JPS5916530B2 - cold rolling method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention solves the problem of partial over-pickling due to abnormalities in the cross-sectional shape of the base metal during cold rolling, large thickness differences in the welded joints of coils with different thicknesses, and troubles in the pickling process. This relates to a rolling method that reduces damage caused by rolling troubles caused by sudden changes in plate thickness, etc.

Due to the cross-sectional shape of the base material during cold rolling, for example, there is an extreme difference in the thickness of both edges, there is a large difference in thickness at the welded connection part of two strips of different thickness, or there are problems in the pickling process. If the thickness of the plate suddenly changes due to partial overpickling due to a long stay in the acid bath, rolling troubles such as breakage or narrowing of the ST-IJ tube will occur during cold rolling.

For example, if a plate breaks at high speed, it takes more than three hours to return to normal operation due to roll replacement and scrap disposal.

Therefore, in order to prevent the occurrence of such rolling troubles, conventionally the rolling speed has been increased when cold rolling the abnormal parts based on the information communication regarding the various abnormalities found during the hot rolling or pickling process. Although the speed was reduced to prevent trouble, there were drawbacks such as the inability to obtain accurate information and the difficulty in enforcing this information.

The present invention eliminates such conventional drawbacks, and the thickness HD of the strip inside the both edges is reduced by a distance sufficient to exclude the edge drop portion of the thickness of the strip at the entrance side of the cold rolling mill.
, Hw and the plate thickness Hc at the center of the plate width are measured at regular intervals Δt, and ΔH1=l HD−Hwl and ΔH2= l (Ha) t (Ha) t
+Δt;, and for ΔH1, ΔH obtained in advance from past rolling work results is calculated according to the plate thickness and Iiyama.
Compare the allowable value Qij of 1 and the allowable value Pi of ΔH2 obtained in advance from past rolling work results according to the plate thickness for ΔH2, and calculate ΔH1≦Qij and ΔH2≦Pi.
If one or both of these conditions are not satisfied, it is determined that there is an abnormality, and the rolling mill is automatically decelerated.

An embodiment of the present invention will be described in detail below with reference to the drawings.

First, as shown in Fig. 1, a thickness gauge
D and W inside the ran (approximately 50m7IL is appropriate)
A total of three units will be installed at each point and point C in the center of the board.

Note that RT is a tension reel and RP is a payoff reel.

And these thickness gauges are XD, Xw and Xc respectively.
The plate thicknesses measured there are HD, Hw, and H6.

The plate thicknesses HD, Hw and Hc are measured at regular intervals of Δt (approximately 200 m5ec is optimal), and the measured values are calculated and taken into the machine as ΔH1-I HD Hw l and ΔH2=l (Ha)t (Ha)t+Δt
1, and for ΔH1, according to the plate thickness and Iiyama, the allowable value of ΔH1 obtained in advance from past rolling work results Q I J 1 For example, thickness 2.3 m, mX width 100
For base material less than 0 mm, 100μ, and for ΔH2, depending on the plate thickness, the allowable value Pi1 of ΔH2 obtained in advance from past rolling work results, for example, 30μ for a thickness of 2 or 3 mm.
If ΔH1>QtJ, the cross-sectional shape of the base material is defective
If ΔH2>Pt, it is determined that there is a sudden change in plate thickness, and the computer issues an automatic deceleration command to the rolling mill S to cause the rolling mill to decelerate.

In this way, even if rolling troubles such as breakage or squeezing occur, damage can be minimized and the operating rate can be improved.
Improvements in roll consumption, etc. can be measured.

In other words, what used to take more than three hours to deal with an accident can now be done in about 10 minutes.

100 by a 5 stand cold rolling tandem mill according to the invention
In production of 1,000 tons/day, the number of breakage accidents that used to occur 5 times a month has decreased to 0, and the number of breakage accidents that used to occur 40 times a month has decreased to 5 times a month.

As a result, the operating rate improved by 3% and the roll consumption rate improved by 150 G/T.

As explained above, the method of the present invention has the effect of minimizing rolling troubles caused by abnormalities in the cross-sectional shape of the base material or sudden changes in plate thickness.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the arrangement of equipment used in the cold rolling method according to the present invention, and FIG. 2 is a plan view showing the installation position of a thickness gauge.

Claims (1)

[Scope of Claims] 1. On the entrance side of the cold rolling mill, the thickness HD, Hw of the plate inside the both edges and the thickness Hc of the central part of Iiyama by a distance enough to exclude the edge drop part of the plate thickness of the strike IJ tube. It is measured every fixed time Δt, and ΔH1=lHD−Hwl and ΔH2=l(Ha)t−(Ha)t+Δt1 are calculated, and for ΔH1, according to the plate thickness and Iiyama,
Compare the allowable value Qij of ΔH1 obtained in advance from the past results of rolling operations, and the allowable value Pi of ΔH2 obtained in advance from the results of past rolling operations for ΔH2 according to the plate thickness, When either or both of ΔH1≦Qij and ΔH2≦Pi are not satisfied, it is judged as abnormal and the rolling mill is automatically decelerated. Rolling trouble caused by abnormal cross-sectional shape of cold rolling base material and sudden change in plate thickness. method of reduction.