JPS5933006A - Method for preventing rupture of plate in cold rolling - Google Patents

Abstract

PURPOSE:To prevent the rupture of a plate without decreasing rolling efficiency by performing rolling under low tension when the length of an edge crack exceeding a set value is detected on the down stream side of a stand in excess of the total draft at which the edge crack is generated. CONSTITUTION:A detector 9 for edge crack length is provided on the downstream side of a stand in excess of 60% total draft at which an edge crack is generated in a cold rolling mill having 5 stands for cold rolling a rolled material 6 of a hot coil. The detection signal thereof is fed to an edge crack controller 10. The signal is compared with the set value of the reference edge crack length corresponding to the rolling conditions inputted from a seter 11 for edge crack length and when the detected length is larger than the set value, a control command is fed to a rolling mill controller 12 which controls the driving device 4b and rolling down device 4c of a rolling mill 4a, thereby performing rolling down under low pressure and preventing the rupture of the plate; at the same time, rolling mills 1a-3a are controlled whereby rolling down under high pressure is accomplished and the decrease in the rolling performance is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing plate breakage during cold rolling, and more specifically, the thickness and appearance of hot coils are 60 mm or more, rolling, adding, and rolling mill stands. downstream i#l
l1vcO: In addition, ・Perform low-tension rolling as necessary to prevent plate breakage during rolling.・Relate to the cold rolling method.

In a general tandem/□ mill, the tension between the two leads is 1"5 to 365 to 36 cracks with a low resistance of 1" to 4L. .

Kon:-゛Ah! '□The rolling force of the plate between the ball stands and the rolling force 1 and 2, which immediately die under low tension, is increased due to the rolling load on the Due to the bad situation, the 8th occurrence of the problem, the increase in fib'' causes the production capacity to bottom out and the bottom is lower than 6. □ -'□□: □ 5゛On the other hand, ordinary - E
I: In a, the hot gong 4 storage room 1 cold pressure □ is carried out, but the supporting temporary end is nitrided 4 □ and 1 cold pressure □ is applied to the 1 □ chair n. Of course, □: A total of 60 or more ゛pressure f was applied to the edge of the board) while looking at the hot goil shape.
61 was lost, and the ear cracked □ and the board broke and the board broke.゛If this plate is 6I/Wr, it is a normal □pressure gong: ``There is a lot of pressure under tension, and there are many □Rugs, and the total □reduction rate is high (especially 10 inches and 9 tops). At Mu, the operating rate of the equipment w'tB'H is above □δze? There is,
.

There are many unknown points: <, same lot material e) Sho/Nobu□
・□ also has different cracking conditions in each ear, so the board breaks.

If you apply low-tension rolling just because there is a possibility of this happening, it will lower the rolling force.

Therefore, in the method of the present invention, 1. A cold rolling method that detects long rolling and performs low tension rolling on all rows at the necessary time to ensure overall high rolling efficiency.
provide

That is, in the case of cold rolling with a plurality of rolling mills, the total reduction rate from the exit side ay rolling and the horizontal rolling of the material is 60. % 'fr Exceeding of the rolling mill stand on one or H2 sides downstream from the rolling mill stand ll1
At lVc, measure the long hair sound at the end of the plate, and measure this]4
- Standard ear 1Ill of cracked feldspar set according to rolling conditions
When f'L is longer than the length, low tension rolling is performed completely as a percentage.

, N below, the method of the present invention will be explained in detail.

,, x'17, the inventors have determined that the additional tension during cold pressing □
The relationship with the Neil rupture rate is shown in Figure 1.
+7/It was as shown. .

Figure 1 shows the final total of 9□2.5% for the lower part and relates to the tension between +4 and 5 stands. Tension ``1''L, :I''C'' on about lO chill of deformation resistance, -
,"-Sukeshipunkyufuda 7"ru.

10,000, plate breakage kr1. @ bending end 9 ears 11tlf1.
tff, map for trimming, 1. Although this is affected by the contamination of foreign matter into the pressed cicada material and the force condition of the inner blade of Milvite during rolling, there is a possibility that the edge side of the paulownia charcoal and plate breakage may occur.
Fi is closely related to... When the present inventors investigated this point, the result was as shown in FIG. 2.

Figure 2 1 shows the relationship between the penetration length and the incidence of fracture at the end of the plate on the exit side of the final stand. When the length increases to about 10 mm, the rupture rate increases rapidly.

In short, from the relationships shown in Figures 1 and 2, it can be concluded that 1. Detecting the side-to-side deviation during rolling, and then lowering it to a certain standard value (this standard value is determined by the rolling condition cost, and the above-mentioned 10 times) By setting the color development rate of adzuki bean, it is possible to suppress the color development rate above the standard value 9. For those with Nagajuku, set tension, (as shown in Figure 1) 10
%) The incidence of fractures can be suppressed by performing tension rolling under a certain temperature.

7, the palm pressure on the ear side fL) is generated above the 1 rate 60 yen, and the pressure i [as shown in Fig. 3,
A gap at the end 6a of the plate of the rolled material 6.

y-fr+. Therefore, the ear side □,n can be detected by a conventional method, for example, by a detection device consisting of a fluorometer and its photoreceiver. 1. Ta, ear @IJfLj-1
The total reduction rate from hotco and il is approximately 60%9.

