JPH07132301A - Universal rolling method of shapes having web and flange - Google Patents

Abstract

PURPOSE:To mold an intermediate material different in web height without recombining a roll into another one by preventing generation of web wave and giving molding caliber function of a rough double caliber mill to a rough universal mill. CONSTITUTION:In the rough stage universal mill, both web and flange commence rolling down simultaneously under such a condition that the web wave does not occur. At this time, before the flange begins being rolled down, both the central line and the central line between horizontal rolls 61, 62 are agreed by the web to mold the intermediate material 54 having the accuracy of the web central position equal to that of the molding caliber. Then, a pass web draft rW and a flange draft rF are controlled in accordance with the inlet side web thickness tW of each pass, the inlet side flange thickness tF and a horizontal roll diameter DH, a horizontal roll barrel width II, a vertical roll diameter DV so that the following expressions I, II are satisfied. DHrWtW @DVrFtF... (I) In {(1-rF)/(1-rW)}<29{tW(1-rW)/U}<2>...(II).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a web of H-section steel, I-section steel or the like from a rough steel slab having a dogbone type cross-sectional shape (hereinafter, simply referred to as "coarse steel slab") by a universal rolling machine. The present invention relates to a method for roll-forming a shaped steel having a flange.

[0002]

2. Description of the Related Art Conventionally, for example, a rolling process for manufacturing an H-shaped steel 55 shown in FIG.
Heavy hole rolling mill 1, first intermediate rough universal rolling mill 2a that is in charge of rolling the intermediate material 54 to final product 55, and an edging rolling mill provided close to the first intermediate rough universal rolling mill 2a 2b, a second intermediate rough universal rolling mill 3a, and an edging rolling mill 3 provided near the second intermediate rough universal rolling mill 3a.
b and finishing universal rolling mill 4. Here, as a rolling material for H-section steel, in recent years, instead of a beam blank formed by soaking and slabbing from a steel ingot, a rectangular cross-section steel slab by continuous casting is often used in order to omit steps and improve quality. It became so. Rough shaping technology for intermediate materials using rectangular cross-section steel slab is
The technology disclosed in Japanese Patent Publication No. 19361, Japanese Patent Publication No. 58-37042, etc. is well known. FIG. 6 is an example of a roll hole type arrangement of the rough double hole type rolling mill 1, in which a pair of upper and lower rolls 1
Four groove molds, that is, a grooved hole mold G1, a widened hole mold G2, a groove eraser hole mold G3, and a molding hole mold G4, are engraved in 1 and 12.
FIG. 7 shows a process in which the intermediate material 54 is formed using the rectangular cross-section steel piece 5 as a raw material by the pair of upper and lower rolls 11 and 12 of the coarse double-hole rolling mill 1 having such a hole shape. In FIG. 7, the rectangular cross-section steel piece 5 has a cross-sectional dimension of width W0 and thickness H0, and the grooved hole mold G1 has a V-shaped groove 5 on the short side of the rectangular cross-section steel piece.
It is a hole type for forming 1a, and a central bulging portion 21a having a top angle θ1 is formed in the central portion of the hole bottom width, and groove portions 21b are formed on both sides of the central bulging portion 21a. The hole bottom width S1 of the grooved hole mold G1 is set to be substantially equal to the thickness H0 of the rectangular cross-section steel piece 5 in order to accurately form the V-shaped groove 51a at the center of the short side of the rectangular cross-section piece 5. As a general rule, in actuality, in order to prevent the occurrence of flaws due to contact with the side wall, it is usually set to be slightly larger than H0. The purpose of the grooved hole mold G1 is to form the V-shaped groove 51a.
The width (hereinafter, referred to as “web height”) W1 of the final finished material is substantially equal to the width W0 of the rectangular cross-section steel piece. The V-shaped groove 51a provided in the short side portion of the rectangular cross-section steel piece 5 by the grooved hole die G1 accurately guides the material to be rolled to the central portion of the widened hole die G2, and tilts or twists during edging rolling. Is prevented. The hole bottom width S2 of the widened hole mold G2 and the apex angle θ2 of the central bulge 22a are determined by the hole bottom width S of the grooved hole mold G1.
1 and the apex angle θ1 of the central bulging portion 21a are set larger. In the widened hole mold G2, the side surface 42 corresponding to the H-shaped steel flange is divided and widened by the central bulging portion 22a by the widthwise edging rolling until the web height becomes W2, and the flange portion is generated and the flange width and the wall thickness are reduced. Expand,
The flange width is finished to a value B2 which is approximately equal to or close to the hole bottom width S2.

