ENDLESS ROLLING METHOD BASED ON TEMPERATURE UNIFORMITY CONTROL

Abstract

The invention provides an endless rolling method based on temperature uniformity control, and belongs to the field of iron and steel metallurgy. By optimizing the process path, a new layout mode is adopted, a double heat storage soaking furnace and a descaling box are additionally arranged, transverse and longitudinal bonding magnetic induction heating device is adopted, transverse and longitudinal temperature uniform of the slab in the rolling process is realized, the cross section temperature difference is reduced, and the product quality is improved. On the basis of five-stand arrangement of a traditional finish rolling mill, a rolling mill is additionally arranged to serve as a standby rolling mill, such that on-line non-shutdown change roller of the finish rolling mill is realized. The method of the invention realizes a full-continuous production of production and meets the high-quality development requirements of iron and steel metallurgy, such that traditional cool rolling can be replaced with hot rolling, traditional thick-specification strip can be replaced with high-added-value thin specification strip. There is important significance in the aspects of productivity optimization layout, green manufacturing, intelligent manufacturing and the like.

Claims

1. An endless rolling method based on temperature uniformity control is characterized in that manufacturing of a slab comprises the following steps: from a continuous casting, to a double regenerative soaking furnace, to a descaling box, to a rough rolling mill, to a pendulum shear, to an induction heating, to a descaling box, to a finish rolling mill, to a laminar cooling, to a flying shear and to a taking-up; temperature of the slab is 1500° C. after the slab is treated through the continuous casting, function of keeping a goal temperature is achieved after the slab passes through the double heat storage soaking furnace, and temperature consistency and uniformity control in the furnace are achieved such that the temperature of the slab is 1300° C., the temperature is reduced to 1250° C. after the slab passes through the descaling box, the temperature of the slab is reduced to 1000±20° C. after the slab is rough rolled in high pressure by passing through a rough rolling mill, the temperature of the slab is increased to 1058±15° C. after the slab is subjected to the induction heating, the temperature of the slab is reduced to 950±20° C. after the slab is finish rolled by passing through the finish rolling mill, the temperature of the slab is reduced to 650±20° C. after the slab is subjected to the laminar cooling, and then the slab is taken up by the taking-up; the double regenerative soaking furnace comprising an upper double-burner nozzle and a lower double-burner nozzle, such that double-sided heating of the slab in the furnace is achieved by diffusing type burning of the double heat storage soaking furnace to reduce longitudinal temperature difference and cross section temperature difference of the slab, edge temperature defect of the slab is reduced, the surface quality of the finished product plate is improved, the furnace can be used as a cooling furnace at the same time, and when lower temperature is required by the rough rolling, the slab is not heated in the furnace, and natural cooling or heat preservation is conducted; the induction heating adopting an induction heating arrangement of bonding a transverse magnetic field as front half section and a longitudinal magnetic field as rear half section, and the transverse magnetic field causes a relatively large temperature difference between the central area and the edge of the slab after heating, such that surface temperature distribution uniformity is poor; the longitudinal magnetic field causes that a large thickness direction temperature difference of the slab is large, such that core temperature distribution uniformity is poor; the temperature in the longitudinal magnetic field is uniform in the width direction, and the temperature in the transverse magnetic field is uniform in the thickness direction, the longitudinal magnetic field is arranged in front of the transverse magnetic field so as to improve initial rolling temperature, and skin effect and edge effect can be avoided by induction heating arrangement of bonding the transverse magnetic field and the longitudinal magnetic field such that temperature difference between thickness direction and width direction of the slab is small, therefore transverse and longitudinal temperature uniformity of the slab before entering the finish rolling mill can be improved; a rolling mill is added in the finish rolling mill to serve as a standby stand, such that in working state, when a certain rack roller in a five-stand rolling mill is seriously worn, the standby stand is put into work, and the worn roller of the worn rolling mill is lifted and exited from a rolling production, and on-line non-shutdown change roller of the finish rolling mill is realized.

2. The endless rolling method based on temperature uniformity control according to claim 1, characterized in that the slab is subjected to rough rolling through the rough rolling unit, is subjected to finish rolling through the finish rolling mill, such that microstructure of the slab is austenite, and then the slab is subjected to laminar cooling, such that the microstructure is converted into ferrite and pearlite.

