing is in a regular state right through operation and the measures to be taken, the faults and preventive measures that the bearing is vulnerable to happen right through operation.


1.5.2 Inspection of bearings at leisure

Take a look at the tightening of the related spare portions, whether or not the portions are in the right kind place, whether or not there’s looseness, and many others. At all times take a look at the bearing seat for tightness and looseness.

Specifically, there should be no axial clearance between the operation facet bearing seat and the rolling stand, and the matching hole between the transmission facet bearing seat and the rolling stand window should be diminished up to conceivable, to be able to cut back the affect of the force shaft runout at the bearing.

As well as, the bearing lubricant will also be examined to test whether or not the lubricating oil enters the sundries, iron oxide scale, water, and many others. Roughing generators are in most cases subjected to sturdy surprise quite a bit, the bearings vibrate a great deal, and the grease is definitely misplaced. Subsequently, the grease is needed to have sturdy adhesion, which will firmly adhere to the outside of the portions, a part of which lubricates the bearing at the raceway, and the remaining is stored within the interior house of the bearing for sealing.

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If exterior dust penetrates into the bearing seat, the primary contamination is the grease close to the outer facet, which reasons the outside of the bearing portions to put on. With the rise of dust, the damage floor will building up, and on the identical time, the cracks within the sign layer will regularly extend, and in the end the ferrule will probably be cracked.


1.5.3 Inspection after dismantling of bearings

Because of the huge rolling capability of the only groove of the roughing mill, the roll converting cycle is lengthy. After the roll is changed, the cleansing agent can be utilized to scrub the bearing, dry it with compressed air, after which investigate cross-check the curler, cage and rolling. The rollers and raceways have dents, pitting and different phenomena, which will have to get replaced consistent with the precise prerequisites. On the identical time, take a look at the radial clearance of the axial sealing field. After the take a look at is right kind, upload lubricant for backup.


Rolling mill bearing classification

(1) Round curler bearings

The configuration of rolling mill bearings at the rolling mill is other. At the moment, two units of round curler bearings had been basically put in at the identical roll neck in parallel. This configuration principally met the manufacturing prerequisites at the moment, and the rolling velocity may achieve 600rpm.

Alternatively, as the velocity will increase, its shortcomings turn into extra distinguished: brief bearing lifestyles, excessive intake, low precision of completed merchandise, critical roll neck put on, massive axial motion of the roll, and many others.


(2) 4-row cylindrical curler bearing + thrust bearing

The internal diameter of the cylindrical curler bearing is tightly fitted with the roll neck and will face up to radial drive. It has the benefits of massive load capability, excessive prohibit velocity, excessive precision, separable and interchangeable interior and outer rings, simple processing, low manufacturing value, and handy set up and disassembly.

The thrust bearing bears the axial drive, and the precise construction kind will also be decided on consistent with the traits of the rolling mill.

When the burden is heavy and the velocity is low, it’s supplied with a thrust curler bearing to endure the thrust load with a small axial clearance. When the rolling velocity is excessive, with angular touch ball bearing, now not most effective the prohibit velocity is excessive, but in addition the axial clearance will also be strictly managed right through operation.

The rolls will also be tightly guided within the axial route and will endure the overall axial load drive. This sort of bearing configuration now not most effective has lengthy bearing lifestyles, excessive reliability, but in addition has many benefits reminiscent of excessive precision and simple regulate of rolling merchandise, so it’s the most generally used, most commonly utilized in cord rod rolling generators, sheet rolling generators, foil rolling generators, and double reinforce rolling generators. Again-up rolls for chilly rolling generators and scorching rolling generators, and many others.


(3) 4-row tapered curler bearings

Tapered curler bearings can endure each radial drive and axial drive, and no thrust bearing is needed, so the primary engine is extra compact. The internal diameter of the tapered curler bearing adopts a free are compatible with the roll neck, which could be very handy for set up and disassembly, however once in a while sliding creep is also led to because of the free are compatible, so the interior diameter is frequently machined with a spiral oil groove.

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This configuration kind continues to be broadly used, such because the paintings rolls of four-high scorching rolling generators and chilly rolling generators, billet generators, metal beam rolling generators and different events.

4-row cylindrical curler bearings and six-row cylindrical curler bearings are virtually completely utilized in roll necks, drums and rolling generators of rolling stands. Those bearings have low friction in comparison to different curler bearings. Since those bearings are in most cases fixed at the roll neck with an interference are compatible, they’re particularly appropriate for rolling mill packages with excessive rolling speeds.

The low cross-section of those bearings permits the usage of rather massive roll neck diameters in comparison to roll diameters. The radial load capability could be very excessive because of the huge collection of rollers that may be accommodated.

Multi-row cylindrical curler bearings can most effective face up to radial quite a bit. Subsequently, those bearings are fixed with deep groove ball bearings or angular touch ball bearings, or tapered curler bearings of radial design or thrust design, which might be subjected to axial quite a bit. 4-row and six-row tapered curler bearings are of break up design, this is, the bearing ring with integral flange and the curler and cage meeting will also be put in one by one from the break up bearing ring, or all bearing elements will also be put in one by one.

This significantly simplifies bearing set up, repairs and inspection. The bearing can endure a undeniable prohibit of axial displacement of the shaft relative to the bearing seat. 4-row cylindrical curler bearings have a cylindrical bore, and a few sizes also are to be had with a tapered bore. Bearings with tapered bores will also be adjusted right through set up to procure a undeniable radial inside clearance or a undeniable preload.


Rolling mill bearing procedure

The design of rolling mill bearings, the burning lack of rolling mill bearings is expounded to many components, which is normally customary. The burning lack of standard angular touch bearings of aluminum foil rolling generators is a world drawback. I in my opinion suppose that lubrication is essential. The impact of oil mist lubrication Quite higher, there could also be the problem of bearing set up clearance.

As well as, there are lots of components reminiscent of the distance between the shaft finish baffle and the bearing seat, and the burden trade of the bearing outer ring led to through the bending cylinder. . There also are bearing outer ring spring buffers and so forth.

  1. 4-row cylindrical small curler bearings are normally used for the backup roll, and the interior ring is statically matched with the curler. Usually, after the taper sleeve is put in, the interior ring is put in, and the outer circle of the curler is finely floor in response to the interior ring. The axial drive generated right through the rolling procedure must be supported through bearings. Usually, back-to-back double-row angular touch ball bearings, face-to-face double-row tapered curler bearings, thrust bearings and four-point angular touch ball bearings are used. , The home producers of the tile shaft merchandise are higher, and the international producers of the American iron mom are higher.
  2. 4-row tapered curler bearings are normally used for paintings roll bearings. As a result of their construction, the interior ring is in dynamic are compatible with the roll, this is to mention, when the roll is regrind, the bearing is got rid of along with the bearing seat, which itself can endure a specific amount of shaft. Subsequently, the axial drive of a few small rolling generators is borne on its own, whilst some better or upper precision rolling generators normally use axial drive bearings.