[0003] Next, the widthwise edging rolling is performed in the groove erasing hole die G3 in which the hole bottom width S3 is set to be larger than the hole bottom width S2 of the widening hole die G2. The flange width and thickness of the material are further expanded to make the flange width a value approximately equal to the hole bottom width S3 or a value in the vicinity thereof B
3 dog bone material 541 is finished. At the same time, the central bulge portion 23a having a top angle θ3 formed larger than the apex angle θ2 of the central bulge portion 22a of the widened hole die G2 moderates the inclination of the V-shaped groove 52a formed by the widened hole die G2. 53a to prevent the occurrence of breakage flaws on the outside of the flange in the subsequent steps. Note that, during the edging rolling from the grooving hole die G1 to the groove erasing hole die G3, the influence of the width reduction does not reach the central portion in the width direction of the rolled material as shown in FIG. Grooved hole type G for rolled material
1, the web thickness H1 in the widened hole die G2, the web thickness H3 in the groove eliminator G3 hardly changes, and is substantially equal to the original thickness H0 of the rectangular cross-section steel piece. Then, in order to form the web portion and the flange portion of the dog bone material 541 by the forming hole die G4,
The intermediate member 5 having a web height of W × a flange width of B × a web thickness of t _WM is formed by pressing down the web portion and shaping the flange portion.
When 4 is obtained, the rolling in the forming hole mold G4 is finished.
At this point, the ratio t _FM / t _WM between the flange thickness t _FM and the web thickness t _{WM at} the center of the flange piece width of the intermediate member 54 is approximately equal to the flange / web plate thickness ratio t _FP / t _WP of the final product 55. Has become. Next, using this intermediate material as a raw material, in each of the universal rolling mills of the first intermediate rough universal rolling mill 2a, the second intermediate rough universal rolling mill 3a, and the finishing universal rolling mill 4, the flange rolling reduction r _F and the web rolling reduction r _The reduction is repeated under the condition that the ratio r _F / r _{W of W is} approximately 1 to mold the final product 55.

The problem with the above conventional rolling method is that in the universal rolling, web center deviation due to web replacement is easily induced. Therefore, conventionally, it has been devised to reduce the amount of reduction in a universal rolling mill in which the center deviation of the web is likely to occur by performing the reduction using the forming die G4 to a shape as close as possible to the final product. That is, the forming hole mold G4 is an indispensable hole mold, and for example, the dog bone material 541 finished with the groove eliminating hole mold G3 does not go through the forming hole mold G4 engraved in the size and shape corresponding to the H-section steel product series. Direct universal rolling on the cross section symmetry,
Above all, there were many problems in securing the accuracy of the web center position, and it was not realized. If a process that can eliminate the forming hole mold G4 is realized by overcoming this problem, the number of sets of rough double hole roll pairs 11 and 12 held for each H-section steel product series will be greatly reduced. It is possible to reduce the roll cost by sharing the rough double-hole type roll pair between the same flange width series.