3. The endless rolling method based on temperature uniformity control according to claim 1, characterized in that the descaling box is a small amount of water and large pressure descaling box.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 is a process flow diagram of a endless rolling production line temperature uniformity control method according to the present invention;

[0022] FIG. 2 is a process diagram of a temperature control method according to the present invention;

[0023] FIG. 3 is schematic diagrams of heating effect comparison of the transverse and longitudinal bonding coil and traditional induction heating in thickness direction according to the present invention;

[0024] FIG. 4 is schematic diagrams of heating effect comparison of the transverse and longitudinal bonding coil and traditional induction heating in width direction according to the present invention.

DETAILED DESCRIPTION

[0025] In the following, embodiments of the present invention will be described with reference to the accompanying drawings. The process flow diagram is shown in FIG. 1, and the temperature control method is as shown in FIG. 2.

Embodiment 1

[0026] In rolling process of this embodiment, temperature of the slab is 1500° C. after the slab is treated by the continuous casting, and the temperature of the slab is 1300° C. after the slab is treated by the double regenerative soaking furnace, wherein a upper and down double-burner device is arranged, such that double-sided heating of the slab is guaranteed, length temperature difference and cross section temperature difference of the slab are effectively reduced, edge temperature defect of the slab is solved, and surface quality of the finished plate is improved.

[0027] The temperature of the slab is reduced to 1250° C. after the slab is treated by the descaling box, which employs high pressure water to remove iron oxide skin existing on surface of the slab by virtue of the small amount of water and large pressure design structure, to improve quality of the slab.

[0028] The temperature of the slab is reduced to 980° C. after the slab is rough rolled through a rough rolling mill. The pendulum shear can shear head and tail of the slab when the finish rolling mill stops due to failure, such that segmented intermediate blank output by the rough rolling mill can be removed. A thin plate production mode is switched to a medium thickness plate production mode so as to achieve normal operation.

[0029] The temperature of the slab is increased to 1043° C. after the slab is treated by the induction heating, wherein the slab is uniformly heated by a transverse and longitudinal magnetic bonding induction heating arrangement, such that influence of uneven temperature in thickness direction of the longitudinal magnetic as well as edge and corner effect of the transverse magnetic is eliminated.

[0030] The temperature of the slab is reduced to 930° C. after the slab is treated by finish rolling through the finish rolling mill, and temperature of the slab is reduced to 630° C. after the slab is treated by the laminar cooling. The finish rolling mill adopts a six-stand arrangement, and when a certain stand roller in the five-stand rolling mill is seriously worn in working state, a ‘5+1’ dynamic change procedure strategy is adopted, a standby stand is put into work, and the worn roller is lift and exited from the rolling production, such that on-line changing roller without shutdown is realized, and yield is guaranteed and production is all continuously carried out. After laminar cooling, microstructure is converted into ferrite and pearlite. The slab is sheared into a preset size through the flying shear, and finished product is finally taken-up by a coiler.

[0031] Through the above process, transverse and longitudinal temperature uniformity of the slab in the rolling process is realized, product quality is improved, and all continuously integrated production is achieved, such that a produced high-added-value thin specification slab can be widely applied to field of automobile industry and the like.

Embodiment 2

[0032] In a rolling process of this embodiment, temperature of a slab is 1500° C. after the slab is treated by continuous casting, and the temperature of the slab is 1300° C. after the slab is treated by the double regenerative soaking furnace, wherein a upper and down double-burner device is arranged, such that double-sided heating of the slab is guaranteed, length temperature difference and cross section temperature difference of the slab are effectively reduced, edge temperature defect of the slab is solved, and surface quality of the finished plate is improved.

[0033] The temperature of the slab is reduced to 1250° C. after the slab is treated by the descaling box, which employs high pressure water to remove iron oxide skin existing on surface of the slab by virtue of the small amount of water and large pressure design structure, to improve quality of the slab.

[0034] The temperature of the slab is reduced to 1000° C. after the slab is rough rolled through a rough rolling mill. The pendulum shear can shear head and tail of the slab when the finish rolling mill stops due to failure, such that segmented intermediate blank output by the rough rolling mill is removed. A thin plate production mode is switched to a medium-thickness plate production mode, and normal operation is achieved.

[0035] The temperature of the slab is increased to 1058° C. after the slab is treated by the induction heating, wherein the slab is uniformly heated by a transverse and longitudinal magnetic bonding induction heating arrangement, such that influence of uneven temperature in thickness direction of the longitudinal magnetic as well as edge and corner effect of the transverse magnetic is eliminated.

