RU2282521C2 - Method for custom-making steel strip - Google Patents

Abstract

FIELD: metallurgy, namely processes for controlling continuous casting of steel strip on base of client demands.

SUBSTANCE: method comprises steps of writing in computer memory characteristics of steel product ordered by client for automatically transforming them to parameters/variables of process. Computer outputs said parameters/variables directly to casting process of strip for automatic control of process for making product ordered by client. Without interrupting continuous casting process client's order for second product is received. Characteristics of product according to second order are converted to new parameters/variables of casting process. Casting process parameters for making first product are changed by new ones and casting process for making second product is realized.

EFFECT: significantly shortened time period between client's request for steel product and its delivery in comparison with usual process for making steel product.

51 cl, 5 dwg, 3 tbl

Description

Cross reference to related application

This application claims the priority and advantage of provisional patent application US No. 60/236,390, filed September 29, 2000.

Field of Invention

The present invention generally relates to systems and methods for providing (providing) a steel strip to order and, in particular, to systems and methods for converting customer requirements for a steel strip into process parameters for controlling the process of continuous casting of a strip, using which it is possible to produce the specified customer steel strip.

BACKGROUND OF THE INVENTION

The usual process in the steel industry, the execution of a customer order for a steel product with specific mechanical and dimensional characteristics is complex and lengthy and may typically take 10 or more weeks to complete. Figure 1, for example, shows a flowchart illustrating the flow of one of the usual methods 10, intended for the manufacture of a customer-ordered steel strip, where the term "strip", as used here, means a product with a thickness of 5 mm or less.

Method 10 begins at step 12, where the steel producer accepts the customer’s order, typically indicating the mechanical and dimensional requirements for the steel strip, as well as its required quantity. After that, at step 14, the steel manufacturer determines, on the basis of a customer order, the specific requirements for the chemical composition of the steel necessary to achieve the basic properties of the product. Requirements for the chemical composition are selected from the existing large list of methods for producing certain chemical compositions of steel (which in many cases refers to the technology of casting ingots / hot rolling, but the chemical composition is the main determining factor of properties). After that, at step 16, the steel manufacturer determines the casting parameters that correspond to the operating parameters and / or variables of the steel casting process that will be used for the manufacture of steel slabs from molten steel, prepared in accordance with the requirements for the chemical composition of the steel. At step 18, the steel manufacturer determines the requirements for the subsequent processing of the slabs, first focusing on achieving the dimensional requirements of the client, such as thickness, etc., and then developing additional stages of the subsequent processing that may be required to obtain the final properties of the product. Such requirements for the subsequent processing of slabs may include, for example, any of the following requirements individually or in combination: (a) parameters for reheating the slab corresponding to the operating parameters of the furnace in the hot rolling mill and / or variables of the device that performs the hot rolling of the strip; (b) parameters of hot rolling corresponding to the operating parameters of the rolling mill and / or variables of the device performing the hot rolling of the strip; (c) cold rolling parameters corresponding to the etching and cold rolling operating parameters and / or variables of the cold rolling apparatus; and (d) heat treatment parameters corresponding to the heat treatment operating parameters and / or variables of the heat treatment device.

After step 18, the execution of method 10 continues at step 20, where the steel producer makes a batch of liquid steel in accordance with the chemical composition requirements for the specified steel product and casts the steel product into a slab billet in accordance with the casting parameters established at step 16. Often client orders (which can be as little as 5 tons) are accumulated until they are enough to carry out one steel melting - typically from 100 to 300 tons, depending on the design tion particular installation of steel production. This introduces an additional delay during the execution of a specific customer order, increasing the total production time as a result to a period significantly exceeding 10 weeks. Be that as it may, after step 20, the execution of method 10 continues at step 22, where the slab billet is reheated and hot rolled in a hot rolling mill in accordance with the parameters for reheating the slab and hot rolling set in step 18, with the aim of manufacturing steel roll blanks of a predetermined thickness. Then, at step 24, etching and cold rolling of the roll stock in the cold rolling mill is performed in accordance with some etching and cold rolling parameters set at step 18 in order to reduce the thickness of the roll stock to the thickness specified by the customer. And finally, at step 26, the roll stock is subjected to heat treatment in a heat treatment device in accordance with some heat treatment parameters set at step 18, in order to anneal the roll blank in such a way that it meets the requirements of a customer order.

The usual technology for the production of steel strip of the type just described makes it necessary to produce many different steel grades (typically more than 50), from which slabs are first cast and which are then hot rolled according to complex production schemes in strip hot rolling mills in which products with thicknesses of only 1.5 mm and yield strengths in the range of 300-450 MPa. If the client needs finer material or properties that fall outside this range, further processing is required, including the use of pickling units, cold-pressing mills and annealing furnaces.

The main disadvantage of the conventional steel strip manufacturing process just described is the long period of time, typically 10 or more weeks, required to produce a steel product that meets the requirements of a customer order. Thus, there is a need for an improved method for manufacturing a steel strip that is more responsive to customer needs by significantly reducing the time required to produce a customer-specified product in the form of a steel strip.

SUMMARY OF THE INVENTION

The above disadvantages characterizing the current level of technology are eliminated by the present invention. In accordance with one aspect of the present invention, a method for controlling a process for continuous casting of strip steel for the manufacture of a steel product specified by a customer comprises receiving an order for a steel product including the requirements specified by the customer regarding the product; converting (displaying) the requirements mentioned by the client into a series of process parameters for controlling the process of continuous casting of strip steel for the purpose of manufacturing said steel product; and displaying said series of process parameters in a process change report provided to the operator of said continuous steel strip casting process.

