JPS6363501A - Rolling method - Google Patents

Abstract

PURPOSE:To improve product quality and roll life by providing an area having a specifically high longitudinal elastic modulus on the outside periphery in the circular columnar part of a back up roll and positioning the end in said area toward the inside by a prescribed length from the end of a rolling stock then rolling the stock. CONSTITUTION:The back up roll 1 is constituted of the circular columnar part 11 and a tapered part 12 and is formed with the high longitudinal elastic modulus part 13 which has a prescribed thickness h1 and, the longitudinal elastic modulus E of which has >=30,000kgf/mm<2> value on the outside periphery of the circular columnar part 11. Rolling is executed by positioning the ends of the high longitudinal elastic modulus parts 13 of the roll toward the inside by the prescribed length l1 from the respective transverse ends of the rolling stock 3. Tapered parts 12 are relatively flatly deformed and the high longitudinal elastic modulus part 13 has the small flattening deformation. The spacing of the roll 2 near the ends of the rolling stock 3 is, therefore, increased, by which crowns and edge drops are decreased. The product quality and the life of the rolls 1, 2 are thereby improved.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention provides a rolling method using a four-high rolling mill in which reinforcing rolls can be shifted in the axial direction, particularly for reducing plate crown and edge drop of rolled material. The present invention relates to a rolling method that allows rolling.

<Conventional technology> FIG. 9 shows an example of a four-high rolling mill.

The four-high rolling mill includes work rolls 2 that directly roll the rolled material 3;
2, and reinforcing rolls 1, 1 pressed against the work roll.

When rolling is performed using such a four-high rolling mill, as in the four-high rolling mill shown in FIG. In FIG. 11, a plate crown represented by H3-H and an edge drop represented by H2-H are produced.

In particular, take a one-pass reduction rate of 70% or more, - strongly reduce the pressure,
In clad rolling, in which composite metal strips are produced by deformation and pressure welding, extreme edge drop causes end cracks and edge elongation, causing waves in the rolled material, making it impossible to obtain a rolled material with good flatness.

In order to improve such plate crowns and edge drops, a rolling method using a four-high rolling mill equipped with reinforcing rolls that have tapered portions on both sides and can be shifted in the axial direction, as shown in Fig. 12, has been proposed. being tested.

By rolling with a four-high rolling mill in which the reinforcing roll 1.1 having such a taper is shifted, the work roll 2,
2 is given a deflection deformation along the tapered part of the reinforcing rolls 1, 1 to widen the gap between the work rolls 2, 2 near the width direction ends of the rolled material 3, and to reduce the plate crown and edge drop of the rolled material 3. let

However, if the reinforcing roll 1.1 and the work roll 2.2 are made of forged steel, especially in rolling with a large rolling reduction such as clad rolling, the reinforcing roll 1.1 and the work roll 2.
The amount of flattening deformation of No. 2 becomes large. Therefore, the gap between the work rolls 2.2 near the ends in the width direction of the rolled material 3 is reduced, and the plate crown and edge drop are increased.

Furthermore, if the reinforcing rolls 1, 1 and the work rolls 2, 2 are made of the same material, the unevenness caused by burn-in, scratches, or abrasion of the work rolls 2, 2 will be directly transferred to the reinforcing roll 1.1, and the reinforcing rolls 1, 1 The circumferential surface of the reinforcing roll 1.1 is rough.
lifespan becomes shorter.

In addition, using a reinforcing roll bender or a work roll bender is effective in reducing plate crown and edge drop, but it has drawbacks such as the need for a large bender load in rolling with a large rolling reduction such as clad rolling. Futa.

<Problems to be Solved by the Invention> The purpose of the present invention is to eliminate the drawbacks of the prior art described above, more reliably reduce plate crowns and edge drops,
Another object of the present invention is to provide a rolling method that can improve the life of the rolls.

〈Means for solving problems〉 Such objects are achieved by the present invention as described below.

