KR20160076655A - method for repair of feed roll housing and repair apparatus - Google Patents

Abstract

The present invention provides a maintenance method and a maintenance device of a feed roll housing. In regard to this, a first maintenance method of the feed roll housing relates to a maintenance method to restore a transformed feed roll assembly hole of the feed roll housing to an original form, and is characterized such that pressure is applied between a first semicircular and second jigs to spread a gap between a first and the second jigs after the first and the second jig rolls are inserted into the feed roll assembly hole to form a circular shape; thereby restoring the feed roll assembly hole to an original form by pressure to be spread by the first and second jigs.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a feed roll housing,

The present invention relates to a method and a device for repairing a feed roll housing.

Particularly, when the feed roll housing is deformed due to an abnormal load acting on the feed roll, radiant heat, etc., it can be restored to the original state, and an erosion preventing plate is attached to the erosion concerned portion of the feed roll housing to prevent erosion by descaling high pressure water And more particularly to a method and a device for repairing a feed roll housing.

In general, the steel process is a process in which molten steel, from which impurities have been removed from iron ore as a raw material, is injected into a mold of a continuous casting process through a steelmaking and steelmaking process to produce a slab or the like, and then the final produced wire, coil, Lt; RTI ID = 0.0 > final product. ≪ / RTI >

In the steel manufacturing process, the rolling process after the casting process changes depending on the final product. Among them, the steel plate manufacturing process uses a rolling device to manufacture the slab produced in the casting process described above to a thickness of about 6 mm to 100 mm And is rolled into a plate.

As shown in FIG. 1, such a thick plate manufacturing process includes a step of heating the slab S in a heating furnace, a step of performing rough rolling and longitudinal rolling using a rolling device, preliminary calibrating, accelerating cooling and hot calibrating Thereby completing the final product. In the case of the step of rolling the heavy plate using the rolling apparatus including the roughing mill 10, the rough rolling mill 10 performs roughing, widthwise rolling and a certain amount of longitudinal rolling to produce an intermediate thickness product, ) To produce the final thickness of the finished product thickness.

A total of four sets of feed rolls 30 for feeding the rolled material 1 to the front and rear sides of the roughing mill 10 and the finishing mill 20 are provided in total. And the roll is assembled. 2, the feed roll housing 31 is formed with three feed roll assembly holes 31a, and the feed rolls 30 are assembled into the respective feed roll assembly holes 31a .

The feed roll housing 31 can be deformed by various factors.

First, the feed rolls 30 are subjected to a lot of forward and reverse operations, and the inner diameter of the feed roll assembly hole 31a of the feed roll housing 31 is deformed due to the operation load generated at this time.

3, the leading end of the rolled material 1 thinned after passing through the roughing mill 10 or the finishing mill 20 is dropped onto the feed roll 30 (portion d in FIG. 3), and a jumping roll is generated As a result, a load is applied to the feed roll assembly hole 31a of the feed roll housing 31 and the inner diameter thereof is deformed.

Thirdly, as shown in FIG. 3, the descaling pressure (e) is generated on the surface of the feed roll housing 31, and due to such erosion, water is supplied to the bearing installed in the feed roll assembly hole 31a As the oil penetrates and corrodes the oil, it affects the smooth rotation of the feed roll 30, causing noise generation and deformation of the housing.

In the first and second cases described above, the hydraulic jack is installed in the radial direction inside the feed roll assembly hole 31a, and then the crushed portion is pushed outward to restore the circular shape. However, in the calibration process, So that the desired calibration is not performed and the portion of the hydraulic jack where the pressing rod touches is locally crushed and the correction work can not be practically performed.

In the third case, the erosion site is restored by build-up welding. Welding is poor in weldability and requires preheating and post-heating. However, since the shape is uneven, preheating and postheating are required for the feed roll housing 31 There is a high risk of deformation and a high risk of cracking due to quenching. Furthermore, during erosion repair welding work, there is a fear that the deformation may be further aggravated by the welding stress, and a countermeasure is required.

Prior Art 1: Korean Patent Application No. 2010-0133218 Prior Art 2: Korean Patent Application No. 2011-0032532 Prior Art 3: Korean Patent Application No. 2010-0061560

SUMMARY OF THE INVENTION It is an object of the present invention to provide a feed roll housing which can be restored to its original position upon deformation of a feed roll assembly hole of a feed roll housing due to an abnormal load acting on the feed roll, Repairing method.

