JPH11216501A - Method and equipment of manufacturing deformed section bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a high level-different thin deformed section bar superior in surface quality and dimensional accuracy of section. SOLUTION: A steel strip 8 is rough-rolled with a pair of upper and lower first die rolls 9 while the outward deformation in the width direction of the steel strip 8 is restricted with a pair of flat rolls 10, and then finish-rolled to predetermined sectional dimensions with upper and lower second die rolls 16 successively arranged at the rear of them. Since the outward in the width direction is restricted, the compressive stress in the rolling direction is reduced and buckling is prevented. Since the finish-rolling is done following the rough-rolling, groove deviation is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing a profiled section having a thickness distribution different in the width direction, that is, a profiled section having a thin portion and a thick portion in the width direction.

[0002]

2. Description of the Related Art A conventional typical strip is manufactured by performing a multi-pass rolling of a metal strip using a mold roll having a mold having a desired shape to generate a material flow in a width direction. I have. According to this method, when a profiled cross section is manufactured from a thin plate, the material flow in the width direction is less likely to occur as the plate thickness decreases, so that the difference in thickness between the thin portion and the thick portion (hereinafter referred to as a step) is limited. Therefore, it is difficult to manufacture an irregularly shaped strip having a large step. Further, when multi-pass rolling is performed with a reduced amount of rolling per pass, a step is reduced, and a defect in which the position of the step is shifted for each pass (hereinafter referred to as a groove shift) is likely to occur. The occurrence of the groove shift lowers the cross-sectional dimensional accuracy of the deformed cross-section strip. The following several prior arts are disclosed as a method of manufacturing a deformed cross-section strip in addition to the above-described method.

Japanese Patent Application Laid-Open No. 52-124454 discloses that both ends of a steel strip are rolled by side rolls to form bulges at both ends, and then the bulges are rolled by a pair of upper and lower rolling rolls. A method for producing an I-section steel that is four-sided rolled by a four-sided roll is disclosed.

Japanese Unexamined Patent Publication (Kokai) No. 63-203201 discloses that a material strip is rolled by applying a rolling force only to a portion where the thickness of a material strip is to be reduced by a grooved roll, and the unrolled portion is buckled by a material flow in a width direction. There is disclosed a method for producing a deformed cross-section in which only a portion which is deformed and then buckled is re-rolled to a predetermined thickness.

[0005] Japanese Patent Application Laid-Open No. 1-297701 discloses that a material is curved and rolled by a pair of upper and lower rolls having a groove having a predetermined curvature and a convex portion having a predetermined curvature, and a pair of materials having a thin portion curved and rolled is provided. A method of forming a thin section in a material by rolling flat by a flat roll, and forming a thin section of the material in which the thin section has been formed is finish-rolled by a pair of mold rolls having a mold equal to the product cross section, is disclosed. I have.

[0006]

SUMMARY OF THE INVENTION The above-mentioned JP-A-52-12
Japanese Patent No. 4454 discloses a process of forming bulges at both ends of a steel strip by rolling down a side roll.
Since this process applies a compressive force in the width direction of the steel strip, the steel strip may be bent. The hip break,
As the thickness of the steel strip becomes thinner, the width of the steel strip becomes larger, and the amount of reduction of the side rolls becomes larger, the more likely it is to occur, the waist break once generated cannot be completely eliminated even if rolling is performed again. . Therefore, the product dimensions of the I-beam in this method are limited, and the manufacturable range is narrow.

Japanese Patent Application Laid-Open No. 63-203201 discloses a process of rolling only a buckled portion. Usually, as the thickness of the material becomes thinner, buckling is more likely to occur, and the buckled boards are more likely to overlap. Therefore, it is difficult to manufacture a thin profiled strip with this prior art.

[0008] Japanese Patent Application Laid-Open No. 1-297701 discloses that
There is disclosed a process of rolling a curved thin-walled portion flat by a pair of flat rolls. In this process, as the thickness of the material becomes thinner, the material is more likely to wrinkle during the flat rolling. Therefore, it is difficult to manufacture a thin profiled strip with this prior art.

An object of the present invention is to provide a manufacturing method and a manufacturing apparatus capable of manufacturing a high-profile-differential cross-section strip without causing buckling and groove displacement even if the material is thin.

[0010]

According to the present invention, there is provided a method for producing a profiled strip having a thickness distribution different in a width direction by rolling a metal strip. The metal strip is roughly rolled by a pair of first mold rolls while being constrained by a flat roll, and subsequently, the metal strip is finish-rolled by a pair of subsequently arranged second mold rolls to have a predetermined cross-sectional dimension. This is a method for producing a deformed cross section.

