MXPA98002605A - Cast steel cut length optimization - Google Patents

Abstract

A continuous steel caster (100) uses cut length optimization to minimize the amount of scrap steel in cutting a steel strand (120, 510, 520, 530, 540) into blooms with a traveling torch cut-off station (136). The steel strand is cut to produce at least one bloom (514, 524, 534, 544) having a determined cut length. The length for a next-to-last bloom (515, 525, 535, 545) is determined (416, 602-630) such that it is within a predetermined range of cut lengths and such that the bloom may be cut into a number of billets each within a predetermined range of lengths. The length for a lastbloom (516, 526, 536, 546) is also determined (416, 602-630) such that it is within a predetermined range of cut lengths and such that the bloom may be cut into a number of billets each having a length within a range of lengths.

Description

OPTIMIZATION OF THE LENGTH OF CUTTING THE STEEL CAST FIELD OF THE INVENTION The present invention relates generally to the field of optimization of the cutting length.

BACKGROUND OF THE INVENTION Continuous casting of steel is a known process for producing elongated steel billets and ingots. For a process, a steel saucepan is treated to produce a desired grade of steel as needed to satisfy a customer's request, for example. A steel saucepan is also called a load. The molten steel is cast to form billets by emptying the molten steel through a mold and cooling the steel as it leaves the mold to form a continuous solid strip. The steel strip travels vertically below the mold and bends along an arcuate path defined by guide rollers in a horizontal travel path. As the strip travels horizontally, it is cut to form a number of elongated steel billets. The steel billets can be reheated, rolled and cut to form elongated steel ingots having a relatively smaller cross-sectional area compared to the billets. The ingots can then be processed in a rolling mill to produce steel bars, or be shipped directly to the customer for the final steel product manufacture by the customer. When requesting steel, each customer may require ingots having a specific cross-sectional area, length, grade of steel and / or weight, for example. When emptying each load, an adequate number of appropriately sized billets is cut from the cast steel strip to process them and form the ingots required by the customer. However, any length of remaining cast steel coming from the cast strip is typically discarded.

BRIEF DESCRIPTION AND OBJECTS OF THE INVENTION An object of the present invention is to provide an optimization method and apparatus for cutting a strip of material into separate pieces. Another object of the present invention is to minimize the amount of waste material in the cut of a strip of material into separate pieces. Another object of the present invention is to minimize the amount of scrap steel in the cut of a steel strip to form billets and ingots. A method for cutting a strip of material is described. A cutting length is determined for at least one piece that will be cut from the strip of material, the which is based on a predetermined sub-sub length, and the strip of material is cut to produce the at least one piece having the determined cut length. The cut length for a mode is reduced by at least a predetermined sub-multiple length if the cut length is greater than a predetermined maximum length. A penultimate length is determined for a penultimate piece that will be cut from the strip of material and a final length for a final piece that will be cut from the strip of material. The penultimate length for the penultimate piece that will be cut from the strip of material is assigned, and the final length for the final piece that will be cut from the strip of material is determined based on the penultimate length assigned. The cut length can be assigned as the penultimate length for the penultimate part. The penultimate length and the final length are adjusted by adding at least one predetermined sub-multiple length from the penultimate length to the final length. The penultimate length and the final length can be adjusted so that the penultimate length and the final length are each greater than a predetermined minimum length. The strip of material is cut to produce the penultimate piece that has the penultimate length and to produce the final piece that has the final length. Another method is described to cut a strip of material. A cutting length is determined for at least one piece that will be cut from the strip of material, such that the cutting length is within a predetermined scale of cutting lengths and such that each of the at least one piece can be cut into a number of subpieces each having a predetermined sub-cleaning length. within a predetermined scale of sub-piece lengths. The cut length for one mode is reduced by at least one predetermined sub-multiple length if the cut length is greater than a predetermined maximum length, and the at least one predetermined sub-multiple length is based on the predetermined sub-length length. The strip of material is cut to produce the at least one piece having the determined cutting length. A penultimate length is determined for a penultimate piece that will be cut from the strip of material and a final length for a final piece that will be cut from the strip of material. The penultimate length is determined so that the penultimate length is within the predetermined scale of cut lengths and so that the penultimate piece can be cut into a number of subpieces each having a first sub-piece length within the predetermined scale of lengths of subpiece. The first sub-piece length for a mode is the predetermined sub-piece length.

The final length is detrminated such that the final length is within the predetermined scale of cut lengths and such that the end piece can be cut into a number of subpieces each having a second sub-piece length within the predetermined scale of sub-piece lengths. The penultimate length and the final length are determined to minimize a length of waste material remaining from the strip. The penultimate length and the final length can be adjusted by adding at least one predetermined sub-multiple length from the penultimate length to the final length, such that the penultimate length and the final length are each greater than a predetermined minimum length. , wherein the at least one predetermined sub-multiple length is based on the first sub-piece length. The strip of material is cut to produce the penultimate piece that has the penultimate length and to produce the final piece that has the final length. The material may comprise steel and may be produced with a continuous steel strainer. Each of the at least one pieces of steel is a billet having a length based on a length of ingot. Each billet can be cut into at least one ingot having the ingot length. The steel strip can be cut with a sliding torch cutting station. The penultimate length and the final length can be determining in response to one of the at least one strip field event that suggests a determination of an alternative cut length for the final piece. The at least one strip field event may comprise an absence of steel in a mold and a stop of the strip. Other objects, features and advantages of the present invention will become apparent from the accompanying drawings and from the detailed description below.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which: Figure 1 illustrates a continuous steel strainer; Figure 2 illustrates the organization of software to control the cutting of steel strips to form billets; Figure 3 illustrates a flow diagram for the optimization of billet production of level 3; Figure 4 illustrates a flow diagram for the optimization of the level 2 billet strainer; Figure 5 illustrates a top view of four strips in which the length of cut will be optimized to produce billets having alternative cut lengths; Y Figure 6 illustrates a flow diagram for determine alternative billet cutting lengths.

