RU2497616C2 - Method and device for making steel reinforcements of required length - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to method and device for making of steel reinforcements cut to length incompliance with customer order. Proposed method comprises producing continuous steel rod at rolling mill and cutting it to required lengths. Each of said length features size the multiple of preset length reinforcement rod. Said length are cut by cold cutting shears arranged in a line, first, to two lengths of rods and, then, to one length thereof. Note here that steel rod is continuously fed from cutting mill. It includes also strapping of cut rods to make piles of reinforcement rods at mill exit side. Invention covers also the device for making steel rods and their strapping.

EFFECT: reduced losses of metal, supply of reinforcement cods cut to preset size.

9 cl, 2 dwg, 1 ex

Description

FIELD OF THE INVENTION

The present invention relates to a method and apparatus for producing packages of steel reinforcement, which is cut along the length, in particular, in the continuous manufacture of the reinforcement itself.

More specifically, the invention relates to the production of such bags, the fittings in which meet the requirements of the customer, and has a specific length.

State of the art

Steel reinforcing bars for concrete reinforcement or highly specialized steel products, all of them have a fundamental drawback in the business model: they are all in mass demand, and they require significant investment in the organization of a steel mill for their production. The present invention transforms the business of “mass-marketed goods” into the business of “mass custom-made products”, benefiting more from the process. The invention will allow the rolling mill to produce steel reinforcing bars cut into measured sections within the production line itself, and at the same time significantly reduce losses associated with trimming the ends. The invention can be implemented in any existing rolling mill with minimal additional investment.

Reinforcing steel bars are usually delivered in the form of “standard length” segments of 12 m, 15 m or 18 m in “standard weight” packages, as a rule, in packages of one-dimensional reinforcement weighing 2 tons. As for the rods for concrete reinforcement, they are all the same further it will be necessary to cut into shorter lengths in accordance with the design of the building structure for specific columns, beams or floor slabs. As a rule, no one expects that in segments of standard length contained an integer number of such short concrete segments, which leads to losses when trimming the ends. Such size cutting is usually performed at the “cutting and bending” site, which is located either on the construction site itself or outside it. In the “cutting and bending” operation, the typical expected loss on the trimming of the ends of the reinforcement is 5% even when using the best computer optimization programs. These 5% constitute a very significant amount in the building design, especially at high current prices for steel reinforcement.

The standard lengths of 12 m, 15 m and 18 m are selected on the basis of ensuring maximum use of the size of the cargo spaces of ships and vehicles, and the standard weight of the packages is chosen to optimize the lifting capacity of lifting equipment on ships and cars.

Along with this, there is a technological need for butt welding of hot ingots, in which the tail end of the ingot is welded to the front end of the next ingot directly in the production line, as the ingots exit the heating furnace. Such an operation will enable continuous, endless rolling of the rods. This is similar to the sequential casting of metal in a continuous casting machine. The main goal of the endless rolling process is to minimize head and tail trimming in the rolling mill and unwanted losses in the refrigerator rack. When using the butt welding process and with the very high accuracy of modern flying scissors in front of the refrigerator rack, for 120 m of rods, a length error of +50 mm / -00 mm can be obtained on the refrigerator rack. This corresponds to an end loss of about 0.05% compared with the industrial norm of 2.5%.

The butt welding process creates elevated temperatures at each junction of the ingots. Due to the fact that the elongation / broadening characteristics of the material depend on temperature, the joints, whose temperature is higher than the rest of the ingot, will experience more elongation than broadening, which will lead to the appearance of “constrictions” - areas with a smaller cross-sectional area than the nominal cross-sectional area of the final product. This means that the cross-sectional area of the joint may fall below the minimum area specified in the steel standard. US Pat. No. 6,929,167 discloses a method that precludes the appearance of such constrictions. According to the patent, in the process of actual operation, measuring devices are installed in the rolling line for continuous control of the size of steel bars, while the results show that the method allows to maintain a uniform cross section along the entire length of the rod, including the butt welding sites.