That is, the present invention provides rolling using a four-high rolling mill that is composed of a pair of work rolls that directly roll a rolled material, and a pair of reinforcing rolls that apply compressive force to the work rolls and are shiftable in the axial direction. In this case, each reinforcing roll is composed of a substantially cylindrical column part and a tapered part at one end or both ends thereof, and has longitudinal elasticity at a predetermined thickness from the outer peripheral surface over at least the entire circumference of the column part in the circumferential direction. Coefficient E is 30000
A reinforcing roll having a high longitudinal elastic modulus portion having a value of Kgf/, lllm2 or more is used, and the end of the high longitudinal elastic modulus portion of the one reinforcing roll is located a predetermined length inward from one widthwise end of the rolled material. and shifting the pair of reinforcing rolls so that the end of the high longitudinal elastic modulus portion of the other reinforcing roll is located inside the other widthwise end of the rolled material by a predetermined length. The present invention provides a rolling method characterized by the following.

EMBODIMENT OF THE INVENTION Hereinafter, the rolling method of the present invention will be described in detail with reference to preferred embodiments shown in the accompanying drawings.

An example of the configuration of a four-high rolling mill used in the method of the present invention is shown in FIG.

The reinforcing roll 1 used in the method of the present invention mainly consists of a cylindrical part 11 that contributes to rolling of the rolled material and tapered parts at one or both ends of the cylindrical part 11 (hereinafter referred to as reinforcing roll tapered part 12). The longitudinal elastic modulus E is 30,000 K at a predetermined thickness hl from the outer peripheral surface over the entire circumferential direction.
It has a high longitudinal elastic modulus portion 13 having a coefficient of gf/mm2 or more.

Note that the taper angle (indicated by 01 in FIG. 1) of the reinforcing roll tapered portion is preferably about 1 to 1.5 degrees.

This high longitudinal elastic modulus portion 13 has a longitudinal elastic modulus E of 30,000.
Kgf/mm2 or more material, such as tank stainless steel (
W), alumina (AJ2203), wc-CO sintered alloy, titanium oxide (TiN), molybdenum (Mo), silicon nitride (Si3N4), etc.
1 and the reinforcing roll tapered portion 12 are made of a material whose longitudinal elastic modulus E is smaller than the above-mentioned materials, such as forged steel, Fe-Ni alloy,
It is formed of Fe-based alloy, copper, copper alloy, etc.

Note that the longitudinal elastic modulus E of the high longitudinal elastic modulus portion 13 is 30,000.
If it is smaller than Kgf/mm2, the effect of reducing plate crown and edge drop will be insufficient, as shown in the examples below.

A pair of reinforcing rolls 1.1 of such a four-high rolling machine are
As shown in the figure, a high longitudinal elastic modulus portion 1 of one reinforcing roll 1
The end of 3 is a predetermined length longer than one widthwise end of the rolled material 3 as shown in 1 in FIG. The end of the high longitudinal elastic modulus portion 13 of the other reinforcing roll 1 is a predetermined length longer than the other widthwise end of the rolled material 3 (indicated by 01 in FIG. 1). Shift and roll as follows.

The length of λ1 is preferably about 10 to 30% of the width of the rolled material 3, or about a length corresponding to a portion of the rolled material 3 where edge drops are expected to occur.

Note that the reinforcing roll tapered portion 12 is not necessarily the same as the columnar portion 11.
It does not have to be formed on both ends of the edge drop, and may be formed only on the side involved in edge drop reduction. The same applies to other configuration examples described later.

When rolling is performed using such a four-high rolling mill, the reinforcing roll 1 has a high longitudinal elastic modulus section 13 on the outer periphery of the columnar section 11 and a longitudinal elasticity section 13 on the side end of the columnar section 11. Since the reinforcing roll tapered part 12 is made of a material with a small modulus, the high longitudinal elastic modulus part 13 hardly undergoes flattening deformation, and the flattening of the reinforcing roll tapered part 12 does not occur, as shown exaggeratedly in FIG. Deformation is relatively large. The flattening deformation of the reinforcing roll 1 at this time is shown, for example, in FIG. 2 as a change from a two-dot chain line to a solid line. For this reason, the deflection deformation of the work roll 2 along the reinforcement roll tapered portion 12 due to the shift of the reinforcement roll 1 increases, and the gap between the work rolls 2.2 near the widthwise ends of the rolled material 3 widens. Therefore, the plate crown and edge drop of the rolled material 3 are reduced.

