Method for preventing bend defect during cut-to-length shearing of cut-to-length rolled reinforcing steel bar

Abstract

The invention discloses a method for preventing bend defects during cut-to-length shearing of cut-to-length rolled reinforcing steel bars, which comprises the following steps: in the process of sliding multiple-length reinforcing steel bars from a brake apron board to a straightening plate, limiting the spatial degree of freedom of the reinforcing steel bars through an adjustable limiting mechanism, so that the reinforcing steel bars sequentially slide into a blanking groove of the straightening plate in a single layer; when the multiple-length reinforcing steel bars are conveyed to the arrangement chain through the cooling bed, the stepping distance of the arrangement chain is accurately controlled through the displacement mechanism, the gap between the adjacent reinforcing steel bars is controlled, and meanwhile the heads of the reinforcing steel bars are directionally cooled; before multiple-length steel bars enter cold shearing, stacking is eliminated through the rolling dredging mechanism, and a temperature control piece is arranged at a shearing position to control the temperature of the steel bars. In the first stage of controlling the double-length steel bars to be between the brake apron board and the cold shear, the compression roller is used for limiting to prevent overturning, the motor encoder is used for controlling the distance to prevent bar combining in the second stage, the dredging roller is separated singly in the third stage, and directional water cooling and final cooling temperature control are adopted; and the bend defect caused by stacking, overhigh temperature and the like when the double-length steel bars are cut to length is prevented.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of section steel rolling, in particular to a method for preventing elbow defects of cut-rolled steel bars during fixed-length shearing. BACKGROUND

[0002] The end of the steel bar should be sheared straight, and local deformation should not affect use. However, during cut-rolling, if the running state of the double-length steel bar between the brake apron and the cold shears and the temperature of the steel bar during fixed-length shearing are not controlled, end bending defects are likely to occur due to stacking, excessive temperature, etc.

[0003] In the prior art, multiple double-length steel bars may be disordered and stacked when sliding into the straightening plate drop chute from the cold bed input roller, i.e., the steel bars near the brake plate end are stacked above the steel bars near the cold bed end, and multiple double-length steel bars in the same tooth groove are turned over, even jumping teeth, i.e., the steel bars originally arranged side by side in the tooth groove are stacked. Multiple double-length steel bars are turned over and stacked when stepping from the last moving tooth groove of the cold bed to the arrangement chain. The diameter of the multiple double-length steel bars is greater than the distance moved to the next process by the arrangement chain, i.e., the free steel receiving area of the arrangement chain is insufficient to accommodate the steel bars conveyed from the cold bed, and the steel bars are stacked on the arrangement chain. Finally, during fixed-length shearing of the double-length steel bars, bending is likely to occur at the shearing position with high temperature, and the pre-treatment steps fail to completely eliminate the stacking of the double-length steel bars, resulting in shearing elbows. SUMMARY

[0004] To overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a method for preventing elbow defects of cut-rolled steel bars during fixed-length shearing by setting corresponding auxiliary devices at each stage from the running of the steel bars from the double-length shears to the cold shears, to avoid bending defects of the double-length steel bars during fixed-length shearing due to stacking, excessive temperature, etc., and to solve the problems raised in the background art.

[0005] The technical solution adopted by the present application to solve its technical problems is as follows: a method for preventing elbow defects of cut-rolled steel bars during fixed-length shearing, comprising the following steps: During the process of the double-length steel bars sliding from the brake apron to the straightening plate, an adjustable limiting mechanism is used to limit the spatial freedom of the steel bars, so that the steel bars are orderly and single-layered when sliding into the straightening plate drop chute; When the double-length steel bars are conveyed to the arrangement chain by the cold bed, a displacement mechanism is used to accurately control the stepping distance of the arrangement chain, control the gap between adjacent steel bars, and simultaneously directionally cool the head of the steel bar; Before the double-length steel bars enter the cold shears, a roller pressing and guiding mechanism is used to eliminate stacking, and a temperature control device is set at the shearing position to control the temperature of the steel bar.

[0006] As a further improvement of the present application: the space freedom of the reinforcing steel bar is limited by the adjustable limiting mechanism, comprising: A press roller device is arranged between the brake apron and the straightening plate, the press roller device is a free roller, the installation height of the press roller device is greater than the straightening plate inclined plane steel throwing point, the distance B between the press roller device and the inclined plane of the straightening plate is greater than the nominal diameter of the reinforcing steel bar, and the inclination angle of the press roller device is greater than the inclination angle of the straightening plate.

[0007] As a further improvement of the present application: the installation height of the press roller device exceeds the straightening plate inclined plane steel throwing point by 10-15mm, the distance B between the press roller device and the inclined plane of the straightening plate is set as: B=nominal diameter of reinforcing steel bar+(3-5mm), and the inclination angle of the press roller device is greater than the inclination angle of the straightening plate by 1-3°.

[0008] As a further improvement of the present application: the head of the reinforcing steel bar is directionally cooled, comprising: A water cooling device is arranged above the head of the double-length reinforcing steel bar at the end of the cooling bed, the spray head of the water cooling device cools the head of the reinforcing steel bar in the form of spray.

[0009] As a further improvement of the present application: the step distance of the arrangement chain is accurately controlled by the displacement mechanism, comprising: The moving distance L of the arrangement chain is controlled by the motor and the encoder, wherein L≥nominal diameter of reinforcing steel bar×number of cutting+(1-3mm), so as to control the stacking of the double-length reinforcing steel bar on the arrangement chain from the movable rack.

