Metal deforming – With use of control means energized in response to activator... – Metal deforming by use of roller or roller-like tool element
Reexamination Certificate
2000-06-23
2001-04-17
Tolan, Ed (Department: 3725)
Metal deforming
With use of control means energized in response to activator...
Metal deforming by use of roller or roller-like tool element
C072S008300, C072S011200, C072S365200
Reexamination Certificate
active
06216503
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to a hot rolling method in which finish rolling is continuously performed. This invention particularly relates to a method for setting operating conditions for hot rolling facilities, which is capable of speedily and accurately performing setting changes regarding rolled material for which was planned endless rolling, wherein a preceding piece of material and a subsequent piece of material are joined each other at the entering side of a finishing mill, to batch rolling, wherein rolling is performed without joining the preceding piece of material and subsequent piece of material, or performing setting changes from batch rolling to endless rolling.
2. Description of Related Art
Conventionally, in hot rolling process, slabs are heated in a reheating furnace, and the slab extracted form the reheating furnace is subjected to rough rolling, and then finish rolling is performed for each roughed sheet bar, i.e., a batch rolling operation has been performed to manufacture steel strips, such as thin articles. However, in recent years, so-called endless rolling operation has been performed to manufacture steel strips, such as thin articles. In these operations, the tail end (rolled) of a preceding material is joined to the head end (rolled) of a subsequent material between a roughing mill and finishing mill, which is repeatedly performed so as to continuously perform finish rolling of the preceding material and the subsequent material.
FIG. 4
schematically shows an apparatus
10
for endless rolling. During the endless rolling operation, the tail end
12
of the preceding (downstream) material
14
and the head end
16
of the subsequent (upstream) material
18
are joined to each other at a sheet bar joining machine
30
provided between a 3-stand roughing mill
20
, for example, and a 7-stand finishing mill
40
, for example, so that finish rolling is continuously performed with the preceding material
14
and the subsequent material
18
being joined. A strip shear
50
for cutting the rolled material is provided downstream from the finishing mill
40
, and multiple coilers
60
(two are shown) are provided downstream from the strip shear
50
, so that the rolled material is subjected to finish rolling in the state in which the preceding material
14
and the subsequent material
18
are joined and is cut by the strip shear
50
into lengths which the coilers
60
can take up, with the rolled material preceding the cutting point, and the rolled material following the cutting point, being taken up on separate respective coilers.
Continuous finish rolling can be performed in the state in which the preceding material
14
and the subsequent material
18
are joined to each other by such an endless rolling operation, so there are no inconsistent portions at the head and tail ends in the finish rolling of individual sheet bars as with batch rolling, and stable rolling can be performed over the entire length of the rolled material. Thus, this arrangement is suitable for the rolling of rolled material for which the passage of inconsistent portions is difficult, such as with thin articles.
Operation condition (OC) settings for the facilities within such a hot rolling line are made by computer, as shown in FIG.
5
. That is, for each slab (material to be rolled), product information (PI) (slab thickness, slab width, product thickness, product width, specifications, etc.) are inputted to an on-line computer
70
, the on-line computer
70
sets the operating conditions (OCI) (tension between stands in the finishing mill, coiling tension, rolling speed, rolling temperature, draft schedule, conditions for cooling rolled material, etc.) for initial settings for the hot rolling facilities based on the slab information, and these operating conditions (OCI) for initial settings are sent to a process computer
72
. Once the slab is placed on the rolling line, the process computer
72
. Once the slab is placed on the rolling line, the process computer
72
reads in rolled material information (IRM), such as detection values (temperature, plate thickness, plate width, etc.) from detectors positioned at various locations on the rolling line. In
FIG. 5
, these detectors are the detector
24
at the exit side of the roughing mill
20
, the detector
32
at the exit side of the sheet bar joining machine
30
, and the detector
44
at the exit side of the finishing mill
40
. The process computer
72
also reads in actual operating data, including the rolling load at the drafting devices
22
of the roughing mill
20
and at the drafting devices
42
of the finishing mill
40
, of the facilities for continuous hot rolling. In the embodiment shown in
FIG. 5
, these facilities include the roughing mill
20
, sheet bar joining machine
30
, finishing mill
40
, strip shear
50
and coiler
60
. The process computer
72
calculates the operating conditions (OC) for the facilities downstream from the current position of the rolled material, so that the rolled material is rolled to the product specifications provided to the on-line computer
70
, based on such rolled material information. Then, operating conditions signals based on the calculation results are sent to the facilities, thereby running these facilities.
For example, for batch rolling operations, the calculation of the operating conditions (OC) of the finishing mill
40
by the process computer
72
is performed as follows. At the stage that the rough rolling is completed at the roughing mill
20
, the rolled material information (IRM) relating to the dimensions and temperature of the roughed sheet bar is detected by the detector
24
at the exit side of the roughing mill
20
, or is calculated based on the actual operating data from the roughing mill
20
, and operating conditions (OC) for the finishing mill
40
(load for each stand, mill gaps, circumferential speed for the reduction rollers, etc.) such that the finish rolling is executed under the finishing operating conditions (OC) sent from the on-line computer
70
, based on the rolled material information.
On the other hand, in the endless rolling operation, the process computer
72
calculates the operating conditions (OC) for the finishing mill
40
regarding the subsequent material
18
, after the preceding material
14
is joined to the subsequent material
18
at the sheet bar joining machine
30
.
However, in some cases, rolled material for which endless rolling was planned must be switched to batch rolling, due to reasons such as operating problems occurring, e.g., malfunctioning of the sheet bar joining machine
30
.
In this case, the operating conditions (OC) settings for the finishing mill
40
regarding the rolled material for which endless rolling was initially planned are based on the operating conditions (OC) provided from the on-line computer
70
assuming that endless rolling is to be performed. Accordingly, in the event that batch rolling is performed with the setting values for the operating conditions (OC) for endless rolling maintained as they are, the target product dimensions cannot be attained. Accordingly, in the event of performing batch rolling for rolled material for which endless rolling was initially planned, the operating conditions (OC) for the finishing mill have been manually changed by the operator to carryout the batch rolling.
However, when such setting changes in operating conditions (OC) are made by manually, not only are the operations extremely complicated, they must also be carried out in the short time period between the tail end
12
of the preceding material
14
completely passing through the finishing mill
40
, and the finishing mill
40
biting the head end
16
of the subsequent material
18
. Accordingly, there have been problems, such as changes in the settings of the operating conditions (OC) not being made accurately, or not being made in time, resulting in operating problems, or in not attaining the target rolled product dimensions, and consequently producing defectiv
Kitajima Hiroaki
Takemoto Shigeo
Kawasaki Steel Corporation
Oliff & Berridg,e PLC
Tolan Ed
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