FIG. 3 shows another example of the structure of the reinforcing roll of the four-high rolling mill used in the method of the present invention. The positional relationship between this reinforcing roll and the rolled material during rolling is the same as that of the four-high rolling mill shown in FIG. 1. The same applies to FIGS. 4 to 6 described below.

The reinforcing roll 1 shown in FIG. 3 has a high longitudinal elastic modulus portion 13 formed so as to form a crown toward the center of the roll body of the reinforcing roll 1.

In FIG. 3, hl is the thickness near the center of the high longitudinal elastic modulus section 13, and h2 is the thickness at the end of the high longitudinal elastic modulus section 13. Further, 1° is the width of the tapered portion of the high longitudinal elastic modulus portion 13. Note that this tapered portion does not need to be formed at both ends of the high modulus of longitudinal elasticity portion 13, and may be formed only on the side involved in reducing the edge drop of the rolled material 3. Moreover, h2=0 may be sufficient.

The high modulus of longitudinal elasticity part 13 is reinforced with the tapered part 1 of the roll in this way.
2, the change in rigidity from the cylindrical portion 11 to the reinforcing roll tapered portion 12 becomes smooth, and edge drop is improved more smoothly.

Also, in order to obtain the effect described in F.
The reinforcing roll 1 is not limited to the structure shown in the figure, but any structure in which the thickness of the high longitudinal elastic modulus part 13 gradually decreases toward the side end of the cylindrical part 11 as shown in Fig. 4 can be used. A reinforcing roll having a high longitudinal elastic modulus portion with a cross-sectional shape may also be used.

Even in such a case, the cross-sectional shape of the high longitudinal elastic modulus portion does not need to be bilaterally symmetrical, and it is sufficient that the thickness of the high longitudinal elastic modulus portion gradually decreases at least toward the side that participates in edge drop reduction.

Further, the high longitudinal elastic modulus portion 13 whose thickness gradually decreases is not limited to the outer periphery of the columnar portion 11, but may be formed extending to the outer periphery of the reinforcing roll tapered portion, as shown in FIG.

By using a reinforcing roll having such a high longitudinal elastic modulus portion, edge drops can be smoothly reduced.

FIG. 6 shows another example of the structure of the reinforcing roll of the four-high rolling mill used in the method of the present invention.

In the example shown in FIG. 6, the high longitudinal elastic modulus portion 13 is formed to have a crown on the roll surface side.

In this case, the taper angle of the high longitudinal elastic modulus portion 13 (0 in FIG.
2) is approximately 1 degree.

When such a reinforcing roll is used, it is possible to improve the plate crown of the rolled material due to the crown of the reinforcing roll, and to improve edge drop due to the deflection deformation of the work roll as shown in FIG. 2 due to the shifting of the reinforcing roll.

In each of the above configuration examples, when the high longitudinal elastic modulus part 13' is formed into a sleeve shape, the high longitudinal elastic modulus part 13 is mechanically combined with the cylindrical part 11, and silver soldering is performed after this combination. , casting (casting), mechanical assembly (
Join by an appropriate method such as press-fitting (screwing) or sintering.

<Example> Hereinafter, the present invention will be described in more detail by giving examples of the present invention.

[Example 1] In the four-high rolling mill shown in FIG.
mm, the taper of the reinforcing roll tapered part 1 is 1 degree, the width of the cylindrical part 13 is 120 mm, and the reinforcing roll tapered part 12 is
And the longitudinal elastic modulus E of the cylindrical part 13 is 21000 Kgf.
/+nm2, and the longitudinal elastic modulus E
The high longitudinal elastic modulus part 13 is made of a wc-co sintered alloy with a gf/mm2 of 63000 gf/mm2, and the thickness hl is 50 m.
m, the width is 120 mm, and the reinforcing roll 1 is mechanically assembled (screwed) and press-fitted so that the width is 120 mm.
m, length 200non work roll 2 and 11 in Fig. 1
were combined so that the distance was 15 mm. Using this 4-high rolling mill, Fe-42% with a width of 50 mm and a plate thickness of 1.5 mm was produced.
The Ni alloy strip was rolled in one pass to a thickness of 0.45 mm.

