JPH0832330B2 - Rolling method for profile with flange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to a profile having a flange, for example, H-section steel, I
The present invention relates to a rolling method for freely forming shaped products such as shaped steel into various sizes during rolling.

(Prior Art) Currently, shaped steel materials that are generally manufactured have a wide variety of types, cross-sectional shapes, and dimensions, and are characterized by an extremely large number of types and sizes. Rough rolling (BD) shown in Fig. 9 to produce these various types and sizes of shaped steel
A universal rolling method is known in which a double or triple rolling mill of No. 1 is arranged, and universal rolling mills are arranged for intermediate rolling (RU-E) 2 and finish rolling (FU) 3.

However, in the conventional universal rolling method, as a general rule, specialized products corresponding to the product must be prepared for the rolling rolls and guide guides used from rough rolling to finish rolling according to the product type and size of the manufactured product. I have to. Therefore, in order to satisfy the needs of customers such as diversification of product dimensions and expansion of manufacturing range, the cost is high and there is a difficulty that it cannot be easily dealt with. Particularly in recent years, as a need from customers, H-section steel having a relatively thin web thickness as compared with the thickness produced by the conventional rolling method, or H-shaped steel having various flange thicknesses with a constant outer width of the web.
Strong demand for shaped steel product series.

However, in the conventional universal rolling, as shown in Fig. 10, due to the function of the universal rolling mill, the size that can be freely changed by the same set of roll pairs during rolling is between the upper horizontal roll 7 and the lower horizontal roll 8. And the gaps 12 and 13 between the left and right vertical rolls 10 and 11. Therefore, H
The web thickness and flange thickness of the shaped steel can be changed, but the web inner width WI must be constant. As a result, when rolling a series of H-section steel products having different flange thicknesses, if the left and right roll gaps 12 and 13 are changed, the web outer width WO, which is the sum of the inner web width WI and the left and right flange thicknesses, will naturally vary. You will have to change the dimensions.

That is, in the H-section steel rolled by the conventional universal method, as shown in FIG. 11, the inner width WI of the web is constant and the outer widths WO ₁ , WO _{2 of the} web are changed by the changes of the flange thicknesses T _f1 , T _f2 . It is a so-called product series with a constant width inside the web, and it is impossible to manufacture a product series with a constant width outside the web. In order to manufacture an H-shaped steel product series having a constant outer width WO of the web by the conventional rolling method using a universal rolling mill, according to the change of the inner width of the web, all processes of rough rolling, intermediate rolling, and finish rolling are performed. Most of the upper and lower horizontal rolls must be prepared, a large number of rolls are required, and frequent roll reassembling work must be performed, resulting in a significantly high manufacturing cost. Have difficulty.

As a means for solving such a drawback of the conventional universal rolling, the applicant of the present application has previously mentioned that "a rolling of a profiled material having a flange by a skew roll method" capable of efficiently manufacturing shaped steels of various sizes. Method ”(JP-A-59-2021)
01) was proposed.

An outline of this oblique roll type rolling method will be described with an H-shaped steel as an example. The characteristic of this rolling method is that, as shown in FIG. 12, two upper and lower skew rolls 15, 15 'and 16, 16' are provided.
The outer surface 19, 19 ', 20, 20' of the inner side of the flange of the material 17 is 21,
22 and the roll axis S in the horizontal plane keeps an angle θ _H with respect to the plane perpendicular to the rolling direction, and the web portion close to the flange of the material is rolled down, so that the material of the rolled portion is pressed in the width direction. To have a function of spreading the web in the width direction without causing any wave or the like.

FIG. 13 (a) shows an example in which a rolling mill 14 adopting this "oblique roll type rolling method" is incorporated in a hot rolling equipment row of H-section steel. Intermediate universal rolling mill (RU-E) in the figure
By combining 2 with the oblique roll type rolling mill 14 and the finishing rolling mill (FU) 3, the "H-shaped steel product series with a constant outer width of the web" shown in Fig. 2 (b), which is a typical need mentioned above.
Alternatively, it is basically possible to manufacture "H-shaped steel product series of arbitrary web height" with a small number of rolls. The means for manufacturing the H-shaped steel product series having a constant outer width WO of the web by the oblique roll type rolling mill will be described in more detail with reference to FIG.