DETAILED DESCRIPTION Figure 1 illustrates a continuous steel strainer 100 for producing billets and steel ingots according to a customer's orders. The waste steel is first heated to a molten state using an electric arc furnace to produce molten steel and transfer it to a bucket 112 by means of a bucket transfer trolley. The molten steel can then be refined in a bucket refining station and degassed in a vacuum degasser as is suitable for casting a desired degree of steel. The molten steel in the bucket 112 is also called loading. As illustrated in FIG. 1, the bucket 112 is moved to a casting position on a casting floor 110 to empty the molten steel to a pan 114 at a controlled rate through a nozzle from the underside of the bucket 112. The release of the molten steel through this nozzle is controlled by a gate. The copper 114 serves as a manifold for routing the molten steel within a mold 116 through a nozzle on the underside of the copper 114. The release of the molten steel through this nozzle is also controlled by a gate. The mold 116 includes a water cover which cools the molten steel while flowing through the mold 116. In the Inside the mold 116, the molten steel begins to form an outer skin or shell as the molten steel solidifies in the steel strip 120. The transverse dimensions of the steel strip 120 are defined by the mold outlet opening 116 and can be of any suitable size. The steel strip 120 falls beyond the mold 116 along an arcuate path defined by guide rollers 124, a curved cooling chamber 126 and guide rollers 128. The cooling chamber 126 includes nozzles that spray water on the surface outer of the steel strip 120 for further solidification of the steel strip 120. Guide rollers 128 guide the steel strip 120 into a horizontal path where withdrawal rollers 130 straighten the steel strip 120. The steel strip 120 can also be subjected to gentle reduction by means of withdrawal rollers 130 to re-give the steel strip 120 a suitable cross-section. As an example, the steel strip 120 can be laminated to a cross section of about 254 mm by about 330 mm. The steel strip 120 is then fed into a surface quenching station 134 to treat the outer surface of the steel strip 120 before cutting the steel strip 120 into elongated billets traveling in the cutting station with the torch 136. A torch-cut control system or digital data processing system 140 is programmed with appropriate software to interconnect with the cutting station 136 and controlling the cutting of the steel strip 120. The data processing system 140 determines the length of cut for each billet and controls the cutting station 136 during cutting of the steel strip 120. The cut billets they are each discharged in a reheating furnace and subsequently rolled to cut into elongated ingots each having a relatively smaller cross-sectional area compared to the billets. The ingots can then be further processed in a rolling mill to produce steel bars, or they can be shipped directly to the customer for the manufacture of the final steel product by the customer. When all the molten steel is drained from the bucket 112 in the pan 114, another bucket can be placed to empty more molten steel into the pan 114 to cast more steel strips 120. In this way, the same or different grades of steel can continuously casting through the strainer 100 to form a steel strip 120. Although the steel strip 120 may have regions of mixed steel as a result of this heat sequencing process, said regions may be subsequently cut from the steel strip 120 or from the resulting billets or ingots. As a convenience, the strainer 100 is illustrated in Figure 1 by straining a steel strip 120. However, the strainer 100 can be configured to cast a plurality of steel strips similar to the steel strip 120. As a For example, the strainer 100 may include a boiler 114 having four nozzles controlled by four gates to simultaneously drain molten steel from the bucket 112 into four separate molds to cast four parallel steel strips. Each of these strips can be directed and processed similarly to the steel strip 120 to produce billets and ingots.

Batch casting for customer orders For each customer's order, the cross-sectional area, the length scale, the steel grade and the weight produced for the steel ingots are specified. A measured quantity of molten steel is treated for each order to cast a load of steel having the specific grade. When each load of molten steel is cast by the strainer 100 to form one or more steel strips, a suitable number of billets of suitable length are cut from the strip or strips cast by the cutting station 136 for further processing and forming the ingots for the order. The data processing system 140 determines an optimized billet cutting program for each load that will be cast in such a way that the resulting billets can be laminated and cut into an adequate number of ingots having a cross-sectional area, a suitable length and weight to satisfy the order. In determining the data processing system 140 the length of cut for each billet, the data processing system 140 attempts to carry to the maximum the cut length of billet to produce a maximum number of ingots from each billet, maximizing at the same time the length of the ingot for the order of each client. However, the billet cutting length may be restricted by other considerations including, for example, mechanical limitations of the reheating furnace used to reheat the billets and process them to form ingots. The data processing system 140 also determines the cutting program for casting as much available molten steel as possible for each heating. The available molten steel excludes losses in the bucket and crusts in the pan. The data processing system 140 attempts to minimize the amount of waste steel that results in the casting of each load or strip. The length of the waste steel can result, for example, from uncut steel that remains at the end of a load or sequence of loads after the billets have been cut for loading or loading sequence. The casting of a load or sequence of charges may be terminated due to a number of conditions. For one condition, the flow of molten steel in the strainer 100 is stopped to stop the casting of a steel strip or strips by the strainer 100. For another condition, the molten steel of one degree is drained in the boiler 114 followed by steel cast of another grade. This condition creates a steel mixed in the boiler 114 which results in the casting of a Strip or steel strips that have a region of mixed steel. This region may or may not be cut from the strip or strips. The mixing of steel in the copper 114 can be prevented with a change of the elevated copper by temporarily stopping the casting of each strip and by changing the copper 114 through another copper to cast a different grade of steel. To separate the different grades of steel for each strip, a transition piece of steel can be dropped into each mold during the change of coppers. Waste steel can also result, for example, from cutting billets around a defective region of the strip or strips. As an example, temporary stopping of the casting operation can cause the steel in the mold or molds to become defective as a result of over-cooling during the dwell time of stopping. The length of the waste steel can remain avoiding the defective region to cut a billet or billets of adequate length from each strip.

