JPS5844904A - Rolling method for thick plate - Google Patents

Abstract

PURPOSE:To correct tapered shapes in good yields by subjecting a tapered steel material of successively varying widths to taper rolling so as to increase the thickness gradually from the broad side toward the narrow side then turning the rolled material at a right angle and rolling the same with horizontal rolls. CONSTITUTION:After a slab 1 of width W0B on a broad side, width W0T on a narrow side, length L0, and thickness H0 is subjected to ordinary rolling to a thickness H, the slab is subjected to tapered rolling so as to increase the thickness gradually from the broad side toward the narrow side under regulated roll gaps, the upward and downward moving speeds of roll screw-down mechanisms and the number of revolutions of rolls, whereby the slab is rolled to a rolled material 3 having H1T=WOB/WOTXH1B in the thickness W1B on the broad side and the thickness H1T on the narrow side is obtained. The rolled material is rotated 90 deg., and is subjected to ordinary rolling with horizontal rolls from the direction at a right angle to the above-described screw down direction, whereby the thickness 1B or suitable thickness below the same is obtained. Thus the H1T and H1B are made equal and the W0T and W0B equal, and a rolled material 4 of a rectangular shape is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thick plate rolling method for manufacturing a rectangular thick plate using only horizontal rolls without using vertical rolls from a tapered steel material having gradually different widths. .

With recent advances in continuous casting technology, a method has been implemented in which the width of the mold is gradually changed during casting without changing the mold to produce many types of continuously cast slabs with different widths.

In the above method, when changing the width of the mold, gradually different, ie tapered, widthwise sections of the steel material are generated.

When manufacturing thick plates from taper slabs with gradually different widths: 1. Three conventional methods are commonly used. +11 is a method of rolling the slab as it is into a single thick plate and cutting a rectangular thick plate product from the tapered thick plate, (2
) is a method in which the slab is cut in the longitudinal direction to form rectangular slabs of equal width and then rolled, and + +31 is a method in which a vertical whirl is especially provided at an appropriate location in the rolling mill row, and the slab is rolled by this vertical roll. This is a method of correcting a tapered shape in which the width of the plate gradually differs by pressing in the width direction from both sides. .

However, the above conventional methods (1) and (21) all have problems that lead to a decrease in yield, and method (3) has the disadvantage of increasing equipment costs and manufacturing costs. be.

The present invention provides a rolling method that can easily correct the 0-tapered shape of the steel material using only horizontal roll equipment and improve the yield when rolling a thick plate from tapered steel materials with gradually different widths. The purpose of this is to avoid a decrease in yield due to the shape of the slab or an increase in cost due to the installation of vertical rolls.

That is, the present invention involves, in plate rolling, taper-rolling tapered steel materials with sequentially different plate widths into rolled materials having a shape in which the thickness gradually increases from the wide side to the narrow side, and then turning the rear limb rolled material by 90 degrees. Then perform normal rolling with horizontal rolls.
It is characterized by being rolled into rectangular thick plates.

The present invention will be explained below.

Figures 1 (a), (b), (c), and (e) are perspective views showing stepwise examples of changes in the shape or arrangement of rolled materials in the method of the present invention, and arrows (a) indicate rolling Show direction.

(a) shows the shape of the continuously cast slab (1) with a tapered width, (b) shows the shape of the rolled material (2) before one pass of taper rolling, and (c) shows the shape of the rolled material (3) after tapering rolling. ) is the shape of the rolled material (illustration is rotated 90 degrees), (e)
The shape of the rolled material (4) in which the taper shape of the plate width of the rolled material (Hani) has been corrected is shown.

The method of the present invention will be explained in detail based on FIG.

As shown in Figure 1 (a), the dimensions of the continuously cast slab [1] with a tapered width are as follows: WOB in the wide side plate, WOT in the narrow side plate, length to, 7%Ho, and Normally rolled to the thickness (6) before one pass of taper rolling and rolled material (2
). Next, this rolled material (2) is tapered in the direction of arrow (a), and as shown in C→, the plate thickness on the wide side HIB 1 Width WOB % Thickness on the narrow side I (xT % Width WOT 1 Length A rolled material (3) of size L! is obtained.

