MX2011005636A

MX2011005636A - Method for producing strips of metal, and production line for performing the method.

Info

Publication number: MX2011005636A
Application number: MX2011005636A
Authority: MX
Inventors: Karl-Heinz Spitzer; Rolf Franz; Hellfried Eichholz; Markus Schaeperkoetter
Original assignee: Sms Siemag Ag
Priority date: 2008-12-09
Filing date: 2009-12-09
Publication date: 2011-06-24
Also published as: EP2376240B1; ZA201103297B; TWI421138B; AU2009326518A1; JP5425218B2; JP2012510897A; CA2745044A1; EP2376240A1; CA2745044C; RU2011128420A; KR101332196B1; AR080265A1; TW201029770A; CN102245319B; KR20110083734A; WO2010066412A1; RU2481903C2; CN102245319A; US20120024434A1

Abstract

The invention relates to a method and to a production line for producing hot-rolled strips of metal, wherein the cast strip, as a leader strip, initially runs through a first process for homogenizing the microstructure under shield gas, and the leader strip is then subjected to at least one further heat treatment before it is subsequentially subjected to a rolling process for reducing the thickness. After the thickness reduction, the leader strip runs through a second process for homogenizing and recrystallizing the microstructure thereof, before the leader strip finally travels through a cutting device and is cut off from the following leader strip as a completely rolled hot-rolled strip.

Description

PROCEDURE FOR THE ELABORATION OF METAL BANDS AND PRODUCTION PLANT FOR THE REALIZATION OF THE PROCEDURE FIELD OF THE INVENTION The present invention comprises a process for the continuous and discontinuous processing of hot-rolled strips of cast metal, especially steel. The invention also comprises a production plant for carrying out said process.

BACKGROUND OF THE INVENTION With a known method of horizontal casting of the strip, it is possible to empty castings of different types of metal, with an approximation to the final dimension, in a band thickness range of less than 20mm. In turn, it is possible to manufacture, advantageously, especially light-weight steels with a high content of C, Mn, Al and Si.

In EP 1 047 510 Bl, for example, a production process for the production of thin flat hot-rolled products is described. It is then emptied, in a horizontal casting installation, the steel melt with an approximation to the final dimension, in a range of 5 mm to 18 mm of strip thickness and before reaching the roughing train of a single box it is It cools in a controlled manner under an inert gas atmosphere.

The previously hot-rolled strip is cooled, heated or maintained in a controlled manner in a system connected to the roughing train and the edges of the hot-rolled strip continue to be heated.

After the train of roughing of a box are a train of finishing of several boxes, a path of exit rollers with a device to cool the hot rolled strip as well as winding machines connected before and after to wind the hot rolled strip .

The rolling temperature before the finishing train of several boxes can be adjusted appropriately through the device arranged after the roughing train to optionally warm, heat or maintain the temperature of the hot rolled strip, in the area of austenite or ferrite or in the transition area from austenite to ferrite.

From WO 2006/066551 Al, a process for the production of hot-rolled steel strips of light construction is also known, very suitable for cold deep drawing and having as main elements Fe, Mn, Si and Al.

The previous band obtained in the melting of the band passes first through a device that is under an inert atmosphere, for homogenization, optionally maintaining the temperature or reducing or increasing it. After that, the previous band is subjected, at least, to a hot rolling process that has at least one pass, with a degree of total deformation of at least 50%. After the last pass, the hot rolled strip is cooled and rolled.

Depending on the proportion of the casting and rolling speed, the hot rolling process is carried out in line or decoupled.

The homogenization zone must cause a temperature compensation on the surface of the hot rolled strip and a reduction of the tension within the hot rolled strip, regardless of whether the temperature level is maintained, raised or reduced.

The question of whether the rolling process is carried out in line or uncoupled from the casting process, will depend mainly on the different speeds during the casting and the rolling, likewise, the recrystallization behavior of the material is also significant.

During the casting process, there is a direct bonding of material in the liquid phase in the area of the casting task and the following processing steps of the solidified material along the casting band.

The cast strip is subsequently processed through a transport section. The following processing steps can be: straightened, rolling, cutting and winding (winding, winding). Due to these other components of a casting installation, oscillations in the traction or the mass flow in the casting band may occur. If these faults propagate in the direction of the liquid steel, faults in the casting may occur and negative influences may be generated in the casting band, for example, fluctuations in thickness, overflows, edge contractions and strip or flow detachment.