In accordance with another aspect of the present invention, a method for controlling a process for continuous casting of strip steel for the manufacture of a steel product specified by a customer, comprises: receiving an order for a steel product, including customer-specified requirements for said product; converting (displaying) the requirements mentioned by the client into a series of process parameters for controlling the process of continuous casting of strip steel for the purpose of manufacturing said steel product; and controlling said continuous steel strip continuous casting process based on said process parameters to manufacture said steel product.

In accordance with another aspect of the present invention, a method for controlling a process for continuous casting of strip steel for manufacturing a steel product specified by a customer, comprising: controlling a process for continuous casting of strip steel based on a set of predetermined process parameters for manufacturing the first steel product; accepting an order for a second steel product, including the requirements specified by the customer regarding said second steel product; converting (displaying) the requirements indicated by the client into a set of new process parameters for controlling said continuous steel strip casting process for the purpose of manufacturing said second steel product; and replacing said set of predetermined process parameters with said set of new process parameters without interrupting said continuous steel strip continuous casting process so that this continuous steel strip continuous casting process immediately switches from the production of said first steel product to the production of said second steel product.

In accordance with a further aspect of the present invention, a method for providing (providing) a steel strip indicated by a customer comprises processing orders for a steel strip meeting the requirements specified by the client, with obtaining a production scheme for a custom steel strip in the production cycle of a strip continuous casting machine casting a steel strip with a single chemical steel composition; the operation of the machine for continuous casting of the strip during the production cycle for the manufacture of cast strip with a single chemical composition of steel; cooling said strip through a temperature range for converting austenite to ferrite; and selectively controlling process parameters to produce a strip that meets customer requirements.

Preferably, this method also comprises a flow line (i.e., one process) line included in the hot rolling of said cast strip before it is cooled through the temperature range of austenite to ferrite conversion.

In each of the above methods corresponding to the present invention, the requirements specified by the client may include the specified steel grade and / or the indicated strip thickness, and the process parameters necessary for the manufacture of the steel product specified by the client may include any of the following parameters individually or in combination: casting speed during continuous strip casting, the thickness of the steel product in the post-cast state, the percentage value of the crimp (i.e., decrease in thickness) of the steel product in hot than the state, the cooling rate of the steel product, the rolling temperature of the steel product, the percentage value of crimping the said steel product in the cold state, the type of annealing cycle and the annealing temperature.

One of the objectives of the present invention is to provide an improved method of manufacturing a steel strip, corresponding to customer orders.

Another objective of the present invention is to minimize the lead time between the receipt of a customer order for a steel strip and the actual manufacture of this steel strip.

These and other objectives of the present invention will become more apparent from the following description of a preferred embodiment.

Brief Description of the Drawings

Figure 1 is a flowchart illustrating a conventional process for manufacturing a steel strip.

Figure 2 - schematic representation of one of the preferred embodiments of the device for continuous casting of a steel strip in accordance with the present invention.

FIG. 3 is a schematic view showing some details of a twin roll strip casting machine included in the apparatus shown in FIG. 1.

Figure 4 is an illustration of a structural diagram of a general-purpose computer system used to convert the customer requirements for a steel strip into process parameters for controlling a steel strip continuous casting device shown in Figures 2 and 3.

FIG. 5 is a flowchart illustrating one preferred embodiment of a process for controlling a steel strip continuous casting apparatus shown in FIGS. 2 and 3 using the general purpose computer system shown in FIG. 4.

Description of Preferred Embodiment

To facilitate understanding of the principles of the present invention, we turn now to the preferred embodiment, depicted in the drawings, and the terminology that will be used to describe it. Nevertheless, it must be understood that this does not imply any limitation of the scope of the invention, but it is assumed that such changes and subsequent modifications of the depicted embodiment and such further application of the principles of this invention as illustrated here are obvious to those skilled in the art. the technical field for which this invention is proposed.

The present invention is based on the manufacture of a steel strip in a continuous strip casting machine. The applicants have carried out extensive research and development work in the field of casting steel strip in a continuous rolling machine of the twin roll type. Generally speaking, continuous casting of a steel strip in a two-roll casting machine involves the introduction of liquid steel between a pair of horizontal casting rolls rotating in opposite directions, which are internally cooled by water, as a result of which the metal layers solidify on the surface of the moving rolls and join in the gap between them to create a hardened strip extending downward from the gap between said rolls, the term “gap” being used to indicate the general area in which the rolls most closely spaced from each other. Liquid metal can be poured from the ladle into a smaller container (intermediate casting device), from which it enters through a pouring cup located above the gap so as to direct this metal into the gap between the rollers, as a result of which a molten bath of molten metal is held, held on casting surfaces of the rolls directly above the gap and extending along the entire length of this gap. This casting bath is usually limited to side plates or sills that can slide over the end surfaces of the rolls to prevent the casting bath from flowing out from two sides, although alternative means such as electromagnetic barriers have also been proposed. Steel strip casting in twin roll casting machines of this type is described, for example, in US Pat. Nos. 5,184,668; 5277243 and 5934359, which by this reference are specifically included in this description.

