JPS61212401A - Method for edging taper slab - Google Patents

Abstract

PURPOSE:To obtain a slab made approximately uniform in width at the time of the next horizontal rolling, by changing the amount of edging in the longitudinal direction in sequence, in consideration of the width restoration produced after the horizontal rolling, to be performed in succession to the continuous edging of a taper slab. CONSTITUTION:A taper slab 8 is rolled down in a hot state by an anvil 6. In case of changing the setting of an opening of anvil 6 at the next edging, the position of anvil 6 is changed while the anvil 6 is raised from its bottom dead point to the top one. For instance, the opening of anvil 6 is opened to advance the slab 8 by a prescribed amount. The slab 8 is edged when the anvil 6 descends to the most rolling-down point again, but its width after edging is different because the opening is changed. When the slab is edged, in such manner, from the front end of slab to its rear end, the slab width, obtained after succeeding horizontal rolling, is made approximately constant when a taper slab is used as a starting stock in edging.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) In continuous steel casting, when the width of a slab is changed during casting, a slab whose width is tapered is transiently generated. Similar to ordinary slabs, this slab also needs to be finished into a uniform width belt by hot rolling at the yield surface.

Regarding technology for changing the width of slabs supplied to continuous hot rolling mills,
In particular, we will discuss the results of development research on improving the continuous medium reduction method by pressing slabs with tapered width shapes.

Slabs used in continuous hot rolling are generally manufactured by continuous casting, but the width of continuous casting slabs is limited and it is necessary to adjust the width of the slab in order to obtain the desired product. This is a commonly used conventional width changing technique.
This is H sizing rolling. Among these, in V rolling, when the slab is bitten, the slab is continuously rolled down in the width direction, and usually
The slab width on the rolling exit side is constant.

Of course, when a slab with a tapered width is V-rolled, a slab with a constant width can be similarly obtained, but since the width reduction amount is different in the longitudinal direction, the dogbone shape is different in the longitudinal direction. When the slab V-rolled in this way is horizontally rolled,
The thickened portion of the tonk bone spreads in the width direction, but in a taper slab, the shape of the tonk bone differs in the longitudinal direction, so the amount of width spread also varies in the longitudinal direction, making it impossible to obtain a slab with a constant width.

(Prior Art) As a new width reduction method for V-H sizing, there is a width reduction press +H sizing disclosed in Japanese Patent Application Laid-Open No. 101201/1982, but even in this case,
Since width reduction is performed so that the width of the taper slab after width reduction remains constant, it is not possible to obtain a slab with a constant width after H rolling.

When width-rolling such a taper slab, if it is rolled so that the width of the plate after width rolling is constant, the width of the plate after horizontal rolling will not be constant.

(Problems to be Solved by the Invention) It is an object of the present invention to enable width reduction of a tapered slab in which the width of the slab can be made constant despite width reversion that inevitably occurs due to horizontal rolling subsequent to width reduction. .

(Means for Solving the Problems) This invention, when continuously reducing the width of a taper slab by hot pressing, takes into account the width return after horizontal rolling that follows this width reduction, and adjusts the amount of width reduction in the length direction. Perform width reduction by changing sequentially,
This is a tapered slab width reduction method that is characterized by obtaining a slab with a constant slab width after horizontal rolling.In short, the width reduction method of a taper slab is performed by taking into account the width return amount in horizontal rolling of a dogbone slab due to width reduction. The key is to vary the amount of width reduction in the longitudinal direction of the slab.

The explanation below will be based on the width reduction of a tapered slab according to the present invention, but to briefly touch on the behavior when width reduction is performed on a more general rectangular slab, in this case, the width direction is Δ
When the slab is rolled down by −0 and horizontally rolled, a width expansion Δ1 occurs. The width reduction efficiency l at this time is defined as follows.

η is usually initial slab width -0, thickness TIIN temperature θ1 width reduction amount Δ-0, horizontal reduction amount ΔHI+ roll diameter, R1・-
It is expressed as follows using functions such as ...-.

η−η(W,, TO, θ, Δen., ΔH+, R+−・)
-(1) Fixing the width reduction amount other than Δ-0, ΔH,
The relationship η-η (Δen.) between and η is shown in Figure 1.

Now, the taper slab l whose planar shape is shown in Fig. 2(a)
The slab width at points A and B is -. ,, Minoru. , and so on.