In the figure, an intermediate universal rolling mill (RU-E) 2, a skew rolling mill (SS) 14 and a finish rolling mill (FU)
The specific role of each rolling mill of No. 3 was shown using the roll hole pattern. First, four beam blanks supplied from BD by the intermediate universal rolling mill 2 are intermediate rolled materials 25 having a sectional shape as shown in the figure, in which the flange thickness and the web thickness of the final product and the inner web widths WI ₅ , WI ₆ are taken into consideration. Modeling up to. The number of types of the intermediate rolled material 25 formed in this way is not limited. In other words, the material is rolled and shaped by the universal rolling mill in the intermediate process, so it is possible to freely change the web thickness and flange thickness, and the required number of different cross-sectional shapes can be shaped according to the product series. It
At this time, the web inner width WI ₁ is constant and the web outer width WO ₁ is not necessarily constant. Here, a surplus portion 18 is formed at both ends of the web of the material formed in the intermediate step, as shown in FIG. The extra thickness portion 18 is added in advance to assist the web widening in the next-stage oblique roll type rolling mill, and the shape has a bulging portion surface parallel to the thin web portion surface 40. Are formed in parallel with each other.

Subsequently, the intermediate rolled material is fed to the oblique roll type rolling mill 14 to become the rolled material 27 which has been widened and rolled into various necessary web internal width dimensions WI ₂ according to the product series. The rolled material 27 produced by the oblique roll type rolling mill has various web inner widths according to the product series by the finishing rolling mill 3.
The rolled material 28 having WI ₄ is shape-rolled to form a product 29 having a constant outer width of the web and an inner width WI ₆ according to the product series. Further, the product 31 having the largest flange thickness and the smallest web inner width in the product series is rolled by the intermediate universal rolling mill (RU-E) 2 without performing the web widening by the skew roll rolling mill 14. It is possible to manufacture the intermediate rolled material 25 directly by using it in the finish rolling mill (FU) 3 in which the width of the horizontal roll can be changed. At this time, the surplus of the intermediate rolled material 25 is pressed and shaped by the horizontal rolls of the finishing mill. However, in this case, the web inner width WI ₃ of the strip 30 corresponding to the finished web in the width WI _5, the inner width WI ₁ intermediate universal rolling mill (RU-E) 2 intermediate rolled material 25 adapted to one another Set to the value.

As described above, the oblique roll type rolling method has an excellent web widening function, and the number of roll changes and the number of roll stocks can be markedly reduced as compared with the conventional universal rolling method, and profile members of various sizes can be rolled. However, when this rolling method was carried out, sometimes a locally reduced thickness portion (hereinafter referred to as "constriction") was generated in the web portion as shown in FIG. The extra thickness 18 previously added to both ends of the web should be set so that the shape after rolling is not deteriorated by an amount commensurate with the widening amount of the web, but conventionally, it is arbitrarily performed based on experience. Therefore, it was extremely difficult to suppress the occurrence of necking within the allowable value.
When a certain amount of constriction occurs, it cannot be flattened even by the horizontal rolls of the finishing rolling mill, and remains in the form of depressions in the web of the product.For example, there is concern that the strength may decrease when the profile products are mutually joined for building structures, Eliminating the constriction was considered an important technical issue. On the other hand, the finish rolling mill in which the body width of the horizontal rolls can be changed is lower in mill rigidity due to its structure than the conventional finish rolling mill, so if the surplus amount is excessive, the rolling load acting on the finish rolling mill will be increased. It becomes too large, the excess thickness of the web cannot be sufficiently shaped, and the web shape is not flat. Therefore, the amount of surplus should be the minimum necessary amount so that no constriction occurs and no defective web shape occurs.

(Problems to be Solved by the Invention) The present invention does not cause a constriction of a web when widening the web by a well-known skew roll rolling, and is the most appropriate shape and thickness of a surplus for producing a good product. It provides a method for determining the amount.

(Means and Actions for Solving Problems) FIG. 1 is a graph obtained by measuring a shape change of a material which is prevented from being caught during widening rolling by a hot model rolling machine by a three-dimensional shape measuring machine. Looking at the change in web thickness in the figure, there is a part where the thickness is extremely reduced compared to the web center thickness (t _C ), but this part is the above-mentioned constriction. By the way, the widening process can be roughly classified into the following three regions.

Area I: An area in which the outer surface of the skew roll comes into contact with the inner surface of the flange before the web is pressed down, and the web is stretched while tilting the flange.

Area II: An area in which the web is stretched while being pressed.

Area III: An area in which the outer surface of the skew roll comes into contact with the inner surface of the flange after the web is pressed down, and the web is stretched while the flange is tilted.

Necking occurs in the above-mentioned region III when viewed in the rolling direction,
In the material cross section, it mainly occurs at the boundary 43 between the excess thickness portion 18 and the web parallel portion 42 (web other than the excess thickness) in FIG. It was estimated that the cause of this occurrence was local stress concentration due to the discontinuity of the shape when the web was stretched in Region III. Therefore, the present inventors have tried to eliminate the discontinuity of the shape, that is, to improve the shape of the excess thickness,
The following facts have been revealed.

