JPS58199607A - Roll stand of rolling mill and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a roll stand having an excellent safety in strength, by welding several rolled steel plates for constructing respective upper and lower blocks and left and right posts separately, in manufacturing a roll stand of a rolling mill. CONSTITUTION:A roll stand 1 of a rolling mill is constituted of upper and lower blocks 2, 3 and left and right posts 4, 5, and each of the blocks is constructed with one piece of rolled steel plate and each of the posts with two pieces among rolled steel plates 4a, 4b, 5a, and 5b, respectively. After tack welding respective rolled steel plates through a starting tab used for electroslag welding, the welded body is layed so that the left post is at the top and is mounted on a base 13 by supporting legs 12. Next, a central butting part A of the post 5, butting parts B, C at its both sides and a central butting part D of the post 4, butting parts E, F at its both sides are respectively welded in sequence, by a nozzle of an electroslag welder travelling on a rail 14, to manufacture a roll stand excellent in strength.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rolling mill roll stand for welding a plurality of rolled steel plates, and a method for manufacturing the same.

Conventionally, cast steel has generally been used as a material for rolling mill roll stands. However, when cast steel is used, there is a drawback that as the roll stand becomes larger, problems such as the occurrence of cavities and segregation in the cast steel and a decrease in strength accompanying this occurrence cannot be avoided.

On the other hand, as an alternative to cast steel, a rolled copper plate with a uniform structure is used, a part of the roll stand is cut out from this rolled steel plate, several pieces are stacked and welded together to form a block, and this block is reassembled. Japanese Patent Publication No. 53-42453 proposes manufacturing a roll stand by joining them together by welding.

However, according to this method, in lap welding, a difference occurs in the amount of welding shrinkage of the next rolled steel plate, which has a different degree of restraint by the weld metal on the welding start side and the welding end side. Since the thickness of the material after round welding cannot be maintained uniformly, the mechanical force and man-hours required after block welding have to increase, and together with the increase in welding locations, the work efficiency and economic efficiency of round stand manufacturing are significantly reduced. The problem of letting it happen is too much. Furthermore, since both #1 stacking and #1 block integration are performed, the parts of the rolled steel plates that can be subject to double Sm heat effects, and the materials are unified, resulting in a large rolling process that includes impact loads. There is a risk that the safety of the roll stand under load may be compromised.

The present invention was made in view of the above-mentioned problems, and an object of the present invention is to manufacture a rolling mill roll stand that is extremely simple and has high strength and safety even when rolled steel plates are used.

Another object of the present invention is to provide a method that can finally cancel the welding thermal deformation during welding of rolled steel plates, and thereby manufacture rolling mill rows and stands with extremely high efficiency.

One feature of the present invention is that the upper block, lower block, and left and right posts of the C1 rolling mill are each made of separate rolled steel plates, and these are welded to form a nine rolling mill roll stand. This idea was created based on the findings of a detailed study of the functions that a roll stand should have.

That is, by reducing the rolling ratio, a rolled steel plate with a large thickness and a uniform structure on the surface due to the rolling effect, that is, an ultra-thick rolled slab can be obtained. When such a slab is used, it is not necessary to overlap the rolled steel plates, and the quality of the welded portion between the slabs is maintained well because the slab surface is rounded.

On the other hand, in the inside of the slab, for example, the solidification inside the ingot is delayed from the surface, so defects such as cavities are likely to occur, and even if rolled, the effect is small in the inside, so the possibility of eliminating the defects is low. However, since such defects are confined within the center of the slab material, cracks do not occur from within even under the action of heavy loads and therefore do not impair the safety of the roll stand. The present invention, which has the above-mentioned features from such 511 points,
This allows us to achieve the purpose stated at the beginning. Furthermore, it is more preferable that the posts and blocks are arranged so that the rolling direction of the upper and lower blocks is perpendicular to the rolling direction of the posts. If placed in this manner, the rolling load and bending moment that actually act on the block will cause the elongation or impact resistance value up to fracture to be large compared to the width and thickness directions of the rolled steel plate. Since the directions of the complex stress and the stress due to the bending moment acting on the block can be made almost the same, safety can be improved in terms of strength.

Another feature of the present invention is that the left and right posts are each made up of at least two rolled steel plates, the abutting portions of these rolled steel plates are welded, and after death, the other side of the post after welding is connected to the upper block and the lower block. The present invention relates to a method of manufacturing a rolling mill roll stand in which abutting portions are welded to each other.