BRIEF DESCRIPTION OF THE INVENTION The object of the present invention is to improve a process for the production of hot rolled strips in a casting installation with a winding or stacking device in such a way that the process steps subsequent to the casting process do not have a negative influence on the casting strip obtained with regard to the quality and its characteristics of the material and that after the casting process the casting band can be divided into the predetermined units of measurement, which can be transported or stored, for example, in sheets stacked, coils or rolls (coils).

This object is achieved, according to the invention, through the features of the independent claims.

According to them, the previous band obtained in the foundry crosses first a device that is under an inert atmosphere, for homogenization, optionally maintaining the temperature or reducing or increasing it. Subsequently, the previous band passes through a device for regulating the temperature to maintain, reduce or optionally raise the temperature of the previous band. Later, the previous band is subjected to a hot rolling process with at least one pass, at a thickness reduction of less than 49%. Then the previous band passes through a second homogenization zone, before being separated as a hot-rolled strip from the next previous band.

In the first homogenization zone a mixture of argon / C02 -nitrogen is used as an inert gas. In the first homogenization zone the temperature is maintained in the range of 900 - 1000 ° C, it is reduced by 200 ° C and it is increased by 250 ° C so that the material can be folded and forms a roll (coil). present an adequate structure that allows deformation in the case of tensile and pressure stresses.

These characteristics of the structure can be achieved through, at least, a rolling process with one pass until reaching a degree of deformation of 49%.

Through the deformation process, a recrystallization of the material is initiated. In a subsequent second homogenization zone, the hot-rolled strip obtained undergoes recrystallization, at least in the edge areas, whether the temperature of the hot-rolled strip is maintained or in the case of a comparatively low temperature or elevated.

In the second homogenization zone connected subsequently to the first rolling stand, the material can be recrystallized and in this way can absorb tensile and pressure stresses. This procedure of recrystallization is particularly suitable, especially for lightweight construction steels which, among others, have a very high solidification interval, that is, a temperature window from the beginning of the solidification of the melt. until complete solidification, and the temperatures of zero strength or zero resistance dependent, and, independently of this, have zero strength or zero resistance.

After the pre-band passes through the second homogenization zone, the hot rolled strip is led to a separation device with a working speed synchronized with the rolling or transport speed, it is cut with a determined length of the previous band and wound in a winding device forming a roller (coil).

However, the procedure for cutting the hot rolled strip can also be carried out as soon as the hot rolled strip leaves the second homogenization zone, then, the cut strip with a certain length is conveyed through a suitable conveying device to the belt. a stacking device and there is stacked in the form of plates.

In carrying out the process according to the invention, the casting process is decoupled from the rolling process.

This has the advantage that on the one hand the casting speed can be guaranteed depending on the development of the solidification process of the melt and on the other hand, the hot rolling process can be carried out at a defined temperature of rolling in hot, until reaching a predetermined degree of deformation.

In another embodiment of the method according to the invention, after the first homogenization process of the structure, the transport speed of the previous web is influenced by a mass flow regulation unit. In this way it is prevented that the failures of the following process developments during the manufacturing process adversely affect the casting process and the casting band and cause, for example, swings in thickness, overflows, edge contractions and detachment of the casting. band or flow.

The production plant for carrying out the process according to the invention consists of a known casting machine, arranged after a first homogenization zone maintained under an inert atmosphere, in which the temperature is optionally maintained, raised or reduced to influence the structure of the previous band.

After the first homogenization zone there is a device for regulating the temperature to optionally maintain, reduce or increase the temperature.

Seen in the transport direction of the previous band, after the first device for regulating the temperature is arranged, placing a mass flow regulation unit between a first transport element of the previous band and a second transport element of the previous band , a second device for regulating the temperature, in which the cast strip is brought to a suitable rolling temperature, namely, optionally maintaining the temperature of the strip, reducing or increasing said temperature.

After the second device for regulating the temperature, a first rolling stand is arranged, in which the pre-strip is subjected to at least one pass, a thickness reduction of less than 49%, in a second connected homogenization zone. subsequently to the first rolling stand, the pre-strip is subjected, as a hot rolled strip and at a temperature of 700-900 ° C, to a recrystallization, especially, in the edge areas of the hot rolled strip, so that the material can absorb tensile or pressure forces as well as plastic deformations that occur during winding or stacking, without affecting the structure.

Finally, after the second homogenization zone there is a separation device operated with a speed of work synchronized with the speed of the transport device of the hot rolled strip. In the separation device, the hot rolled strip that enters continuously is rolled or stacked as plates.