It is another object of the present invention to provide a method of repairing a feed roll housing in which an erosion preventing plate is attached to an erosion preventing portion of a feed roll housing to prevent erosion by descaling high pressure water.

It is still another object of the present invention to provide a feed roller housing maintenance apparatus used in a method of repairing a feed roll housing.

According to a first aspect of the present invention, there is provided a repair method for restoring a deformed feed roll assembly hole of a feed roll housing to a circular shape, wherein first and second semi-circular jigs The first and second jigs are opened so as to spread between the first and second jigs by applying pressure between the first and second jigs so that the feed roll assembly hole is circular There is provided a method of repairing a feed roll housing adapted to be reshaped.

According to a second aspect of the present invention, there is provided a feed roll assembly for a feed roll, comprising a feed roll assembly for supporting a feed roll, wherein a semicircular first and second jigs are inserted into a circular shape, A method of repairing a feed roll housing, wherein the erosion resistant plate is welded, is provided.

Further, in the second aspect, it may further include preheating the welding portion to a predetermined temperature before welding, and posteriorizing the welding superiority to a predetermined temperature after the welding.

Further, in the second aspect, the material of the erosion preventing plate may be an austenitic stainless steel.

Further, in the second aspect, the welding may be a plug welding in which a plug groove is formed in the erosion preventing plate, and the plug groove is welded and welded.

According to a third aspect of the present invention, there is provided a maintenance apparatus for use in a method for repairing a feed roll housing, comprising: a semi-cylindrical shape corresponding to a half shape of the feed roll assembly hole; A first jig having an injection groove formed in an axial direction; And a second jig having a semicylindrical shape corresponding to the other half shape of the feed roll assembly hole and having a semicircular hydraulic injection groove formed in a plane portion of the semicircular cylinder in an axial direction, do.

In the third aspect, the diameter of the arc portion of the first jig and the second jig is equal to the diameter of the feed roll assembly hole, and the length of the plane portion in the radial direction can be made shorter than the diameter of the arc portion.

Further, in the third aspect, the position of the bottom surface of the oil pressure injection groove may coincide with the center of gravity of each of the jigs.

The present invention as described above can be restored to the original state when the feed roll housing is deformed by an abnormal load acting on the feed roll, radiant heat or the like. Particularly, when restoring the feed roll assembly hole of the feed roll housing by using a pair of semicircular repair devices, the load can be evenly distributed over the entire inner diameter, so that a desired degree of restoration can be obtained without local distortion.

In addition, the present invention can prevent the erosion of the feed roll housing by extending the erosion prevention plate of the erosion resistant material to the erosion preventing area of the feed roll housing, and further, it can extend the service life of the feed roll housing. The erosion prevention plate can be fixed by welding while being pulled into the feed roll assembly hole, thereby preventing the erosion prevention plate from being deformed by welding.

1 shows a process of manufacturing a thick plate
Fig. 2 shows the structure of the feed roll and the feed roll housing
3 is a view for explaining the cause of jumping rolls
4A to 4E are flowcharts for explaining a correction method of the feed roll housing according to the first embodiment of the present invention
5 is a view for explaining a correction method of the feed roll housing according to the second embodiment of the present invention;
6 is a perspective view of a correction device according to the present invention;
Fig. 7 is a plan view of Fig. 6
8 is a sectional view taken along the line AA in Fig. 7

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified, and that other specific features, regions, integers, steps, operations, elements, components, and / And the like.

Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Commonly used predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

Hereinafter, preferred embodiments will be described with reference to the drawings.

1st Example  : Feed roll Of the housing Feed roll Assembly hole  Calibration method

4A to 4E are flowcharts for explaining a correction method of the feed roll housing according to the first embodiment of the present invention.

4A to 4E, a method of calibrating a feed roll housing according to a first embodiment of the present invention includes a feed roll housing 31 for supporting both sides of a feed roll 30 (shown in Figs. 1 to 3) The feed roll assembly hole 31a of the feed roll assembly hole 31a may be easily and accurately restored by using the repair device 100 when the feed roll assembly hole 31a of the feed roll assembly hole 31a is deformed. The semicircular first and second jigs 110 and 120 are inserted into a circular shape and a pressure is applied between the first and second jigs 110 and 120 to expand the outer diameter of the first and second jigs 110 and 120, So that the roll assembly hole 31a is restored to a circular shape.