The planar shape after width reduction by a press is shown in FIG. 2(b), and the reduction amount at point A' (corresponding to point A) and point B' (corresponding to point B) is 6w. 1. The score shall be 8-01. Moreover, the width (target width) of the slab 3 whose planar shape after subsequent horizontal rolling is shown in FIG. 2(c) is -. Here, the relationship is organized as follows.

L=Woa-ηΔ-0,-1. 3−ηΔ−0,−(2)
However, η=η. Therefore, the width reduction amount at points A and B can be obtained by solving the following equation.

η (Δ−0A)・Δen. 1 = Ga. a −W+ −(
3) −1η (Δ−0,)・Δ−0. =-0,-W,
-(3)-2 The installation positions of the width reduction press 4 and the width gauge 5 are shown in FIG. At the same time as the slab passes the width gauge 5, the slab width is measured, and the above formula +31-1 is calculated from the target width after horizontal reduction and the initial slab width. +31-2 is solved to determine the amount of width reduction at each point in the longitudinal direction of the slab. From this, the opening degree of the press anvil 6 is -. , -Δ-0. ．． -0. -81. Set as 8.

Such opening adjustment of the press anvil 6 is performed by a high-speed width adjustment device 7.
It will be held in

(Function) In other words, as shown in Fig. 4, when the slab 8 is rolled down by the anvil 6 (a) and the anvil opening setting changes in the next width reduction, the anvil 6 moves from the bottom dead center to the top dead center. Change the position of the anvil by a high-speed width adjustment device while rising to the point (mouth). The figure shows a case where the opening is opened, and at the same time the slab is advanced by a predetermined amount by the high-speed slab conveying device 9.

When the anvil 6 reaches the maximum reduction point again (c), the slab 8 is rolled down, but since the opening degree is changed, the width of the slab after the width reduction is different between the previous reduction and the current reduction.

By performing this width reduction method from the tip to the rear end of the slab, width reduction using the taper slab 1 as a starting material,
The width of the slab after subsequent horizontal rolling can be made substantially constant, such as 1.

FIG. 5 shows the relationship between the width reduction amount Δ-0 and the width reduction efficiency η.

η is a multivariable function as shown in equation (1), but here, the initial slab width is 1200 to 2000 tm and the thickness is 2
The width reduction efficiency when 20 Tsuru's material is reduced by Δ-0 = 100 to 350 f1 width and horizontally reduced to the initial slab thickness by horizontal rolling is summarized. The width reduction efficiency η is a linear function of Δ-0. It turns out that it can be approximated.

(Example) Table 1 shows the width of a slab with a length of approximately 6 to 8 mm when the tapered amount slab 8 is rolled down in width and then horizontally rolled.The target width is to change the maximum slab width by 300 w width. I decided as. Also, in horizontal rolling.

The ground slab is being rolled down to its initial thickness.

Table 1 Slab Width After Horizontal Rolling In the width reduction press, it is not possible to change the slab width continuously in the longitudinal direction, so approximately 2 (maximum) unevenness 11 is produced at the end of the slab 10 after horizontal rolling. However, the slab width (measured at the recess) was able to be kept within the target width + 10 m. Note that the width of the leading end and the width of the trailing end are the portions excluding the unsteady deformation region as shown in FIG.

(Effects of the Invention) According to the method of this invention, a slab with a tapered shape can be reduced to a medium level by a press and then horizontally rolled into a slab of almost uniform width, without impeding efficiency. ,
The improvement in yield through the use of taper slabs is remarkable.

[Brief explanation of drawings]

Figure 1 is a diagram showing the relationship between I-η (Δ), Figure 2 is an explanatory diagram showing changes in slab width, and Figure 3 is the relationship between width reduction press equipment and width gauge. FIG. 4 is an explanatory diagram of how to change the opening of the anvil, FIG. 5 is a diagram of the width reduction efficiency obtained in the experiment, and FIG. FIG. 7 is a plan view of the slab after horizontal rolling. 1--Initial taper slab 2--Slab after width reduction press 3--Slab after horizontal rolling 4--Width reduction press 5
- Width meter 6 - Anvil 7 - High-speed width adjustment device a- Varnish slab 9 - High-speed slab conveyance device Fig. 4) q Death, Hiroshi 1 sho slab reduction during preparation Fig. 5 Width reduction amount ΔWo ( mat)

Claims (1)

[Claims] 1. When a taper slab is subjected to continuous width reduction by hot pressing, the width reduction is performed by sequentially changing the width reduction amount in the length direction, taking into consideration the width return after horizontal rolling that follows this width reduction, and after horizontal rolling. A tapered slab width reduction method characterized by obtaining a slab with a constant slab width.