Here, the reason why the web replacement, which is a cause of the deterioration of the accuracy of the web center position, is easily induced in the universal rolling will be described below. FIG. 8: is explanatory drawing of rolling of H-section steel by a universal rolling mill. FIG. 8A is a plan view showing a state of universal rolling. F is a sectional shape of the material to be rolled before rolling, and F ₀ is a sectional shape of the material to be rolled after rolling. The flange of the material to be rolled F traveling in the direction of the arrow 6 is formed by the side surfaces of the horizontal rolls 61 and 62 and the vertical rolls 71 and 72.
With, rolling between 13 and 14 results in a flange thickness of t _F to t _F0 . FIG. 8B is the same as FIG.
In the explanatory view of the longitudinal section taken along the arrow EE, the web of the material F to be rolled is
In the meantime, 15 to 14 by the horizontal rolls 61 and 62
Rolled between, the web thickness goes from t _W to t _W0 .
FIG.8 (c) is explanatory drawing of the example in which guidance of the to-be-rolled material F is inconvenient. This state is caused by many factors such as improper setting of the pass line, wear of the roller table that loads and conveys the material to be rolled, warpage of the material to be rolled, and deformation of the tip of the lower flange due to the weight of the material to be rolled. Be done. In this case, the height F of the web center line C-1 of the material F to be rolled is different from that of the center line C-2 of the gap between the horizontal rolls 61 and 62. In the example of FIGS. 8A and 8B,
The rolling of the material to be rolled F is started at 13 with the rolling of the flange first, and then delayed by Δl and the web rolling is started at 15. As shown in FIG. 8 (a), when the web is being rolled, the flange is also on the side surface of the horizontal roll 61 (62) and the vertical roll 7.
Since it is rolled with 1 (72), the rolled material F is shown in FIG.
It cannot move freely in the direction of arrow 7 in (c). Therefore, in the rolled material F shown in FIG. 8 (c), in which guidance is inconvenient, the web is fed into the roll gap between the horizontal rolls 61 and 62 and rolled in a state where the material to be rolled F cannot move in the direction of arrow 7. Therefore, after rolling, as shown in the post-rolling cross-sectional shape F ₀ of FIG. 8C, a web center deviation ΔC occurs in the rolled material. A web guide guide can be considered as one of means for preventing this, but this is effective when the rolling of the material to be rolled is at the final stage. That is, in the final stage of rolling, for example, the web guide guide 8 having the web guide rollers 91, 92, 93 as shown in FIG.
1, 82, it is possible to correct the warp of the material F to be rolled, and to guide the web center line C-1 and the roll gap center lines C-2 of the upper and lower horizontal rolls 61, 62 by aligning them. It is possible to suppress the occurrence of web center deviation. However, since the section modulus of the material to be rolled is large at the initial stage of universal rolling such as rough shaping rolling in the first intermediate rough universal rolling, it is not possible to expect the straightening of the warp by the guide and the effect of preventing the web center deviation. .

[0006]

The problem to be solved by the present invention is to overcome the drawback of the universal rolling mill, that is, to easily induce the deviation of the center of the web, and to solve the problem of forming holes in the rough double hole rolling mill. By providing the rough universal rolling mill with the function of the mold G4 and omitting this forming hole mold G4, that is, the groove mold to be engraved on the rough double hole roll is grooved hole mold G.
By using only 1, the widening hole type G2 and the groove erasing hole type G3, the rough double hole type roll can be shared among a plurality of series to reduce the roll cost and the work cost associated with the roll.

[0007]

The features of the present invention are as follows:
In the universal rolling at the rough stage, the web and the flange are simultaneously started to be rolled within a condition range where rolling web waves (web back ring) are not generated, and the web center line C-1 and the horizontal roll are rolled by the web before the flange is rolled down. The center lines C-2 of the roll gaps 61 and 62 are made to coincide with each other to form an intermediate material having a web center position accuracy equivalent to that of the intermediate material 54 formed by the conventional molding die G4. In this case, the reason for adding the condition for preventing the web wave is the flange preceding reduction under normal rolling conditions, and therefore, in order to start the reduction of the web and the flange at the same time (that is, the flange reduction start point 13 and the web reduction start point). 15
This is because the web needs to be pressed down more strongly than in the conventional case (in order to roll the webs in conformity with each other). That is, the gist of the present invention is, "in a method for manufacturing a shaped steel having a web and a flange by means of an intermediate rough universal rolling mill and a finishing universal rolling mill using a rough shaped billet as a raw material, in the rolling step by the intermediate rough universal rolling mill. Based on the inlet web thickness t _W and the inlet flange thickness t _{F of} each pass, the horizontal roll diameter D _{H of} the intermediate rough universal mill, the horizontal roll body width U, and the vertical roll diameter D _V , the web reduction ratio of the pass. r _W and flange reduction r _F are controlled so as to satisfy the following formulas (1) and (2). Formula (1) is a condition for starting simultaneous reduction of the web and the flange, and formula (2) is a condition for preventing rolling web wave.

D _H r _W t _W ≈2D _V r _F t _F (1) ln {(1-r _F ) / (1-r _W )} <29 {t _W (1-r _W ) / U} ² (2) where ln is a natural logarithmic function.

The present invention will be described in more detail below.

FIG. 1 shows a manufacturing means of the present invention, which will be described in comparison with the conventional method shown in FIG. In FIG. 1, the same reference numerals as those in FIG. 7 are omitted. In the case of the conventional method, a rectangular cross-section steel piece 5 having a width W0 and a thickness H0 is guided by a grooved hole die G1 by the side wall 31 of the end of the long side of the rectangular cross-section, and the material width is almost unchanged (W1.
V-shaped groove 51a is formed in the state of ≈W0). Subsequently, the web thickness H3 (≈H0) and the flange width B3 are obtained by widthwise edging rolling using the widening hole die G2 and the groove eliminating hole die G3.
The rough shaped steel slab 541 is finished, and the intermediate material 54 having a web height W × flange width B × web thickness t _WM is shaped while the web portion is rolled down by the forming hole die G4.