FIG. 3 is a graph showing the relationship between the amount of constriction and the amount of widening of the parallel portion for each of the various surplus shapes shown in FIG. 2. The largest constriction is shown in FIG. 2 (a). In the case of the parallel extra thickness, the second smallest is when the linear extra thickness is formed from the flange in the web direction as shown in (b). From the above tendency of (a) and (b),
In order to reduce the constriction, it was estimated that the thickness change from the flange to the web should be made more continuous, and the arc taper surplus shown in (c) was conceived. According to this arcuate taper surplus, it has been found that the constriction amount can be minimized if the web parallel portion widening amount (widening amount by web stretching) is the same as shown in FIG. The cross-section ridgeline of the arcuate taper surplus is composed of a combination of two or more arcs having different curvatures from the flange portion in the web direction. One is an arc of the _first large curvature R ₁ formed in the flange root part,
This is the corner radius R that has been added conventionally.
The second arc is formed by setting a large radius of curvature R ₂ with respect to the radius of curvature R ₁ of the first arc and combining with the first arc so that the entire ridge line has a gentle arc shape. The second arc is not limited to one, and a plurality of arcs having different curvatures may be combined. The specific values of the radius of curvature R ₁ and the radius of curvature R ₂ are set in consideration of conditions such as a set amount of surplus and a product size which will be described later.

Next, a method for determining the amount of extra thickness will be described in detail. It is obvious from FIG. 3 that there is a limit value (ΔW _C1 ) in the amount of widening ΔW _{1 of the} parallel portion of the web in order to keep the amount of constriction within the allowable value. Therefore, in order to secure the target widening amount ΔW while suppressing the constriction that occurs during widening within the allowable constriction amount, the difference between the target widening amount and the limit value (ΔW _C1 ) of the web parallel part widening amount is determined by the widening Must be covered by That is, it is indispensable to make the amount of excess thickness appropriate and to secure the amount of widening due to reduction of excess thickness. Therefore, the minimum surplus amount necessary to secure the target maximum widening amount while keeping the constriction within the allowable value was determined by the following procedure.

In the widening rolling with the skew roll, the elongation of the whole material hardly occurs. That is, in the partial rolling method of rolling down the excess thickness, it is usual that the elongation of the entire material is basically extremely small because most of the flanges and webs are not directly rolled down. Since the material is squeezed and rolled, the crushed material almost flows in the width direction. This means that the metal flow can be considered as two-dimensional when the relationship between the width expansion amount and the surplus amount is obtained. That is, in FIG. 6, the total widening amount Δ
It can be considered that ΔW _{1 of} W is a portion where the web parallel portion is extended, and ΔW _{2 of} the shaded portion is a portion covered by the extra thickness portion.

FIG. 7 shows a flow for determining the minimum necessary surplus amount. First, under various assumptions, the limit value (ΔW
_{If c1} ) is obtained, the amount of widening to be shared by the extra thickness portion is the target widening amount ΔW minus ΔW _c1 , and the required amount of extra thickening is obtained from the amount of widening to be shared and the product web thickness.

Next, the method of determining ΔW _c1 will be described. Factors related to ΔW _c1 are the web parallel part length l, the web thickness t _w , the temperature distribution of the rolled material, the roll cross angle, etc. Among these, the temperature distribution and the roll cross angle are conditions predetermined in the rolling operation. It was found that the main factor related to _c1 is the relation between the web parallel length l and the web thickness t _w .

The relationship between ΔW _c1 , web parallel part length 1 and web thickness t _w is as follows.

ΔW _c1 increases linearly as the web parallel length l increases (FIG. 5).

ΔW _c1 is inversely proportional to the web thickness t _w (Fig. 4).

From the above results, ΔW _c1 can be expressed by the following empirical formula (1).

ΔW _c1 = [{Δ (ΔW _c1 ) / Δl} · l + C] · C _w (1) where Δ (ΔW _c1 ) / Δl: tan θ C in FIG. 5: Y axis intercept C _{w in} FIG. 5: Thickness correction factor When the limited value (ΔW _c1 ) of the width expansion of the parallel part of the web is found,
From the relationship between the target web widening amount (ΔW) and the web thickness (t _w1 ) after being rolled by the skew roll, the required minimum extra amount (M) can be obtained by the following equation (2).

M = (ΔW−ΔW _c1 ) × t _w1 (2) The required minimum surplus amount can be determined by the above determination flow, and this required minimum surplus amount is equally divided into four corners of the web end section of the material to be rolled. To do.