Organization of the data processing system As illustrated in Figure 2, the data processing system 140 executes software organized at levels 210, 220 and 230 to determine an optimized billet cutting program and to control the cutting of billets from of each steel strip by means of cutting station 136. Levels 210, 220 and 230 are also called level 3, level 2 and level 1, respectively. The data processing system 140 can include any suitable hardware architecture, including any suitable programmable logic sliders, for example, to run the software in the control of the cutting station 136. At level 3, the processing system of Data 140 executes a production program 212 that maintains an information database to track the production of steel and to control the cutting of the billets. Production program 212 generates a load chart 214 to maintain information and track each load of steel to be cast. Each load is identified in the load chart 214 by a heat identifier "id. The loading frame 214 can be used to store relevant information for each load, such as steel grade and test codes, for example. The production program 212 also generates a separate laminate ordering table 216 for each load and for maintaining information and tracking each customer's order that will be cast from each load. The location of the laminate ordering table 216 for each load can be identified in the loading table 214. The laminate ordering table 216 identifies each rolling order for a load by means of an ID identifier. The laminate ordering box 216 can be used to store relevant information for each rolling order, such as a specified minimum ingot length, a maximum ingot length specified and a specified produced weight, for example. For each laminate order identified in the laminate ordering table 216, production schedule 212 determines billet and ingot production information suitable for optimized billet production regardless of the amount of steel available and regardless of the occurrence of any event of strip field. This production information is stored in the laminate ordering table 216 and includes, for example, cold billet cutting lengths and the number of billets that will be cut for each laminate order. At level 2, the data processing system 140 executes software that includes a cut optimization model 226 to determine, among other things, programmed billet cutting lengths and alternative billet cutting lengths based on the production information. of billets and ingots stored in laminate ordering box 216 of level 3, the amount of steel available and the occurrence of strip field events when the steel is cast. The cut optimization model 226 may also allocate each programmed and alternative billet cut length to a specific strip of a plurality of strips being cast by the strainer 100. The level 2 software also includes a metallurgical database that has casting program tables 222 and cutting optimization model parameters 224. Casting program tables 222 store much information, including: (1) the length of a waste clipping (Lcrop); (2) density of steel billet; (3) soft reduction schedules (Pstrand); and (4) billet temperature schedules (T). The cut optimization model parameters 224 store a cutting optimization model configuration for use by the cut optimization model 226. At level 1, the data processing system 140 executes a strip cutting program 232 for controlling the cutting station 136 during the cutting of billets from each strip based on the cut lengths determined at level 2. The data processing system also executes strip field event software 234 at level 1 for report to the cutting optimization model 226 at level 2 the different strip field events as they occur, including: (1) length of uncut material left in each strip; (2) length of the projecting billet for each strip; (3) length of the last cut billet for each strip; (4) open bucket gate (yes / no indicator); (5) presence or absence of steel in the mold (yes / no indicator); (6) temporary stop of the strip or restart (indicator yes / no); and (7) quality separation point (yes / no indicator).

