JPH0761482B2 - Variable flange width rolling method for rough rolled material for H-section steel - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for rolling a rough rolled material for H-section steel using a steel strip having a rectangular cross section represented by a slab as a raw material.

[Conventional technology]

As shown in FIG. 4, for example, the process of manufacturing H-section steel by universal rolling is performed by a double-hole rolling mill (breakdown mill) 1 for roughly shaping a rolling material, an intermediate first coarse universal 2a, and an intermediate coarse mill 2a. Edger mill 3a provided close to the universal 2a, intermediate second coarse universal mill 2
The rolling process consisting of b, edger mill 3b and finishing universal mill 4 is well known. Recently, slabs have been widely used as a rolling material for H-section steel. That is, until the slab material was used, the steel ingot was slab-rolled to form a dockbone-shaped rough steel slab, which was then subjected to a breakdown mill. The effect of omitting the ingot process and soaking furnace has come to contribute greatly to the reduction of manufacturing costs. The rough modeling technique using a slab as a material is disclosed in, for example, Japanese Patent Publication No. Sho 58-19 previously proposed by the applicant of the present application.
The technology disclosed in Japanese Patent Publication No. 361 or Japanese Patent Publication No. 58-37042 is well known. FIG. 5 shows an example of the hole type arrangement in the double hole type roll of the breakdown mill used in the prior art, in which the upper and lower rolls 11 and 11 have caliber K-1 to K-1.
The hole type of K-4 is engraved. FIG. 6 shows in detail the shaping process of rolling the slab 5 of the rolling material using the roll, in which the thickness of the slab 5 is t and the width is S.
An imaginary line 51 indicates the outer shape of the material to be rolled in the hole type after the last pass rolling. The caliber K-1 is a hole type for forming the V-shaped groove 5a on the side surface of the slab 5 corresponding to the flange of the H-shaped steel, and has a predetermined wedge angle θ in the center of the hole bottom width.
_A central bulge 21a and a groove 21b are formed on both sides thereof. The hole bottom width s ₁ is formed to be slightly larger than the thickness t of the slab 5. As described above, in this caliber K-1, the side surface of the slab 5 is first cut to form the V-shaped groove 5a, which facilitates the guiding of the material to be rolled at the next caliber K-2. Bottom hole width s ₂ and wedge angle theta ₂ of the central bulging portion 21a of the caliber K-2 is the caliber K-
The hole bottom width s ₁ and the wedge angle θ ₁ are set to be even larger. In this caliber K-2, the flange-equivalent portion of the material to be rolled is split and expanded by the central bulging portion 21a to expand the flange width and edging in the web height direction. Then caliber angle of K-3 of bottom hole width s ₃ and the central bulging portion 21a theta ₃
Is formed larger than that of the caliber K-2, the flange of the material to be rolled is further widened, and the V-shaped groove 5a is smoothed to prevent the occurrence of flaws. Caliber K
-4 is a shaping hole type having a hole bottom width s ₄ , and the web portion and the flange portion of the material to be rolled are pressed down to finish the rough shaping step. Although illustration of the path order is omitted, the actual path order is K.
-1 to K-4 are not sequentially performed, but once during rolling, the caliber K-4 is first rolled and then caliber K-3.
It is also done to go back to edging and to finish again with Caliber K-4.

By the way, the rolls of the breakdown mill used in the conventional rough rolling means for H-section steel made from slabs as described above have the hole shape and dimensions determined according to the series of H-section steel products. Therefore, it was necessary to prepare a dedicated roll for each series. For example H600 × 300
After (H-shaped steel with a web height of 600 mm and a flange width of 300 mm)
When rolling H600 × 250, H600 × 200, etc., naturally the rolls of the breakdown mill had to be replaced. That is, the concept of rolling in the conventional breakdown mill is as follows: at least in the final pass of each flange widening hole type and shaping hole type as shown in phantom lines in FIG. If the flange equivalent part of the rolled material is filled and the flange part is not formed symmetrically with respect to the web center axis, bending of the rolled material occurs when rolling into the next hole type, This is because there was a concern that problems such as the upper and lower flange piece width dimensions not being equal may occur in the intermediate first coarse universal mill. Therefore,
Rolls must be prepared for each series, and there are problems that roll purchase costs and roll maintenance costs are high, roll reassembling work is increased, and a wide storage space is required.