Applicants have determined that it is possible to manufacture a steel strip of a given composition, which is characterized by a wide range of microstructure and, therefore, a wide range of mechanical properties, by continuously casting this strip and then selectively changing the parameters of the subsequent processing. For example, based on work using unalloyed carbon steel (including unalloyed carbon steel, deoxidized with silicon / manganese), the applicants determined that by choosing cooling rates from 0.1 ° C / s to more than 100 ° C / s when passing through the temperature the austenite to ferrite conversion range, a steel strip can be made which has a yield strength in the range of 200 MPa to more than 550 MPa. One example of the flexibility of the strip continuous casting process that was selected by the applicants for this reason is that the production cycle of a continuous strip casting machine casting a steel strip of a given composition can be controlled in such a way that various cooling rates can be selectively applied to the cast strip passing through the temperature range of the conversion of austenite to ferrite, as a result of which it is possible to produce a strip having, by choice, any set from the range of various microstructures and, consequently tionary, the required mechanical properties.

Applicants have generally found that by selectively changing the parameters of the subsequent strip processing during the continuous casting of strip steel, significant flexibility can be achieved in terms of the operation of the continuous strip casting machine that meets the production requirements (i.e., customer). This means that orders placed by customers for the manufacture of a steel strip having specified dimensional characteristics and a range of different mechanical properties can be performed using a single (unchanged) chemical composition of steel in a single production cycle. In addition, this means that the production cycle can be regulated during its execution. This was appreciated by applicants as an important advantage of continuous casting strip in terms of customer satisfaction with urgent orders.

The following description of a preferred embodiment of the present invention is for continuous casting of a steel strip using a twin roll casting machine. The present invention, however, is not limited to the use of twin roll casting machines and extends to other types of continuous strip casting machines.

Figure 2 shows a device / method 50 for continuous casting of strip steel in the form of successive components of a production line on which a steel strip can be manufactured in accordance with the present invention. Figures 2 and 3 show a twin-roll casting machine, indicated by the general number 54, which produces a cast steel strip 56 along route 52 along the guide roller 58 to the stand 60 of the pulling rolls containing the pulling rolls 60A. Immediately after pulling rolls exit from stand 60, the strip passes into hot rolling mill (stand) 62, which contains a pair of crimp rolls 62A and a pair of backup rolls 62B and in which it is hot rolled to reduce thickness. The rolled strip enters the discharge roller 64, on which it can be forcedly cooled by means of water nozzles 66, and passes through the cage 70 of the pulling rolls containing a pair of pulling rolls 70A and 70B, and then into the winding device 68.

As shown in FIG. 3, the twin roll casting machine 54 comprises a main bed 72 of the machine on which a pair of parallel casting rolls 74 having casting surfaces 74A and 74B are mounted. During casting, molten metal is supplied from a ladle (not shown) to the intermediate casting device 80, then through the refractory nozzle 82 to the distributor 84, and then through the casting nozzle 86 to the gap 88 between the casting rolls 74. The liquid metal thus fed into the gap 88 creates a bath 92 above this gap, and this bath is limited at the ends of the rolls by a pair of lateral closing sills or plates 90, which are adjacent to the end surfaces of the rolls under the action of a pair of jacks (not shown) containing hydraulic cylinder blocks, nnyh with bracket side plates. The upper surface of the bath 92 (commonly referred to as the meniscus level) may rise above the lower end of the casting nozzle 86, as a result of which the lower end of the casting nozzle 86 is immersed in this tub 92.

The casting rolls 74 are water-cooled, whereby the metal layers solidify on the moving surfaces of the rolls and are connected to each other in the gap 88 between the rollers to create a hardened strip 56, which is fed downward from the gap 88 between the rollers 74. The twin-roll casting machine 54 may include to the type given and described in sufficient detail in US patents Nos. 5184668 and 5277243 or US patent No. 5488988, which by this reference are specifically included in this description.

In accordance with the present invention, customer orders for the steel strip are entered into a general-purpose computer system, such as the computer system 150 shown in FIG. 4, and processed in such a way as to be more fully described subsequently in order to determine process parameters and / or variables ( i.e., the set values of the process variables controlled in this process) of the process for controlling the continuous casting of a steel strip, for example, the continuous casting process of a steel strip 50 just described using Figures 2 and 3 so as to fulfill a customer order. As shown in FIG. 4, a general purpose computer system 150 comprises a general purpose computer 152, which may be a conventional desktop personal computer (PC), laptop computer or laptop, or other known general purpose computer having such a configuration to operate as described below way. Computer system 150 comprises a conventional keyboard 154 connected to a computer 152 for inputting information regarding a customer order into it, and may include any information output device or a combination of such devices. For example, computer 152 can be connected to printer 156, while computer 152 can be configured to print a group of process parameters in the form of a process change report or a similar report, where parameters and / or variables are indicated in the process change report a process for controlling a continuous casting process of a steel strip (for example, a continuous casting process of a steel strip 50 of FIGS. 2 and 3) so as to produce a steel strip ordered by a customer. In one embodiment of the present invention, the operator of a continuous casting process for a steel strip, such as process 50, views the progress report and manually makes the appropriate changes to the continuous casting process for the steel strip to produce a customer-ordered steel strip.

