JP2000158002A - Method for hot-rolling shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a product having different flange widths from rough shape billets having the same shape with respect to a wide-flange shape and shapes similar to that by reducing the flange width of a rough shape billet after rolling for forming to the flange width corresponding to the shapes having different sizes by greatly edging the flange width by edger rolling in a rough rolling stage. SOLUTION: The rough shape billet 31 having the flange width of leg length Ho which is rolled with a forming mill on the hot rolling line for manufacturing the shapes is greatly reduced to a leg length He corresponding to the different size in the rolling stage with a universal roughing mill group consisting of a universal mill and edger and the flange width of the rough shape billet is reduced. For example, using rolls for forming the rough shape billet in the forming mill, the rough shape billet 31 for the wide flange shape of H600×300 is rolled into the leg length Ho and, next, the flange width is greatly reduced into the leg length He equivalent to H600×250 with the edger in the rough universal rolling stage and, after that, the universal rolling is executed and the product of H600×250 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot rolling method for a shaped steel capable of producing a shaped steel product having a different flange width from a raw steel slab having the same shape.

[0002]

2. Description of the Related Art FIG. 5 is a schematic view showing a hot rolling process of a section steel such as an H section steel. A raw material such as a slab, a bloom or a beam blank is heated to a predetermined temperature in a heating furnace 1 and is rolled into a coarse shaped slab by a shaping and rolling mill 2. Thereafter, a coarse universal rolling comprising a universal rolling mill 3 and an edger 4 is performed. The rolls are rolled to the product shape and dimensions by the finishing mill 5 and the rolling mill group.

As shown in FIG. 6, for example, as shown in FIG. 6, when a slab 11 is used as a raw material for rolling a rough steel slab for an H-beam, a plurality of edging rolling box holes for forming a flange portion are usually used. The thickness of the dies 12, 13, and 14 and the portion corresponding to the web are reduced, and the slab 15 is rolled into a desired coarse shaped slab by a hole die 15 which is rolled and formed into a substantially H shape.

[0004] In the rough universal rolling mill group in the next step, the coarse shaped billet is used as a rough universal rolling mill 3 as shown in FIG.
And rolled by the edger 4. Usually, the ratio T2 ₀ / T1 ₀ of web thickness T1 ₀ and the flange thickness T2 ₀ of coarse shaped steel specimen after shaping rolling by shaping rolling mill 2, as shown in FIG. 8 is a web thickness t1 and the flange thickness of the product is substantially equal to the ratio t2 / t1 of t2, also leg H ₀ of the crude shaped steel strip 31 is finished so as to be substantially equal to the leg length He products 33.

[0005] This, in the rough rolling step by coarse universal rolling mill 3 and the edger 4 in the rough universal mill group, web thickness T1 ₀ and the flange thickness T2 ₀ is reduced by approximately the same reduction ratio, of the flange By adjusting the leg length He so as to be almost constant by edging, the product 33
This is due to the fact that the rolling was performed by finish rolling.

In the conventional rolling method as described above, when rolling a series having a different flange width, a grooved roll for forming and rolling is held for each series having a different flange width, and an edger corresponding to a difference in flange leg length He. Rolling is performed by rearranging the rolls 4, so that the number of rolls held becomes enormous, and since the rolls are rearranged for each different series, the improvement of the operation rate has been neglected.

To solve this problem, Japanese Patent Laid-Open Publication No. Hei 2-290105 discloses a technique of reducing the flange width by rolling the flange width at the flat portion of the roll after rolling with a finishing hole die in the forming and rolling step shown in FIG. (Prior Art 1).

Further, as shown in FIG. 10, a technique disclosed in Japanese Patent Publication No. 7-61482 can be used as a technique for changing the flange width in the forming and rolling step of converting a slab into a coarse steel slab. Conventional technology 2).

[0009] For example, Japanese Patent Publication No. 4-55761 discloses an edger 4 whose leg length can be changed by eccentricity of a web restraining sleeve 4a with respect to an edging sleeve 4b as shown in FIG. Further, Japanese Patent Laid-Open No. 9-1
No. 08710 discloses an edger 4 having a variable leg length He by a stepped edging sleeve 4b as shown in FIG.
A technique has been proposed in which H series steels having different flange widths can be rolled without changing the edger 4 (prior art 3).