According to this method, a reverse opening is first applied to the post by welding the central part, and then the amount of reverse opening can be canceled by deformation due to welding on the other side, which greatly simplifies machining after integral welding and improves work efficiency. can be improved.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an overall perspective view showing a state in which the roll stand is welded, and FIG. 2 is a schematic diagram showing a deformed shape a of the roll stand after welding the central portion of the post.

The roll stand 1 has an upper block 2 and a lower block 3.
It is composed of a left post 4 and a right post 5 arranged between these blocks. The upper and lower blocks 2 and 3 are each made of one rolled steel plate, and the left and right posts are each made of two rolled steel plates 4a, 4b, and 5a.

Consisting of 5b. In addition, the rolling direction of the rolled steel plates that make up the post coincides with the longitudinal direction of the post (the direction in which rolling load acts), and the rolling direction of the rolled steel plates that make up the upper and lower blocks corresponds to the rolling direction of the post. is placed perpendicular to the Each rolled steel plate is tack welded via an electroslag welding start tab plate 10, and is restrained and formed into a body. fjiIll is an end tab plate for electroslag welding.

The nine-roll stand 1 integrated in this way is
The left post 4 is placed sideways on top, and the support 12
It is placed on the pace 13 via.

In front of the roll stand, there is a rail 14 laid parallel to the stand, and on this rail 14,
A manipulator 16 is mounted that allows the nozzle 15 of the electroslag welding machine to be moved laterally (left and right in FIG. 1), up and down, and back and forth.

In this embodiment, there are a total of six abutting portions of the rolled steel plates. The order of welding is the abutting part 11 at the center of the post 5 located on the lower side in Figure 1, then the abutting parts B and C on both sides (whichever comes first), and then the upper side in the same figure. It is preferable to do this at the abutting portion D at the center of the post 4 located at , and at the abutting portions E and F on both sides (whichever comes first). Further, welding at each abutting portion is performed from bottom to top in order to eliminate the influence of the molten part flowing down. According to such a welding procedure, the influence of thermal deformation due to welding can be finally canceled. That is, when the butt part A is welded from the bottom to the top, cooling first progresses from the lower part of the welded part to the upper part of IIIK, and as this progresses, the molten part contracts. At this time, a start tab plate that restrains the rolled steel plate is temporarily attached to the lower part of the abutting portion, so that it acts to restrain shrinkage. Therefore, the amount of contraction in the upper part of the abutting part increases, and the second
As shown by the dotted line in the figure, the upward direction is deformed into a concave shape.

If abutting parts B and C are welded in this state, the upper part will contract more than the lower part on both sides of the abutting part A for the same reason as described in 9 above, so that the concave bend will be corrected. This can also be said to indicate that the boss was opened in reverse during the first welding process.

In this embodiment, first, the lower abutting portions A and B.

In this case, we will be welding C, but in this case, as shown in Figure 2, the openings at the top of the upper mating parts E and F can be slightly opened, making it easier to insert the nozzle of the electroslag welding machine.
This has the advantage of improving workability.

Next, selection of the positions of the abutting portions B, C, E, and F will be explained. Stress concentration occurs at the four corners of the window of the roll stand during rolling, so the inside of the upper and lower block (window side)
It is preferable to cut the part and separate the abutting part from the corner part.The radius of curvature of the corner part of the lower block is 8, and the point at which the corner part switches from an arc to a straight line is Hl.
The end of the mating part is the machining part. In general, in electroslag welding, about 30 parts from the mating end I are melted, and about 1O2 of the non-melted parts adjacent to this melted part are affected by heat, resulting in a decrease in impact resistance. Therefore, it is preferable to separate the mating end from the inner surface of the lower block by t=(R+40)m or more. On the other hand, from the viewpoint of machining the block, the smaller the depth of cut, the better, but it is also possible to use the cut-out member as a tab plate. In this case, there is an advantage that even if some of the weld metal from the tab plate flows into the roll stand during welding, there will be no deterioration in quality because the tab plate, block, and post are originally the same member.

When considering the use as such a tab plate, practically, t is about 50 to 300.

Incidentally, the upper block or the lower block is equipped with a reduction cylinder or a reduction screw, but it is desirable that the dimensions of this attachment part be larger than other parts.In consideration of work efficiency, it is desirable to make the mounting part larger than other parts. It is preferable to form a block by previously welding a member thicker than the post as an intermediate member 20 between two members having the same thickness as the post.