[Problems to be Solved by the Invention]

The present invention uses a slab having a rectangular cross section as a raw material to produce a rough rolled material of H-section steel in a breakdown mill using a double-hole type roll, without changing the roll, and only one roll pair has a flange width. A rolling means capable of rolling a plurality of series of rough rolled materials having different web heights is provided.

[Means for Solving the Problems]

The gist of the present invention is to provide a plurality of flange widening hole dies having a central bulge portion in the widthwise center of the hole bottom and grooves on both sides of the central bulge portion, and a shaping hole die for pressing down the web portion and the flange portion. Using a double-hole type roll having a rectangular cross-section steel slab, the flange widening hole type is used to widen and roll the side surface corresponding to the H-section steel flange by interruption rolling of the side surface corresponding to the H-section steel flange and edging in the web height direction. In the method for rolling a rough rolled material for H-section steel, which is subsequently subjected to shaping rolling in the shaping hole type, an increase amount of the flange width with respect to the total edging amount in the web height direction in the flange widening hole type and the shaping hole Using a rectangular cross-section steel piece in which the width dimension of the rectangular cross-section steel piece is determined in advance from the reduction amount of the flange width due to the web reduction in the die, a hole die and a shaping hole other than the first hole die among the flange widening hole die In a mold The flange width of the rough rolled material for H-section steel is varied by making the flange width of the rolled material after the final pass narrower than the hole bottom width of the perforated die so as not to fill the flange equivalent part of the rolled material in each die. It is a rolling method.

[Operation / Example]

The present inventors, assuming the above-mentioned conventional rough rolling means, for example,
Various experiments were attempted to find a means for rolling another series of rough shaped materials with the same web height and a narrow flange width using a roll for H600 × 300. As a result, in order to obtain the target flange width, the width dimension of the slab to be used is set in advance in consideration of the total reduction amount in the width direction, the increase of the flange width with respect to this total reduction amount, and the reduction of the flange width due to the web reduction. Rolled using this slab as the material, the flange width of the rolled material after the final pass in the relevant groove types other than the first type among the flange widening hole types is made narrower than the hole bottom width of the relevant hole type. Then, it was found that a rough shaped material having a flange with a width narrower than the flange width of the rolling series originally intended for the roll can be arbitrarily manufactured. The details will be described below based on examples.

Table 1 shows an example of a conventional pass schedule for rough rolling a rough rolled material for production of the final product size H600 × 300 of H600 × 300 with a breakdown mill.

This example thickness 250 mm, but using the rolls above the 6 Figure caliber K-1 to K-4 is formed a slab of width 1230mm as the material, the widening caliber of bottom hole width (S ₁ ~ S ₄ ) has caliber K-1 of 252 mm, caliber K-2 450 mm, and caliber K-3 480 mm. Breakdown finished dimensions are web thickness 80mm, flange thickness 137mm, web height 8
A rough rolled material of 70 mm and flange width of 386 mm is obtained.
According to Table 1, the flange widening hole type caliber K-1,
The total amount of reduction in the width direction of the slab using K-2 and K-3,
That is, the total edging amount (A) is 1230-850 = 380 mm because the finished web height of the caliber K-3 is 850 mm.

As a result of conducting edging rolling of 380 mm, it was confirmed in the field experiment how much the flange width was expanded, and as shown in Fig. 2, the relationship between the total edging amount and the flange width expansion ratio was found. In this case, it can be seen that the flange width expansion ratio is about 0.63.

The flange width expansion rate is defined by the following equation (1).

For the convenience of explanation, when considering the left half of the material to be rolled as shown in FIG. 2 (b), the total edging amount is 190 mm with 1/2 edging amount, so the flange width dimension is (1). From the formula, the flange width = 0.63 x 190 = 119.7 mm, and the total flange width (F) is as follows: total flange width (F) = 119.7 × 2 + 250 ≈ 489 mm.

By the way, when the web of the material to be rolled is pressed in the shaping hole type K-4, the flange width of the flange portion becomes narrow as a result of the metal flow to the length direction of the material to be rolled and to the web portion. If the degree of flange width reduction is defined as the flange width shrinkage ratio (β), the relationship is expressed by equation (2) based on the dimensional specifications in FIG. 3 (b).