[0010]

However, the prior art 1 is effective when the roll has a flat portion, but is not applicable when the flat portion as shown in FIG. 6 cannot be obtained. It is. Further, in the prior art 2, it is possible to change the flange width by changing the slab width without changing the rolls. However, since the material to be rolled does not fill the groove, it is necessary to maintain good rolling stability. It is difficult to maintain high dimensional accuracy, and it is particularly difficult to maintain good thickness deviation and center deviation. Further, in the prior art 3, it is possible to roll shaped steel pieces having different flange widths without changing the rolls in the universal rolling process. And

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it has been made possible to manufacture an H-section steel and a similar section steel from the same shaped crude steel slab with different flange widths. It is an object of the present invention to provide a method for hot rolling a shaped steel.

[0012]

According to a first aspect of the present invention, there is provided a method for hot rolling a shaped steel in a rough rolling step of a hot rolling line for producing a shaped steel, wherein the rough shaped steel slab after forming and rolling is formed. Is greatly reduced by edger rolling to reduce the flange width to flange widths corresponding to differently shaped steel bars.

In a second aspect of the present invention, in a rough rolling step of a hot rolling line for manufacturing a shaped steel, a rough shaped steel slab after shaping and rolling is adapted to a shaped steel of a different size by greatly reducing a flange width by edger rolling. In consideration of a change in the web thickness when the flange width is reduced, the shaped steel slab after forming and rolling is finished to a desired web thickness.

According to a third aspect of the present invention, in a rough rolling step of a hot rolling line for producing a section steel, the flange width is largely reduced by an edger capable of changing an edging height so that a flange width corresponding to a section steel having a different size can be obtained. Is to be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory diagram showing an outline of an embodiment of the present invention. In the figure, a crude steel slab 31 is rolled by a shaping mill 2 (see FIG. 5) of a hot rolling line for manufacturing a shaped steel. Such crude shaped steel strip 31, in the rolling process in the universal rolling mill 3 and consisting edger 4 rough universal mill group as shown in FIG. 2, the size of different ones of the flange width of the leg H ₀ by edger rolling Leg length He corresponding to To reduce the flange width of the crude steel slab.

For example, in a molding and rolling mill 2 as shown in FIG.
The rough steel slab 31 for H-section steel of 00 × 300 is rolled to the leg length H ₀ , and then the flange width is set to H600 × 25 in the edger 4 in the rough universal rolling process as shown in FIG.
Leg length He equivalent to 0 After that, a general universal rolling is performed, and a product of H600 × 250 is manufactured.
In the edger 4 in the universal rolling process, when a material to be rolled having a small flange thickness is subjected to a large width reduction in one pass, the flange buckles, and the flange width cannot be appropriately rolled. The crude shaped steel piece after shaping rolling in the present invention, although significantly reduction to reduce the flange width by edger 4, because the flange thickness T2 ₀ coarse shape steel piece 31 is thicker, the flange is not buckling during edging This enables a large width reduction in one pass.

Conventionally, in the series having different flange widths, the forming rolls are individually held, and the forming rolls are rearranged for each rolling chance to roll the rough slab 31.
As described above, even in a series with different flange widths, it is possible to perform rolling without changing the molding rolls, and to use the conventional molding rolls as they are, and to make moldings corresponding to individual flange width series. It is not necessary to have all the rolling rolls. As a result, it is possible to reduce the number of shaping rolls and the number of shaping rolls to be changed. Further, under the width reduction of the flange by the edger, a large reduction can be obtained in one pass, so that the increase in the number of rolling passes can be minimized.

As described above, in the rough rolling process in the rough universal rolling mill group including the universal rolling mill 3 and the edger 4, the edger 3 of the crude steel slab 31 is used to greatly reduce the flange width of the leg length H ₀ by the edger 3. Leg length He for different sizes One of the major reasons why it has not been possible to reduce the flange width to the conventional one is that the flange thickness is increased and the web thickness is reduced by reducing the flange width by an edger after forming and rolling. Because it was difficult to predict, a detailed description will be given below based on normal rolling of an H-section steel.

For example, if the web height is H, the flange width is B,
(Flange leg length is the He), if the web thickness is the flange thickness at t1 is rolled H-section steel of t2 (see FIG. 8), the crude shaped steel strip 31 after shaping rolling, web thickness T1 ₀ and the flange Thickness T2
₀ ratio and _{T2 0 / T1 0 = 1.0 ~1.25} * t2 n / t1 n, leg length of the flange H ₀ ≒ the He Set so that This is due to the following characteristics of universal rolling.

In the universal rolling, the horizontal roll load PH and the vertical roll load PV and the reduction strain ε of the web are given.
It is known that the difference εwt−εft (hereinafter referred to as “rolling balance”) between wt and the rolling strain εft of the flange has a relationship shown in FIG. When the rolling balance is 0.0 or less, the horizontal roll load PH increases, and when the rolling balance is 0.05 or more, the vertical roll load PV increases. ~ 0.05 is suitable.