Optimization of level 3 billet production When customers request that the steel be cast, a laminate order is defined in level 3 according to the steel requirements of each client. The rolling order ^ 5 specifies: (1) a desired transverse dimension for cold ingots; (2) a minimum length (lmin) for cold ingots; 10 (3) a maximum length (Imax) for cold ingots; and (4) a produced weight (Wro) required to satisfy a customer's order. The production program 212 stores this information in the rolling order box 216 for the load having the desired grade of steel to be cast. The production program 212 executes an algorithm, as illustrated in figure 3 in the form of a flowchart, to determine a solution for cutting from a steel strip or strips a suitable number of nominal billets and a final billet, each cut billet having an adequate length to produce a whole number of ingots having a nominal ingot length, taking into account the cut-outs, and so that the Wro produced weight for the customer's order is obtained. The production program 212 determines the solution for each rolling order when the rolling order is defined first and then any update for the rolling order. The solution includes the following: (1) a whole number of nominal billets (Nn); (2) a nominal billet length (Ln); (3) a final billet length ((Ll), (4) a whole number of ingots per nominal billet (nn), (5) a whole number of ingots for the final billet (ni), (6) a length of nominal ingot (1); and (7) a submultiple length of billet (Lbs) For the solution, the length of ingot 1 is greater than, or equal to, the minimum ingot length l in, as defined in the order of laminate, and less than, or equal to, the maximum ingot length Imax, as defined in the rolling order. Likewise, the nominal billet length Ln and the final billet length Ll are each greater than or equal to a minimum billet length (Lmin) and less than or equal to a maximum billet length (Lmax) The maximum billet length Lmax is defined in the metallurgical database of level 2 and is determined by the maximum allowable length for a billet that will be unloaded and heated in the reheating furnace for the production of ingots. or minimum Lmin is also defined in the metallurgical database of level 2. The production program 212 determines a solution for each laminate order regardless of the amount of steel available and regardless of the occurrence of any strip field event. For step 302 of Figure 3, the nominal billet length Ln is initialized to the maximum billet length Lmax, while the ingot length 1 is initialized to the maximum ingot length Imax. Likewise, a smaller potential steel waste length Ldiff is initialized to the minimum billet length Lmin. For steps 304-314, the nominal ingot number nn is determined for a nominal billet length Ln as large as possible according to the following equation: (nn * l + icrop) l_n = (1) rho where: lcrop = a length of ingot trimming; and rho = a reduction factor of ingot rolling mill (BRM). The ingot cutout length lcrop depends on the size and can be equal to, for example, twice the length of an upper cutout as defined in casting program tables 222 of level 2. The reduction factor of rolling mill Roth ingot is size dependent and can be determined by the cross section of the billet divided between the specified ingot cross section as calculated at level 3 or as defined in casting program tables 222 of level 2. For step 304, the nominal ingot number nn is determined according to equation (1) above, based on the nominal billet length Ln and ingot length 1 as initialized for step 302, and the nominal ingot number nn calculated is rounded to the nearest integer for step 306. The length of ingot 1 is then determined for the step 308 according to equation (1) above, based on the nominal ingot length Ln initialized and the nominal ingot number nn rounded. If the length of calculated ingot 1 is less than the minimum ingot length lmin as determined for step 310, the nominal ingot number nn and the length of ingot 1 are recalculated. For step 312, the length of ingot 1 is reprogrammed to the maximum ingot length Imax, while the nominal billet length Ln is reduced by delta_L. As long as the nominal billet length Ln is greater than or equal to the minimum billet length Lmin as determined for step 314, the nominal ingot number nn and the ingot length 1 are recalculated for steps 304-312 through that the length of ingot 1 as calculated for step 308 is greater than or equal to the minimum ingot length lmin as determined for step 310. If the nominal billet length Ln is reduced to a value below the length of minimum billet Lmin as determined for the Step 314, the control proceeds to step 338 to determine suitable default values as a final solution for the present laminate order. When a suitable ingot number nn and a suitable ingot length 1 are determined for steps 304-314, the nominal billet number Nn, the final billet number ni and the final billet length Ll are determined for steps 316 -324 according to the following equations: Nn * nn * l * Wlnorm = Wro (2) (Nn * nn + nl) * l * Wlnorm > Wro (3) (nl * l + lcrop) Li = () rho where: Wlnorm = cold bar weight per unit length. The cold bar weight per unit length Wlnorm depends on the size and can be defined in casting program tables 222 or calculated from the dimensions and densities of the ingot. For step 316, the nominal billet number Nn is determined according to equation (2) above, based on the nominal ingot number nn calculated and the ingot length 1 calculated, and the nominal billet number Nn calculated is truncated to the nearest integer for step 318. The final billet ingot number is then determined for step 320 according to equation (3) above, based on number of nominal ingot nn calculated, to the calculated ingot length 1, and to the nominal billet number Nn truncated, and the number of final billet ingot calculated is rounded to the nearest integer for step 322. Based on the No. of final billet ingot calculated and the length of ingot 1 calculated, the final billet length Ll for step 324 is determined according to equation (4) above. If it is determined for step 326 that the final billet length Ll is greater than or equal to the minimum billet length Lmin, a suitable solution based on the current calculated values has been determined for the present rolling order and the control proceeds to step 334. If it is determined for step 326 that the final billet length Ll is less than the minimum billet length Lmin, then another potential solution is calculated on the basis of a shorter billet length Ln until a minimum billet length is found. final billet length Ll suitable as that determined for step 326. For step 328, the difference in end billet length Ll from the minimum billet length Lmin is determined, compared to the waste length is steel potential Smallest Ldiff. When the waste length Ldiff is initialized to the minimum billet length Lmin for step 302, this difference is less than the waste length Ldiff the first time the comparison is carried out for step 328 for the present laminate order . The length of waste Ldiff is programmed to the difference of the final billet length Ll from the minimum billet length Lmin for step 330 and represents the smallest potential steel loss in case a final billet length is not found greater than or equal to the minimum billet length Lmin. The current calculated values are saved for step 332 as a possible final solution for the present rolling order. To calculate another potential solution for the present rolling order, the control proceeds to step 312 where the nominal billet length Ln is reduced by delta "L. Steps 304-332 are repeated, as long as the nominal billet length Ln remains greater than or equal to the minimum billet length Lmin as determined for the strike 314, and until a suitable solution has been found as determined for step 326. If the final billet length Ll for the new potential solution is less than the minimum billet length Lmin as determined for step 326, the difference in this final billet length Ll is determined from the length of The minimum billet Lmin is compared to the smallest waste length Ldiff for step 328. If this difference is less than the smallest waste length Ldiff, this difference becomes the new smallest waste length Ldiff for step 330. The new potential solution is saved for step 332 as a potential final solution for the present laminate order that would take the quantity to the minimum of steel waste compared to the previous saved eolution. The control p then proceeds to step 312 in an attempt to calculate for the present rolling order a solution having a final billet length Ll greater than or equal to the minimum billet length Lmin as determined for step 326 or which would reduce the amount of steel waste compared to the newly stored solution. If the difference of the final billet length Ll for the new potential solution from the minimum billet length Lmin is greater than or equal to the smallest waste length Ldiff for step 328, then the new potential solution would not lead to the The minimum amount of steel scrap compared to the solution just before saved. The control then proceeds to step 312 in an attempt to calculate for the present rolling order a solution having an end billet length greater than or equal to the minimum billet length Lmin as determined for step 326 or which could reduce the amount of scrap steel compared to the freshly stored solution for step 328. If a suitable solution having an end billet length greater than or equal to the minimum billet length Lmin is determined for step 326, the control proceeds to step 334 and the calculated values for this particular solution are used for the present rolling order. For step 336, the submultiple length of billet Lbsm is calculated according to the following equation.

Lbsm = l rho (5) However, if the nominal billet length Ln is reduced to a value less than the minimum billet length Lmin as determined for step 314, the control proceeds to step 338. If the nominal billet length Ln was reduced to a value less than the minimum billet length Lmin as determined for step 314 before the determination of a first potential solution for the present laminate order as determined for step 338, omission values are used for the present laminate order. For step 340, the nominal billet length Ln and the ingot length 1 are programmed to nominal lengths Lnom and lnom, respectively. The nominal ingot number nn is then determined for step 342 according to equation (1) above and truncated to the nearest integer for step 344. The nominal billet number nn is then determined for step 346 according to the equation (2) above and truncated to the nearest integer for step 348. The number of final billet ingot is not later determined for step 350 according to equation (3) above and rounded to the nearest integer for step 352 For step 354, the final billet length Ll for step 354 is determined according to equation (4) above. The submultiple billet length Lbsm is then determined for step 336 according to equation (5) above.

