JPH0245521B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thick plate rolling method for manufacturing thick steel plates having different width dimensions with a high yield.

Traditionally, thick steel plates have been made to order, and the dimensions (width and length) of the steel plates that are ordered vary widely. Conventionally, thick steel plates with different dimensions are produced by combining a plurality of thick steel plates 1, 1, 2, 2 to form a steel plate 3 of a single size, as shown in FIG. It is manufactured by shearing into 2.2. However, as shown by diagonal lines in the figure, a loss portion 4 occurs and the yield decreases, so it is advantageous to form steel plates of different widths that are similar in size to the combined thick steel plates. FIG. 2 is a diagram showing the steel plate having different widths. Reference numeral 1 indicates three thick steel plates with wide dimensions, 2 indicates two thick steel plates with narrow width dimensions, and 5 indicates steel plates with different widths. As a manufacturing method for such steel plates of different widths, the thickness of the rolled material is changed by changing the amount of reduction in the middle of rolling the heated slab.
There is a method in which this rolled material is turned 90° to perform widening rolling. FIG. 3 is a diagram showing the conventional rolling order of steel plates of different widths. In the figure, ⇒ indicates the pass transition, and → indicates the rolling direction. A is a slab, and this slab 6 is made into a rolled material 7 in the shape b having different wall thicknesses in the rolling direction by changing the reduction rate during the initial forming pass rolling. Next, roll this rolled material 7 at 90°
A method of turning and widening pass rolling to obtain a rolled material 8 having a shape of c, and then turning this rolled material 8 by 90 degrees and performing forming bath rolling to form steel plates 9 of different widths from the intermediate part. It is. However, as shown in FIG. 3a, this method has the disadvantage that the width change of the stepped portion 10 between the wide width portion and the narrow width portion is slow, resulting in a large amount of cutting during shearing.

This invention eliminates these drawbacks by making the width change of the stepped part steeper to form a steel plate with different widths that more closely approximates the width of the assembled product, thereby reducing the amount of cutoff during shearing and increasing the yield. This was done for the purpose of improving the rolling material, and after forming a rolled material having a recess with a thinner wall at a predetermined position in the middle of the rolled material during the rough forming pass at the initial stage of rolling, the rolled material was turned 90 degrees to form the above-mentioned shape. By performing tentering rolling until the thin-walled concave portion disappears, a rolled material having a concave portion in which the thin-walled concave portion forming portion becomes narrow in the tentering direction is formed, and this rolled material is further turned 90 degrees and subjected to forming pass rolling. I do. In the middle of this forming pass rolling, the amount of reduction is changed at the narrow recess position as a boundary to create a rolled material with a thickness difference in the rolling direction, and then this rolled material is further turned 90 degrees and rolled. This method is characterized by rolling steel plates of different widths having planar shapes with different widths from the middle part.

The present invention will be explained below based on the drawings. FIG. 4 is a diagram showing the rolling pass transition in the case of manufacturing a steel plate having different widths in which the top portion and the bottom portion have different width dimensions according to the present invention. ⇒ in the figure is the path transition →
is the rolling direction. Reference numeral A denotes a heated slab, and after forming and rolling the slab 11 in two or three passes in the longitudinal direction, a strong reduction is applied to a predetermined position in the middle of the rolled material to form a thin recess 13. B is a rolled material 12 in which a recess 13 is formed. Next, this rolled material 12 is turned 90 degrees and width rolling is performed until the recess 13 disappears. C shows the rolled material 14 after width rolling.The concave portion 13 formed in B is thin and the width is smaller than other thick parts, so the middle part of the rolled material 14 is narrow. Thus, narrow portions 15 are formed on both widths. Continue with this rolled material 14
Rotate 90° and perform forming pass rolling. In the final pass of this forming pass rolling, the amount of reduction is changed at the narrow portion 15 as a boundary to form a rolled material whose wall thickness changes in the rolling direction. D shows the rolled material 16 having different wall thicknesses.
Subsequently, this rolled material 16 is turned 90 degrees and width pass rolling is performed to a predetermined rolling width. At this time, the amount of width expansion differs depending on the difference in wall thickness, and the area before the narrow part 15 is thin and therefore has a narrow width, and the area after the narrow part 15 is thick and therefore has a wide width.

