JPS58181402A - Hot broadside rolling method - Google Patents

Abstract

PURPOSE:To obtain a hot rolled plate of the width much wider than the original width of a slab by subjecting the transverse central area of a slab to grooving rolling down with a roll having a rolling down body of a min. width and performing the stepwise width reduction rolling down in the remaining areas on both sides in succession to the central area with rolls having rolling down bodies of successively increasing widths. CONSTITUTION:Plural rolls having the rolling down bodies which are narrower in width as compared to the width of a slab and differ mutually in the width with respect to the other are prepared. The transverse central area of the slab is first subjected to local grooving rolling down with the roll having the rolling down body of a min. width. The stepwise width reduction rolling down in the remaining areas on both sides in succession to said area where the groove width is increased is accomplished with the rolls having the rolling down bodies of successively increasing widths. The unrolled down areas remaining along both side edges of the slab are thereafter rolled with flat rolls.

Description

[Detailed Description of the Invention] The invention relates to a hot-rolling method, and
From the special 61tk on JJl Tsuru, we are trying to propose new development results for advantageously obtaining thick plates and hot-rolled plates that are much wider than slab ledgers among various plate widths. It is.

Conventionally, slabs used as rolling materials such as thick plates and hot-rolled plates have been made exclusively by blooming rolling of steel ingots, so it has been possible to deal with relatively low valleys by ingot-forming or blooming rolling according to product dimensions. Ta.

However, in recent years, the continuous WJe and @I manufacturing methods, which are more advantageous in terms of quality and cost) have become popular, and more recently, processes that directly connect this to #1 rolling have been adopted. In the process of continuous casting, slabs of different widths are produced.However, the necessary use of molds and the operation of changing the molds are both labor-intensive and time-consuming. In the case of a continuous hot pressurization process, it is necessary to reduce the number of slab tanks to a minimum.
It is said that doing so is more convenient in terms of production and quality.

Therefore, during hot rolling, it is essential to change the radius of the transmission material, which is narrower than the slab width (4kiIw).
! Although width reduction or width division is also a necessary procedure, so-called tenter rolling is particularly important when a plate elongation that far exceeds the width expansion associated with slab rolling is required.

For tenter rolling of slabs, after the forming bath in which the thickness of the slab is slightly reduced in the longitudinal direction, as in conventional plate rolling, it is horizontally turned 90' and rolled between rolls in the width direction. After repeated sheet threading and rolling until the width matches the product width! It is customary to turn the sheet by +90 degrees and roll it to M final plate thickness VC.

When performing rolling with a 90° turn, the threading length may be shorter or shorter (
・So-) The whole area is affected by unsteady rolling at the front and rear ends of rolling. In other words, as illustrated in each step in Figure 1) to (F), the slab l that has undergone the forming pass shown in Figure 1 (A) K is subjected to QO' rotation (Figure 1 (B)) and then transformed into Figure 1 (H). ), the center of both the front and rear edges of the width rolling protruded, as shown in the same figure. , Furthermore, the A-A' cross section of the same figure shows a 90° portrait rotation as shown in the same figure (E), with an eyebrow-shaped double bulge ((G) produced in the rolled material 1', and the same figure (F) J). There was a disadvantage that the double bulge IJ was folded along both side edges f in the subsequent longitudinal rolling, and in each figure, a is the short side of the slab, b is the long side, and the width is directional rolling tik
Cl) As shown above, the fact that the 90' turn is repeated twice and fills the mouth of the raw meat by 1 inch is the reason why the planar shape of the upper pi is particularly cone-shaped and dove-shaped. Due to the addition of half a five step trade decline to the basic one, it is no longer suitable for rational thick plate or hot rolled ()) raw machining/U-tsuin made of continuous disease j blue soup material. It is.