When using butt welding and with uniform cross-section at the joints, it is possible to produce steel bars on the rolling mills with “cutting to measured lengths directly in the line” without losses associated with trimming the ends. Typically, steel rods are rolled from square ingots with a side of 150 mm and a length of 12 m. Such ingots are rolled to produce final steel rods of various diameters from 50 mm to 10 mm. Due to the fact that the initial weight of the ingot has a certain final value, the ingot during the rolling process of each diameter will turn into rods of different lengths. The total lengths of the rods obtained from each piece of the ingot will not be exact multiples of the normal length of 12 m of the final rods, and therefore there will be losses associated with trimming the ends. Losses are usually 2.5%. In the case of the above endless rolling, the ingots are welded end-to-end, forming a continuous endless billet, and there is no loss of trimming of the ends.

The technical requirements for a steel bar of BS4449 or ASTM 615 standard allow size deviation provided that it does not violate the strength of the bar. Typically, according to BS4449 (2005), this tolerance is ± 4.5%. The goal is to provide a tolerance of -3%, i.e. obtaining lighter rods, but without reducing the strength of the rod at a nominal diameter. When rolling a single ingot, reducing the diameter of the final bar by 3% will give an end elongation of the same 3%. And such an elongated end will go to waste. In the case of endless rolling of welded ingots, the elongated end will enter the next incoming ingot and become a part of it, and a 3% reduction in diameter will be completely useful and the material will not go to waste.

For reasons of shipping and road transport, such finished steel rods are usually cut into 12 m, 15 m or 18 m segments. Due to differences in the lengths of columns, beams or slabs, the actual length requirements at the construction site are never exactly 12 m , 15 m or 18 m. The rods have to be cut in a separate operation. Typical end losses when cutting rods to specific lengths are 5%.

Disclosure of invention

The objective of the invention is to create a method and device for cutting steel reinforcing bars into segments of any arbitrary specific length simultaneously with the progress of the continuous rolling process.

Additionally, the objective of the invention is that the method and device are suitable for the continuous manufacture of short segments of reinforcement, which usually requires interruption of the process.

In particular, the objective of the invention is to provide a method and device that allows the manufacture of short rods cut to size with a given length simultaneously with the progress of the continuous rolling process without affecting this process.

According to the invention, this problem is solved by setting the length of the segments cut by the first cut from a continuous steel reinforcing bar, the length of which is set to a multiple of the length of the short rods of the final product, and by cutting the segments obtained by the first cut into their length segments during continuous operation of the rolling mill.

Thus, according to the present invention, in one aspect, a method for manufacturing steel reinforcement in segments of a given length with the formation of packages of reinforcing bars, comprising the steps of obtaining a continuous steel bar from a rolling mill, cutting a continuous steel bar into successive segments, each of which has a length, a multiple of the specified length of the reinforcement segment, cutting the indicated segments with cold shears installed in line, first by a length equal to two specified lengths, and then cutting and in half into lengths equal to the predetermined length, while preserving the continuity of producing a steel rod rolling mill, and binding the reinforcing bar cut to a predetermined size, to their production from a rolling mill to form a package of reinforcing bars.

According to the present invention, in another aspect thereof, there is provided a device for manufacturing steel reinforcement in segments of a given length with forming reinforcing bar packages, comprising a rolling mill for producing a continuous steel reinforcing bar; flying shears installed at the exit of the rolling mill; CPU connected to flying shears for cutting a continuous steel reinforcing bar into segments, each of which has a length that is a multiple of a given length of the rods; two cold cutting shears installed in a line to which the indicated segments are continuously fed, and the cold cutting shears have corresponding adjustable stops, while the cold cutting shears and adjustable stops are connected to the CPU, which is configured to control the setting of the stops in the required position and bringing the action of cold cutting shears, so that some cold cutting shears cut these segments into segments whose length is two lengths of reinforcing bars, and other cold shears cutting, the resulting sections are cut in half to obtain rods cut to a predetermined size, the cold cutting shears being driven during the production of a continuous steel reinforcing bar; and installation of strapping, located so as to receive chopped rods from cold cutting shears to form packages of reinforcing bars of a given length.

The appended claims include dependent claims that define preferred embodiments of the above-described aspects of the invention.

Embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

Brief Description of the Drawings

Figure 1 schematically depicts a part of a rolling mill, where from the rolled reinforcing bar are formed packages of rods cut to the desired length.

Figure 2 schematically depicts a Central processing unit (CPU), which controls the operations of forming packets of rods cut into the desired length.