However, F ₀ : Rolling material flange width generated by edging T ₀ : Slab thickness F ₁ : Breakdown mill finished flange width T ₁ : Breakdown mill finished web thickness Flange width reduction ratio (β) is H type It was confirmed that there is a strong correlation with the in-web method for steel products, but Fig. 3 (a)
The graph of shows the relationship. When this example is applied to the relationship between the equation (2) and the grab shown in FIG. 3 (a), the breakdown finished flange width is 386 mm, so the material to be rolled after the material with a slab thickness of 250 mm is reduced to a web thickness of 80 mm. The material flange width (F ₀ ) is as follows.

F ₀ = (T ₀ −T ₁ ) × β + F ₁ = (250−80) × 0.57 + 386 ≈483 mm Therefore, the flange width shrinkage is 483−386 = 97 mm.

By the way, since the flange width after 10 passes in Table 1 is 489 mm for the total edging amount from caliber K-1 to K-3 to 380 mm, the actual amount of flange reduction in the shaping hole type K-4 is 489 mm. -483 = 6 mm.

That is, in the conventional rough-rolling means of the well-formed hole type, the flange portion was also reduced by 6 mm simultaneously with the reduction of the web portion. As described above, this amount of reduction was indispensable for ensuring sufficient shaping of the flange portion and ensuring the material permeability and the accuracy of the size and shape in the next intermediate coarse universal mill.

By the way, in the leftmost column of Table 1, a circle indicates a path in which the flange-equivalent portion of the material to be rolled is filled with a hole shape.
The inventors of the present invention compared the number of O-shaped passes in which the flange portion is filled with a hole shape with the number of unfilled passes, and noticed that the ratio of the number of unfilled passes was high. Then, it was thought that if the hole type was rolled without filling the flange-corresponding part, a series rolled material having a width narrower than the flange width rolled by the hole type could be manufactured. Based on this idea, an experiment was conducted by using a conventional breakdown roll and omitting the step of filling the portion corresponding to the flange of the material to be rolled into the hole shape during the pass. That is, take out the test piece from the material to be rolled in the intermediate pass of the widening hole type and the unfilled pass of the shaping hole type,
The vertical and horizontal dimensions and symmetry of the shape of the flange were investigated. As a result, it was found that even in the unfilled pass, the above-mentioned problem with the profile can be rolled without any trouble not only in the breakdown but also in the material passing property in the intermediate coarse universal mill in the next step. Based on the above experimental results, the rolling roll used for rolling the final product H600 × 300 is the same roll as the breakdown roll with the same web height and small flange width. Examples of typical rolling will be described below.

First of all, the breakdown finish dimension of the rough shaped material for H600 × 200 is the same as the standard by the conventional rolling method, the web thickness is 80 mm,
The flange thickness was 137 mm, the web height was 870 mm, the flange width was 286 mm, and the slab thickness used was also 250 mm. The difference from the above-mentioned breakdown finish dimension of the comparative material H600 × 300 is that only the flange width is set to be 100 mm smaller. When rolling such a rough shaped material, the premise is that no reduction in the width direction of the flange portion is performed in all passes of the breakdown mill.
Therefore, the rolled material flange width (F ₀ ) after the final edging pass at Caliber K-3 is as follows from the equation (2).

F ₀ = (T ₀ −T ₁ ) × β + F ₁ = (250−80) × 0.57 + 286 = 96.9 + 286 ≈383 mm That is, 96.9 mm in the above equation is the flange width reduction due to the web pressure. Next, the total edging amount necessary to obtain the flange width of 383 mm is However, 133 mm is the flange width expansion amount, and is the product of the total edging amount and the flange width expansion ratio. Therefore, the total edging amount is 182 mm and the flange width expansion ratio is 0.73 from the relationship in the graph of FIG. 2 (a).
Becomes

That is, the width dimension of the raw material slab is the total edging amount plus the Caliber K-3 finishing web height of 850 mm, so the required slab width dimension is slab width = 850 + 182 = 1032 mm.

Table 2 is a pass schedule of the above examination results. The flange width in the table is the bottom width (S ₂
= 450 mm, S ₃ = 480 mm) and the hole gap between the upper and lower rolls is 386 mm when the web gap is 80 mm in the shaping hole type, it is clear that it is narrower than the hole bottom width in all passes.
In the present invention, only the final pass of the caliber K-1 has a hole-like shape and fills the flange-corresponding portion of the material to be rolled. The reason is that if the first stage caliber K-1 hole type that forms a V-shaped groove on the side surface of the slab is filled with the flange equivalent part symmetrically with respect to the web center axis of the material to be rolled, caliber K-
This is because it has been confirmed that the object of the present invention can be achieved even in the hole type of 2 or later and the portion corresponding to the flange is not filled. In the present invention, only the first hole type of the flange widening hole type is specified so that the flange corresponding portion is filled.