Computer 152 can alternatively or additionally be connected to a conventional monitor 158, while computer 152 can be configured to display a set of process parameters in the form of a process change report or similar report, where parameters are indicated in the process change report and / or process variables for controlling the continuous casting process of the steel strip (for example, the continuous casting process of the steel strip 50 shown in FIGS. 2 and 3) so as to produce the customer ordered m steel strip. The operator of the continuous casting process of a steel strip, such as process 50, can view the process change report displayed on the monitor 158 in addition to or instead of the printed report and manually make the appropriate changes to the continuous casting process of the steel strip to produce a customer-ordered steel strip.

Computer 152 is also electrically connected to a conventional media carrier reader / writer 160, where computer 152 is configured to store information using reader / writer 160 or retrieve information using this device in a known manner. In one embodiment, the computer 152 is configured to save (load) a set of process parameters in the form of a process change report or a similar report on the storage medium 162 using a read / write device 160, where parameters are indicated in the process change report and / or process variables for controlling the continuous casting process of the steel strip (for example, the continuous casting process of the steel strip 50 shown in FIGS. 2 and 3) so as to produce the ordered ient steel strip. The operator of a continuous casting process for a steel strip, such as process 50, can then access the contents of the storage medium using conventional techniques to view a report of the process changes and manually make the appropriate changes to the continuous casting process of the steel strip to thereby produce a customer-ordered steel strip. The device 160 for reading / writing the storage medium and the storage medium 162 of the information can be implemented in the form of any known combination of a reading / writing device for the storage medium and the storage medium. Examples include a magnetic disk reader / writer 160 and a magnetic diskette 162, a CD-ROM reader / writer 160, and a CD-ROM disk 162 and the like, but are not limited to the above.

In an alternative embodiment of the present invention, a steel strip continuous casting process, for example a steel strip continuous casting process 50 shown in FIGS. 2 and 3, is a computer controlled process, in which case the computer system 150 may be configured to report about changes to the process directly (in electronic form) to the process 50 through the corresponding communication line 164, as conventionally shown in FIG. As another alternative, computer 152 in a similar embodiment of the present invention may be configured to save (download) a process change report on the information medium 162, and the operator installs the information medium 162 containing the process change report on the reader / write (not shown), similar to the device 160 read / write information carrier, which is part of the equipment of the process 50, which is shown in Figure 4 by the dashed line 166. In any case, the continuous casting process a steel strip, for example process 50, responds to a process change report in order to automatically make corresponding process changes and / or device variable changes. However, it must be understood that, despite the way in which the process and / or variables are made that affect the process of continuous casting of a steel strip, a device that implements the process of casting a strip reacts to such changes for an immediate transition from the manufacture of a steel strip made in present, to the manufacture of steel strip in accordance with new information on process parameters / process variables.

5 is a flowchart illustrating one preferred embodiment of a method 200 for controlling a continuous casting process of a steel strip, such as the process 50 depicted in FIGS. 2 and 3 and described using them, for the purpose of manufacturing a steel product specified by a customer. Method 200 begins at the initial step 202 of receiving a customer order for a steel strip having the indicated mechanical properties or its characteristics as a product. In one embodiment, the product characteristics include the required grade of steel, the required strip thickness, and the total number of strip, although the present invention contemplates requesting additional or alternative information regarding a customer ordered product. After that, at step 204, the product characteristics are entered into the computer 152 accordingly by any known technology. For example, the operator can enter information into the computer 152 from the keyboard 154 or, if the information is provided by the client on a storage medium, such as a floppy disk, the operator can simply download information to the computer using the device 160 read / write media. Otherwise, the present invention contemplates entering the characteristics of the product into the computer 152 in accordance with other known technologies not described in detail in the accompanying drawings, where such technologies may include transmitting the characteristics of the product via a modem line between the computer 152 and the client computer, transmitting the characteristics of the product through An Internet connection or the like, but is not limited to the foregoing.

In any case, the execution of method 200 after step 204 continues to step 206, where computer 152 is used to calculate process parameters and / or process variables to control the continuous casting process of the steel strip (e.g., process 50) so as to produce a steel product ordered by a customer on based on the product characteristics entered into the computer 152 in step 204. In accordance with the present invention, the computer 152 is programmed using one or more sets of rules regarding product characteristics I entered into computer 152 at step 204 to obtain a set of process parameters / variables for controlling the process of continuous casting of a steel strip so as to produce a steel product ordered by a customer. One or more sets of rules can be implemented in the form of any of the following objects individually or in any combination of them: one or more tables, one or more graphs, one or more equations, etc. An example of one illustrative set of rules is given below in Tables I, II and III.

Table I shows in detail a set of rules that translate characteristics regarding steel products that can be ordered by any customer into processing parameters / variables for a hot-rolled strip product for the steel strip continuous casting process 50 described and described herein.

The steel grades for hot rolled strip products shown in Table I certified by the American Society for Testing Materials (ASTM) have the following yield strengths and elongations in percent:

ASTM brand Yield Strength (kg / sq.inch) Relates. elongation,% Brand 33 33-43 30-35 Brand 40 40-50 25-30 Brand 50 50-60 20-25 Brand 65 65-75 15-20 Brand 80 80-90 10-15,

and indicators H, C and B of the level of residual impurities are determined by the ratios: Low (H) <0.35%, Medium (C) = 0.8% and High (B) = 1.2%.