The implementation of the invention

Figure 1 shows the output side 10 of the rolling mill 11, from which the rolled bar 12 exits in a continuous manner at a certain high speed. The rolled bar 12 is obtained from a continuous ingot (which in turn was obtained by the serial connection of individual ingots), rolled hot in the rolling mill. Behind the output side 10 of the rolling mill are flying scissors 13, which are driven by a central processing unit (CPU) for cutting the bar 12 on the go and get cut-to-size segments 14 that accumulate on the rollers 15 of the roller table 16.

As mentioned earlier, at present, in practice, the length of the rods obtained at the exit of the rolling mill is limited to about 120 m, since these are the minimum lengths that can be obtained in modern rolling plants at high rolling speeds.

The present invention allows to obtain shorter lengths of arbitrary length without compromising performance, and, in particular, allows cutting rods into lengths in accordance with customer requirements, according to the lengths required at the place of their final use, thereby completely eliminating the losses associated with trimming the ends at the end-use site, and also eliminating the need for cutting operations themselves at the end-use site.

The cut segment 14 is then moved to the chute of the refrigerator rack 16 for cooling. Segment 14 is moved step by step, from the gutter to the gutter, until it reaches the last gutter, where it is already cooled and ready to be moved in the transverse direction to the discharge device (DC), where a given number of segments, for example 10, accumulate and form as a packet layer segments 14.

The design and operation of the refrigerator-rack and CSS are standard and are not described in further detail.

The package of segments 14 located on the reset device is then moved to the roller table 17, which is located next to the CSS. Roller table 17 contains rollers 18, which are driven in rotation so as to feed the package of rods 14 in the direction opposite to the direction in which the segments were fed to the refrigerator rack.

In order to keep up with the performance of the rolling mill and get short segments of a given length from segments 14, one after the other, two cold cutting shears 19, 20 and corresponding adjustable stops 21, 22 are installed along the roller table 17. Cold cutting shears are massive large aggregates that develop effort of 1000 tons or more, and they are fixedly fixed on a rigid base. Two cold cutting shears are mounted at a distance of 20 m from each other to ensure that the longest possible lengths are obtained. Specifically, the segments 14 are moved to the locked position, controlled by an adjustable stop 21, at which the cold cutting shears 19 will be located from the ends of the rods at a distance equal to two lengths of the segment of the rod that should be obtained at the end of the cutting operation. The cut rods are fed to the adjustable stop 22, and the cold cutting shears 20 cut the cut rods in half to obtain the final desired length. After the scissors 19, 20 cut the rods, segments of the rods 23 with a length equal to the desired final length will be obtained. Adjustable stops 21, 22 allow you to adjust the position in which the cold cutting shears cut the rods 14, and change the length of the resulting segments. Due to such double cutting of the rods, high productivity of the operation can be maintained. Also, when it is required to change the length of the cut rods for the subsequent package, the adjustable stops are rebuilt to fit the new required length.

The pieces cut to size are then moved laterally to the packaging unit 24, where the lengths 23 are tied into bags, after which they are ready for transportation.

The packaging unit 24 includes a roller table 25, on which segments 23 are accumulated. The segments 26 enter the standard manifold 26, where the rollers are arranged in a circle to collect the rods in round packets.

To tie a pack of chopped rods when they are short, i.e. when their length is significantly less than 12 m, for example, is 8 m or less, strapping is required in three distant places. When there is a change in the length of short segments, based on a new customer order, respectively, a change is made in the binding step. In addition, according to the present invention, the strapping operation is performed in one step in order to keep pace with the operation of the rolling mill. As a rule, two end strands are performed at a given distance from the ends of the package, and the central strapping is made in the middle between the end strands. The assembled segments of the rods are fed into three standard strapping machines 27, 28, 29 installed at a distance from each other, which fasten the package of rods by strapping 30, 31, 32 in appropriate places. The strapping 30, 31, 32 is performed simultaneously, and then the package is removed from the packaging unit 24.

According to the invention, the first and third strapping machines 27, 29 are movably mounted so that they can be quickly reconfigured when it is necessary to change the strapping pitch when changing the length of the cut rods. Mobile strapping machines 27, 29 are connected to respective hydraulic cylinders 33, 34, which are connected to the CPU to control the position of the machines.

The invention makes it possible to cut the rods into specific short segments that are required at the construction site, which eliminates all the losses inherent in the existing technology, and at the same time does not reduce the productivity of the rolling mill.