The rolled material 17 formed in this manner is shown in E. Subsequently, this rolled material 17 is turned 90° and finish rolled to the final thickness, as shown in F, resulting in a stepped part 10 indicated by a solid line with a steeper change in width than the stepped part 10 indicated by two-dot diagonal lines obtained by the conventional method. A steel plate 18 of different widths having attached portions 19 is formed. This stepped part 19
In this case, the formation of the narrow part by forming the recess and the forming of the wall thickness difference during the forming pass combine to make the width change more steep (acute angle), resulting in a steel plate with a different width having a shape that approximates the predetermined product width. This reduces the amount of time cutoff and improves yield.

Next, Figure 4B is necessary to obtain the above-mentioned steel plate with different widths.
When calculating the dimensions of the rolled materials 12 and 14 shown in FIG. Therefore, if the rolling length (L ₁ ) is the sheet thickness (T ₀ ), then L ₁ =t ₀ ×w ₀ ×l ₁ /w ₀ ×T ₀ ……(1) This formula (1) When the length calculated in is reached, the amount of reduction may be changed to form the recess.

Note that the length can be measured using a length meter or the like that uses rotation of a roll.

Further, the length of _L2 can be determined in advance by the amount of thickness reduction to a desired depth, and the rolling speed and the rolling speed for adjusting the distance between the upper and lower rolls to a desired distance.

Next, the depth (T ₀ - T ₁ ) of the moldable recess 13 is:
It depends on the length of the thickness change portion (L ₆ ) of the rolled material 16 in FIG. 4D. In other words, this thickness change part (L ₆ )
As the length increases, the length of the stepped portion 19 of the different width steel plate 18 shown in FIG. It is preferable to make the length (L ₆ ) of the thickness change part as short as possible. Therefore this length (L ₆ )
The maximum depth that the recess can be formed within the same length range is 1/2 or less of the plate thickness variation ΔT (T ₂ - T ₃ ).

Next, the amount of plate thickness variation △T (T ₂ - T ₃ ) during forming of the rolled material 16 in figure D is △T/T ₂ = △w/w ₀ ...(2), and △w= (w ₀ −w ₁ ).

From this, △T=T ₂ ×△w/w ₀ ……(3) Therefore, T ₃ =T ₂ −△T=T ₂ (1−△w/w ₀ ) ……(4) This (4) ) The rolled material 16 is formed by changing the rolling reduction amount at the narrow portion or when the length (L ₅ ) is reached so as to have the thickness calculated by the equation (2).

Next, a case will be described in which a steel plate 20 of different widths is manufactured, as shown in FIG. 5, in which the top and bottom portions have approximately the same width and the center portion has a wider width.

The method of manufacturing the steel plate 20 of different widths is substantially the same as the method of rolling the steel plate 18 of different widths having different widths at the top and bottom portions shown in FIG. 4F, and will be described with reference to FIG. 4.

After the heated slab 11 is formed and rolled for two to three passes in the longitudinal direction, a strong reduction is applied to a predetermined position in the middle of the rolled material to form a thin recess 13. Subsequently, the rolled material 12 having the recessed portion 13 is turned 90° and widening pass rolling is performed until the recessed portion 13 disappears, thereby forming the rolled material 14 having the narrowed portion 15.
This rolled material 14 is turned 90 degrees and subjected to forming pass rolling to a length that provides a predetermined rolling width, and in the final pass of this forming pass rolling, the amount of reduction is changed to change the thickness of the rolled material 16 in the rolling direction. form. Subsequently, this rolled material 16 is turned 90° and rolled until it reaches a predetermined thickness, thereby forming a steel plate 20 of different widths, as shown in FIG. 5, in which the top and bottom parts have approximately the same width and the middle part has a wider width. .

Next, examples of the present invention will be described.