On the other hand, in FIG. 1 of the present invention, as in the conventional case, the V-shaped groove 51a is formed by the grooving hole die G1, the width direction edging rolling is performed by the widening hole die G2, and the groove erasing hole die G3. A rough steel piece having H3 and a flange width B3 is finished, and the rough steel piece 541 is projected by the upper and lower horizontal rolls 61 and 62 and the left and right vertical rolls 71 and 72 of the first intermediate coarse universal rolling mill 2a to project a web contact arc length l. _The condition that _W and the flange projected contact arc length l _F are almost equal (that is,
l _W ≈ (1 / 2D _H r _{w tw} ) ^1/2 , l _F ≈ (D _V r _F
t _F ) ^1/2 , rolled under _DH r _W t _W ≈ 2D _V r _F t _F ), and intermediate the predetermined web height W × flange width B × web thickness t _WM × flange thickness t _FM . The material 54 is obtained. At this time, generally, in order to satisfy this condition, the web is relatively strongly pressed (r _W > r _F ) as compared with the flange due to the roll diameter of the universal rolling mill. It is necessary to perform the stress within a range in which the web buckling limit stress is not exceeded.

Therefore, the inventors have clarified the relationship between the reduction ratio of the web and the flange for preventing generation of the rolling web wave and the size and shape of the material to be rolled. First, the internal compressive stress σ _W generated in the web during rolling is caused by the difference between the web stretch λ _W and the flange stretch λ _F. If λ _W > λ _F , the compressive stress in the web is λ _W <λ _F. For example, tensile stress is generated in the web. That is, the internal compressive stress generated in the web is given by the equation (3).

Σ _W = k _l · ln (λ _W / λ _F ) ... (3) where k _l is a constant determined by the physical properties of the material and rolling conditions, and ln is a natural logarithmic function.

In the universal rolling, the strip width of the web is almost equal to the body width U of the horizontal roll. Therefore, if the strip after the rolling is considered as a strip having the width U and the thickness t _W0 , the buckling theory of the strip causes the buckling. The critical stress σ _b is given by σ _b = k ₂ · (t _W0 / U) ² (4). However, k ₂ is a constant determined by the physical property values of the web and the constraint conditions. Therefore, the condition for not generating the rolling web wave is σ _W <σ _b, that is, k ₁ ln (λ _W / λ _F ) <k ₂ (t _W0 / U) ² (5). Therefore, in order to determine the constant ratio k ₂ / k ₁ , universal rolling experiments were carried out under various reduction conditions, and the relationship between the reduction conditions and web waves was investigated. The result is shown in FIG. The vertical axis represents ln (λ _W / λ _F ) and the horizontal axis represents (t _W0 / U) ² , and the generation state of rolling web waves is plotted. The constant ratio k ₂ / k ₁ was determined to be 29 from the limit of rolling web wave generation.

Here, since the width expansion of the web and the flange and the metal flow between the web and the flange can be approximately ignored, λ _W = (1-r _W ) ^-1 (6) λ _F = (1-r _F ) ^-1 … (7) Further, from t _W0 = t _w (1-r _W ), the equation (5) can be rewritten as the above equation (2).

[0016]

EXAMPLES An example of carrying out the rolling shaping of the intermediate material based on the above-mentioned means of the present invention will be described below. H400 x 3
00 intermediate material, rough double rolling rolls 11,
12 grooved hole molds G1, widened hole molds G2, groove elimination hole molds G3
Via the rough steel slab according to the first intermediate coarse universal rolling machine using the rough steel slab as a raw material
The two pass schedules at the time of modeling an intermediate material having a flange / web plate thickness ratio (t _FM / t _WM ) of 20 mm and 1.6 are shown. First, Table 1 (a) shows "Web.
"Flange simultaneous reduction universal rolling method"
(B) shows the pass schedule of the "normal universal rolling method (flange preceding rolling)" of the prior art. Here, the roll gaps S _H and S _V have the dimensions shown in FIGS. 2 and 3. The projected contact arc lengths l _F and l _w are defined by the lengths shown in FIGS. 8 (a) and 8 (b), and are given by equations (8) and (9) when the higher-order terms are ignored.