In another embodiment of the production plant according to the invention, after the first device for regulating the temperature there is a mass flow regulation unit configured as a compensating roller or loop elevator. The mass flow control unit is, in turn, arranged in the direction of transport of the pre-band, between a first transport element of the pre-band and a second transport element of the pre-band.

In addition, in the embodiment of the invention, before the rolling box there is a second device for regulating the temperature at which the pre-band is brought to a suitable rolling temperature, so that the previous band can be subjected to a process of hot rolling with at least one pass, so that the previous band has a degree of deformation of less than 49% of the total deformation.

Finally, in the embodiment of the invention, the separation device is subsequently connected to a stacking or winding device, in which the hot rolled strip is wound into a roll (coil) or is stacked in the form of individual plates.

Other features and advantages of the invention are apparent from the following description of an exemplary embodiment depicted in the drawings.

BRIEF DESCRIPTION OF THE APPENDIX DRAWINGS Figure 1 shows a diagram of the production plant for carrying out the method according to the invention for a strip casting in dimensions with an approximation to the final dimension with a winding or stacking device.

DETAILED DESCRIPTION OF THE INVENTION The only figure 1 shows a diagram of a production plant for carrying out the process according to the invention. For the production of the casting process or process, the production plant has a casting machine 1 in the form of a horizontal casting installation, comprising a transport device in the form of a continuous conveyor belt 2 with two investment pulleys 3, 3 '. The casting machine 1 further comprises a side closure 4 which prevents the melt 5 from flowing to the right and left of the transport device 2. The melt 5 is transported by a boiler 6 to the brewing machine 1 and through from an opening 7 in the base of the boiler 6 flows into the feed container 8. Said container 8 is shaped as an expansion vessel.

The devices for intense cooling of the lower face of the upper branch of the transport device 2 as well as the complete isolation of the brewing machine 1 with the corresponding inert gas atmosphere are not shown in greater detail.

After placing the melt 5 on the circular conveyor belt of the transport device 2, due to the intense cooling it hardens and a pre-band or cast strip 9 is obtained which at the end of the transport device 2 has already been solidified practically by full .

To compensate the temperature and reduce the voltage, a first homogenization zone 10 is connected to the brewing machine 1. This comprises a thermal insulation 11 and a roller path. This first homogenization zone can optionally be used to maintain the temperature of the previous band or laundry band 9, to cool it or, alternatively, to increase it a little. It is provided, in particular, that in this first homogenization zone 10 the pre-band or casting strip 9 is exposed to a first homogenization process of the structure under an inert gas atmosphere formed by a mixture of argon-C02-nitrogen as gas inert, either maintaining the temperature at 900-1000 ° C, reducing the temperature by approximately 200 ° C or by increasing the temperature by approximately 250 ° C.

Subsequently, the previous band or laundry band 9 travels through a first device for regulating the temperature 12 and is led to a second device for regulating the temperature 15 by means of a first transport element of the pre-band 14 and a second transport element of the pre-band 14 'through a mass flow regulating unit 13 configured as a compensating roller or loop elevator and disposed between the first transport element of the pre-band 14 and the second transport element of the pre-band 14'. In this second device for regulating the temperature 15, the strip 9 is brought to the rolling temperature, before being subjected, in a subsequent first rolling stand 16 to a hot rolling process of, at least, one pass, until that the band 9 has a degree of deformation of less than 49% of the total deformation. In this second device for regulating the temperature 15, the band 9 is optionally maintained at a temperature of approximately 880-940 ° C, the temperature is reduced by approximately 50 ° C or high by approximately 50 °. C. After passing through the first rolling stand 16, the strip 9 is subsequently conveyed to a second homogenization zone 17., in which the band 9 is subjected to a second process for homogenization, especially the recrystallization of the structure. This is carried out since the temperature of the band 9 in the second homogenization zone 17 is, optionally, maintained at a temperature of about 700-900 ° C, the temperature is reduced by about 100 ° C or elevated by approximately 50 ° C. After the second homogenization zone 17, the band passes through a separation device 18 in the form of a shear, synchronized with the transport speed or the web and then, separated in the form of a finished hot band from the previous web 9, is driven to a winding device 19 or a stacking device 20.