In the above embodiment, the left and right posts are each made of two rolled steel plates, but in the case of a not-so-large roll stand, each post is made of one piece of rolled steel plate as shown in Figure 4.
It may be composed of individuals. In addition, if the thickness of the rolled steel plate is thicker than the desired roll-out thickness, the rolled steel plate is divided in half in the rolling direction as shown in Fig. Outer surface of stand 1m1K
You may arrange it so that it is located. In this case, aoa, ao
Although there is a possibility that a defect 31 exists in the center outer part of b, the tensile load distribution under the combined force of rolling load and bending moment on the post is as shown in the same figure, which is higher on the inner and outer sides of the stand. Since the outer surface is low, the presence of this defect often causes the grain to break.

By the way, as mentioned above, in the case of electroslag welding, the weld heat affected zone is approximately 40 mm, so it is necessary to confine at least defects within 40 mm or more from the surface of the rolled steel sheet by rolling. To achieve this, in the case of a roll stand with practical dimensions, the rolling ratio defined by the cross-sectional area ratio before and after rolling should be 1.3 or more.On the other hand, if the rolling ratio is normally 5 or more, Internal defects can be compressed and the structure can be made uniform; however, according to the present invention, since internal defects are tolerated as already explained in detail, it is not necessary to use a rolling ratio of 5 or more. That is, the rolling ratio that can be practically used in the present invention is 1.3 to 5. , O.

A large roll stand with the structure shown in Figure 1, for example, has a width of approximately 3 m, a height of approximately 9 m, a stand thickness of approximately 60 mm, and a window width of approximately 1.5 m, but is basically installed in only 6 locations. It has the advantage of being easily manufactured by welding.

According to the present invention, a rolling mill roll stand that is extremely simple and has high strength and safety can be manufactured using a rolled steel plate.

[Brief explanation of the drawing]

Fig. 1 is an overall perspective view showing a rolling mill roll stand manufacturing device; Fig. 2 is a diagram for explaining the deformed state of the roll stand; Fig. 3 is a diagram showing the dimensions of the abutting portion of rolled steel plates. FIG. 4 is a diagram for explaining another embodiment of the present invention. 1...Rolling mill roll stand, 2...Upper block, 3...Lower block, 4, 5...Boss), A,
B.C. Figure 3 Figure 4

Claims (1)

[Claims] 1. In a rolling mill roll stand composed of a plurality of rolled steel plates joined by welding, an upper block, a lower block, and left and right posts of the rolling mill are each composed of separate rolled steel plates, The upper block and the lower block,
A rolling mill roll stand, characterized in that each roll stand is arranged so that its rolling direction is perpendicular to the rolling direction of the post. 2. The rolling method according to claim 1, characterized in that the left and right posts are formed by halving nine rolled steel plates in the rolling direction and arranging them so that the half surfaces of the nine rolled steel plates are on the outer surface side of the roll stand. Machine roll stand. 3.% Allowance In claim 1 or 2, the abutment portions for ** provided at both ends of the upper block and the lower protrusion are arranged from 50 to 30 mm from the central inner surface of the block.
0 ■ A rolling mill roll stand that is formed to protrude to prevent t% mold. 4. The rolling mill according to claim 1 or 2, characterized in that a rounded intermediate member for attaching a rolling device to the center of the upper block or lower block is integrally formed by welding. roll stand. 5. A method for manufacturing a rolling mill roll stand composed of a plurality of rolled steel plates joined by welding, in which a post on one side of the rolling mill is welded to the abutting portion of at least two rolled steel plates, and then the post is A method for manufacturing a rolling mill roll stand, which comprises welding the mating portions of the other side and the upper and lower blocks, respectively. 6. The rolling mill according to claim 5, wherein the welding is performed from bottom to top with the upper block, lower block, and post temporarily attached and placed laterally. How to manufacture a roll stand. 7. A rolling mill roll according to claim 5, wherein the upper block and the lower block are made of rolled steel plates, and the rolled steel plates are arranged in one corner direction such that the roll direction of the rolled steel plates is set to the boss) KJ. ] How to make tando. 8. Range of %#'F#fl In item 6, after welding all the abutting parts located on the lower side, the % image is to weld all the abutting parts located on the upper side. A method of manufacturing a rolling mill roll stand. 9.%Claim 4. A method for manufacturing a rolling mill roll stand, characterized in that the tacking is performed using a tab plate. 10. The method of manufacturing a rolling mill roll stand according to claim 9, wherein the tab plate is a member cut out from the upper block or the lower block. 11.4F? 'The method for creating a rolling mill roll stand, characterized in that the welding is electroslag welding in any one of items 1 to tsio of the FWfI search range.