A key component of the present invention is a CPU, which, when loading ingots, controls the following elements:

a) flying scissors 13,

b) a drop comb bar,

c) roller table 17,

d) roller table 25,

e) cold cutting scissors 19, 20,

f) adjustable stops 21, 22

g) machines 27, 28, 29 for strapping,

h) hydraulic cylinders 33, 34.

Example

In the following example, the operation of the rolling mill when receiving cut into size reinforcing bars is described in detail.

The weight of each ingot is recorded when the ingot is loaded into a heating furnace. The load weights will be compared with the final product weights to obtain material loss data for a given shift, which will mainly be oxidation losses. Losses associated with trimming the front end will be minimal, and losses associated with trimming the tail ends will not be at all, due to the use of the butt welding method described above.

The operator enters the data of the exact number and exact specific lengths of the bar of a certain size, the rolling of which is currently being performed, to generate commands for the flying scissors 13.

When working in standard ways:

If by order it was required to cut rods with a length of 6.4 m from workpieces of a standard length of 12 m, then from the workpiece one rod would be obtained 6.4 m and a short remainder of 5.6 m.

If the same lengths were to be cut from workpieces of a standard length of 15 m, then two pieces of 6.4 m and a short remainder of 2.2 m would be obtained from the workpiece.

If the same lengths were required to be cut from workpieces of a standard length of 18 m, then two pieces of 6.4 m and a short remainder of 5.2 m would be obtained from the workpiece.

These short residues are usually set aside for another part of the building design, which may require lengths of rods shorter than these residues, or the remains are sent to scrap. All of these options are undesirable.

When operating according to the present invention, the operator enters into the programmable logic of the CPU a sequence of data for the operation of the flying scissors 13 in order to obtain pieces of rods that are multiples of the specific lengths of the final product. Suppose a typical refrigerator rack is capable of accepting a bar 120 m long, then the programmed logic of the CPU will allow the operator to configure the flying shears to cut a length of 115.2 m, which is an 18-fold value from 6.4 m. If the order requires the manufacture of 500 pieces rods of 6.4 m, the operator will ask 27 cuts of 115.2 m, and the last cut of 89.6 m, which will give a total length of 3200 m or 500 pieces of 6.4 m.

The command signal to the refrigerator rack will move two steps after the last cut 89.6 m to separate this batch from the next.

If the next order requires 5.2 m long rods, the operator will enter 109.2 m, which will give 21 pieces of 5.2 m each, which will go after the previous batch of 6.4 m long. If this order of 5.2 m segments has a volume for example, 400 pieces, then the number of cuts of 109.2 m will be 18, and the last cut will be 114.4 m. The total length of this order is 2080 m, which gives 400 pieces of 5.2 m of the final length. And again, the double step of the refrigerator rack will separate this batch from the next. The same process will be repeated for any other specific lengths and quantities of rods of the same diameter.

When using a comb and a dumping bar, each batch of rods is removed from the cooling rack 16, it enters the roller table 17 in a standard way. Each batch individually will be fed to cold cutting shears 19, 20 for final cutting to the ordered lengths. In this example, the blanks of the first batch will have a length of 115.2 m, and the last piece 89.6 m for the final cutting of pieces of 6.4 m, and the blanks of the second batch will have a length of 109.2 m, and the last piece 114.4 m for the final cutting of pieces of 5.2 m. The cutting ability of the cold cutting shears will determine how many batch rods with the same length are fed for cutting each time. It should be noted that since the tail end of each rod entering the refrigerator rack is fed to the cold cutting shears in the opposite direction, these tail ends, being cleanly cut by flying shears 13, will not require head trimming on the cold cutting shears. This contributes to additional material savings.

Two cold cutting shears 19, 20, mounted motionless in a line, are used so that by cutting such short pieces of rods to keep up with the performance of the rolling mill. Each of the cold cutting shears has its own adjustable stop 21, 22. In this example, the first adjustable stop 21 will be set to 12.8 m, which is 2 × 6.4 m, and then the cut rods will be fed to the next adjustable stop 24 , which is set to 6.4 m, and will be cut off by second cold cutting shears to a length of 6.4 m. After each batch with specific lengths is completed, the adjustable stops 21, 22 will automatically be transferred to the next position according to the CPU signal, and fixed. In this example, the first adjustable stop 21 will be moved to 10.4 m, which is 2 × 5.2 m, and the second adjustable stop 22 will be moved to 5.2 m.

