JP4615141B2 - I-section bar manufacturing method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for manufacturing an I-shaped cross-section bar having a thick edge portion in one forming bar manufacturing line.
[0002]
[Prior art]
When a high-strength bar is required for grating or the like, an I-shaped cross-section bar 60 as shown in FIG. 3 may be used. The bar 60 is composed of thick edge portions 62 and 63 whose both edge portions are thick and a thin central portion 61 whose central portion is thin. Since the edge portions 62 and 63 of the bar 60 are thick, the bar 60 is characterized by being lighter and more rigid than a general flat bar.
[0003]
Conventionally, as a manufacturing method of the I-shaped cross section bar 60, the following can be cited.
(1) Hot rolling method from billet (hot rolling method)
(2) Cold rolling method (cold rolling method) with a four-way forming roll from a steel strip having a thickness equal to or greater than the edge of the product
[0004]
[Problems to be solved by the invention]
However, the following problems have been pointed out in the above method.
(1) In the product I-shaped cross section bar (hot product) obtained by the hot rolling method, the thick edge portion also has a pickled skin finish and loses gloss. Moreover, since it anneals, the yield strength is low as a whole.
(2) The cold rolling method requires expensive and highly rigid equipment. In addition, the product I-shaped cross section bar (cold product) by this method is hard as a whole, including the thin central portion, and post-processing is severe.
[0005]
The latter problem in the cold rolling method (2) will be described in detail.
FIG. 4 is an explanatory view for explaining the cold rolling method (2). A steel strip 70 having a thickness a shown in (A) is passed (passed) through a four-way forming roll 80 shown in (B). The four-way forming roll 80 includes upper, lower, left and right forming rolls, and mainly pressurizes the steel strip 70 from the upper roll 81 and the lower roll 82.
[0006]
When the steel strip 70 is passed 4 to 6 times through such a four-way forming roll 80, a steel strip 71 having a cross-sectional shape shown in FIG. That is, the thin central portion 76 of the steel strip 71 is pressed by the upper roll 81 and the lower roll 82 to become thin. For this reason, the thickness b of the thin-walled central portion 76 of the steel strip 71 is less than the thickness a of the steel strip 70, and the cross-sectional shape of the I-shaped cross-section bar is formed.
[0007]
In this case, the thin central portion 76 of the steel strip 71 having the plate thickness b is cured as a result of rolling. Accordingly, the steel strip 71 is generally harder around the thin central portion 76, and post-processing such as drilling of the thin central portion 76 becomes severe. On the other hand, the edge portions 77 and 78 have a small processing history and are softer than the thin central portion 76.
The cross-sectional performance (bending rigidity) around the X axis of the I-shaped cross-section bar 60 shown in FIG. 5 is that the thin-walled central portion 61 is harder than the edge portions 62 and 63 and the edge portions 62 and 63 are thin-walled. With the I-shaped cross-section bar 60 that is harder than the central portion 61, the latter has proved to be higher in rigidity. Therefore, the I-shaped cross-section bar 60 composed of the steel strip 71 is generally hard with the thin central portion 76 as a center, but its rigidity is not high.
[0008]
Accordingly, the present invention provides a technique for manufacturing an I-shaped cross-section bar that solves these problems and has high rigidity, easy post-processing of a thin central portion, good dimensional accuracy, and is beautiful and inexpensive. With the goal.
[0009]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the invention according to claim 1 is an I-shaped cross-section bar manufacturing method for manufacturing an I-shaped cross-section bar having a thick edge portion from a steel strip. The production line includes a thick-wall forming process in which the edge portion of the steel strip is thickly formed, and the thick-wall forming step is a four-way rolling forming in which a forming roll is applied to the flat portion and the edge portion of the steel strip. This is a method for producing an I-shaped cross-section bar mainly for pressing a forming roll onto an edge portion .
[0010]
Here, the “steel strip” is a material for manufacturing a forming bar, and refers to a metal material such as iron or stainless steel. In the present invention, a hoop wound in a roll of stainless steel is used. Say.
[0011]
“Mainly pressurizing the forming roll on the edge part” means that the pressurization by the forming roll on the edge part is stronger than that on the flat part and mainly deforms the shape of the edge part. Say.