The relationship between the flange width expansion strain εfw and the rolling balance in universal rolling is shown in FIG. 12. Again, the flange width decreases when the rolling balance is 0.0 or less, and the width expansion increases when the rolling balance is large. In order not to make the width reduction by the edger for the purpose of adjusting the flange width excessively, the reduction balance is 0.0 ~ 0.05.
Rolling in the range is suitable.

Furthermore, when edging is performed by an edger, the flange thickness slightly increases. Therefore, in consideration of this, in the universal rolling after the edger rolling, the rolling balance from the thickness before the edger rolling is almost zero. And rolling is performed so that the rolling balance is substantially in the range of 0.0 to 0.05. If the finish, for example, universal rolling 10 pass in accordance with the rolling method, the web thickness T1 ₀ of the crude shaped steel strip 31 after shaping rolling
All flange thickness T2 ₀ is equal to or less than the ratio.

[0023] When the pressure balance and A 1 pass; Universal → Universal _{εwt 1 = ln (t1 1 /} T1 0) (1) εft 1 = ln (t1 1 / T1 0) + A (2) 2 pass; edger → Universal εwt ₂ = ln (t1 ₁ / T1 ₀ ) (3) εft ₂ = ln (t1 ₁ / T1 ₀ ) (4) Similarly, the total rolling strain when rolling from 3 passes to 10 passes is εwt _{1 + εwt 2 + ... = ln (} t1 n / T1 0) (5) εft 1 + εft 2 + ... = ln (t1 n / T1 0) + n / 2 * A = ln (t2 n / T2 0) (n = 10 path ) (6)

The next, shaping ratio of the thickness of the web and the flanges of the crude shaped steel strip after rolling T2 ₀ / T1 ₀ is _{T2 0 / T1 0 = t2 n} / t1 n * exp (N / 2 * A) ≒ t2 about 1 to _{n / t1 n * (1.0 +} 5A) (7), the ratio of the flange thickness of the product t2 and web thickness t1.
0 such that 1.25 times, the crude shaped steel strip 31 web thickness T1 ₀ at shaping rolling roll gap setting, flange thickness
T2 ₀ is finished with a finishing hole type.

Here, if the flange width of the coarse steel slab 31 is greatly reduced by the edger 4, the flange thickness increases and the web thickness decreases. The pass schedule in the universal rolling cannot be set, that is, rolling to a desired product size cannot be performed.

Based on the above findings, the present invention accurately determines the width reduction amount of the edger and the variation amounts of the flange thickness and the web thickness when the flange width of the shaped steel slab after shaping and rolling is greatly reduced by an edger. The universal rolling of a series with different flange widths has been made possible by appropriately adjusting the thickness of the finished web of the shaped steel billet in the shaping and rolling based on the amount of change.

The above embodiment of the present invention will be described in more detail with reference to specific examples. Web height is H, flange width is B, (flange leg length is He ), H-shaped steel H _n × B _n with 50 mm smaller flange width by using a forming roll for H-shaped steel with a web thickness t1 and a flange thickness t2 (H × B × t1 / t2)
× t1 _n / t2 _n (web height; H _n , flange width; B _n ,
When the web thickness: t1 _n and the flange thickness: t2 _n ) are rolled in 10 passes in the universal rolling, if the rolling balance is 0.03, the flange thickness of the crude steel slab after appropriate shaping and rolling is obtained from the equation (7). And the web thickness ratio is t2 ₀ / t1 ₀ = 1.15 * t2 _n / t1 _n = η (8) Note the H-shaped steel H × B × t1 / t2 for finishing the caliber of the flange thickness and t2 _0. The amount of increase in the flange thickness when the flange width of the coarse slab is reduced by 50 mm by the edger can be predicted, for example, as follows.