Table I Hot Rolled Strip Product Features
CUSTOMER ORDER Variables of the process carried out in a molding machine Thickness (mm) ASTM brand Level of residual impurities (Cu + Sn + Mo + Ni + Cr) Casting speed (m / min) Thickness after casting (mm) Hot crimping,% Conversion Curve (ROT) Cooling rate *
(° C / s) Coagulation temperature (° C) one 2 3 four 5 6 7 8 0.04 "(1.0 mm) Brand 33 Cannot be manufactured with current chemical composition 0.04 "(1.0 mm) Brand 40 N 80 1,6 38 700 0.04 "(1.0 mm) Brand 50 N 80 1,6 38 150 FROM 80 1,6 38 700 0.04 "(1.0 mm) Brand 65 N 80 1,6 38 200 FROM 80 1,6 38 150 AT 80 1,6 38 650 0.04 "(1.0 mm) Brand 80 FROM 80 1,6 38 200 N 80 1,6 38 250 0.047 "(1.2 mm) Brand 33 Cannot be manufactured with current chemical composition 0.047 "(1.2 mm) Brand 40 N 80 1,6 25.0 700 0.047 "(1.2 mm) Brand 50 N 80 1,6 25.0 150 FROM 80 1,6 25.0 700 N 45 1.9 37 650 0.047 "(1.2 mm) Brand 65 N 80 1,6 25.0 200 FROM 80 1,6 25.0 150 AT 80 1,6 25.0 650 0.047 "(1.2 mm) Brand 80 AT 80 1,6 25.0 200 FROM 80 1,6 25.0 250 0.055 "(1.4 mm) Brand 33 Cannot be manufactured with current chemical composition 0.055 "(1.4 mm) Brand 40 N 80 1,6 12.5 700 0.055 "(1.4 mm) Brand 50 N 80 1,6 12.5 60 FROM 80 1,6 12.5 650 N 45 1.9 26.0 650 0.055 "(1.4 mm) Brand 65 N 80 1,6 12.5 one hundred 0.055 "(1.4 mm) Brand 80 N 80 1,6 12.5 150 AT 80 1,6 12.5 650 0.063 "(1.6 mm) Brand 33 Cannot be manufactured with current chemical composition 0.063 "(1.6 mm) Brand 40 N 80 1,6 0,0 700 0.063 "(1.6 mm) Brand 50 N 80 1,6 0,0 60 FROM 80 1,6 0,0 650 0.063 "(1.6 mm) Brand 65 N 80 1,6 0,0 one hundred 0.063 "(1.6 mm) Brand 80 N 80 1,6 0,0 150 AT 80 1,6 0,0 650 0.075 "(1.9 mm) Brand 33 Cannot be manufactured with current chemical composition 0.075 "(1.9 mm) Brand 40 N 45 1.9 0,0 700 0.075 "(1.9 mm) Brand 50 FROM 45 1.9 0,0 650 0.075 "(1.9 mm) Brand 65 AT 45 1.9 0,0 650 0.075 "(1.9 mm) Brand 80 Fabrication is unlikely, as the conversion will occur before the ROT is reached. * - cooling rate in the temperature range 800-500 ° С

The basic set of rules for hot rolled strip products used to generate the values of Table I is summarized in Table II below, where the term “chemical composition” refers to the level of residual impurities in the steel product and where the Low, Medium and High levels are as described above.

Table II Chemical composition Rockwell hardness HR,% Cooling rate Yield Strength, MPa Low <15 150 550 Low 25-40 250 550 Average 25-40 200 550 Tall 0-50 thirty* 550 Low <15 one hundred 475 Low 25-40 200 475 Average 25-40 150 475 Tall 0-50 thirty* 475 Low <15 60 400 Low 25-40 150 400 Average 25-40 thirty* 400 Low 0-50 thirty* 350 * - standard cooling rate to obtain coiling temperatures of about 650-700 ° C

Based on the data obtained during the actual cycles, it was determined that 1.2% of residual impurities resulted in an increase in yield strength of approximately 120 MPa and therefore it is assumed that an increase in the content of residual impurities by 0.1% leads to a corresponding increase in the limit fluidity at 10 MPa.

From Table I, it should be apparent that the process parameters required for the manufacture of the hot rolled strip steel product specified by the customer may include any of the following parameters individually or in combination: casting speed during continuous strip casting, thickness of the steel product after casting, the percentage value of the crimp (decrease in thickness) of the steel product in the hot state, the cooling rate of the steel product and its rolling temperature.

Table III shows in detail a set of rules that translate characteristics relating to steel products that can be ordered by any customer into processing parameters / variables for a cold rolled product for the continuous steel strip casting process 50 described and described herein. The grades of steel for cold-rolled products shown in Table III certified by the American Society for Testing of Materials (ASTM) have the following yield strengths and elongations in percent:

ASTM brand Yield Strength (kg / sq.inch) Relates. elongation,% Brand 33 33-43 30-35 Brand 40 40-50 30-35 Brand 50 50-60 25-30 Brand 65 65-75 10-15 Brand 80 80-90 2 minutes.