If at least one first potential solution has been determined for step 338, then for step 356 the newly stored solution is used for the requested laminate preend, while for step 358 the final billet length Ll is programmed. equal to the minimum billet length Lmin for the present laminate order. This solution is determined to minimize the amount of waste steel remaining for the final billet for the present rolling order. The submultiple billet length Lbsm is then determined for step 336 according to equation (5) above. The production program 212 stores in the laminate ordering table 216 the final solution determined for each laminate order that will be used by the cut optimization model 226 at level 2.

Bilge Strainer Optimization of Level 2 The cutting optimization model 226 in level 2 determines the billet cutting lengths (L) at which each billet will be cut from a steel strip by cutting station 136 in based on the information that comes from the laminate ordering table 216 in level 3, the information that comes from the metallurgical database in level 2, the amount of steel available and the occurrence of strip field events reported from the events of strip 234 in level 1 while the steel is cast. Figure 4 illustrates in flowchart form an algorithm for the cut optimization model 226. For step 402 of FIG. 4, the cut optimization model 226 begins by determining programmed cut billet lengths L after the occurrence of one of a number of field events indicating the determination of the programmed LB billet cut lengths. These field events include the opening of the bucket gate and the occurrence of a strip reset. The opening event of the bucket gate indicates that the molten steel coming from the bucket 112 has been released in the boiler 114 to initiate the casting of a steel strip or strips. The reboot event indicates that the casting of the strip has been restarted after a temporary stoppage of the strip. For step 404 of Figure 4, a subsequent length of cold billet (Lcut) is thrown from the laminate ordering table 216. The length of cold billet Lcut corresponds to the nominal billet length Ln or the final billet length Ll for each laminate order from the laminate ordering table 216. The cut optimization model 226 treats the laminate ordering table 216 as an initial or final input (FIFO) stack to help load billets in the production reheat furnace of ingots in the same order in which they were cut. In this way, the billets for a certain order of rolling can be grouped in the reheating furnace to facilitate the production of ingot for the laminate order For step 406 of Figure 4, the length of cold billet Lcut thrown is assigned to the steel strip having the largest protruding billet length reported by strip events 234 of level 1. For example, the table Rolling order 216 may include the following information.

The strip events 234 may include the following information.

Data of level 1 Strip 1 Strip 2 Strip 3 Strip 4 Outgoing length 4500 5500 8000 9000 For this example, the cut optimization model 226 can output from the laminate ordering table 216 the cold billet length 10000 for the rolling order ID 1 as the next length of cold billet for the step 404. The optimization model of cut 226 may then assign for step 406 this billet to strip 4 because strip 4 at this time has the longest protruding billet length of the strips. In other words, strip 4 has the longest length of unallocated and uncut steel that has passed the cutting station 136. For a next step 404, the cut optimization model 226 can output the cold billet length 11000 from the laminate ordering table 216 for the rolling order ID 2 as the next length of cold billet. The cutting optimization model 226 may then allocate for a subsequent step 406 this billet to the strip 3 which would then have the longest protruding billet length of the strips. For subsequent steps 404 and 406, the assignment of the lengths of cold billet thrown to the strips may be as follows. -20 For step 408 of FIG. 4, the programmed length of billet cutting L for each length of cold billet Lcut thrown can be determined according to the following equation. 25 If Li, j > Lmax, then the length of cold billet.

Lcuti is reduced by a submultiple of the Lbsmi billet length according to the following equation.

Lcut ^ Lcu i i (7) I 2 Pi Then, Li, j is calculated again according to equation (6). The cut optimization model 226 determines the programmed cut length of billet Li, j, according to equations (6) and (7) until Li, < Lmax For equations (6) and (7): i = lamination order identifier (RO); j = billet identifier; k = ingot identifier; Li. j = programmed cutting length for identified billet; Ktemp = experimental coefficient; T = billet temperature; Lcuti - length of cold billet for RO identified; Delta-testi, = test length for identified billet; rhoi = reduction factor of the ingot mill (BRM) for RO identified; testei, j = whole test number of BRM in the ingots for identified billet; deltai, j, = length of the BRM test cut for identified ingot; CLL = loss of length per cut; rhostrand = soft reduction on the strip; Lmax = maximum billet length; li = cold bar length for RO identified; and Lbsmi = length of submultiple of billet for RO identified.