On the other hand, in the central region in the width direction of the slab l regarding the rolling,
Attempts have been made in the past to add a local downstream roll using a roll 8 or 4 with an annular protrusion such as that shown in Figure 2. However, such rolls were generally only incorporated into the hot mass rolling process, and the rolls were used to roll the grooved plate + Al#1 produced locally downstream of the roll. The surface-shaped groove 11 is glued with a roll in Figure 8 fal, part 2, z, tal, and the N6 section is removed at the groove bottom y, and the remaining area r downstream of - is the original slab. Since the thickness remains unchanged, during subsequent rolling by the pair of flat rolls 5 shown in FIG. Elongation in the rolling direction is likely to occur, and effective width expansion cannot be fully expected, and the planar shape after rolling with the pair of flat rolls 5 is shown in FIG. It is easy to cause a tongue-like capital t on the edge and a defective shape, and the results obtained by the roll shown in Fig. 2 fbl of this fish nest are almost the same.

In other words, in the partial rolling method such as Oki, although the width due to the local reduction at the beginning of the trowel is greater than that in flat roll rolling, the overall width of the slab is not so large. It is important to adequately deal with the wide-ranging demands for expansion of the four, such as those that seek to suppress the number of types of people to a minimum while also satisfying all the inevitable board members.

Now, according to the inventors' horizontal materials, in order to bring the rolling surface of the slab to a beautiful and refreshing appearance, first, it was necessary to roughly measure the rolling surface of the slab by non-rolling. Applying strong grooving pressure, and reducing the thickness by expanding the width from the center of the slab toward both sides.
The key condition for avoiding restraint in Ivc is and <gi
It turned out to be important.

Here, the unrolled cross-sectional lateral ratio is shown in Figure S, for example.
When forcing the groove forming pressure F on the transfer center area of the slab l with the roll 6 having a narrow reduction side at, the non-pressure F
The total cross-sectional area So of the slab with a cross-sectional area SF0 of 4411 minutes
It is expressed as the ratio F'a/Bo. The inventors have determined that between the stretching ratio λ in the rolling direction and the unpressed F cross-sectional area ratio "" Fo/Bo and C/-2, based on numerous experimental results (σ) in cases where the slab dimensions vary sharply over a wide range, It was submitted that Figure 6 shows 71 Kushita phase 1 arrow IJ). Here, the stretching ratio λ is < the ratio of the slab length after stretching to K to the slab length t before stretching. As is clear, SFo/8o achieved a high score (・Cheng,
There is little elongation deformation due to mosquitoes, and this is due to the reduction area IF 6;
The metal flow towards the LE side is the dog, ;+lF
This is because it is restrained by 1 need oil > PI, and as a natural consequence of suppressing elongation deformation in this way, the width increases. Incidentally, in normal slab flat roll rolling, 8Fo/60 is 0, and the elongation deformation is maximum.

Next, the center groove in the width direction thus obtained is sequentially subjected to thickness reduction reductions 8 and 9 as shown in FIG. 7, which cause the groove width to expand in the +@ direction. teeth(
・So-called freedom I2! Since there is no material outside of lCt, metal flow in the direction perpendicular to this easily occurs during rolling. Here, as shown in Fig. 7, the above-mentioned grooving pressure σ)
The residual areas ri and r on both sides are divided into several sections in the width direction, respectively, into divided areas d, , d,'.

(For each 1, a, d, ', the width becomes wider/-σ) Rolls with pressure cylinders apply gradual reduction, and in this way, the metal 70- facing both 1-Yamada 4 is applied in the width direction. It is extremely effective in obtaining a significantly wide range of results. On the other hand, an unrolled area F is left in the center of the rolled material, and a thinning pressure F is applied to both sides of the unrolled area. Stretchy [)shi, big and wide &'! It can't be expected (・.

Both sides of the rolled material are rolled during each step-by-step, sequential thinning reduction.
If the upper and lower surfaces are restrained by contact with the rolls, the spreading will be restricted and the metal flow will have to change to elongation in the rolling direction, so the free end will remain unrestricted. Yes (Rina l width spread cannot be obtained).

In this way, π, one foot, from the − slab, each step 4
ic M lv + rolling reduction amount (which makes it possible to perform the necessary width widening due to the troublesome width widening, and the rolling of the rolled material with a slight leakage on both sides fle of the material to be rolled) allows various machines to be rolled. ``We can't get Shima's thick plates or hot-rolled plates.