[Example 2] High longitudinal elastic modulus portion 13 in the reinforcing roll 1 shown in FIG.
The thickness h2 at the end is 5 mm, and the thickness hl at the center is 50 m.
m, the width 12 of the tapered part of the high longitudinal elastic modulus part 13 is 50 mm.
Rolling was carried out in the same manner as in Example 1, except that.

[Comparative Example 1] Rolling was performed in the same manner as in Examples 1 and 2, except that the reinforcing roll 1 having the same shape as in Examples 1 and 2 was formed of forged steel having a longitudinal elastic modulus E of 21000 Kgf/mm2.

The plate crown, edge drop, and cross-sectional plate thickness distribution profile of the rolled materials in Example 1.2 and Comparative Example 1 were compared.

Note that the edge drop measurement position differs somewhat depending on the material, shape, rolling conditions, etc. of the rolled material, but in this specification, the edge drop measurement position is
As shown in Figure 1, the edge drop was measured at a position 5 mm from the end in the width direction of the rolled material.

The results are shown in Table 1 and FIG.

Table 1 As shown in Table 1, compared to Comparative Example 1, Examples 1 and 2 showed remarkable improvement in plate crown and edge drop.

This is also clear from FIG. 7, which shows the cross-sectional thickness distribution profile of the edge drop region of the rolled material.

In FIG. 7, the cross-sectional plate thickness distribution profile in the edge drop region of Example 1 has fewer steps than that of Comparative Example 1, and furthermore, the profile of Example 2 is even smoother.

In Examples 1 and 2, the edge drop was reduced, so compared to Comparative Example 1, the generation of waves and the amount of rolling at the ends of the rolled material in the width direction were reduced, and as a result, the edges of the rolled material in the width direction were reduced. Due to reduced burn-in on the work roll surface,
The occurrence of wear grooves on the reinforcing roll was no longer observed.

[Example 3] In the reinforcing roll 1 of a four-high rolling mill shown in FIG. A 4-high rolling mill similar to that in Example 1 was used, except that sintering (hot isostatic pressure sintering treatment) and joining was performed so that the length hl was 50 mm. %Ni alloy strip was rolled in one bath to a plate thickness of 0.4 mm.

1, 7 [Example 4] The high longitudinal elastic modulus portion 13 has a longitudinal elastic modulus E of 35000 K
Rolling was performed in the same manner as in Example 3, except that tungsten (W) having a gf/mm2 was used.

[Example 5] The high longitudinal elastic modulus portion 13 has a longitudinal elastic modulus E of 41000 K.
Rolling was carried out in the same manner as in Examples 3 and 4, except that alumina (Aj2203) having a gf/mm2 was used.

[Example 6] The high longitudinal elastic modulus portion 13 has a longitudinal elastic modulus E of 64,000 g
Rolling was carried out in the same manner as in Examples 3.4 and 5, except that the sintered alloy was made of wc-co sintered alloy with a diameter of f/mm2.

[Comparative Example 2] The high longitudinal elastic modulus portion 13 was made of forged steel with a longitudinal elastic modulus E of 21000 and gf 7 mm2, and the cylindrical portion 11 and the reinforcing roll taper portion 12 were made of forged steel with a longitudinal elastic modulus E of 1250.
0 Kgf/mm2 except for the +2-
-1 Rolling was performed in the same manner as in Examples 3.4.5 and 6.

[Comparative Example 3] Rolling was performed in the same manner as in Comparative Example 2, except that the high longitudinal elastic modulus portion 13 was formed of silicon nitride ceramic (Si3N4) having a longitudinal elastic modulus E of 25,000 and gf/+nm2.

[Comparative Example 4] Rolling was performed in the same manner as in Comparative Examples 2 and 3, except that the high longitudinal elastic modulus portion 13 was formed of silicon nitride ceramic (513N4) having a longitudinal elastic modulus E of 28000 Kgf/mm2.