The values for Lcuti, rhoi, testsi, j, deltai.jk, li, and Lbsmi can be defined in the rolling order table 216. The values for Kte p, delta-testi, j, CLL and Lmax, can be defined in the Metallurgical database at Level 2. The values for T and rho.trand can be defined in the melting program tables 222 of the metallurgical database at Level 2. For step 410 of Figure 4, the model cutting optimization 226 sends the programmed billet cutting length Li, determined for step 408 to the strip cutting program 232 at Level 1, so that a billet having this programmed billet cutting length Li can be cut , Of the assigned strip. The cut optimization model 226 continues to determine programmed billet cut lengths Li, j for step 404, through step 410, until the occurrence of one of several field events that drive the determination of billet cutting lengths alternatives L, determined for step 402. Such field events include the absence of steel in the mold or molds and the temporary stoppage of a strip or strips. Mold steel or molds may be absent due to a programmed stoppage of a corresponding strip, or 5 due to disconnection of a strip. Also, a strip or strips can be stopped to effect a high boiler change, for example. When said field event has occurred, you can stop each strip, if necessary, for step 414 of the figure 4, so that the cutting optimization model 226 can determine alternative billet cutting lengths L to minimize the amount of waste steel that can be caused by cutting the billets of each strip. For step 416 of Figure 4, the cutting optimization model 226 determines the alternative cut lengths L for a last '* - billet and a penultimate billet to be cut from each strip at the end of a load or a loading sequence, or anteater from a defective region of the strip. Figure 5 illustrates a top view of four strips, 510, 520, 530, and 540 to be cut to an optimized length for cast billets having alternative cut lengths determined for step 416 of Figure 4. Shaper 100 moves each strip 510, 520, 530 , and 540, along the direction indicated by arrow 502. Each strip 510, 520, 530, and 540 of Figure 5 includes a trimming portion 512, 522, 532, and 542, respectively. Each trimming portion 512, 522, 532, and 542 may represent a defective region of the strip or may represent a tail cut or transition piece for the end of a load or a loading sequence. Strips 510, 520, 530, and 540 also include billet portions 514-515, 524-525, 534-535, and 544-545, which can be cut from strips 510, 520, 530, and 540, illustrated in Figure 5. Each strip 510, 520, 530, and 540, also includes a remaining portion 516, 526, 536, and 546, respectively. Cutting lengths for billet portions 514-515, 524-525, 534-535, and 544-545, are programmed billet cut lengths determined for pairing 408 of Figure 4. The length of each remaining portion 516, 526, 536, and 546, is less than necessary so that the billets have the programmed cutting lengths. In determining alternative cut lengths, each remaining portion 516, 526, 536, and 546, corresponds to the last billet for each individual strip 510, 520, 530, and 540, respectively, and each billet portion 515, 525, 535, and 545 corresponds to the penultimate billet for each strip. For step 416 of Figure 4, the last billet length for each strip is first compared with the minimum billet length Lmin. If the length of the last billet is greater than or equal to the minimum billet length Lmin, then the lengths for the last billet and the penultimate billet are sent to level 1 for step 410 without modification.

Otherwise, the length of the last billet is reduced by a submultiple of the length or billet lengths to elongate the last billet until the length of the last billet is greater than or equal to the minimum billet length Lmin. The alternative cut length for the last billet can be determined for each strip according to the following equation.

The alternative cut length for the next to last billet can be determined for each strip according to the following equation.

For equations (8) and (9): i = lamination order identifier (RO); j = billet identifier; = ingot identifier; Li, j = alternative cutting length for the last Tocho Li, j-? = alternative cut length for the penultimate billet Ktemp = experimental coefficient; T = billet temperature; r = whole number of ingots for the last billet; s = whole number of ingots for the penultimate billet; lai = length of cold ingot for the last identified RO billet; li = length of cold ingot for the penultimate billet of RO identified; rhoi = reduction factor of the ingot mill (BRM) for RO identified Delta-testi, j = test length for identified billet; testsi, j = whole number of test BRM in the ingot for identified billet; deltai, j, k = length of the BRM test cut for identified ingot; CLL = loss of length per cut; rhostr nd = soft reduction on the strip; For equations 8 and 9, the number of ingots r for the last billet, the number of ingots s for the penultimate billet, and the length of ingot lai for the last billet, are determined so that the following five criteria are satisfied: (a) s is as large as possible; (b) lmini < lai < lmaxi; (c) Lmin < Li, j < Lmax; (d) Lmin < Li, j < Lmax; and (e) Llost is reduced to the minimum according to the following equation: Llost = Lres-Li, j -Li, ji -Lcrop (10) where: lmini = minimum length of cold bar for RO identified maxxi = maximum length of cold ingot for RO identified Lmin = minimum length of billet; Lmax = maximum billet length; Llost = lost length of waste material; Lres = length of the remaining portion of the strip for the last two billets and trimming; and Lcrop ~ length for clipping of target tail, transition piece, or defective region.

The values for li, rhoi, testsi.j, di, _¡,, Imi i, and Imaxi can be defined in the laminate ordering table 216. The values for Ktemp, testi, j, CLL, Lmin, and Lmax can be defined in the level 2 metallurgical data bank. values for T, rhostrand, and Lcrop can be defined in the melting program tables 222 of the metallurgical database at level 2. The value for Lres is defined from the length of uncut material on each strip of strip events 234 in level 1. If the cut optimization model 226 does not determine a solution for the equations (8) and (9), satisfies the five criteria (a) to (e) above, the original programmed cut length for the penultimate billet is sent to level 1 for step 410 while, that alternative cutting length is not sent for the last billet, since the last billet becomes part of the trim for disposal. Figure 6 illustrates in flowchart form an algorithm for determining alternative billet cutting lengths 1 for each strip of step 416 of Figure 4. For step 600 of Figure 6, the initial length of the penultimate billet Lnextiast is determined. and the last length of Liast billet. The initial length of the penultimate billet -xtia-t is the programmed cutting length for the penultimate billet determined by step 408 of Figure 4. The initial length of the last billet Liast is determined according to the following equation. Ll a s t = L res-Ln e x t l a e t-Lc rop (11) In this initial length of last billet Liast is greater than or equal to the minimum billet length Lmin determined by step 604, then the ingot number r, the ingot length la, and the length of billet Liast are determined by step 606. The ingot number r and the ingot length can be determined to maximize the length of the last billet Lia-t, according to equation (8) above, so as to minimize the lost length of waste material Llost, according to equation (10) above. For an example, two solutions can be selected for step 606. For a solution, the ingot length can be set to the maximum length of ingot Imax to determine the number of ingot r according to equation (8) above, using the initial length of the last billet L? ast determined by step 602. This number of ingot r can be rounded to the nearest integer and the length of the ingot can be cut so that Liaet remains at its initial value according to equation (8) ) previous. For the second solution of this Example, the length of ingot can be set up to the minimum length of ingot lmin to determine the number of ingot r according to equation (8) above, using the initial length of the last billet Lias determined for the step 602. This ingot number r can be truncated to the nearest integer and the ingot length can be lengthened so that Liaßt remains at its initial value according to equation (8) above.