The feed roll assembly hole 31a is deformed into an elliptical shape so that the elliptical long axis direction and the flat portion 111 of the first jig 110 are positioned in the same direction, The first operation is completed by first inserting the first jig 110 into the half area of the first jig 110 and then inserting the second jig 120 symmetrically with the first jig 110. [ Then, the first and second jigs 110 and 120 are inserted into a circular shape.

Next, the hydraulic jack j is inserted into a circular groove in which the hydraulic injection groove 112 of the first jig 110 and the hydraulic injection groove 122 of the second jig 120 are engaged, and then the hydraulic jack j is operated The hydraulic pressure is injected. The outer diameter of the first and second jigs 110 and 120 is expanded by the hydraulic pressure between the first jig 110 and the second jig 120 so that the outer diameter of the elliptical feed roll assembly hole 31a ) Is restored to its original form.

At this time, the front end of the hydraulic jack (j) must be pressurized in a state of being inserted until it reaches the bottom of the circular groove. Accordingly, when the first and second jigs 110 and 120 are expanded, the first and second jigs 110 and 120 can be uniformly expanded since hydraulic pressure is applied to the center of the expansion. A detailed description thereof will be supplemented when the configuration of the maintenance apparatus is described in detail.

On the other hand, when pressure (hydraulic pressure) is injected into the circular groove by the hydraulic jack j, the amount of deformation of the feed roll assembly hole 31a is 10 to 20 kg / cm ² The pressure is gradually increased while the pressure is increased. In this process, the calibration is repeated while repeating measurement and pressurization.

Since the feed roll assembly hole 31a is restored to a circular shape while applying pressure to the inner surface of the feed roll assembly hole by the repair device 100 having a circular shape in the assembled state, .

Second Example  : Feed roll Of the housing  Erosion repair method

5 is a view for explaining a correction method of the feed roll housing according to the second embodiment of the present invention.

The second embodiment of the present invention is to prevent erosion due to descaling high-pressure water on the surface of the feed roll housing 31. An erosion preventing plate 200 is attached to a portion of the feed roll housing 31 where erosion is likely to occur It is a method to prevent erosion in advance.

When the erosion preventing plate 200 is fixed to the erosion preventing plate 200 by welding, the erosion preventing plate 200 may be deformed. Therefore, the repairing apparatus 200 may be used do.

The first and second jigs 110 and 120 are inserted into the feed roll assembly hole 31a of the feeding roll housing 31 so as to have a circular shape and then a portion of the surface of the feeding roll housing 31, The erosion prevention plate 200 is padded and fixed by welding. In this case, since the first and second jigs 110 and 120 are inserted into the feed roll assembly hole 31a, deformation of the feed roll assembly hole 31a can be prevented, and stable welding operation is possible.

In addition, in the case of the above welding, when the whole is welded by build up welding, there is a risk of occurrence of crack due to change in inner diameter of the feed roll assembly hole 31a and generation of stress during welding. When the plug welding is performed in the plug groove 210 while the erosion preventing plate 200 is attached, the effect of preventing the erosion and the effect of preventing the crack can be obtained at the same time.

Here, the material of the erosion preventing plate 200 is preferably an austenitic stainless steel having excellent erosion resistance, but is not limited thereto.

In addition, the material of the welding rod at the time of the plug welding is low in hardness during welding, excellent in fluidity and weldability, has a high affinity with the base material, has little change in texture after welding and can prevent cracks and the like. It is preferable to use an age hardening electrode capable of improving the abrasion resistance.

On the other hand, in the welding work, for example, a post heat operation is essential. Preheating can prevent the cooling rate control and quenching of the welded part by heating the welding part before welding, prevent pore, hydrogen permeation crack, etc. by removing surface moisture, and reduce deformation and residual stress. The residual stress generated in the heating and cooling process due to the welding heat can be removed.

In this embodiment, the preheating temperature is 200 ° C or higher, and the postheating temperature is preferably maintained at a temperature immediately above the martensitic transformation for a long time in order to perform the amassing heat treatment in consideration of the conventional heat-treated structure.