The plate crown and edge drop of the rolled material were compared for each side.

The results are shown in Table 2 and FIG.

O Table 2 As is clear from Table 2 and FIG. Compared to the comparative example in which the elastic modulus E is 30,000, which is smaller than gf/mm2, the effect of reducing plate crown and edge drop is remarkable.

<Effects of the Invention> According to the rolling method of the present invention, by providing the high longitudinal elastic modulus portion on the outer periphery of the reinforcing roll cylindrical portion, the flattening deformation of the reinforcing roll tapered portion during rolling is less than that of the high longitudinal elastic modulus portion. It gets bigger. Therefore, the deflection deformation of the work roll along the reinforcement roll tapered portion due to the shift of the reinforcement roll becomes large, and the gap between the work rolls near the widthwise end of the rolled material widens. Therefore, the plate crown and edge drop of the rolled material are reduced.

By reducing the edge drop, it is possible to prevent the occurrence of waves in the rolled material due to edge cracking, edge elongation, etc., and a rolled material with good flatness can be obtained.

Furthermore, since the substantial reduction amount of the widthwise end portions of the rolled material is reduced, seizure or grooves do not occur on the surface of the work roll, and the lifespan of the reinforcing roll and the work roll is improved.

Furthermore, edge drop is improved by incorporating reinforcing rolls with a high longitudinal elastic modulus into a conventional shiftable rolling mill without requiring a large penta device in the rolling mill, making it an industrially effective edge drop. This is a reduction method.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of the configuration of a four-high rolling mill used in the method of the present invention. FIG. 2 is a partially sectional view showing an exaggerated state in which the method of the present invention is implemented. FIG. 3, FIG. 4, FIG. 5, and FIG. 6 are cross-sectional views showing various configuration examples of reinforcing rolls of a four-high rolling mill used in the method of the present invention. FIG. 7 is a diagram showing cross-sectional plate thickness distribution profiles of rolled materials obtained by Examples and Comparative Examples of the method of the present invention. FIG. 8 is a diagram showing a plate crown obtained by an example and a comparative example of the method of the present invention. FIG. 9 is a schematic front view for explaining a general four-high rolling mill. FIG. 10 is a front view showing the rolling state when the general four-high rolling mill shown in FIG. 9 is used. FIG. 11 is a cross-sectional view of a rolled material for explaining plate crowns and edge drops. FIG. 12 is a schematic front view for explaining the four-high rolling mill with the reinforcing rolls shifted. Explanation of symbols 1... Reinforcement roll, 2... Work roll, 3... Rolled material, 11... Cylindrical part, 12... Reinforcement roll taper part, 13... High longitudinal elastic modulus part

Claims (4)

[Claims] (1) When rolling a material using a four-high rolling mill consisting of a pair of work rolls that directly roll the material and a pair of reinforcing rolls that apply rolling force to the work rolls and are shiftable in the axial direction, Each reinforcing roll is composed of a substantially cylindrical cylindrical part and a tapered part at one or both ends of the cylindrical part, and has a longitudinal elastic modulus E of 30,000 Kgf at a predetermined thickness from the outer peripheral surface over at least the entire circumference of the cylindrical part in the circumferential direction. /mm^2 or more, using a reinforcing roll having a high longitudinal elastic modulus part of the one reinforcing roll, such that the end of the high longitudinal elastic modulus part of the one reinforcing roll is a predetermined length inside the one widthwise end of the rolled material. and shifting the pair of reinforcing rolls so that the end of the high longitudinal elastic modulus portion of the other reinforcing roll is located inside the other widthwise end of the rolled material by a predetermined length. A rolling method characterized by: (2) The rolling method according to claim 1, wherein the thickness of the high longitudinal elastic modulus portion varies in the roll axis direction. (3) The rolling method according to claim 2, wherein the high longitudinal elastic modulus portion extends to the outer periphery of the tapered portion. (4) The rolling method according to claim 1 or 2, wherein the cylindrical portion has a spindle shape whose diameter decreases continuously from the axial center of the cylindrical portion toward both ends.