Of the two previous solutions, the solution that could produce the longest length of ingot is selected, greater than or equal to, the minimum length of ingot lmin, and less than or equal to, the maximum length of ingot Imax, for the step 606. If no solution produces said ingot length la, then a suitable ingot number r and a suitable ingot length are determined, so as to maximize the length of the last Liast billet so that the last billet is cut from the web. strip. For one embodiment, the ingot number r can be truncated to the nearest integer for each of the two previous solutions, and the resulting solution can be used in the highest performance. If the length of the last billet Liast determined by step 606 is greater than or equal to the minimum billet length Lmin determined by step 608, then for spanning 610, the length of the penultimate billet Lnexties-t determined for step 602 and the length of the last billet Li st determined for step 606 is sent to level 1 for step 410 of Figure 4. If the initial length of the last billet Liaet is less than the minimum billet length Lmin, determined for step 604 , or if alternate billet lengths are to be determined for paving 612, then the length of the penultimate billet -xtia-t is reduced by a submultiple length or billet lengths in an attempt to elongate the last billet to an appropriate length Liast that is greater than, or equal to, the minimum billet length Lmin. For paving 614, the length of the penultimate billet Lnextiast to the maximum billet length Lmax is restored. The number of ingots s for the next to last billet is then determined for step 616 according to equation (9) above based on restoration of billet length entia-t and truncated to the nearest integer for step 618. In Based on this truncated ingot number, the length of the next-to-last billet Lnextiast is determined for the stroke 620 according to equation (9) above. If this length of the penultimate billet Lnextiast is less than the minimum billet length Lmin determined for step 622, then for step 624, the initial length of the penultimate U-xt st determined for step 602 can be sent to level 1 for the step 410 of Figure 4, while no cutting length is sent for the last billet, since the last billet becomes part of the trim for scrap. If the length of the penultimate billet is -t is greater than or equal to, the minimum billet length Lmin, determined for step 622, then the length of the last billet L -t is determined for step 626 according to equation (11) above based on the length of the penultimate billet -xtia-t determined for step 620. If the length of last billet Liaet is greater than or equal to the minimum billet length Lmin, determined for step 628, then the ingot number r, the ingot length, and the length of the last billet Liaet are determined for the step 606. Step 606 to step 612 is performed in a manner similar to that described above. If the last length of billet Liast is less than the minimum billet length Lmin determined for step 628, or if alternative billet lengths are determined for step 612, then the number of ingots is reduced by one for step 630 to reduce the length of the penultimate billet Ueuia-t in a submultiple of billet in an attempt to lengthen the last billet to an adequate length. The steps 620 to 630 and the steps 606 and 612 eeta repeat that a length of the last suitable billet L st, determined for step 606, is greater than or equal to the minimum billet length Lmin determined for step 608, or until the length of the penultimate billet Lnextiaet has been reduced below the minimum billet length Lmin determined for step 622.

Re-allocation of billet cut lengths The cut optimization model 226 can also reorder the allocation of billet cut lengths for strips, in response to a field event of strip events 234 in which one or more strips have been stopped as another strip or strips continue to be melted. If the emerging billet length for a strip or strips becomes greater than that of a stopped strip or strips, the cut optimization model 226 can reassign cut lengths for the strip cutting program 232, based on the lengths of the strip. billet current emerging for the strips. As with the previous example, strip events 234 may include the following information.

The cut optimization model 226 can allocate cold billet lengths thrown to the strips in the following manner.

For this example, if the strip 4 is stopped and the billet length emerging for the strip 3 becomes greater than that of the strip 4, the cutting optimization model 226 can reorder the allocation of billet cutting lengths as follows.

The billet length previously assigned to strip 4 is now assigned to strip 3 as the length of emerging billet for strip 3 becomes greater than for strip 4. If strip 4 is reinitiated with steel in the mold, reported by the strip events 234, the cut optimization model 226 can determine alternative billet cutting lengths for the strip 4 to interpenetrate the defective region in the rebooted strip that results from over cooling of the steel in the mold. If the strip 4 is restarted without steel in the mold, reported by the strip events 234, the cut optimization model 226 can determine alternative billet cutting lengths for the strip 4 to compensate for the length of the end glue trimming. of the rebooted strip. The cut optimization model 226 may continue to reassign cut lengths for the strip cut program 232 as the billet emerging lengths change for each strip. The optimization model Cutting 226 may also continue to determine suitable lengths of scheduled billet cutting and alternative billet cutting lengths, as necessary to compensate for defective regions, transition pieces, and tailings. »» 5 of the strips.

Level 1 strip cutting program The strip cutting program 232 at level 1, as illustrated in figure 2, stores for each strip to be melted in the moulder 100, the billet cutting lengths L sent from the cutting optimization model 226 to the level 2. Based on these billet cutting lengths L, the strip cutting program 232 controls the cutting station 136. to cut the billets of each strip. 15 The data processing system 140 may be * configured to run software at level 1 to display on a monitor or monitors the cut lengths of billet L sent to the cutting program 232 to be obeyed by an operator as the cutting station 136 cuts the strips of strip or strips. The data processor system 140 can also execute software at level 1 to provide interactive modification of cut lengths as desired by the operator, so that the operator can also control the cut of billets by means of the station. cut 136.