Table III Characteristics of a cold-rolled product CUSTOMER ORDER Hot rolled strip specifications Parameters of cold rolling / annealing Thickness after cold rolling (mm) Cold Rolled ASTM Steel Grade Hot Rolled Strip Thickness (mm) Steel grade ASTM hot rolled strip Cold crimping,% Annealing cycle Annealing Temperature, ° F one 2 3 four 5 6 7 0.008 "(0.2 mm) Brand 33 1.0-1.6 Brand 40 80-88 Batch Annealing (OP) Lab data * - see footnote 0.008 "(0.2 mm) Brand 40 1.0-1.6 Brand 40 80-88 Batch Annealing / Continuous Annealing (BUT) 1250-1350 0.008 "(0.2 mm) Brand 50 1.4-1.6 Brand 50 86-88 BUT 1250-1350 0.008 "(0.2 mm) Brand 65 0.008 "(0.2 mm) Brand 80 1.0-1.6 ** Brand 40 80-88 - - 0.016 "(0.4 mm) Brand 33 1.0-1.6 Brand 40 60-75 OP 0.016 "(0.4 mm) Brand 40 1.0-1.6 Brand 40 60-75 OP / BUT 1250-1350 0.016 "(0.4 mm) Brand 50 1.4-1.6 Brand 50 70-75 BUT 1250-1350 0.016 "(0.4 mm) Brand 65 0.016 "(0.4 mm) Brand 80 1.0-1.6 ** Brand 40 60-75 - - 0.024 "(0.6 mm) Brand 33 1.4-1.6 Brand 40 57-63 OP 0.024 "(0.6 mm) Brand 40 1.4-1.6 Brand 40 57-63 BUT 1250-1350 0.024 "(0.6 mm) Brand 50 1.6-1.9 *** Brand 50 57-68 BUT 1250-1350 0.024 "(0.6 mm) Brand 65 0.024 "(0.6mm) Brand 80 1.0-1.6 ** Brand 40 40-63 ^- - 0.032 "(0.8 mm) Brand 33 1.4-1.6 Brand 40 43-50 OP 0.032 "(0.8 mm) Brand 40 1.6-1.9 *** Brand 40 50-58 OP 0.032 "(0.8 mm) Brand 50 0.032 "(0.8 mm) Brand 65 1,0 Brand 40 twenty - ^- 0.032 "(0.8 mm) Brand 80 1.2-1.6 ** Brand 40 33-50 - - 0.040 "(1.0 mm) Brand 33 1.9 Brand 40 47 OP 0.040 "(1.0 mm) Brand 40 1.9 Brand 40 47 OP 0.040 "(1.0 mm) Brand 50 0.040 "(1.0 mm) Brand 65 1.3 Brand 40 23 - - 0.040 "(1.0 mm) Brand 80 1.6-1.9 *** Brand 40 38-48 - - * 1250-1350 ° F correspond to 676.7-732.2 ° C; lab. batch annealing data - slow heating to 1275 ° F (690.6 ° C) (takes about 33 hours) followed by slow cooling from 1275 ° F (690.6 ° C) to 750 ° F (398.9 ° C) (takes about 8 hours). The yield strength of the material was quite low (23 kg / sq. Inch), respectively, for Brand 33, there is the opportunity to optimize the batch annealing.
** Preferred hot-rolled strip of smaller thickness, since a smaller cold crimp will provide better elongation.
*** a hot-rolled strip of greater thickness is preferred in order to obtain a higher yield strength with good elongation after annealing.

The general set of rules for cold rolled material used to generate Table III is as follows:

 (i) cold crimping of more than 35-40% is required to obtain Brand 80,

(ii) at least 50% cold pressing is required to conduct continuous annealing; and

(iii) at least 40% cold crimping is required to conduct batch annealing.

From Table III, it should be obvious that the process parameters required for the manufacture of the cold rolled steel product specified by the customer may include any of the parameters of the process for manufacturing hot rolled strip products and additionally any of the following parameters individually or in combination: percentage value of cold crimping (crimping cold), type of annealing, e.g. batch annealing or batch annealing / continuous annealing, and annealing temperature.

Referring again to FIG. 5, after step 206, execution of method 200 continues to step 208, where computer 152, in one embodiment of the present invention, can be used to display process parameters in a progress report to a continuous casting process operator. Obviously, step 208 is typically included in method 200 only when computer 152 cannot automatically control the steel strip continuous casting process 50, as described above; otherwise, this step may be omitted from method 200. If this step is included in method 200, then computer 152 may be configured to display a report of process changes using one or more of the information output devices described above with respect to FIG. four. In this embodiment, the steps of the method 200 performed by the computer 152 are enclosed in a rectangle 210 formed by a dashed line. In addition, as described above, the present invention contemplates embodiments where the computer 152 may receive a customer order electronically, and in the case of such variants, a dashed line rectangle 210 may include a step 202.

After step 208, the method 200 continues to step 212, where the continuous casting process (for example, the continuous casting process 50 of the strip shown and described using FIGS. 2 and 3) is controlled depending on the process parameters calculated (obtained) at step 206 so as to manufacture the steel product specified by the customer. In process variants including step 208, step 212 is generally not performed by computer 152, but instead is performed by an operator of a continuous casting process of a steel strip. In such embodiments, the operator performs step 212 by manually entering the parameters / process variables indicated in the process change report. In embodiments where the computer 152 is configured to provide parameters / variables directly (electronically) to the continuous casting process of the steel strip, step 208 may be omitted, and after step 206, it may proceed directly to step 212. In such embodiments, the computer 152 may be configured to automatically enter the parameters / process variables calculated (obtained) in step 206 into the continuous casting process of the steel strip, and in these cases, the rectangle 210 made by the dashed line, including includes step 212.