Claims

NOVELTY OF THE INVENTION Having described the invention as above, it is considered as a novelty and, therefore, is claimed as property contained in the following: CLAIMS

1. Process for the continuous or discontinuous manufacture of hot-rolled strips of cast metal, especially steel, where the cast strip is subjected, as a prior band, to at least one heat treatment process and subsequently stacked or rolled up as a laminated strip in hot, characterized because: the previous band obtained with the casting process is exposed to an inert gas atmosphere, in a first procedure for the homogenization of the structure, either maintaining a temperature of approximately 900 1000 ° C, by reducing the temperature by approximately 200 ° C or increasing the temperature by approximately 250 ° C, After the first homogenization process, the previous band is subjected, at least, to another thermal treatment process, either maintaining the temperature at 880-940 ° C, reducing the temperature by approximately 50 ° C or increasing the temperature by approximately 50 ° C , subsequently, the previous band is subjected to a hot rolling process that has at least one pass, in which the previous band is subjected to a thickness reduction of less than 49%, then the previous band is subjected to a second homogenization process or to a recrystallization of the structure, either maintaining the temperature at 700-900 ° C, reducing the temperature by approximately 50 ° C or increasing the temperature by approximately 50 ° C, and the pre-band then passes through a separation device synchronized with the transport speed or the web speed and is separated as hot-rolled strip from the previous web.

2. Process according to claim 1, characterized in that the casting process is decoupled from the rolling process.

3. Method according to one of the preceding claims, characterized in that the transport speed of the previous band is influenced by a mass flow regulation unit.

4. Process according to claims 1 to 3, characterized in that before the hot rolling, the previous band is subjected to a second thermal treatment process, either maintaining the temperature at 880-940 ° C, reducing the temperature approximately 50 ° C or increasing the temperature approximately 50 ° C.

5. Process according to claims 1 to 4, characterized in that the pre-strip is hot rolled after the second heat treatment process.

6. Process according to claims 1 to 5, characterized in that after the hot rolling, the previous band is subjected to a second homogenization process, especially, to a recrystallization of the previous band at the edges, either maintaining the temperature at 700 - 900 ° C, reducing the temperature by approximately 100 ° C or by increasing the temperature by approximately 50 ° C.

7. Process according to claims 1 to 6, characterized in that after the second homogenization process, the pre-band passes through, as a hot-rolled strip, a separation device synchronized with the transport speed of the previous band and subsequently, the previous band It is stacked or rolled as hot rolled strip.

8. Production plant for carrying out the process according to one or more of claims 1 to 7, comprising at least one casting machine (1) for the production of a pre-band or cast strip (9) of a predetermined thickness, with , at least, a transport device (2) for transferring the cast strip, with, at least, a homogenization zone (10), in which the temperature is maintained, raised or reduced to influence the structure of the previous band or cast strip, with, at least, another zone of additional temperature in which the temperature is maintained, raised or reduced, at least with a first rolling stand (16) to achieve at least partial molding of the previous band (9). ), with at least one separation device (18) and with at least one stacking or winding device (19; 20), characterized in that: the brewing machine (1) is arranged after a first homogenization zone (10) maintained under an inert atmosphere, in which the temperature is optionally maintained, raised or reduced, after the first homogenization zone (10) there is a device for regulating the temperature (15) to optionally maintain, reduce or increase the temperature, the device for regulating the temperature (15) is arranged after a first rolling stand (16), in which the previous band is subjected to at least one pass, a thickness reduction of less than 49%, behind the rolling stand (16) there is a second homogenization zone (17), in which the temperature is maintained, raised or reduced optionally, to obtain a recrystallization of the hot rolled strip, at least at the edges, Y after the second homogenization zone (17) a separation device (18) is arranged, whose working speed is synchronized with the speed of the transport device (2), and in which the laminated pre-band (9) is separated, as hot-rolled strip, from the previous band.

9. Production plant according to claim 8, characterized in that the casting process is decoupled from the rolling process.

10. Production plant according to claim 8 or 9, characterized in that after the first homogenization zone (10) there is a mass flow regulation unit (13) configured as a compensating roller or loop elevator.

11. Production plant according to one of claims 8 to 10, characterized in that a mass flow control unit (13) is arranged, viewed in the transport direction of the pre-band (9), between a first transport element of the previous band (14) and a second transport element of the previous band (14).

12. Production plant according to one of claims 8 - 11, characterized in that in the conveying direction of the strip, after the first homogenization zone (10) there is a first device for regulating the temperature (12) and a unit of mass flow regulation (13), wherein the mass flow regulation unit is arranged before the second device to regulate the temperature (15).

13. Production plant according to claim 12, characterized in that between the first device for regulating the temperature (12) and the mass flow regulation unit (13) and / or between the mass flow regulation unit (13) and the second device for regulating the temperature (15) is arranged a transport element (14, 14 ').

14. Production plant according to one of claims 8 to 13, characterized in that the separation device (18) is subsequently connected to a winding device (19) or a stacking device