FIG. 1 illustrates the shaping process of the present invention, in which the outer shape of the material 51 to be rolled in the final pass in each of the flange widening hole types K-1 to K-3 and the shaping hole type K-4 is represented by a virtual line. It shows with. That is, comparing with the conventional shaping process based on FIG. 6 described above, the flange equivalent portion of the rolled material 51 of the final pass in the K-2, K-3 and K-4 except for the caliber K-1. The feature is that the width of is smaller than the hole bottom width (S ₂ , S ₃ , S ₄ ).

In carrying out the present invention, first, on the premise of using a breakdown roll having a hole-shaped design for a predetermined H-section steel product series, a breakdown width narrower than the flange width originally produced by the roll is used. Determine the finished dimensions. Next, the flange width shrinkage amount with respect to the total web reduction amount in the shaping hole type is obtained to obtain the flange width in the final pass of the widening hole type. Subsequently, the edging amount required to supplement the flange width shrinkage amount is obtained, and the value obtained by adding the target breakdown finish web height to this edging amount is set as the width dimension of the slab to obtain the target flange width. It is possible to obtain a rough finished material having a breakdown finish.

〔The invention's effect〕

According to the method of the present invention, not only the rough rolled material for H-section steel which can be originally rolled by the rolls but also various series of rough rolled materials having the same web height and narrow flange width are rolled by one set of breakdown rolls. It will be possible. As a result, since the rolls can be shared, the number of rolls prepared can be reduced and the roll purchase cost can be reduced. In addition, roll maintenance costs and roll reassembling work can be saved, and a wide storage space is not required.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining the rough shaping means of the present invention, FIG. 2 (a) is a graph showing the relationship between the flange width expansion ratio and the total edging amount, and FIG. 2 (b) is a schematic diagram for explaining the flange generation. FIG. 3 (a) is a graph showing the relationship between the flange width shrinkage ratio and the in-web method, FIG. 3 (b) is a schematic drawing of the dimensions of the rolled material for explaining the flange width reduction, and FIG.
FIG. 5 is a layout view of a universal rolling apparatus train for shaped steel, FIG. 5 is a schematic view showing a roll hole type arrangement of a breakdown mill, and FIG. 6 is an explanatory view of a conventional rough shaping procedure. 1 …… Breakdown mill 11 …… Upper and lower rolls of breakdown mill 1a …… Center bulge 1b …… Groove 2a …… First intermediate coarse universal mill 2b …… Second intermediate coarse universal mill 3a, 3b …… Edger mill 4 …… Finishing universal mill 5a …… V-shaped groove 5 …… Slab

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 59-53121 (JP, B2) JP 59-42563 (JP, B2) JP 58-19361 (JP, B2) JP 58- 37042 (JP, B2)

Claims (1)

[Claims] 1. A plurality of flange widening hole dies having a central bulge portion in the widthwise center of the hole bottom and grooves on both sides of the central bulge portion, and a shaping hole die for pressing down the web portion and the flange portion. Using a double-hole type roll having the above, using a rectangular cross-section steel slab as a raw material, the flange widening hole type widens and rolls the side surface corresponding to the H-section steel flange by interruption rolling of the side surface corresponding to the H-section steel flange and edging in the web height direction Subsequently, in the rolling method for the rough rolled material for H-section steel, which is performed by the shaping hole type shaping rolling,
The width dimension of the rectangular cross-section steel piece was previously determined from the increase amount of the flange width with respect to the total edging amount in the web height direction in the flange widening hole type and the decrease amount of the flange width due to the web reduction in the shaping hole type. A rectangular cross-section steel piece is used, and the flange width of the rolled material after the final pass in the hole types other than the first hole type and the shaping hole type among the flange widening hole types is made narrower than the hole bottom width of the hole type. A variable flange width rolling method for a rough rolled material for H-section steel, characterized in that rolling is performed in a hole shape such that the flange equivalent portion of the rolled material is not filled.