According to the present invention, the rough rolling is performed while restricting the outward deformation of the metal strip in the width direction. Therefore, for example, when a thick portion having a deformed cross section exists at the plate end, the thick portion is formed. In the rolling direction is reduced. As a result, the compressive stress in the rolling direction in the thin portion of the irregularly shaped cross-section strip is reduced, so that even if the metal strip is thin, buckling due to the compressive stress after rolling can be suppressed. Further, after the intermediate forming by the rough rolling, the finish rolling is continuously performed, so that the step, which is the thickness difference between the thick portion and the thin portion, can be increased while suppressing the occurrence of buckling.

The present invention also relates to an apparatus for rolling a metal strip to produce a profiled strip having a thickness distribution different in the width direction. The apparatus has an almost horizontal axis and abuts both upper and lower surfaces of the metal strip. A pair of upper and lower first mold rolls that can be provided, and one or a plurality of rough rolling stands including a pair of flat rolls that have a substantially vertical axis and are provided so as to be able to abut on both ends in the width direction of the metal band; One or more finishing rolling stands which are arranged downstream of the rough rolling stand in the rolling direction, have a substantially horizontal axis, and are provided with a pair of upper and lower second mold rolls provided so as to be able to abut on one and the other surfaces of the metal strip. And an apparatus for producing a profiled strip.

According to the present invention, since the rough rolling stand and the finish rolling stand are arranged in series, the deformed cross section can be manufactured by one-pass rolling. Therefore, the position of the step in the width direction is less likely to be shifted as compared with the case where the deformed cross-section strip is manufactured by multi-pass rolling.

[0014]

FIG. 1 is a simplified side view showing a configuration of an apparatus for manufacturing a profiled strip according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line II-II of FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. The manufacturing device 1 for a modified cross section (hereinafter abbreviated as manufacturing device) includes a payoff reel 3, a rough rolling stand 4, a finish rolling stand 5, and a tension reel 6. The payoff reel 3 is a payout machine that sends out a metal band, for example, a steel band 8 as a material, and is arranged at the uppermost stream of the manufacturing apparatus 1.

The rough rolling stand 4 is one or more (one in the present embodiment) rolling stands for rough rolling the steel strip 8, and is located downstream of the payoff reel 3 in the rolling direction of the steel strip 8 (hereinafter referred to as “rolling stand”). , Downstream side). As shown in FIG. 2, a pair of upper and lower first rolling
A mold roll 9 and a pair of flat rolls 10 are provided.
The pair of upper and lower first mold rolls 9 has a substantially horizontal axis 13 and is provided so as to be in contact with one and the other surfaces of the steel strip 8. The pair of flat rolls 10 are vertical straight rolls having a substantially vertical axis 14, and are provided to be able to abut on both ends in the width direction of the steel strip 8. The pair of upper and lower first rolls 9 and the pair of flat rolls 10 are driven rolls driven by the steel strip 8, and are rotatably provided around the horizontal axis 13 and the vertical axis 14. The pair of upper and lower first mold rolls 9 is a roll with a projection, and a substantially cylindrical projection 15 is formed at the center of the body.

The finish rolling stand 5 is one or more (one in the present embodiment) rolling stands for finish rolling the steel strip 8 to have a predetermined cross-sectional dimension, and is a downstream side of the rough rolling stand 4. Are located in The finishing roll stand 5 is provided with a pair of upper and lower second mold rolls 16 as shown in FIG. Upper and lower pair of second mold rolls 1
6 has a substantially horizontal axis 17, and is provided so as to be able to abut on one and the other surfaces of the steel strip 8. The pair of upper and lower second mold rolls 16 are drive rolls, and are driven to rotate about the horizontal axis 17 by a motor (not shown). The pair of upper and lower second mold rolls 16 are rolls with protrusions, and substantially right columnar protrusions 18 are formed at the center of the body like the first mold roll 9. The tension reel 6 is a winder for winding the steel strip 8, and is disposed downstream of the finishing rolling stand 5.

A first deflector roll 19 is provided between the payoff reel 3 and the rough rolling stand 4, and a second deflector roll 20 is provided between the finish rolling stand 5 and the tension reel 6. ing.
The steel strip 8 includes the payoff reel 3 and the first deflector roll 1.
9, the rough rolling stand 4, the finishing rolling stand 5, the second deflector roll 20, and the tension reel 6 are conveyed in a state where tension is applied in this order. The tension is controlled by a tension reel 6 and a payoff reel 3.

As described above, since the rough rolling stand 4 and the finishing stand 5 are arranged in series, it is possible to manufacture an irregularly shaped strip by one-pass rolling. Therefore, the displacement of the step in the width direction, that is, the groove displacement is less likely to occur than in the case of multi-pass rolling. In the multi-pass rolling, a process of setting the deformed cross-section strip once wound on the tension reel 6 on the pay-off reel 3 and re-rolling is repeated once or a plurality of times, so that groove misalignment easily occurs.