Example 1 Wide thick steel plate 2 of 10mm thickness x 3000mm width x 6000mm length
In manufacturing three narrow steel plates of 10 mm thickness x 2800 mm width x 6000 mm length, 215 mm thickness x 1615 mm width x
After heating a 2840mm long slab to a specified temperature, it is formed and rolled in two passes in the longitudinal direction to form a slab of 200mm thick x 1615mm wide x
After rolling the material to a length of 3053mm, it is 1230mm from the bottom.
Change the amount of reduction from (L ₁ ) to a depth of 2.9mm.
(T ₀ −T ₁ /2) After forming a circular concave portion with a length of 710 mm (L ₂ ) on the front and back surfaces, it was turned by 90° and width rolling was performed to a plate thickness of 180 mm to form a narrow portion. Subsequently, this rolled material was turned 90 degrees and the narrow part (from the bottom side
1230mm) and change the reduction amount to increase the bottom plate thickness.
After making the plate thickness at the 180mm top part 168mm, it was turned 90° and widening rolled to a wide part of 3100mm and narrow part 2900mm, then turned 90° and finished rolled to a thickness of 10mm, as shown in Figure 6. As shown, steel plates with different widths were obtained in which the top and bottom widths of the rolled material were different. As can be seen from Fig. 6, a steel plate with different widths is formed which has a stepped portion shown by a solid line that is steeper than the stepped portion of the conventional rolled material with different widths shown by a two-dot chain line, and as a result, the yield is 0.4 compared to the conventional one.
% improved.

Example 2 Two thick steel plates 10mm thick x 1500mm wide x 11000mm long and one thick steel plate 10mm thick x 1500mm wide x 9000mm long.
To manufacture one thick steel plate with a thickness of 10 mm x 1500 mm width x 11000 mm length, a slab of 215 mm thickness x 1615 mm width x 2014 mm length is heated to a specified temperature and then formed and rolled in two passes in the longitudinal direction, resulting in a plate thickness of 142 mm x 1615 mm width. After making a rolled material of ×3015mm, change the amount of rolling from 1598mm (L ₁ ) from the bottom to form a circular recess with a depth of 3mm (T ₀ - _{T 1} /2) and a length of 735mm (L ₂ ). Thereafter, the material was turned 90 degrees and widened to a thickness of 130 mm to form a narrow portion. Subsequently, this rolled material was turned 90 degrees and the reduction amount was changed at the narrow part (1598 mm from the bottom side), so that the thickness of the bottom part was 130 mm and the thickness of the top part was 118 mm.
mm, then turned 90 degrees and rolled to a predetermined thickness of 10 mm to obtain a steel plate of different widths, with the top and bottom parts having approximately the same width and the middle part having a wider width, as shown in FIG.

As can be seen from Fig. 7, a steel plate of different widths is formed which has a stepped part shown by a solid line that is steeper than the stepped part of the conventional steel plate of different widths shown by a two-dot chain line, and as a result, the yield is improved by about 0.35% compared to the conventional one. .

As described above, the manufacturing method of the present invention sharply changes the width of the stepped portion to approximate the width of the finished product, thereby reducing the amount of cutoff during shearing, and is highly effective in improving yield.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a conventional steel plate, Fig. 2 is a plan view showing a steel plate of different widths, Fig. 3 is a drawing showing the rolling order of a conventional steel plate of different widths, and Fig. 4 is a top view of the present invention. FIG. 5 is a plan view showing the rolling order of steel plates of different widths having different widths at the bottom, and FIG. 7 is a diagram showing dimensions of a steel plate of different widths according to Example 1 of the present invention, and FIG. 7 is a diagram showing dimensions of a steel plate of different widths according to Example 2 of this invention. In the figure, 1... Steel plate with wide width dimension, 2... Steel plate with narrow width dimension, 3... Steel plate with single dimension, 4... Loss part, 5... Steel plate with different widths, 6... Slab, 7... Rolled material with different shapes of wall thickness, 8... Rolled material after width rolling, 9... Different width steel plate with different dimensions, 10... Stepped portion, 11... Slab, 12... Concave portion formed Rolled material, 13... Concavity, 14... Rolled material subjected to widening rolling, 15... Narrow portion, 16... Rolled material with different wall thickness, 17... Molded rolled material, 18...
Different width steel plate having stepped portion, 19...Stepped portion, 20
...The center part is a steel plate of different widths.

Claims (1)

[Claims] 1 Rough forming pass at the initial stage of rolling After forming a recess where the thickness becomes thinner at a predetermined position in the middle of the rolled material during rolling, the rolled material is turned 90 degrees and tenting rolling is performed until the thin recess disappears. By this, a rolled material having a concave portion in which the thin-walled concave portion forming portion becomes narrow in the width direction is formed, and this rolled material is further turned 90 degrees to perform forming pass rolling, and the narrowing portion is formed in the middle of this forming pass rolling. The method is characterized by changing the amount of rolling with the width recess position as a boundary to form a rolled material with a difference in wall thickness, and then turning this rolled material further 90 degrees and rolling to roll steel plates with different width dimensions. A thick plate rolling method.