In the above taper rolling, first, the roll interval is set to an interval that obtains a plate thickness of 1 (tii), and then the lifting and lowering speed of the roll rolling mechanism and the roll rotation speed are adjusted as required, and the rolled material (2) is rolled.
is rolled into a shape in which the plate thickness gradually increases from the wide side to the narrow side. In this case, the medium wave of the rolled material during rolling is so small that it can be almost ignored, so the board width is equal to the slab + 11
Similarly, the wide side is WOB% and the narrow side is WoT. In addition, the plate thickness HIB on the wide width side is set to an appropriate thickness within the range of the rolling reduction rate that can be rolled down without any problem from the plate thickness 2 of the rolled material (2).
, Q. In addition, it is long! ” ” HIT+H
Let the length be one pair of IB.

Next, the rolled material (3) is turned 90 degrees to obtain the rolled material (3).
Perpendicular to the direction of extension? In this direction, obtain a plate thickness of HIB or less. Normally rolled with horizontal rolls with the roll spacing. For rolled material (3), Hrr X as described above.
Since WOT = HIB
The OB is also straightened, and the taper shape of the plate width is corrected, resulting in a normal rectangular rolled material. From then on, the rolled materials (4) to 7
A plank of the desired size is obtained by conventional rolling.

Next, a general method for implementing the method of the present invention by incorporating it into a process computer control system commonly used in thick plate rolling operations will be described.

Figure 2 shows the process for carrying out the method of the present invention (5)
is a rolling mill with upper and lower horizontal rolls [10] Ool,
(B) is a host computer that inputs the necessary data for implementing the method of the present invention; (7) is a process computer that automatically controls the roll reduction amount, roll rotation speed, etc.;
8) is a horizontal roll (a reduction control device that controls the amount of reduction of the sound and is connected to the reduction mechanism (II) (II) of the reduction machine,
9) is a roll speed control device that controls the rotation speed of the roll (!Φ) (connected to the rotation mechanism of the field (1).

A schematic method for automatically controlling the taper rolling shown in FIG. 1 based on FIG. 2 will be described below. However, the rolling mill may be a double rolling mill, a quadruple rolling mill, or the like, and the rolling device is not limited to either an electric rolling method or a hydraulic double rolling method. Also, among the methods below, the first
Symbols for board width, board thickness, board length, etc. used in the figures are used in the same way.

+1) W of receiving slab from upper combiator (6)
Enter dimensions such as OT, WOB, Ho, Lg, etc. and product dimensions into the process computer (7), and enter the cart.

(2) Calculate or measure the thickness (6) before one pass of taper rolling.

+31 Calculation of Htr, Hta (a) Calculate HIB taking into account the load limit and torque limit specific to the rolling mill.

(b) Calculate HIT from Htr=TanX HfB.・f4) Calculation of SIT, SIB, ΔS (a) Since the mill rigidity coefficient is given as a function of the width of the rolled material, the plate width W! The mill stiffness coefficient (MET) of the narrow width part and the mill stiffness coefficient (1!i(I'ts)) of the wide width part are calculated from the above function and WfB according to a conventional method.

(middle) Plate thickness H and HIT %HI before 1 pass of taper rolling
B s woTs WOB etc. are known, so the following formula (
11 (Sims equation) P = 1.15kfmW4'QP 1. +0. +,
+++, [ll where, P: rolling load, kfm: average deformation resistance of material R': roll radius considering flattening Δh: difference between plate thickness before rolling and plate thickness after rolling, W: width of material, QP: Rolling load PIT of narrow width part and rolling load Pin of wide width part from the king blade function
Calculate.

(c) Mill stiffness coefficient of narrow part and wide part (MITIMI
B), thickness (HIT, HIB), rolling load (PITIPI
Since B) is known, the roll spacing of the narrow width section (SIT)
And the roll spacing (SIB) of the wide part is calculated by the following formula +21 +3
1 SIT = HIT - Forceps・・・・・・・・・＋2
) to calculate.

) Required change amount ΔS of set roll spacing during taper rolling
is calculated from ΔS''SIT-SOB.

(5) Calculation of roll elevation speed M during taper rolling and roll rotation speed NWR during taper rolling (() f-c during rolling, h=!=cons,.

While detecting both or either of NWR and V, the command outputs NWR or V so that V π・DWR・ΔS. However, the DWR in the above formula (2) is the lie diameter, and may be input into the process combinator before rolling. ■L,,]! Ω"-1, it is necessary to set a limit range in consideration of the risk of seizing of NWRla bearings, rolling properties, etc.