FIG. 4 is a perspective view showing the surface appearance of the irregularly shaped strip manufactured by the manufacturing apparatus shown in FIG. The irregularly shaped section 22 is a section in which the thickness distribution differs in the width direction. In the present embodiment, the section 22 has a thin portion 23 at the center in the width direction and has thick portions 24 at both ends in the width direction.

In manufacturing the irregularly shaped cross section, the steel strip 8 sent out from the pay-off reel 3 is roughly rolled by the rough rolling stand 4 and then finish-rolled by the finish rolling stand 5 to form a predetermined cross-sectional dimension. This is performed by winding in a coil shape in step 3.

In the rough rolling, the steel strip 8 is rolled by a pair of upper and lower first mold rolls 9 while restraining the outward deformation of the steel strip 8 in the width direction by a pair of flat rolls 10 as shown in FIG. This is done by: In this manner, since the outward deformation of the steel strip 8 in the width direction is restrained, plastic flow in the width direction of the steel strip 8 is suppressed, and the material is filled in the roll gap of the thick part 24. As a result, the tensile stress in the rolling direction in the thick portion 24 based on the difference in the amount of deformation in the rolling direction between the thin portion 23 and the thick portion 24 is reduced, and the rolling direction in the thin portion 23 is reduced according to the reduction. Is also reduced. Therefore, buckling (hereinafter, abbreviated as buckling) due to compressive stress after rolling is less likely to occur in the thin portion 23, and a step is likely to occur between the thick portion 24 and the thin portion 23. However, since rolling is performed while constraining the width direction, the rolling load is increased and the rolling reduction cannot be increased. For this reason, the rough rolling is an intermediate forming, and the finish rolling is required subsequently.

The finish rolling is performed by rolling down a pair of upper and lower second mold rolls 16 in the thickness direction so as to have a predetermined rolling reduction. In the finish rolling, since the intermediate forming is performed by the rough rolling, the difference in the deformation amount in the rolling direction is reduced, and the compressive stress in the rolling direction in the thin portion 23 is reduced. Further, since the work hardening occurs in the rough rolling, the bending rigidity of the thin portion 23 increases. Therefore, in the finish rolling, even if the rolling ratio is set large, the thin portion 23
Buckling can be suppressed. As described above, in the present embodiment, the rough rolling is performed on all sides, and then the finish rolling is performed. Therefore, even when the thickness of the steel strip 8 is thin, the deformed section having a large step without causing buckling. Articles can be manufactured. In addition, since a modified cross-section having a predetermined cross-sectional dimension can be manufactured by one-pass rolling, the occurrence of the groove shift can be prevented, and the cross-sectional dimension accuracy of the modified cross-section can be improved.

As described above, in the present embodiment, the thick sections are formed at both ends in the width direction of the modified cross section, but the thin sections are formed at both ends in the width direction of the modified cross section. You may comprise. In this case, since the deformation of the thin portion outward in the width direction is restricted, the compressive stress in the rolling direction of the thin portion is reduced, and the buckling of the thin portion is suppressed. Further, in the present embodiment, the rough rolling stand 4 and the finish rolling stand 5 are provided one by one, but a plurality of bases may be provided. In this case, it is possible to manufacture an irregularly shaped strip having a higher step.

(Example 1) Using the manufacturing apparatus 1 shown in FIG. The production of the deformed cross section was carried out for an example of the invention satisfying the requirements of the present invention and a comparative example not satisfying the requirements of the present invention. The rolling stands, roll dimensions, and rolling conditions used in the production of the invention examples and the comparative examples are as shown in Table 1. The production of the comparative example was performed by opening the rough rolling stand 4 of the production apparatus 1 and performing two-pass rolling using only the finishing rolling stand 5.
The steel type of the material steel strip 8 used for manufacturing the deformed cross-section strip was carbon tool steel SK4M, and the dimensions were a thickness of 1.0 mm and a width of 80 mm. After the production of the irregularly shaped strip, the surface appearance was evaluated, and the presence or absence of buckling and groove displacement was determined by visual observation. The evaluation results of the surface appearance are as shown in Table 2. The buckling in Table 2 was evaluated as follows: the surface appearance of the deformed cross-section streaked on the thin portion 23 as shown in FIG.
5 indicates that it is occurring.