Therefore, it is sufficient to detect the ear 1111t''L long awn using the normal tandem mille with 4+3 stand J-J descending.However, the total reduction rate is high and the plate breakage occurs Moreover, it is most effective to install it between the rolling mill stands including the final stage abutment, which has a high tension setting.

Therefore, the method of the present invention will be explained in detail using the rolling apparatus shown in FIG. 4 as follows.・First, FIG. 4 shows the arrangement of the rolling device 11 in which the method of the present invention is carried out.
It is a mill equipped with 5 units, nondo'f, and ≠4 stands, and 9 is installed in the ear crack length detection device. .

"-z"r, co4""'1゛゛4""j (i-!?
. In effect, tension control is performed between +4 and +5 stands.

Also, in the m4 diagram, the symbols] a, 2a, 3a'
b4a, 58 is the work roll of each stand, Ib.

2b, 3b, 4b, 5bU drive motor, lc,
.

2C, 3C,... 4c, 5c are rolling devices, ■ is rolling
:1.11 Material, ■5. ■Niso□zo□Saio7. Lee, Yatoga,
■□□ Indicates John Leal.

When rolling is carried out in the usual manner with the above-mentioned Ei-h condition, the rolling bar is under the tension shown in FIG. According to the tenth aspect of the present invention, during pressing, the detection device kQ&c detects the ear split j71. If a long piece is detected 12 and exceeds the reference value shown by the point spinning in Fig. 2, the signal from the detection device 9 is sent to the plate breakage control device io, and the signal is sent to the plate breakage control device io to determine whether this selvedge is stoned or the reference selvage 111J.
It is determined that the reference length from the A length setting device 11 has been exceeded.7
′! : If so, send the on signal to the control device (to) 32,
For example, the allowable tension C]ν) determined from the example shown in FIG.
In the dotted line area 1, the rolling conditions are controlled as shown by the dotted line in Figure 415 (setting device).
Set it to a long time).

1. If the tension chipping is reduced in this way, the product thickness will increase dramatically, so the control device 12 automatically controls the H-rolling conditions so that the normal plate thickness is obtained. For example, control is carried out such that the tension is increased by +3 to 4 stands.1. In this way, by the method of the present invention, all materials that are expected to break in the plate will be subjected to low tension stress, and Rather than rolling at the risk of risk, high production efficiency can be achieved by locally rolling with low Vr build-up force.

Furthermore, (a) the case where the conventional method allows temporary breakage and the fc field is polished, (b) the case where low tension rolling is performed to prevent the temporary breakage, and (c) the case of rolling with the method of the present invention. When the pressure 1# and the capacity 4+ were calculated for the total rolling reduction ratio, the results shown in FIG. 6 were obtained.

In Fig. 6, symbol (a) is σ conventional method, (b) is low tension rolling, (9 is the method of the present study, and from this Mj, according to the method of the present invention, a significantly crushed Ei = frog is achieved. I know what will happen.

As explained in detail earlier, the present invention @ is by Lord Shi1, <D
Ef=, rolling mill stand ν) When cold rolling the hot coil f with the cold pressure a- with the upper roller, the total reduction rate from the hot coil of the rolled material a exceeds 60 qb from the finishing stand. On the inside of the rolling mill stand above one or two pieces of downstream steel, measure the re-crack length of the plate end 1, and use the name of this re-crack length or the standard ear fJn set according to the rolling conditions.
When the length is longer than the length, a low tension pressure mechanism is applied to K.

Therefore, breakage of the plate end portions can be effectively prevented during cold rolling of the hot coil, and since the rolling is carried out only locally at low tension, rolling efficiency does not decrease.

[Brief explanation of drawings]

1st button F3: Graph showing the relationship between the tension applied to the rolling mill stand and the fracture occurrence rate, No. 28! Is J the relationship between fracture incidence and re-cracked feldspar? Fig. 3 is an explanatory diagram of an example of the re-division of the root end, and the fourth factor is a layout diagram of an example of a device that implements the method of the present invention, and Fig. 5 a shows the method of the present invention and a conventional example. FIG. 6 is a graph showing the rolling capacity of the method of the present invention, the conventional method, and the low tension rolling method. Codes 1a to 5a... Pressure machine work roll 1b
~5b---Rolling mill drive unit Tk'IC~5C・
...Reducing device of the rolling machine 6 ...Rolled material 7
...Payoff Reel II'
""' (918... tension reel 9... ear side n, length detection device 10... ear tt+r+- control device) 2...
...Rolling mill control system patent originator: 111 Saki Steel Co., Ltd. Patent attorney Yoshikatsu Matsushita Fraudulent Fumio Sajima 1''. Diagram: Total sword "Five seasons (%)"

Claims (1)

[Claims] ・Hot coil cold rolling is carried out in a cold rolling mill with multiple rolling mill stands. Side 1: ・The individual was determined. When the standard re-crack length is longer than □, VC#''r low tension rolling is performed Characteristic cold Ek: In the ground: Plate fracture
Prevention methods, laws.