JPS5950902A - Rolling method of deformed steel bar - Google Patents

Abstract

PURPOSE:To obtain an 8-shaped blank material from which a deformed steel bar having good nodes and having no ribs can be formed by using rolls having calibers each of which has a projecting part at the center and recesses on both sides thereof and is formed of inclined side walls, in rolling a square blank material. CONSTITUTION:A square blank material 21 is rolled by upper and lower rolls 19, 20 having calibers each of which has a projecting part 28 at the center and recesses 29 on both sides thereof and is formed by sloped side faces 30. Then the material 21 and the walls 30 contact with each other in the part X and the material 21 and the projecting part 28 contact with each other in the part Y; therefore, deviation is prevented and the narrowed part of an 8-shape can be correctly rolled. The narrowing rate H1 of such 8-chaped blank material is kept in a 0.5-0.5 range in a narrowing ratio H1/H2. Such 8-shped blank material is subjected to finish rolling in varying the direction of rolling down, whereby the product having good nodes 15, 16 and having no ribs is obtd.

Description

[Detailed Description of the Invention] Yes. Deformed steel bars used in reinforced concrete construction have L ribs and nodes extending in the circular direction on the outer circumferential surface, and these ribs and nodes are It's useful for getting dressed.

These ribs and knots are formed during rolling through holes formed in the final finishing mill roll of the deformed steel bar rolling process, but according to the conventional rolling method, concrete and reinforcing bars are While some of the knots that are primarily useful for adhesion tend to be missing, there is also the drawback that the height of the ribs, which are not helpful for adhesion between concrete and reinforcing bars, is excessive (C).

FIG. 1 is an explanatory diagram showing the arrangement of rolling stands in a general method of rolling a deformed steel bar and the cross-sectional shape formed by each rolling stand. The heated steel billet is rolled in order to gradually reduce its cross-sectional area from square to diamond to square, nine to oval to round (ordinary steel bars) and suchenoyuru, and then passed through the first roll (N-1) of the finishing mill. The bar is rolled into an oval shape as shown in Fig. 2, and is then formed into a deformed steel bar having ribs and knots on the Nth and final day of rolling.

In other words, the groove shape of the final two rolls is as shown in FIG. 3. Shallow grooves are cut at equal intervals in the inner circular direction in the groove shapes 2 of the upper roll 1 and lower roll 1', and the cross section shown in FIG. 2 is obtained. The shaped material is rolled with its long axis direction as the rolling direction, and the fourth
The knots 4 shown in the figure are formed, and at the same time, material is intentionally ejected into the gaps 5 between the upper and lower rolls to form ribs 6.
and rolled into a deformed steel bar with the cross-sectional shape shown in Fig. 5'4.
-

However, the bar rolled by the above method: H...1・ji14
As shown in FIG. 6, the joints 4 of the upper and lower rolls were poorly filled, and the rims were sometimes formed into an undesirable shape with partial defects 4'.

Regarding the formation of the ribs, as shown in Fig. 5, the tensile strength of the concrete 1. It is also known that the adhesive strength of concrete is increased by the protrusion shape of the nodes and the number of V than by the ribs.

In addition, as an IIE rolling method that reduces the formation of ribs, there is, for example, Japanese Patent Application Laid-open No. 50-61369, in which a depression is formed in the center as shown in Fig. 7-0 (the shape of the material entering the finishing stand in the final stage of 1). The concavity height and Ho at that time were determined by the constriction ratio to L, and good results were obtained when the constriction ratio was 0.02 to 0.2 or 0.1 to 0.4. This is what it is said to bring about.

In this way, deformed steel bars that have no ribs at all have the effect that the height of the nodes can be increased by the amount of ribs that do not contribute much to the bonding force between reinforcing bars and concrete.
However, the following problems tend to occur during the rolling process in order to produce this steady figure-of-eight leader material. That is, in order to form a figure 8-shaped leader material, it is necessary to perform rolling using a hole pattern as shown in FIG. 7 (I:I), for example. Thus, the blanks fed to a roll having such a hole shape are generally circular as shown in FIG. 8 or oblong as shown in FIG. 9. FIG. 10 shows a combination of a circular material and a figure-eight hole pattern. If we sequentially consider the deformation process of the material in this case, Figure 11 (a)
It becomes like ~(c). That is, FIG. 11(A) shows the initial state where the material 7 is bitten by the rolling rolls 8 and 9, and FIG. 11(B) shows the intermediate deformed state where the material 7 has been further rolled down. is transformed as shown in 7'.

The figure (c) shows the final state, in which the desired figure-8 shaped material 7'' is obtained.