Steel reinforcing rods of each specific length will be separately assembled in a standard way, and bundled into packages, the weight of which is convenient for loading. Additional commands of the programmed logic of the CPU will be sent to the machines 27, 28, 29 for strapping, so that strapping will be carried out in appropriate places that are apart from each other along the length of the short rods. The first and third strapping machines 27, 29 are movable, and the central strapping machine 28 is left stationary so that you can set the required strapping step and be able to strand at all places simultaneously. Each bundled bag is weighed and tagged with an appropriate barcode that indicates the contract number, diameter, length, number of rods, and bending sheet. It may be necessary to organize additional strapping installations in order to increase the strapping capacity of short rods to match the performance of the rolling mill.

As part of a separate operation, packages of rods of a specific length are transferred to a bending site located near the rolling mill. At the bending site, the necessary bending of each of the rods will be made according to the technological map of bending. These bent sized cut rods will be ready for delivery to the construction site for installation in various beams, columns or plates.

In general, the rolling operation in accordance with the present invention should provide metal savings with losses of up to 10% loss in standard manufacturing, and enable delivery of cut-to-size rods in specific quantities to customers at no additional cost.

Although the present invention has been described by way of examples of preferred options, it will be understood by those skilled in the art that changes may be made to the form and details of the invention without departing from the spirit and scope of the invention.

Claims (9)

1. A method of manufacturing steel reinforcement in segments of a given length with the formation of packages of reinforcing bars, which includes the steps of obtaining a continuous steel bar from a rolling mill, cutting a continuous steel bar into successive segments, each of which has a length that is a multiple of a given length of reinforcing bars, cutting these segments set in line with cold cutting shears, first at a length equal to two lengths of reinforcing bars, and then cutting in half at lengths equal to the lengths of reinforcing bars, while maintaining the continuity of receiving a steel bar from a rolling mill, and strapping of reinforcing bars cut into a given size for their release from a rolling mill with the formation of packages of reinforcing bars. 2. The method according to claim 1, characterized in that when changing the specified length of the reinforcing bars, a change in the length of these segments and a change in the position of these segments relative to the cold cutting shears are made to obtain the length of the bars corresponding to the changed length. 3. The method according to claim 2, characterized in that the CPU is used to control the cutting of a continuous steel bar with flying shears and the cutting of rods mounted in line with cold cutting shears. 4. The method according to claim 3, characterized in that it includes the operation of adjusting the position of these segments relative to the cold cutting shears for cutting segments into segments of the desired length in response to CPU signals. 5. The method according to claim 4, characterized in that the steel reinforcing bars are strapped simultaneously by three strapping machines installed in a line, one of which is stationary, and the other two are made with the possibility of moving to the desired position in response to the CPU signal. 6. The method according to claim 4, characterized in that the cold cutting shears are equipped with adjustable stops, and the CPU is configured to send signals to move the adjustable stops to positions in which the cold cutting shears cut segments into segments of a given length. 7. A device for the manufacture of steel reinforcement in segments of a given length with the formation of packages of reinforcing bars, containing a rolling mill for producing a continuous steel bar, flying shears installed at the outlet of the rolling mill, a CPU connected with flying shears for cutting a continuous steel bar into segments, each of which has a length that is a multiple of the specified length of the reinforcing bars, two cold shears installed in a line, to which the indicated segments are continuously fed and which are equipped with adjustable removable stops, while the cold cutting shears and adjustable stops are connected to the CPU, configured to control the installation of the stops in the desired position and actuating the cold cutting shears in such a way that some cold cutting shears cut these segments into segments whose length is two the lengths of the reinforcing bars, and other cold cutting shears cut the resulting sections in half to obtain bars cut into a given size, the cold cutting shears being driven during reception of a continuous steel rod, and strapping unit, disposed to receive the chopped reinforcing bars from the cold shears cut to form packages of reinforcing rods having a predetermined length. 8. The device according to claim 7, characterized in that the strapping installation includes three in-line strapping machines, the first and third machines being movable, and the second machine stationary. 9. The device according to claim 8, characterized in that the first and third strapping machines are connected to the CPU to move them in response to changes in the specified length of the rods.

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