Feed roll Of the housing  Repair device

FIG. 6 is a perspective view of a correction apparatus according to the present invention, FIG. 7 is a plan sectional view of FIG. 6, and FIG. 8 is a sectional view taken along line A-A of FIG.

6 to 8, the repair apparatus 100 of the feed roll housing according to the present invention is used at the time of repairing the feed roll housing 31 described above. The shape of the half of the feed roll assembly hole 31a And a first jig 110 having a semicircular oil pressure injection groove 112 formed in the axial direction O on the plane portion 111 of the semicircular column.

In addition, the maintenance apparatus 100 has a semicylindrical shape corresponding to the other half shape of the feed roll assembly hole 31a, and a semicircular hydraulic injection groove 122 is formed in the semi- And a second jig 120 formed in the second direction.

Therefore, when the first and second jigs 110 and 120 face each other and face each other, they have a cylindrical shape.

The diameters d of the arcuate portions 113 and 123 of the first and second jigs 110 and 120 are the same as the diameters of the feed roll assembly holes 31a while the diameter d of the flat portions 111 and 121 The length d 'of the direction is shorter than the diameter d of the arcuate portions 113 and 123 (d> d'). Therefore, when the first and second jigs 110 and 120 are mated together, they have a shape close to an ellipse rather than a true circle.

The reason for adopting this configuration is to allow the first and second jigs 110 and 120 to be easily inserted into the deformed feed roll assembly hole 31a at the time of a maintenance work, This is because of the two reasons for allowing a clearance between the jigs 110 and 120 to be easily removed from the feed roll assembly hole 31a.

In addition, it is preferable that the bottom surface positions of the oil pressure injection grooves 112 and 122 are located at the positions corresponding to the center of gravity of the jigs 110 and 120. This corresponds to the reason for uniformly expanding the first and second jigs 110 and 120 described in the first embodiment.

That is, when the space between the first and second jigs 110 and 120 is expanded by the hydraulic pressure, the first and second jigs 110 and 120 must be uniformly extended without being shifted to one side. To this end, the point of application of the hydraulic pressure must be the center of gravity of the first and second jigs 110 and 120 The position of the bottom surface of the inflow inlet grooves 112 and 122 is set for this reason.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the same is by way of illustration and example only and is not to be construed as limiting the present invention. It is obvious that the modification or improvement is possible.

It is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

31: Feed roll housing 31a: Feed roll assembly hole
100: repairing device 110: first jig
111: flat portion 112: hydraulic injection groove
113: arc part 120: second jig
121: plane portion 122: hydraulic pressure injection groove
123: arc part 200: erosion prevention plate

Claims (8)

A repair method for restoring a deformed feed roll assembly hole of a feed roll housing to a circular shape,
The semicircular first and second jigs are inserted into the feed roll assembly hole so as to have a circular shape and then a pressure is applied between the first and second jigs to spread between the first and second jigs. Wherein the feed roll assembly hole is formed in a circular shape by restoring pressure of the feed roll.
The first and second semi-circular jigs are inserted into the feed roll assembly hole of the feed roll housing for supporting the feed roll, and the erosion prevention plate is welded to the erosion concerned portion of the feed roll housing, A method of repairing a feed roll housing.
The method of claim 2,
Further comprising preheating the welding site to a predetermined temperature before the welding and posteriorizing the welding superiority to a predetermined temperature after the welding.
The method of claim 2,
Wherein the material of the erosion preventing plate is austenitic stainless steel.
The method of claim 2,
Wherein the welding is a plug welding in which a plug groove is formed in the erosion preventing plate and the plug groove is welded and welded.
A maintenance device for use in a method of repairing a feed roll housing according to claim 1 or claim 2,
A first jig having a semicylindrical shape corresponding to the shape of the half of the feed roll assembly hole and having a semicircular hydraulic injection groove formed in the axial direction on a plane portion of the semicircular column; And
And a second jig having a semicylindrical shape corresponding to the other half shape of the feed roll assembly hole and having a semicircular hydraulic injection groove formed in an axial direction on a plane portion of the semicircular column.
The method of claim 6,
Wherein the diameter of the arc portion of the first jig and the second jig is equal to the diameter of the feed roll assembly hole and the length of the flat portion in the radial direction is shorter than the diameter of the arc portion.
The method of claim 6,
And the position of the bottom surface of the hydraulic pressure injection groove coincides with the center of gravity of each of the jigs.

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