[0012]
In the first aspect of the present invention, the edge portion of the steel strip is formed to be thick by the thick-wall forming step, and the I-shaped cross-section bar is manufactured in one I-shaped cross-section bar manufacturing line. In the four-direction rolling forming in, an I-shaped cross-section bar is manufactured by applying a forming roll to the flat portion and the edge portion of the steel strip, and mainly pressing the forming roll to the edge portion.
[0013]
The invention according to claim 2 is the I-shaped cross-section bar manufacturing method according to claim 1, wherein the roll width of the forming roll applied to the flat portion of the steel strip is narrower than the width of the steel strip, and the flat portion of the steel strip It is an I-shaped cross-section bar manufacturing method in which the forming roll does not hit both end portions.
[0014]
In the invention according to claim 2, since the roll width of the forming roll applied to the flat portion of the steel strip is narrower than the width of the steel strip, the forming roll does not hit the both ends of the flat portion of the steel strip, and other forming It becomes easy to form the edge portion pressed by the roll.
[0015]
The invention according to claim 3 is an I-shaped cross-section bar manufacturing apparatus for manufacturing an I-shaped cross-section bar having a thick edge portion from a steel strip, and the edge of the steel strip in one forming bar manufacturing line. The thick-wall forming function is a four-way rolling forming machine that applies a forming roll to the flat surface portion and the edge portion of the steel strip. It is an I-shaped cross-section bar manufacturing apparatus mainly for pressurization .
[0016]
The invention according to claim 4 is the I-shaped cross-section bar manufacturing apparatus according to claim 3 , wherein the roll width of the forming roll applied to the flat portion of the steel strip is narrower than the width of the steel strip, and the flat portion of the steel strip It is an I-shaped cross-section bar manufacturing apparatus in which the forming roll does not hit both end portions.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment (this embodiment) of the present invention will be described with reference to the drawings. In the present embodiment, description will be made using stainless steel as an example of the metal material. The stainless steel I-shaped cross-section bar is manufactured on a manufacturing line as shown in FIG. That is, in the unit a, the centering guide guides the stainless steel strip to be formed to the production line.
[0018]
In the unit b, the four-way forming roll 10 shown in FIG. 2 is used. The four-way forming roll 10 includes an upper roll 11, a lower roll 12, a left side roll 13 and a right side roll 14. About four to six of the four-way forming rolls 10 are provided in the production line, and a stainless steel strip 50 having a thickness of c is passed. That is, the four-way forming roll 10 is passed 4 to 6 times. At this time, the flat portions 51 and 52 of the steel strip 50 are pressurized by the upper roll 11 and the lower roll 12, respectively. Further, the side surfaces 53 and 54 of the steel strip 50 are also subjected to pressure from the left side roll 13 and the right side roll 14, respectively.
[0019]
Rolling with the four-way forming roll 10 is mainly performed by pressurization from the left side roll 13 and the right side roll 14, and sequentially passes from the left side roll 13 and the right side roll 14 each time one four-way forming roll 10 is passed. Increase the pressure. Then, the edge parts 57 and 58 of the steel strip 50 which received the pressure swell in the up-down direction of the steel strip 50, and form cross-sectional shape like a dock bone.
[0020]
In this case, the roll width h of the upper roll 11 and the lower roll 12 is made narrower than the width i of the steel strip 50, and the upper roll 11 and the lower roll 12 hit the both end portions of the flat portions 51 and 52 of the steel strip 50. Do not. By doing so, the edge portions 57 and 58 are smoothly formed by pressurization from the left side roll 13 and the right side roll 14, and the thick edge portions 57 and 58 can be efficiently formed.
[0021]
The edge portions 57 and 58 of the steel strip 55 after being formed by the forming roll 10 are processed by pressurization and work hardened. On the other hand, the thin central portion 56 of the steel strip 55 has little processing history, and the plate thickness d is also approximate to the plate thickness c of the steel strip 50 before forming.
[0022]
Thereafter, in the unit c, the correction unit corrects the warp or twist of the steel strip 50.
[0023]
And the fixed-size cutting machine cuts the steel strip 50 into fixed length by the unit d. This completes the product I-shaped cross-section bar.