In accordance with the present invention, the computer system 150 may convert the customer-specified product characteristics into a production cycle diagram for steel of a selected composition. In a typical case, the production cycle diagram for a given chemical composition of steel may exist for at least several days, during which the steel strip is continuously cast by a twin-roll casting machine 54. Depending on the number of orders and quantities ordered, the entire production cycle may be associated with the manufacture of a steel strip having one specific set of mechanical properties or may be intended for the manufacture of a steel strip with selected mechanical properties varying in the length of this strip.

The production cycle takes into account parameters such as casting speed, temperature range of hot rolling, degree of hot crimping and cooling rate through the temperature range of transformation of austenite to ferrite (typically from 900 to 550 ° C), to obtain the final microstructure of the cast strip, which provides the required mechanical properties and lays down the possibilities of subsequent processing associated with changes in the cooling rates of the strip.

When regulating the cooling rate in the range from 0.1 ° C / s to more than 100 ° C / s, it is possible to produce a casting having microstructures, including:

(i) mainly polygonal ferrite;

(ii) a mixture of polygonal ferrite and low temperature conversion products such as needle ferrite, Widmanstätt oriented ferrite, and bainite; and

(iii) mainly low temperature conversion products.

In the case of unalloyed carbon steels, this range of microstructures can provide yield strengths in the range from 200 MPa to more than 700 MPa. Once the production cycle pattern has been determined, the twin roll casting machine 54 can function to operate to produce the cast strip in accordance with this production pattern, and this strip can be delivered to customers upon request.

One advantageous feature of the method according to the present invention is that it is possible to adjust the production cycle scheme during the execution of this cycle in order to urgently proceed to the production of the ordered strip with the required mechanical properties. Thus, in the method proposed by the present invention, a single chemical composition of steel is used to obtain a wide range of mechanical properties, as a result of which it is no longer necessary to delay the execution of customer orders until the smelting / batch is completed; strip casting with simultaneous control of the rolling temperature, the degree of hot crimping and the cooling rate of the final product can ensure the simultaneous receipt of the dimensional characteristics specified by the client and the required mechanical properties within the same production line, typically having a length of less than 70 meters; properties can be changed in real time by modifying the corresponding variables in the key process control loops in the central control computer, as a result of which the time elapsing from the receipt of the customer order to the delivery of the product can take less than 8 hours, as opposed to the usual steel production process, the duration of which is from 14 to 30 days; a very short period of time from order to delivery allows you to implement the concept of "virtual warehouse" through the use of electronic commerce.

Although the invention has been and is described in detail using the above drawings and descriptions, they should be considered as illustrative and non-limiting, accordingly, it should be understood that only preferred embodiments of this invention are shown and described, and that all changes and modifications not exiting are protected. beyond the scope of the invention.

Claims (51)