Coarse billet web required after shaping and rolling
Thickness T1₀ Flange width B after molding and rolling₀ Flange thickness after shaping and rolling (specified by finishing hole type) T2₀ Web thickness t1e after edger rolling  Flange thickness t2e after edger rolling  Flange width Be after edger rolling

Then, the distortion of each part of the flange portion during the edger rolling is as follows. Width distortion _{εfw = ln (Be / B 0} ) (9) thick distortion _{εft = ln (t2e / t2 0} ) (10) rolling direction distortions εfl = K (11) edger each part distortion of the web portion during rolling width distortion εww = 0 (12) thickness strain _{εwt = Aln (t1e / t1 0} ) (13) rolling direction distortions εwl = K (14)

Strain εwt in web thickness direction during edger rolling
Have been derived by various experiments that _{εwt = αln (Be / B 0} ) (15) α = 0.25 * Aw / (Aw + Af) Aw; web portion cross-sectional area Af; at the flange portion sectional area web portion, a constant volume (εww + εwl + εwt =
0) from K = -εwt = -αln (Be / B 0) (16) this and εft from a constant volume conditions flanges _{= ln (t2e / t2 0)} = - ln (Be / B O) + αln (Be _{/ B O) = (1-} α) ln (Be / B O) (17)

The equation (8) from equation (15) and (17), determine the t1 _0. For solving the equations of these 3 Ke it is complicated, as considering only the first-order small section can be determined simply by the t1 ₀ as follows. When the thickness and flange width after the edger are expressed as follows, t1e = T1 ₀ + Δt1e Δt1e ; Web thickness change due to edging (18) t2e = T2 ₀ + Δt2e Δt2e ; Flange thickness change due to edging (19) Be = B ₀ + ΔB ΔB; Edging amount (20) B ₀ = 2H ₀ + t _{1 0} H ₀ ; Flange leg length (21) t ₁₀ is obtained by a quadratic expression of the following expression (22). ^{_{ηt1 0 2 + {η (2H}} 0 -αΔB) -t2 0} t1 0 -t2 0 {2H 0 + (1-α) ΔB} = 0 (22)

As described above, the thickness of the web at the end of shaping and rolling
t1 ₀ can be determined, since the flange thickness t2 ₀ is defined by the hole type, the crude shaped steel piece after molding rolling may significantly decreased the flange width by edger, the schedule of the conventional universal rolling process Rolling becomes possible.

As an edger in the universal rolling process,
An edger that can cope with a change in leg length of a flange has been proposed so that a series having a different flange width can be edged. This type of conventional edger manufactures rough shaped steel slabs with different flange widths in shape rolling, and rolls series with different flange widths using the rough steel slabs with different flange widths. It was necessary to change the flange width of the coarse billet in the process.

This is because, as described above, when the flange width is reduced by using a rough slab with these edgers, the flange thickness and the web thickness change, but it is difficult to predict this. This is because the product could not be rolled to the desired product size in the universal rolling process. In the present invention, in the rough rolling step, the web of the rough billet is thickened by shaping and rolling based on the prediction of the above knowledge, and the flange width is greatly reduced by an edger capable of coping with a change in the leg length of the flange, thereby reducing the flange width. Can be manufactured.

[0035]

[Embodiment 1] Web height 600mm, flange width 30
0mm H600 × 300 series rolled, 50mm flange width different web height 600mm, flange width 250mm H
The 600 × 250 series was implemented based on the above-mentioned embodiment without changing the rolls of the shape rolling. H6
The thickness of the flange of the finishing hole die of the molding roll for the 00 × 300 series is 100 mm and the leg length H ₀ of the flange is 145 m
m. Here, the rolling of H600 × 250 × 12/22 will be described as an example.

In the universal rolling of the H600 × 250 series, the rolling balance is about 0.03 and rolling is performed in 10 passes. First, from equation (8), t2 ₀ / t1 ₀ = 1.15 * t2 _n / t1 _n = 1.15 * 22/12 = 2.108 = η Flange width is reduced by 50 mm in two passes by an edger on a shaped steel slab after shaping and rolling. And In the formula (22), η = 2.108 H 0 = 145mm ΔB = 50mm t2 0 = 100mm α = AW / (AW + AF) = 0.282 and then, the web thickness of the resulting shaped rolling after the rough shape steel piece t1 is
51.8 mm.

In the actual shaping and rolling, the target of the web thickness of the crude billet is 51.8 mm, and the rolling is performed.
After two-pass rolling with 25 mm per pass (under a flange width reduction of a total of 50 mm), universal rolling was performed according to a rolling schedule similar to that of ordinary H600 × 250 × 12/22. 10
The finished dimensions after the pass are shown in Table 1. The finished dimensions were well within the target dimensional tolerance, confirming the effectiveness of the present invention.

Embodiment 2 FIG. Web height 600mm, flange width 3
00mm H600 × 300 series flange width after rolling
100mm H with different web height 600mm and flange width 200mm
Using the edger roll shown in FIG. 8, the 600 × 200 series was shaped and rolled based on the above embodiment without changing the roll of the edger. H600
The thickness of the flange of the finishing hole die of the molding roll for × 300 series is 100 mm, and the leg length H ₀ of the flange is 145 mm. Here, rolling of H600 × 200 × 11/17 will be described as an example.