[0024]
When the edge portion was formed thick using the production line as described above, the following results could be obtained. That is, SUS304, No1 finish 3t × 41w steel strip is processed in the production line process shown in FIG. 1 to obtain a target I-shaped cross-section bar (5t / 2.5t × 30w × 4000L) with a width accuracy of ± An excellent product having a gloss of the edge portion at 0.1 mm and easy to be post-processed was obtained.
[0025]
Compared with a conventional product I-shaped cross-section bar, it is as follows.
(1) In the hot product, the thick-walled edge portion is also pickled skin, the width accuracy is about ± 0.5 mm, and is inferior to the I-shaped cross section bar of the product according to the present embodiment in terms of appearance and accuracy. Moreover, even if it anneals as a whole and the cross-sectional performance (bending rigidity) around the X-axis is equal, it tends to be permanently deformed with a light load.
(2) The accuracy of the cold product is the same as that of the product I-shaped cross-section bar according to the present embodiment, but the thin central part is work hardened as a whole (about HV400), and the thin central part is frequently implemented. Drilling is difficult, and there is a problem of tool life. Further, since a highly rigid facility is required, the processing cost becomes expensive.
[0026]
【The invention's effect】
According to the present invention, a high-rigidity four-way forming roll facility as in the case of a cold rolling method for producing a cold product is unnecessary, and it can be manufactured with a normal four-way forming roll for shape steel. . Therefore, it can be provided at a lower cost than a cold product.
[0027]
Regarding the cross-sectional performance (bending rigidity) around the X axis of the I-shaped cross-section bar, the thick-walled edge where the load is most applied to the bar is hardened by molding, so it has high yield strength, high strength, and high rigidity ing. On the other hand, in the conventional cold product, the thin central portion is hardened by molding, and the edge portion is soft with little processing history. Therefore, even though the thin central portion is work-hardened, the thick edge portion where the load is most applied to the bar is soft, so that the rigidity as in the present invention does not appear. In addition, since the present invention is stronger than the cold product, it can be handled with an I-shaped cross-section bar that is one rank lower than the conventional size. Accordingly, the cost can be reduced.
[0028]
On the other hand, the thin central portion of the I-shaped cross section bar of the present invention has a small processing history and is flexible (about HV280). For this reason, the hole processing etc. which are frequently implemented in a post process can be performed easily.
[0029]
In addition, the edge portion is smoother and more glossy than hot products, and is beautiful.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram for explaining a production line for an I-shaped cross-section bar.
FIG. 2 is a front view showing a four-way forming roll.
FIG. 3 is a perspective view showing an I-shaped cross-section bar.
FIG. 4 is an explanatory diagram for explaining a cold rolling method.
FIG. 5 is an explanatory diagram of cross-sectional performance around the X axis of an I-shaped cross-section bar.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Four direction forming roll 11 Upper roll 12 Lower roll 13 Left side roll 14 Right side roll 50,55 Steel strip 56 Thin center part 57,58 Edge part 71 Cold goods

Claims (4)

An I-shaped cross-section bar manufacturing method for manufacturing an I-shaped cross-section bar having a thick edge portion from a steel strip, and a thick-wall forming method for thickly forming an edge portion of a steel strip in one forming bar manufacturing line The thick-walled forming step is a four-way rolling forming method in which a forming roll is applied to the flat portion and the edge portion of the steel strip, and the I-shaped cross section mainly for pressing the forming roll to the edge portion. Bar manufacturing method. The method for producing an I-shaped cross-section bar according to claim 1, wherein the roll width of the forming roll applied to the flat portion of the steel strip is narrower than the width of the steel strip, and the forming roll does not hit both end portions of the flat portion of the steel strip . An I-shaped cross-section bar manufacturing apparatus for manufacturing an I-shaped cross-section bar having a thick edge from a steel strip, and a thick wall for forming an edge of a steel strip thick in one forming bar manufacturing line The thick-wall forming function is a four-way rolling forming machine that applies a forming roll to a flat surface portion and an edge portion of a steel strip. Section bar manufacturing equipment. The I-shaped cross-section bar manufacturing apparatus according to claim 3, wherein the roll width of the forming roll applied to the flat portion of the steel strip is narrower than the width of the steel strip, and the forming roll does not hit both end portions of the flat portion of the steel strip .

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