L _F = (D _V Δt _F ) ^1/2 (8) l _W = ( ^1/2 D _H Δt _W ) ^1/2 (9) Further, the flange reduction ratio r _F and the web reduction ratio r _W Are given by equations (10) and (11), respectively.

R _F = Δt _F / t _F (10) r _W = Δt _W / t _W (11) where D _H and D _V are horizontal roll diameter and vertical roll diameter, respectively, and Δt _F (= t _F −t _F0 ) and Δt _W (= t _W −t
_W0 ) is the flange thickness reduction amount, web thickness reduction amount, t
_W and t _F are web thickness and flange thickness on the rolling-in side of the rolled material, and t _W0 and t _F0 are web thickness and flange thickness on the rolling-out side of the rolled material.

In the rolling shaping, the rectangular cross-section steel slab, which is a raw material, has a cross-sectional dimension of 1100 mm width × 250 mm thickness,
The roll hole type arrangement and main dimensions of the used rough double hole rolling mill 1 are shown in FIG.
The roll size and shape of a are shown in FIG.

Both of Tables 1 (a) and 1 (b) are pass schedules for roll-molding an intermediate material of the same cross section having a web thickness of 75 mm and a flange thickness of about 120 mm. Further, the rolling schedules by the rough double rolling hole type are the same for both, but the rolling schedules for the first intermediate rough universal are different for both. That is, with respect to Table 1 (a), l _W ≈l _{F in the} third and subsequent passes, so that the web reduction and the flange reduction start almost at the same time and end at the same time. Here, l _W ≠ l _F for the first pass and the second pass, but this enables the rolling condition of l _W = l _F in the third and subsequent passes, in order to obtain an intermediate material with a predetermined cross-sectional dimension. It is an adjustment pass that strongly depresses the web. On the other hand, in Table 1 (b), in order to obtain an intermediate material having the same cross-sectional dimension as above, almost only the web was rolled down until the 6th pass as in the case of forming and rolling by the conventional forming hole die G4, and 7 passes were performed. From the eye onward, it is a normal universal rolling method, that is, a rolling method in which the web reduction and the flange reduction are substantially the same (r _W ≈r _W ) and the reduction is continued. Further, as shown in the rightmost columns of Tables 1 (a) and 1 (b), each condition value in each pass was substituted into the formula (2) to evaluate the presence or absence of the rolling web wave. In this case, rolling was performed after confirming in advance that no web wave was generated.

The sectional shape of the finally obtained intermediate material is shown in FIG.
Shown in (a) and (b). FIGS. 4A and 4B are cross-sectional shapes of the intermediate material according to the pass schedules in FIGS. 1A and 1B, respectively. In the cross-sectional shape of the intermediate material to which the method of the present invention shown in Table 1 (a) was applied, the deviation of the web center was slight, and a good cross-sectional shape could be obtained. On the other hand, in the latter half pass of universal rolling, in order to match the web reduction rate with the flange reduction rate and perform rolling, it is necessary to continue the single web reduction for a long time, which is the same as the conventional shaping method using the forming hole die G4. In the case of the pass schedule), the start of the reduction of the flange starts earlier than that of the web, so that the web replacement is likely to occur and a large web center deviation occurs. In addition, Table 1 for rolling web waves
In both pass schedules (a) and (b), there was no occurrence, as evaluated by the equation (2).
In this embodiment, since the edging rolling machine did not shape the tip of the flange, the tip of the flange is rounded. It is conventional that the final product 55 can be obtained from the intermediate material shaped by edging rolling and then through the second intermediate rough universal rolling mill 3a, edging rolling mill 3b and finishing universal rolling mill 4 corresponding to each series. Is the same as. That is, this means that by replacing the forming and rolling by the conventional forming hole die G4 with the rolling method that satisfies both the formula (1) and the formula (2) in the first intermediate coarse universal rolling mill 2a, a rough double hole is obtained. It is shown that it is possible to omit the forming hole G4 of the die rolling roll, and to realize sharing of the rough double-hole rolling rolls 11 and 12 between different web height series.

Note that, as shown in the present embodiment, the rolling that can satisfy the formulas (1) and (2) at the same time, the web buckling limit stress σ _b at the stage when the web thickness becomes thin. Is small, the effect of applying this is small, and this method should be applied when the web thickness is large.

Further, in the present invention, the rough shaped steel slab used as a raw material for the intermediate coarse universal rolling mill is not limited to the steel slab roughly shaped by the rough double hole rolling mill of the above-mentioned embodiment, but a beam blank by continuous casting. Of course, a slab can also be used.