In the universal rolling of the H600 × 200 series, the rolling balance is about 0.03 and rolling is performed in 10 passes. First, from equation (8), t2 ₀ / t1 ₀ = 1.15 * t2 _n / t1 _n = 1.15 * 17/11 = 1.78 = η Flange width is reduced by 100 mm in three passes by an edger on a shaped steel slab after shaping and rolling. And

The formula (22), η = 1.78 H 0 = 145mm ΔB = 100mm t2 0 = 100mm α = Aw /(Aw+Af)=0.48 and then, web thickness of the rough-shaped steel piece after shaping rolling obtained t1 ₀
Was 74 mm.

In the actual shaping and rolling, the target of the web thickness of the coarse billet was set to 74 mm, and the rolling was performed at the edger.
After three-pass rolling with 33 mm pass (under a flange width reduction of a total of 100 mm), universal rolling was performed according to a rolling schedule similar to that of ordinary H600 × 200 × 11/17. Compared with normal universal rolling, the edger load was slightly higher (10 to 20%) in the previous pass, but the finished dimensions after 10 passes are shown in Table 1, but they were well within the dimensional tolerance of the target dimensions. Thus, the effectiveness of the present invention was confirmed.

[0042]

[Table 1]

[0043]

As apparent from the above, according to the present invention, (1) the number of shaping and rolling rolls held can be reduced, and the number of shaping and rolling roll replacements can be reduced. Further, under the width reduction of the flange by the edger, a large reduction can be obtained in one pass, so that the increase in the number of rolling passes can be minimized. (2) Since the web thickness at the end of shaping and rolling can be determined and the flange thickness is determined by the hole shape, even if the flange width of the shaped steel slab after shaping and rolling is greatly reduced by an edger, Can be rolled according to the schedule of the universal rolling process. (3) In addition to the advantages of reducing the number of shaping rolls and the number of shaping rolls to be replaced, the number of edgers to be replaced in the universal rolling process can be reduced. Because different series can be rolled, flexible production planning that can meet the short delivery time needs of customers becomes possible.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an outline of an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a large rolling state by edger rolling in a group of coarse universal rolling mills.

FIG. 3 is a graph showing a relationship between a rolling load and a rolling balance;

FIG. 4 is a graph showing the relationship between flange width spreading distortion and rolling balance.

FIG. 5 is a schematic diagram showing a hot rolling process for shaped steels.

FIG. 6 is an explanatory diagram showing an embodiment of conventional shaping and rolling of a crude steel slab.

FIG. 7 is an explanatory diagram showing an embodiment of a conventional group of coarse universal rolling mills.

FIG. 8 is a schematic view showing a relationship between a crude steel slab and an H-section steel.

FIG. 9 is an explanatory diagram showing an embodiment of conventional shaping and rolling of a crude steel slab.

FIG. 10 is an explanatory view showing an embodiment of conventional shaping and rolling of a crude steel slab.

FIG. 11 is an explanatory diagram showing a conventional edger.

FIG. 12 is an explanatory diagram showing a conventional edger.

[Explanation of symbols]

1 oven 2 shaped rolling mill 3 universal rolling mill 4 edger 5 finishing mill 11 slab 12, 13, 14, 15 caliber 31 crude shaped steel strip 32 the material to be rolled 33 products H _0, the He leg B _0, Be flange width T1 ₀ , t1 Web thickness T2 ₀ , t2 Flange thickness

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Motohisa Yoshida 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. F-term (reference) 4E002 AC03 BA03 BA04 BB05 BB07 BC05 CA20 4E016 AA07 BA01 BA08 CA05 CA08

Claims (3)

[Claims] In a rough rolling step of a hot rolling line for producing a shaped steel, the shaped steel strip after forming and rolling is greatly reduced in flange width by edger rolling to a flange width corresponding to shaped steel of different sizes. A method for hot rolling a section steel, wherein the method is to reduce it. 2. In a rough rolling step of a hot rolling line for producing a shaped steel, the shaped steel slab after shaping and rolling is greatly reduced in flange width by edger rolling to a flange width corresponding to shaped steel of different sizes. A hot-rolling method for a shaped steel, which comprises shaping a shaped steel slab after shaping and rolling to a desired web thickness in consideration of a change in web thickness when the web is reduced. 3. In a rough rolling step of a hot rolling line for producing a section steel, a flange width is largely reduced by an edger capable of changing an edging height to reduce the flange width to a flange width corresponding to a section steel of a different size. A method for hot rolling a section steel.