(Example) Product nominal dimensions (web height x flange width) 600 x 200
The representative H-section steel of No. 1 was selected and actually rolled, and the presence or absence of a constriction was confirmed. The material of the rolled material was C: 0.2% plain carbon steel, and the rolling temperature was about 850 ° C at the web margin, about 700 ° C at the center in the web width direction, and the flange temperature of about 900 ° C. The skew roll used is the roll profile shown in FIG. 8, and its dimensional specifications are shown in Table 1 and its roll position setting conditions are shown in Table 2. Table 3 shows the results of comparative rolling under the above conditions between the case where the amount and shape of the surplus in the present invention are provided and the case where the conventional parallel form surplus. In addition,
In the comparative example of the conventional parallel-shaped excess thickness, a width of 90 mm in the web direction from the inside of one side flange, with a uniform thickness of 0.6 mm, a excess thickness of a cross-sectional area of about 200 mm ² is added, and in the method of the present invention, the same is applied in the web direction. The cross-sectional area is about 500 mm ² with the first radius R ₁ of the flange root being 20 mm and the second radius R ₂ of 940 mm over a width of 90 mm.
And As is clear from Table 3, the constriction amount of 2.4 mm occurs in the conventional method, whereas the constriction amount of the present invention method is 0.4 mm.
mm, the web height before and after rolling, the flange width,
Despite the fact that the main dimensions such as flange thickness hardly change, the reduction in necking is 1/6. In the case of rolled H-section steel that is generally used, the reduced amount of necking achieved by the present invention can be sufficiently put to practical use.

(Effects of the Invention) In the present invention, when a web having a flange such as an H-section steel or an I-section steel is subjected to widening rolling of a web by using an oblique roll, the occurrence of the necking in the web portion, which is the most problematic, occurs. Since it can be manufactured with almost no occurrence and a conventional device can be used without requiring a special device, the effect of improving the product quality is industrially extremely large.

[Brief description of drawings]

FIG. 1 is a graph for explaining the condition of occurrence of “constriction” targeted by the present invention, and FIG. 2 is a partial cross-sectional view showing the shape of extra thickness,
FIG. 3 is a graph showing the relationship between the widening amount and “constriction”, and FIG. 4 is a graph showing the relationship between the web thickness and the limit value of the widening amount,
FIG. 5 is a graph showing the relationship between the length of the parallel portion of the web and the limit value of the amount of widening, FIG. 6 is a partial cross-sectional view showing changes in the excess thickness portion before rolling and the web portion after rolling, and FIG. FIG. 8 is a flow chart showing the procedure for determining the minimum required surplus amount, FIG. 8 is an explanatory view showing the shape of the skew roll, FIG. 9 is a schematic diagram showing a conventional universal rolling process, and FIG. 10 is a schematic front view of a universal rolling mill. FIG. 11 is an explanatory view of a conventional H-section steel with a constant web inner width, FIG. 12 is a schematic plan view showing a state of the oblique roll system rolling, and FIG. 13 is a universal rolling adopting the oblique roll system rolling. Schematic diagram, Fig. 14 is a schematic front view showing the occurrence of constriction of H-section steel.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Tetsuji Nishino, No. 1 Tsukiko Hachiman-cho, Sakai City, Osaka Prefecture Shin-Nippon Steel Co., Ltd. Sakai Iron Works Co., Ltd. (72) Kazuo Fujita, No. 1 Tsukiko Yawata-cho, Sakai City, Osaka Prefecture Nippon Steel Co., Ltd. Sakai Works (56) References JP-A-61-262404 (JP, A)

Claims (1)

[Claims] Claim: What is claimed is: 1. A shaft rolling in a rolling direction at any one or more paths between the intermediate rolling step and the finish rolling step of a profile rolling process comprising a rough rolling step, an intermediate rolling step and a finish rolling step. A method of widening and rolling the height of a web by arranging a pair of left and right skew rolls having a predetermined angle θ _H with respect to a plane that is horizontal and vertical to the rolling direction, inside the flange of the material to be rolled. In, in order to suppress the constriction amount of the web from the function of the parallel portion length and web thickness of the rolled material web before being rolled by the roll to obtain the limit value of the web parallel portion widening amount for suppressing the constriction amount below the allowable value, The difference between the target widening amount of the web and the limit value of the widening amount of the parallel portion of the web, and the required surplus amount are obtained from the product web thickness, and the required surplus amount is equally divided into four corners of the web end cross section of the material to be rolled. The ridge line of the extra meat After molding by the intermediate rolling step so that the radius of the combination of a plurality of arcs, the rolling method of profiles having flanges, characterized in that rolling at the skew rolls.