Production of Bars and Ingots After having been cut from the strip or strips by means of the cutting station 136, each billet can be discharged into the reheating furnace and subsequently rolled and cut into ingots. For each rolling order, the ingots are rolled to a cross-sectional size according to the rho reduction factor of the ingot mill for the rolling order. The ingots are also cut to lengths according to the length of ingot L for the order of laminate determined in level 3 or with the length of the ingot The one determined by the cut optimization model 226 in level 2 for a last billet. Once cut, the ingots can be further processed in a laminator to produce steel bars or be shipped ".15 directly to the customer for custom manufacturing of ? final steel product. - In the above description, the invention has been described with reference to specific specimen modalities of the same. However, it will be evident that they can be made to the Same several modifications and changes without departing from the broader spirit or scope of the present invention defined in the appended claims. Therefore, the specification and the drawings are considered as in an illustrative sense instead of a restrictive sense. 25

Claims (11)

1. NOVELTY OF THE INVENTION CLAIMS * 1. 5 1. A method for cutting a strip of material, comprising the steps of: a) determining a cutting length for at least one piece to be cut from the strip of material, wherein the determined cutting length is based in a submultiple of predetermined length; b) Cut the strip 10 material to produce the piece (at least 1) that has the determined cutting length; c) determining a penultimate length for a penultimate piece to be cut from the strip of material, and a last length for a last piece to be cut from the strip of material, wherein the step of determining r (c) comprises the steps of: i) assign the penultimate length for the penultimate piece to be cut from the strip of material, ii) determine the last length for the last piece to be cut from the strip of material based on the penultimate length assigned, and iii) adjust the penultimate 20 length and the last length adding at least one submultiple of predetermined length from the penultimate length to the last length; and d) cutting the strip of material to produce the penultimate piece that has the penultimate length and to produce the last piece that has the last length.
2. 2. The method according to claim 1, characterized in that the step (a) of determination comprises the step of reducing the cutting length in at least one submultiple of predetermined length, if the length of the cut is greater than a predetermined maximum length.
3. 3. The method according to claim 1, # 5 characterized in that the assignment step (c) (i) comprises the step of assigning the cut length as the penultimate length for the penultimate piece.
4. 4. The method according to claim 1, characterized in that the adjustment step (c) (iii) comprises the step of adjusting the penultimate length and the last length, so that the penultimate length and the last length are each one of them greater than a predetermined minimum length.
5. 5. The method according to claim 1, characterized in that the material comprises steel, wherein each of the pieces of material (at least one) is a billet, and wherein the submultiple of predetermined length is based on a predetermined length of ingot.
6. 6. The method according to claim 5, characterized in that it comprises the step of cutting each billet in at least one ingot having the predetermined length of ingot.
7. 7. The method according to claim 1, characterized in that the step (c) of determination comprises the step of determining the penultimate length and the last length 25 in response to one of at least one strip field event that promotes a determination of a cut length alternative for the last piece.
8. 8. The method according to claim 7, characterized in that the material comprises steel, and because the * strip field event (at least one) comprises an absence of steel in a mold and a stoppage of the strip.
9. 9. The method according to claim 1, characterized in that it comprises the step of producing the strip with a continuous steel moulder.
10. 10. The method according to claim 10, characterized in that the cutting passages (b) and (d) each comprise the step of cutting the strip with a sliding earthen cutting action.
11. 11. A cut of a billet of a strip of material comprising steel, in accordance with the method of claim 5. * 12.- A length cut of a billet comprising steel in accordance with the method of the claim 6. A method for cutting a strip of material, comprising the step of: a) determining a length of cut 20 for at least one piece to be cut from the strip of material, so that the length of cut is within a predetermined scale of cut lengths, and so that the piece (at least 1) can be cut into a number of subpieces, each having a predetermined length of 25 sub-piece within a predetermined range of lengths of sub-pieces; b) Cut the strip of material to produce the piece (at least 1) that has the determined cutting length; c) determine a penultimate length for a penultimate piece to be cut from the strip of material and a last length for a fc last piece to be cut from the strip of material, where the i? Step of determination c) comprises the steps of: i) determining the penultimate length such that the penultimate length is within the predetermined scale of cutting lengths, and so that the penultimate piece can be cut into a number of subpieces, each one having a first piece length 10 within the predetermined scale of sub-piece lengths; ii) determining the last length, so that the last length is within the predetermined scale of cut lengths, and so that the last piece can be cut into a number of subpieces, each having a second length of 15 sub-piece within the predetermined scale of sub-piece lengths, and iii) determine the penultimate length and the last length to minimize the length of remaining de-cling material of the strip; and d) cut the strip of material to produce the penultimate piece that has the penultimate 20 length, and to produce the last piece that has the last length. 14. The method according to claim 13, characterized in that the determination step (a) comprises the step of reducing the cutting length by at least 25 a submultiple of the predetermined length if the cutting length is greater than a predetermined maximum length, wherein the submultiple of predetermined length (at least one) is based on the predetermined sub-piece length. 15. The method according to claim 13, characterized in that the determination step c) comprises p 5 the step of adjusting the penultimate length and the last length by adding at least a submultiple of predetermined length from the penultimate length to the last length, so that the penultimate length and the last length are greater than a predefined minimum length, while the 10 eubmultiple of predetermined length (at least one) is based on the first sub-piece length. 16. The method according to claim 13, characterized in that the first sub-piece length is the predetermined sub-piece length. 15 17.- The method according to the claim 13, characterized in that the material comprises steel, in which each of the pieces of material (at least one) is a billet, and wherein each sub-piece is an ingot. 18.- The method of compliance with the claim 20 17, characterized in that it comprises the step of cutting each billet in at least one ingot having the predetermined sub-cleaning length. 19. The method according to claim 13, characterized in that the determination step (c) comprises 25 the step of determining the penultimate length and the last length in reepueeta to one of the strip field events (at least one) that promotes a determination of an alternative cutting length for the last piece. 20. The method according to claim 19, characterized in that the material comprises steel and in that 1-5 the strip field event (at least one) comprises an absence of steel in a mold and a stoppage of the strip. 21. The method according to claim 13, characterized in that it comprises the step of producing the strip with a continuous steel moulder. 10 22.- The method according to the claim 21, characterized in that the cutting steps (b) and (d) each comprise the step of cutting the strip with a sliding torch cutting station. 23. A cut of a billet of a strip of material comprising steel according to the method of claim 17. 24. A cut of billet of a billet comprising steel, in accordance with the method of the invention. claim 18