[0036] The temperature of the slab is reduced to 950° C. after the slab is treated by finish rolling through the finish rolling mill, and the temperature of the slab is reduced to 650° C. after the slab is treated by the laminar cooling. The finish rolling mill adopts a six-stand arrangement, and when a certain stand roller in the five-stand rolling mill is seriously worn in working state, a ‘5+1’ dynamic change procedure strategy is adopted, a standby stand is put into work, and the worn roller is lift and exited from the rolling production, such that on-line changing roller without shutdown is realized, and yield is guaranteed and production is all continuously carried out. After the laminar cooling, microstructure is converted into ferrite and pearlite. The slab is sheared into a preset size by a flying shear, and finished product is finally taken-up by a coiler.

[0037] With above process, transverse and longitudinal temperature uniformity of the slab in the rolling process is realized, product quality is improved, and all continuously integrated production is achieved, such that a produced high-added-value thin specification slab can be widely applied to field of automobile industry and the like.

Embodiment 3

[0038] In a rolling process of this embodiment, temperature of a slab is 1500° C. after the slab is treated by continuous casting, and the temperature of the slab is 1300° C. after the slab is treated by the double regenerative soaking furnace, wherein a upper and down double-burner device is arranged, such that double-sided heating of the slab is guaranteed, length temperature difference and cross section temperature difference of the slab are effectively reduced, edge temperature defect of the slab is solved, and surface quality of the finished plate is improved.

[0039] The temperature of the slab is reduced to 1250° C. after the slab is treated by the descaling box, which employs high pressure water to remove iron oxide skin existing on surface of the slab by virtue of the small amount of water and large pressure design structure, to improve quality of the slab.

[0040] The temperature of the slab is reduced to 1020° C. after the slab is rough rolled through a rough rolling mill. A pendulum shear can shear head and tail of the slab when the finish rolling mill stops due to failure, such that segmented intermediate blank output by the rough rolling unit is removed. A thin plate production mode is switched to a medium-thickness plate production mode, and normal operation is achieved.

[0041] The temperature of the slab is increased to 1073° C. after the slab is treated by the induction heating, wherein the slab is uniformly heated by a transverse and longitudinal magnetic bonding induction heating arrangement, such that influence of uneven temperature in thickness direction of the longitudinal magnetic as well as edge and corner effect of the transverse magnetic is eliminated.

[0042] The temperature of the slab is reduced to 970° C. after the slab is treated by finish rolling through the finish rolling mill, and the temperature of the slab is reduced to 670° C. after the slab is treated by laminar cooling. The finish rolling mill adopts a six-stand arrangement, and when a certain stand roller in the five-stand rolling mill is seriously stand in working state, a ‘5+1’ dynamic change procedure strategy is adopted, a standby stand is put into work, and the worn roller is lift and exited from the rolling production, such that on-line changing roller without shutdown is realized, and yield is guaranteed and production is all continuously carried out. After laminar cooling, microstructure is converted into ferrite and pearlite. The slab is sheared into a preset size by a flying shear, and a finished product is finally taken-up by a coiler.

[0043] FIG. 3 and FIG. 4 are schematic diagrams of heating effect comparison of the transverse and longitudinal bonding coil with traditional induction heating in thickness direction and width direction according to the embodiment 3 of the present invention respectively.

[0044] It can be seen from the figures that, the transverse magnetic field causes that temperature difference between center region of the strip steel and edge portion after heating is large, the highest temperature difference is 58.8° C., and surface temperature distribution uniformity is poor; the longitudinal magnetic field causes that thickness direction temperature difference of the plate and strip is large, the highest temperature difference is 54.4° C., core temperature distribution uniformity is poor, when the transverse and longitudinal bonding magnetic field heating is adopted, temperature difference between thickness direction and width direction of the plate and strip is small, and temperature difference is 30.2° C. and 10.5° C. respectively. The heating has better uniformity, such that the transverse and longitudinal temperature uniformity of the slab in the rolling process is realized, the product quality is improved, full-continuous integrated production is achieved, and the produced high-added-value thin specification plate and strip blank can be widely applied to the field of automobile industry and the like.

[0045] The above embodiments are only described for preferred embodiments of the present invention and are not intended to limit scope of the present invention, and various modifications and improvements made by a person of ordinary skill in the art without departing from the spirit of the present invention shall fall within scope of protection defined by claims of the present invention.