However, the shape of the roll groove for a circular material as shown in FIG. 11 is rolled with a hole having a curved surface R in the opposite direction to the curved surface R' of the material as shown in FIG. Depending on the center accuracy of the entrance guide in the left and right direction, the material 7 that can fit 6 into the hole is likely to be rolled sideways to the left and right, and the material 7 that can fit into the hole is likely to be rolled sideways to the left and right. As shown in FIG. 16(a) or FIG. 16(b), the material of the letter shape has an uneven thickness 10 when either side is biased to one side.

14(a) to e9 show the state in which the normally formed 8-shaped material 11 is sequentially compressed by the rolling rolls 12.13, and FIG. 14(a) (d) shows the initial biting state, and (o) shows the material deformed to 11' at an intermediate stage. (c) shows the final state, where the material is deformed to 11". This results in product 14. 15th
The figure and FIG. 16 show the form of the product 14,
Good knots 15 and 16 are formed, indicating that the desired product without ribs is finished.

On the other hand, Fig. 17 0) to 3) show the deformation process in the case of the 80-character material 15 with uneven thickness, and the rolling roll 1
2 and 13 show a state in which the pressure is sequentially lowered in the same manner as υ.

Figure 17 (a) shows the initial biting state.

In the same figure (b), the material is at an intermediate stage and has been deformed to 15'.

The same figure (c) shows the final state, and shows that the moon is deformed to 15'' to become a product 16.

FIGS. 18 and 19 show the form of the rolled product 27 produced in this manner. As a result, the influence of uneven thickness f/c, J:
The p-node 17 is unfilled, and the heights H3 and H4 are not equal compared to the other node 18, and H3<H. Such products are clearly defective.

The present invention provides a method for rolling a deformed steel bar that prevents the material from shifting during the initial rolling, has complete knots without defects, and does not form any ribs at all.

FIG. 20 shows an embodiment of the rolling method based on the present invention, and also shows the rolling stand arrangement and the cross-sectional shape of the steel bar material formed by each rolling stand, where N is the final Indicates when it is a finishing stand.

FIG. 21 is an explanatory diagram showing the progress of rolling in the case of rolling an 8-shaped material without deviation, which is the gist of the present invention. First, a rectangular shape is selected as the material to be rolled.

This square material is rolled by (N to 4) stands in the row of rolling stands shown in FIG. 20 shown above, for example. Figure 21 (A) shows the initial state starting from biting into the rolling roll, Figure 21 (B) shows the state that has progressed further downstream, and Figure 21 (C) shows the final 80-character monthly state. It shows. That is, in the present invention, the upper roll 19. Bottom roll 2
In order to introduce the rectangular material 21 into the hole shape formed by 0 without shifting, a part of the corner of the rectangular material 21 is restrained from all sides at the initial stage of biting by the X portions of both side walls of the roll, and at the same time, the center A convex part 28 is provided on the roll in order to give a constriction to the part, and the tip of the convex part is Y on the side of the square moon.
It makes contact at a point.

That is, since the material 21 contacts the X part and also contacts the Y part at the same time, there is no room for deviation, and the material 21 is rolled as shown in Figures (B) and (C) of ητ21, resulting in a depression in the center, that is, a figure 8. The narrow part can be rolled correctly.

Therefore, the rolling roll for forming the material used in the present invention has a convex portion 28 in the center, four portions 29 on both sides of the convex portion 28, and a hole formed by the sloped side walls 60.

Figure 20 shows such a material forming roll assembled into the (N-6) stand, where the material formed into a rectangular shape by the (N-4) stand is twisted by 45° to form the next (N-3). )
It will be formed into a figure 8 material on the stand. 20th
In the case of the figure, the (N-2) stand uses figure 8 material,
This is an intermediate stand that applies pressure to make the 80-character material more effective for forming desired products. The details are in the second
Shown in Figure 2.

The roll hole pattern shown in FIG. 22 and the rolling roll rolled using the roll hole pattern shown in FIG. The portion [24] may be made of a material having a gentle depression as shown in FIG. This recess 24 is both -1l
Since the following (N-
1) In the stand, the concavity 24' of the material 26 matches well with the curved part of the roll hole that forms the neck of the figure-eight moon, h, and therefore, biting can be performed without causing left-right deviation. It will help you to do so. (N-1) The situation using the stand is shown in FIG. In FIG. 26, reference numeral 25 is a roll hole-shaped convex film (which is a gentle curve) for forming a constriction in the figure-8 material.

The figure 8 material formed in this way has a good top, bottom, left and right sides, so it can be used for the next ``chi final'' Nistand (N) as shown in Figures 15 and 16. It is possible to obtain products with different shapes. In particular, the free surface 26 without ribs is well formed.

Furthermore, when using such a rolling method, in order to improve the bulge of the knots, to form a smooth surface without ribs on the free surface, and to prevent at least the base radius of the steel bar from expanding. The amount of constriction shown in Figure 7 (A) is preferably set in the range of 0.2 to 0.5 in terms of constriction ratio H1/R2.

This is shown in Figures 24 and 25, where the shape of the node is spiral.
It is extremely effective in the case of reinforcing bars with threaded parts as shown in the figure.