From Table 2, it can be seen that the invention example shows that, regardless of the level of the total rolling reduction (hereinafter, referred to as the total rolling reduction) of the thin portion after finish rolling, buckling which lowers the surface quality and grooves which lower the cross-sectional dimensional accuracy. In the comparative example, no buckling was observed at a total rolling reduction of 20%, but the occurrence of buckling was observed at a total rolling ratio of 30% or more. It can be seen that the groove shift occurs regardless of the height of the groove. The occurrence of buckling in the invention example is not recognized at all because the compressive stress in the rolling direction in the thin-walled portion 23 is reduced by the rough rolling in which the four sides are constrained and rolled as described above. The occurrence of no deviation is attributable to the fact that the production is performed by one-pass rolling. In the comparative example, the occurrence of groove misregistration regardless of the level of the total rolling reduction is due to the production performed by two-pass rolling, and buckling occurs at a total rolling reduction of 30% or more. This is because the compressive stress in the rolling direction in the thin portion 23 increases. As described above, according to the present invention, since neither buckling nor groove misalignment occurs, it is possible to manufacture a thin-walled irregularly shaped strip having excellent surface quality and sectional dimensional accuracy.

[0026]

[Table 1]

[0027]

[Table 2]

(Example 2) By using the manufacturing apparatus 1 shown in Fig. 1, a profiled strip was manufactured in the same manner as in Example 1, and a comparison was made between the invention example and the comparative example in terms of the critical step amount without buckling. went. The thickness of the steel strip 8 as the material is 1.0 m
m. Of the roll dimensions, the projection height is 0.2
It was varied in the range of 0 to 0.38 mm. The total rolling reduction of the thin portion 23 was varied in the range of 20 to 46%. Other conditions were set the same as in Example 1. FIG. 6 shows the relationship between the thickness of the thin portion 23 and the limit step amount. In FIG. 6, a circle indicates an invention example, and a square indicates a comparative example.

From FIG. 6, it can be seen that the critical example is larger in the invention example than in the comparative example regardless of the thickness of the thin portion 23. That is, the invention example can form a larger step without causing buckling than the comparative example. this is,
This is because the compressive stress in the rolling direction in the thin portion 23 is reduced by the rough rolling in which the rolling is performed while being restrained on all sides as described above. Therefore, according to the present invention, it is possible to produce a thin irregularly shaped cross section having a high step.

[0030]

As described above, according to the first aspect of the present invention, since the rough rolling is performed while restraining the outward deformation of the metal strip in the width direction, even if the thickness of the metal strip is small. The occurrence of buckling can be suppressed. Further, after the intermediate forming by the rough rolling, the finish rolling is continuously performed, so that the step, which is the thickness difference between the thick portion and the thin portion, can be increased while suppressing the occurrence of buckling. Therefore, it is possible to reliably manufacture a high-step thin-walled irregularly shaped cross-section having a good surface quality.

According to the second aspect of the present invention, since the deformed cross-section strip can be manufactured by rolling in one pass, the position of the step in the width direction is less likely to be shifted. Therefore, it is possible to easily manufacture a deformed cross-section strip having good cross-section dimensional accuracy.

[Brief description of the drawings]

FIG. 1 is a simplified side view showing a configuration of an apparatus for manufacturing a modified cross-section strip according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

FIG. 3 is a cross-sectional view taken along line III-III in FIG.

FIG. 4 is a perspective view showing a surface appearance of a profiled strip manufactured by the manufacturing apparatus shown in FIG. 1;

FIG. 5 is a perspective view showing a surface appearance of a deformed cross section in which buckling has occurred.

FIG. 6 is a graph showing a relationship between a thickness of a thin portion and a limit step amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Manufacturing apparatus of irregular cross section 3 Payoff reel 4 Rough rolling stand 5 Finish rolling stand 6 Tension reel 8 Steel strip 9 First type roll 10 Flat roll 16 Second type roll 22 Deformed cross section 23 Thin part 24 Thick part

Claims (2)

[Claims] In a method of rolling a metal strip to produce a profiled cross section having a different thickness distribution in the width direction, a pair of flat rolls restrains the metal strip from deforming outward in the width direction. The metal strip is roughly rolled by the first mold roll,
A method for producing a deformed cross-section strip, wherein the metal strip is finally rolled to a predetermined cross-sectional dimension by a pair of second die rolls disposed subsequently. 2. An apparatus for rolling a metal strip to produce a profiled strip having a different thickness distribution in the width direction, wherein the strip has a substantially horizontal axis and is provided so as to be in contact with both upper and lower surfaces of the metal strip. One or more coarse rolling stands comprising a pair of upper and lower first mold rolls, and a pair of flat rolls having a substantially vertical axis and provided in contact with both ends in the width direction of the metal strip; And one or a plurality of finishing rolling stands having a pair of upper and lower second mold rolls which are disposed on the downstream side in the rolling direction, have a substantially horizontal axis, and are provided so as to be able to abut on one and the other surfaces of the metal strip. An apparatus for producing a profiled strip.