(6) Taper rolling is performed based on the calculated value of +3+14+(5) above.

Note that the units of symbols in each formula of the above flow are shown in Table 1.

Chapter 1 Table Next, examples of the present invention will be described.

A continuous casting slab with a thickness of 200 m x wide side medium 1800111JIX narrow side width 1750 w x length 2000 mm was produced using a hydraulic submerged rolling mill with upper and lower horizontal work rolls with a roll diameter of 1000 m as shown in Figure 1. An example of rolling a thick plate by the method of the present invention will be described below. In the above-mentioned rolling, taper rolling was carried out based on the values calculated according to the above-mentioned flow using an automatic control device using a process computer shown in FIG.

After uniformly heating the above slab to about 1000° C. in a heating furnace, it was subjected to one pass of normal rolling to obtain a rolled material with a thickness of 185M before one pass of taper rolling.

Next, when attempting to perform taper rolling in one pass, due to restrictions such as rolling load and rolling torque, HIB = 165
If it is m, then 1ist = 170750 out of 165 days.

In addition, the mill stiffness coefficient (MxttMtn) is given as a function of the width of the rolled material as described above, so WOT =: 1750ar in the narrow part according to the usual calculation formula, so Mt
t = 355ttn/m, WOB = 18 in the wide section
Since it is 00saw, MIB = 360w- is calculated, and the rolling load P is positive as P''1.15kfm'Wi, and in the qp formula, kfm = 7.65, R'=
550 [, A11 = wide side 2°, narrow side 15ym,
W com width side 1800ffl, narrow side 1750mm, QP
= 1.8, so the rolling load at the narrow part J'lT =,
The rolling loads P and B of the 21,901 m wide section were calculated to be 3,000 rolls.

Therefore, the required change amount (△S) in the roll spacing is the roll spacing in the narrow part SIT = HIT -- Shuki λfl
T 162.9fl Wide part roll spacing SIB = HIB-E1-11
Since B=156.7*a+, it was calculated as ΔS:SIT SIB262MM.

The required amount of change in the fixed roll spacing is within the control stroke range of the hydraulic cylinder, and rolling is possible.

Next, the length Ll of the material after taper rolling is the aforementioned 2HOL
.

Like! -■Wτ1i, L+=2388
It will be a battle.

Therefore, NwR = 6 kokuto = 5 yen = 7.3.
! :V π'DWR'ΔS πX1000X6.2.

Now, if taper rolling is performed with the lifting speed of the hydraulic lower cylinder at 511 V/S, NWR = 5 x 7.3 = 365 r, p, m
However, this is a work roll rotation speed that is outside the danger range of bearing seizure under the above-mentioned rolling load, and it is determined that rolling is possible.

Based on the above calculation results, taper rolling was performed in one pass using the computer-based automatic control device shown in FIG. 2 from a rolled material (2) with a tapered width and a thickness of 185 mm. The hind limb rolled material was turned 90 degrees, normal rolling was performed in a direction perpendicular to the rolling direction to correct the tapered shape of the width of the board, and then several passes of normal rolling were performed, resulting in a thickness of 12011 x width of 2480.
A rectangular rolled material having a length of 2385 fi was obtained, and thick plate rolling could be performed without reducing the yield.

As explained above, the method of the present invention does not require any special equipment,
Since it is possible to correct the curved shape of the sheet width of the steel material very easily and with good yield, it has a great effect on improving the yield and reducing costs in rolling thick plates from continuously cast slabs with a tapered width. : Interpose.

[Brief explanation of drawings]

Figures 1 (a), (b), (c), and (e) are perspective views showing the method of the present invention step by step, and Figure 2 is an automatic control device using a process computer for carrying out the method of the present invention. FIG. 2 is a schematic diagram showing an outline of the configuration. 1: Continuous casting slab, 2.3.4: Rolled material, 5: Rolled material, 6: Upper computer, 7: Process computer, 8: Rolling down control device, 9: Roll speed control device, 1
0: horizontal roll, 11: rolling mill rolling mechanism, 12: roll rotation mechanism = 1i

Claims (1)

[Claims] (In thick plate rolling, a tapered steel material with gradually different plate widths is tapered into a rolled material whose thickness gradually increases from the wide side to the narrow side, and then the rolled material is
A method for rolling a thick plate, characterized by rolling it into a rectangular thick plate by performing normal rolling with horizontal rolls with a 0 degree turn.