[0024]

[Table 1]

[0025]

As described above, according to the present invention, it becomes possible to omit the forming die G4 in the conventional coarse double-hole rolling mill when forming an intermediate material for H-section steel made of a steel piece having a rectangular cross section. As a result, it is possible to form multiple series of intermediate materials with different web heights without changing the rolls of the rough double-hole rolling mill, and further reduce the roll cost and roll of the rough double-hole rolling mill. It has become possible to reduce the associated work costs.

[Brief description of drawings]

FIG. 1 is an explanatory view of a rolling situation of the present invention.

FIG. 2 is a roll layout diagram of a coarse double-hole rolling mill having a grooved hole die G1, a widened hole die G2, and a groove eraser die G3 in the embodiment of the present invention.

FIG. 3 is an explanatory view of the dimensions and shape of the first intermediate coarse universal rolling roll in the example of the present invention.

4 (a) New method and (b) in the embodiment of the present invention.
Schematic cross-sectional view of the intermediate material by the comparative method.

FIG. 5 is an explanatory view showing rolling equipment for a section steel such as an H section steel and an I section steel having a web portion and a flange portion.

FIG. 6 is an explanatory diagram showing an example of roll hole type arrangement of a conventional rough double hole type rolling mill.

FIG. 7 is an explanatory view showing a method for manufacturing a rough-shaped steel slab from a rectangular-section steel slab in a conventional coarse double-hole rolling mill.

8 (a), (b) and (c) are explanatory views of H-section steel rolling by a universal rolling mill.

FIG. 9 is an explanatory view of a situation of a web center deviation prevention rolling method using a web guide guide.

FIG. 10 is an explanatory view of results of a rolling web wave generation limit condition grasping test.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rough double hole rolling mill 2a ... 1st intermediate rough universal rolling mill 2b ... 1st edging rolling mill 3a ... 2nd intermediate rough universal rolling mill 3b ... 2nd edging rolling mill 4 ... Finishing universal rolling mill 5 ... Rectangle Cross-section steel strip 6 ... Rolling direction of rolled material 7 ... Direction perpendicular to rolling direction of rolled material 11,12 ... Upper and lower roll pairs of coarse double-hole rolling mill 13 ... Start of rolling of rolled material flange in universal rolling Point 14 ... Rolling end point of rolled material web and flange in universal rolling 15 ... Rolling point starting point of rolled material web in universal rolling 21a, 22a, 23a ... Grooving hole type G1 and widening hole type G
2, central bulging portion 21b of each groove erasing hole die G3 ... Groove portions on both sides of the central bulging portion in the hole die G1 ... Side wall portions of the hole die G1 ... Side surfaces corresponding to the flange of the rolled material in the hole die G2 51a, 52a, 53a ... Hole type G1, hole type G2, hole type G
3 V-shaped groove of the material to be rolled in each 3 541 ... Dog bone material shaped by the hole type G3 54 ... Formed by the first intermediate rough universal rolling machine of the conventional forming hole type G4 finish or the method of the present invention Intermediate material 55 ... H-shaped steel final product 61, 62 ... Vertical horizontal roll pair 71, 72 of the first intermediate rough universal rolling machine 71, 72 ... Horizontal vertical roll pair 81, 82 of the first intermediate rough universal rolling machine 81, 82 ... Web guiding guide 91, 92, 93 ... Rolls for guiding the web supported by the guide

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B21B 37/00 BBG 37/16

Claims (1)

[Claims] 1. A method for producing a shaped steel sheet having a web and a flange by using an intermediate rough universal rolling mill and a finishing universal rolling mill, using a crude shaped steel slab as a raw material, wherein each pass of the rolling process by the intermediate rough universal rolling mill is inserted. Based on the side web thickness t _W , the entrance side flange thickness t _F, the horizontal roll diameter D _{H of} the intermediate rough universal rolling mill, the horizontal roll body width U, and the vertical roll diameter D _V , the web rolling reduction r _{W of the} pass and the flange The rolling reduction r _F is calculated by the following equation (1).
And the formula (2) are satisfied so as to satisfy the formula (2). Universal rolling forming method for a shaped steel having a web and a flange D _H r _W t _W ≈ 2D _V r _F t _F (1) ln {( 1−r _F ) / (1−r _W )} <29 {t _W (1−r _W ) / U} ² (2) where ln is a natural logarithmic function.