1. The method of controlling the process of continuous casting of a steel strip for the manufacture of a variety of steel products specified by the client with various mechanical properties, including receiving an order for the first steel product containing the requirements specified by the client, including mechanical properties related to the said first steel product, conversion the requirements mentioned by the client into a set of predefined process parameters for controlling said continuous casting process a steel strip for the purpose of manufacturing said first steel product, controlling a process of continuous casting of a steel strip based on said set of predefined process parameters for the manufacture of the first steel product, accepting an order for a second steel product containing requirements specified by the client, including mechanical properties related to said second steel product, wherein these mechanical properties differ from the mechanical properties of the first steel product, introducing the requirements mentioned by the client into a set of new process parameters for controlling said continuous steel strip casting process for the purpose of manufacturing said second steel product and replacing said set of predetermined process parameters with said set of new process parameters without interrupting said continuous steel strip casting process, as a result whereby this process of continuous casting of a steel strip proceeds from the manufacture of said first steel from a division for the manufacture of said second steel product. 2. The method according to claim 1, wherein said requirements specified by a customer include the thickness of said steel products. 3. The method according to claim 1 or 2, in which the aforementioned requirements specified by the client include the brand of the said steel products. 4. The method according to any one of claims 1 to 3, in which said set of new process parameters includes a casting speed in said continuous casting process of a steel strip. 5. The method according to any one of claims 1 to 4, in which said set of new process parameters includes the thickness of said steel product in a state after casting. 6. The method according to any one of claims 1 to 5, in which said set of new process parameters includes the percentage value of crimping said steel product in a hot state. 7. The method according to any one of claims 1 to 6, in which said set of new process parameters includes a cooling rate of said steel product. 8. The method according to any one of claims 1 to 7, in which said set of new process parameters includes the temperature of coiling of the said steel product. 9. The method according to any one of claims 1 to 8, in which said set of new process parameters includes the percentage value of crimping said steel product in a cold state. 10. The method according to any one of claims 1 to 9, wherein said set of new process parameters includes an annealing cycle type. 11. The method of claim 10, wherein said set of new process parameters includes annealing temperature. 12. A method of obtaining a steel strip indicated by a client, including processing orders for a steel strip that meets the requirements specified by the client, with obtaining a production scheme of the ordered steel strip in the production cycle of a continuous casting machine casting a steel strip with a single chemical composition of steel, the operation of the machine for continuous casting of a strip during the production cycle for the manufacture of cast strip with a single chemical composition of steel, cooling the strip through a temperature range converting austenite to ferrite and selectively controlling the parameters of the cast strip manufacturing process and cooling said strip to obtain a strip that meets the requirements specified by the client. 13. The method according to item 12, further comprising in-line hot rolling of the cast strip before it is cooled through the temperature range of transformation of austenite to ferrite. 14. The method according to item 12 or 13, in which the aforementioned requirements specified by the client include the thickness of said steel strip. 15. The method according to any one of claims 12-14, wherein said requirements specified by a customer include a brand of said steel strip. 16. The method according to any one of claims 12-15, wherein said process parameters include a casting speed in a continuous casting process of a steel strip. 17. The method according to any one of claims 12-16, wherein said process parameters include the thickness of said steel strip in a post-cast state. 18. The method according to any one of claims 12-17, wherein said process parameters include a percentage of crimping said steel strip in a hot state. 19. The method according to any one of claims 12-18, wherein said process parameters include a cooling rate of said steel strip. 20. The method according to any one of claims 12-19, wherein said process parameters include a roll-up temperature of said steel strip. 21. The method according to any one of paragraphs.12-20, in which the aforementioned process parameters include the percentage value of the crimp mentioned steel strip in the cold state. 22. The method according to any one of claims 12-21, wherein said process parameters include an annealing cycle type. 23. The method of claim 22, wherein said process parameters include annealing temperature. 24. The method of controlling the process of continuous casting of a steel strip for the manufacture of a variety of steel products specified by the client with various mechanical properties without changing the composition of the steel entering the strip casting process, which includes receiving multiple orders for steel products containing requirements specified by the client for various mechanical properties, related to said products, converting said customer requirements into a series of process parameters to control the continuous casting process cial band with the purpose of making said steel products and production of said plurality of steel products with different mechanical properties corresponding to said obtained from the transformation process parameters without changing the steel composition supplied to the strip casting process. 25. The method according to paragraph 24, including the additional step of displaying the aforementioned series of process parameters in a report of process changes to the operator of the aforementioned process of continuous casting of steel strip. 26. The method of claim 25, further comprising controlling said continuous steel strip continuous casting process based on said process parameters displayed in said process change report for manufacturing said steel product. 27. The method according to any one of paragraphs.24-26, in which the aforementioned set of requirements specified by the client for various mechanical properties includes various grades of said steel products. 28. The method according to any one of paragraphs.24-27, wherein said series of process parameters includes a casting speed in a continuous casting process of a steel strip. 29. The method according to any one of paragraphs.24-28, in which the aforementioned series of process parameters includes the percentage value of the crimp mentioned steel products in a hot state. 30. The method according to any one of paragraphs.24-29, wherein said series of process parameters includes a cooling rate of said steel products. 31. The method according to any one of paragraphs.24-30, wherein said series of process parameters includes a hot rolling temperature of said steel products. 32. The method according to any one of paragraphs.24-31, in which the aforementioned series of process parameters includes the temperature of the coiling of said steel products. 33. The method according to any one of paragraphs.24-32, in which the aforementioned series of process parameters includes the percentage value of the crimp mentioned steel products in the cold state. 34. The method according to any one of paragraphs.24-33, wherein said series of process parameters includes an annealing cycle type. 35. The method of controlling the process of continuous casting of a steel strip for the manufacture of a steel product specified by the customer, comprising receiving an order for a steel product containing the requirements specified by the client related to the product, converting the requirements specified by the client into a series of process parameters for controlling the process of continuous casting of steel strips for the purpose of manufacturing said steel product and controlling said continuous casting process of a steel strip based on said process parameters to obtain said steel product. 36. The method according to clause 35, in which the aforementioned requirements specified by the client include the thickness of said steel product. 37. The method according to clause 36, in which the aforementioned requirements specified by the client include the brand of said steel product. 38. The method of claim 35, wherein said series of process parameters includes a casting speed in said continuous casting process of a steel strip. 39. The method of claim 38, wherein said series of process parameters includes a thickness of said steel product in a cast state. 40. The method according to § 39, in which the aforementioned series of process parameters includes the percentage value of the crimp mentioned steel products in a hot state. 41. The method of claim 40, wherein said series of process parameters includes a cooling rate of said steel product. 42. The method according to paragraph 41, wherein said series of process parameters includes a hot rolling temperature of said steel product. 43. A method of controlling the process of continuous casting of a steel strip for the manufacture of a steel product specified by a customer, comprising receiving an order for a steel product containing the requirements specified by the customer related to the product and converting the requirements specified by the customer into a series of process parameters for controlling the continuous casting process a steel strip for the purpose of manufacturing said steel product. 44. The method according to item 43, further comprising controlling the mentioned process of continuous casting of a steel strip based on the process parameters displayed in the report on the changes in the process for the manufacture of the said steel product. 45. The method according to item 43, in which the aforementioned requirements specified by the client include the thickness of the said steel product. 46. The method according to item 43, in which the aforementioned requirements specified by the client include the brand of said steel product. 47. The method according to item 43, wherein said series of process parameters includes a casting speed in said continuous casting process of a steel strip. 48. The method according to item 43, in which the aforementioned series of process parameters includes the thickness of the said steel product in the state after casting. 49. The method according to item 43, in which the aforementioned series of process parameters includes the percentage value of the crimp mentioned steel products in a hot state. 50. The method of claim 43, wherein said series of process parameters includes a cooling rate of said steel product. 51. The method of claim 50, wherein said series of process parameters includes a hot rolling temperature of said steel product.

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