#81m lal ~ fdl K, KoC') Invention K El U'm lh L-Pressure't= Each stage,
11 is a roll having an EFT cylinder with a different f width for each stage, and each of them is attached p(,31, ibl・=tol, (n+i)
The distinction between stages is t1, soil f, and 9, and 4(a) to t.
dl, well, each stage 8: 4 tons of rolled material before and after rolling
The planar shape of l l is shown in its cross-sectional shape.

@ Figures 10 fal and fbl show an example of the roll shape of the w71.1 stand and the third stand, which are particularly suitable for use in carrying out the present invention, where W represents the rolling reduction amount, and subscripts 1-4 wl is BQ when differentiated by
Om, y, 400I1312ws is 800mm, W is 20001111, cross section 1200XROO■
After heating a continuously cast slab of 1250'cK as a raw material, first, a roll with a rolling width w0 was used to make a two-pass groove reduction in the center width area with a 1-pass compressor with 50 rolls, and then a rolling @w.
, , w are used to sequentially apply a stepwise thickness reduction with a thinner width to the remaining regions on both sides of the grooving reduction with the same amount of reduction in each of the widthwise divided regions, and then Chihei roll lol
In 2 passes of step 4, the friction-reducing pressure was applied to the unpressurized areas on both sides.

The full width spread ratio at each rolling stage, that is, the ratio of the width after rolling to the ledger, changes as shown in Figure 11. Here, when the material thickness BQQtm is reduced to 10001, the full width spread ratio of the spear is 1. .4, it is noticeably larger. Incidentally, the full width spread ratio at a similar reduction of 1 in normal flat rolling is approximately 1.018.

The above example describes the case with two stands, but if each roll is divided into one stand for multi-stand tandem rolling, and usable rolling is performed only on a single stand, the width widening effect can be improved. , can be realized similarly, and also in each roll mother as above *#! In addition to performing i-bath rolling, it is also possible to make the rolling amount of each roll the same and repeat it over several cycles.

According to the present invention, one of the rolled materials is
The local grooving reduction in the center area of the reduction and the subsequent gradual thickness reduction F in both residual areas are each Kb, and the cross-sectional area of the material part that is not affected by the reduction during each reduction is Since the metal flow in the width direction, which is effective under dependent elongation control, significantly increases the width of the width, it contributes to the enhancement of productivity in the rolling process, especially through the process of making continuous slabs. Large writing.

[Brief explanation of the drawing]

Figures 11a) to (f) are explanatory diagrams showing the conventional method of tentering rolling at the valley rolling stage, wXz diagrams + al and fbl are explanatory diagrams of the rolling procedure in another conventional method of tentering rolling, Figure 8 ( at, fbl are explanatory diagrams showing the planar shape immediately after rolling and after flat rolling, FIG. 4 is an explanatory diagram of the flat rolling behavior, and w and FIG. 6 is a graph showing the influence of the unrolled cross-sectional area ratio 8Fo/B0 on the drawing ratio λ, FIG. 7 is a cross-sectional view explaining the divisional rolling method according to the basic idea of the present invention, and FIG. (a) - fdl, Fig. 9 fal - Id) are a cross-sectional view and a plan view showing the stepwise rolling procedure according to the present invention, and Fig. 10 fat and Ibl are used for each stand of the first and second groups. FIG. 11 is a graph showing the width expansion ratio of each corrugated roll. 11ial, 111b)...l 1fnl: Rolls with mutually different rolling cylinders, 11(n+i): Flat roll. Figure 1 Figure 2 (a) 1. l) ) No. 41 λ1 Fig. 5 Fig. 7 Fig. 8 (C) (d. Fig. 9 (a) (b) (C (d) τVlO Fig.) ] r'Kl

Claims (1)

[Claims] When hot rolling an L slab, a plurality of rolls each having a rolling cylinder having a width narrower than the width of the slab and whose width differs from the others is prepared, and the slab is rolled. First, use a roll with the smallest width roll to roll down the central area of the slab in the middle of the width of the slab. For each divided area divided in the width direction of A hot tentering rolling method characterized by applying maximum compensation Vc to the flat roll rolling of the unrolled area that remains after healing.