In this case, in order to obtain the cross-sectional shape of the roll to be supplied to the final finishing stand, it is effective that the roll holes are all formed in circular arcs as shown in FIG. 7(b). R1, R2
, R3 indicates the radius of the circular arc.

Since the present invention is configured as described above, it is possible to produce extremely good rolled products without deviation in the shaping of knots and ribs, especially in the shaping of deformed steel bars that aim to completely form knots and eliminate ribs. can be manufactured. There are strong restraint methods such as roller guides (C) that are normally considered to prevent slight deviation, but poor twisting may cause the material to be caught in an abnormal position, which may cause misrolls. .

In consideration of these cases, it is generally necessary for operation to set the entrance guide wide, but even in such cases, according to the present invention, the rE can be set without any problems and without deviation. It is something that can be extended.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the arrangement of rolling stands in the conventionally known irregular-shaped bar adjustment rolling method 1 and the cross-sectional shape of the material formed by each rolling stand. Cross-sectional view, No. 1 + +a Diagram showing the state of the leader material supplied to the final rolling mill in the conventionally known down rolling method together with the rolling rolls, Figure 4 is a plan view of a conventional deformed steel bar Figure 5 is a cross-sectional view of a conventional irregular-shaped steel 1, Figure 6 is a cross-sectional view showing a state of missing knots, and Figure 7 @) is a cross-sectional view showing the shape of the leader oval according to the present invention. B) is an explanatory diagram showing an example of the roll hole shape in that case, FIGS. ←) is an explanatory diagram showing A111 together with the rolling roll shown in Figure 8 that is made into a roll groove shape, and Figures 11 (A) to (C) are disassembled views of the rolling combination shown in Figure 10 from the initial stage of rolling. FIG. 12 is an explanatory diagram showing the cause of deviation in conventional rolling, and FIG.
The figures are explanatory diagrams showing the state when the material is offset by the constriction forming roll. ) (b) (9 is 8
Explanatory drawings sequentially showing the rolling process in the stand when there is no deviation in the shape material, Fig. 15 is a front view of the product manufactured by the process shown in Fig. 14, and Fig. 16 is a side view as well. , Fig. 17 (a), (b), and (c) are explanatory diagrams sequentially showing the rolling process in the finishing stand when the 80-shaped material has offset 9, and Fig. 18 shows the rolling process produced by the process shown in Fig. 17. The front view of the product, Figure 19 is also a side view, Figure 2
Figure 0 is an explanatory diagram showing the rolling stand arrangement and the cross-sectional shape of the material formed by each stand in one embodiment of the present invention,
Figures 1 (A), (B), and (C) are explanatory diagrams sequentially showing the embodiment of the present invention from the time of biting into the rolling roll, and Figure 22 is the rolling in the (N-2) stand shown in Figure 20. FIG. 26 is an explanatory diagram showing in detail the state of rolling in the (N-1) stand also shown in FIG. 20, FIG. 24 is a side view of the threaded joint reinforcing bar, FIG. 25 is a front view thereof. In the figure, 14 is a deformed steel bar product, 15 and 16 are knots, 19 is an upper roll, 20 is a lower roll, 21 is a square material, 22 is a round part, 26 is a raw material, 24 is a gentle recess, and 25 is a roll hole. Convex portions of the mold, 28 are convex portions of the upper roll and lower roll, 29 are concave portions i of the upper roll and lower roll.
Sl+, filter 0 is the slope Lf11f of the upper roll and lower roll
f111 wall. Rod 1 N-4 Figure N -3N-2N-I N Figure 3 Figure 7 (a) H3 (p) Section 22 Figure 23 Figure 6

Claims (3)

[Claims] (1) In rolling a deformed steel bar, the leader material is rolled by a roll having a convex portion in the center and four portions on both sides thereof and a hole formed by the sloped side walls, and a square material. The leader material is rolled so that a part of the corner of the material is restrained by the side wall of the roll hole while forming a constriction in the center, and the leader material is rolled in a different direction. A method of rolling deformed steel bars. (2) In the rolling of a deformed steel bar, prior to the Nth final finishing rolling, the (N-3)th rolling is performed using a hole shape that has a convex portion in the center and concave portions on both sides, and is formed by sloped side walls. The square material is rolled using a roll having a diameter and a square material so that a part of the corner of the material is restrained by the side wall of the roll hole and a constriction is formed in the center, and the material thus obtained is rolled. The rolling direction is changed (N-2), and then the rolling direction is changed again to form a leader material having a constriction in the center (N-"I), and thus obtained. A method for rolling a deformed steel bar, characterized by performing finish rolling on a material that has been rolled in a different direction. (3) The method for rolling a deformed steel bar according to claim 2, wherein the leader material having a constriction in the center has a constriction ratio of 0.2 to 0.5.