[0010] As a further improvement of the present application: the stack is eliminated by the roller pressure guiding mechanism, comprising: A pressure guiding roller is arranged on the cooling bed output roller, the pressure guiding roller is a free roller, and the gap D between the pressure guiding roller and the output roller is set as: D=nominal diameter of reinforcing steel bar+(3-5mm).

[0011] As a further improvement of the present application: a temperature control device is arranged at the cutting position to control the temperature of the reinforcing steel bar, comprising: A fan or a water cooling device is arranged on the output roller at the inlet of the cutting machine, so that the temperature of the reinforcing steel bar is ≤180℃ when cutting.

[0012] As a further improvement of the present application: the press roller device is installed at the inlet of the cooling bed, and the number is one or more.

[0013] As a further improvement of the present application: the diameter of the spray head of the water cooling device is ≥30mm, and the coverage length is ≥800mm.

[0014] As a further improvement of the present application: the roller body length of the pressure guiding roller is equal to or greater than the corresponding cooling bed output roller body length, and the installation height of the pressure guiding roller is adjustably arranged.

[0015] Compared with the prior art, the present application has the beneficial effects that: The present application prevents the stacking of the multiple-length steel bars during the cutting-to-length shearing by means of the three-stage cooperation of the first-stage anti-overturning by the press roller position limiting, the second-stage anti-parallel steel bar by the motor encoder distance control, and the third-stage single-bar separation by the guiding roller, and the directional water cooling and the final cooling temperature control, and the cutting-to-length shearing position of the steel bar is supplemented with certain cooling conditions to solve the plastic deformation problem during the high-temperature shearing, thereby preventing the elbow defects of the multiple-length steel bars during the cutting-to-length shearing due to the stacking, high temperature, etc. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The present application is a structural schematic diagram. DETAILED DESCRIPTION

[0017] In order to clearly and completely understand the technical solutions, the present application will be further described in conjunction with the embodiments and the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, and all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0018] It should be understood that when used in the specification and the appended claims, the terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0019] It should also be understood that the terms used in the present application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the present application specification and the appended claims, unless otherwise clearly indicated by the context, the singular forms "a", "an" and "the" are intended to include the plural forms.

[0020] It should be further understood that the term "and / or" used in the present application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0021] Firstly, in the cutting and rolling process, after the rolled piece is formed by rolling, the basic flow of conveying to the cold shears for cutting-to-length shearing is: multiple-length shears → cold bed input roller → brake apron → cold bed (straightening plate) → cold bed (alignment roller) → arrangement chain → unloading trolley → cold bed output roller → cold shears, such as Figure 1For the convenience of description, we call the process of running the reinforcing steel from the double-length shear to the straightening plate the first stage, the process of running the reinforcing steel from the straightening plate to the cold bed output roller the second stage, and the process of running the reinforcing steel from the cold bed output roller to the cold shear for final sizing and shearing the third stage. The specific running route or track of the reinforcing steel in each stage is as follows: First stage: After the rolling piece is segmented and sheared into double-length reinforcing steel by the double-length shear, the double-length reinforcing steel first runs continuously at speed to the cold bed direction through the cold bed input roller, so as to pull away a certain distance from the rolling piece which is still being rolled and has not been cut yet, and then the double-length rolling piece is safely put on the cold bed by the action of the brake apron located between the cold bed input roller and the straightening plate (when the brake plate descends, the double-length reinforcing steel on the input roller slides into the brake plate and starts to brake; when the brake plate rises, the double-length rolling piece on the brake plate slides into the blanking groove of the straightening plate).

[0022] Second stage: The reinforcing steel falling into the straightening plate is transported step by step to the arrangement chain by the eccentric wheel step-by-step rack type cold bed in the process of natural cooling and straightening (at the same time, the automatic head alignment of the double-length reinforcing steel is completed by the alignment roller located in the middle of the cold bed), and the arrangement chain moves a certain distance in the direction of the next process every time it accepts the double-length reinforcing steel stepped over by the moving rack of the cold bed, i.e. the double-length reinforcing steel is arranged at a certain interval, the storage amount of the double-length reinforcing steel on the arrangement chain is set according to the capacity of the cold shear, the unloading trolley, the cold bed output roller and other equipment and the reinforcing steel specification, and after the storage amount meets the requirements, the double-length reinforcing steel is horizontally lifted to the cold bed output roller by the unloading trolley.

[0023] Third stage: The cold bed output roller transports the double-length reinforcing steel to the cold shear, and then the cold shear shears the double-length reinforcing steel into the required length according to the requirements.

[0024] Article 6.5 of "GB / T 1499.2-2018 Steel for Reinforced Concrete Part 2 Hot Rolled Ribbed Steel" clearly stipulates that the end of the reinforcing steel should be sheared straight, and the local deformation should not affect the use. However, during the cutting and rolling process, if the running state of the double-length reinforcing steel between the brake apron and the cold shear and the temperature of the reinforcing steel during sizing and shearing are not controlled, end bending defects are likely to occur due to stacking, high temperature, etc. The main reasons are as follows: In the first stage, since there is no corresponding limiting device above the straightening plate material chute, multiple lengths of steel bars may be disordered and stacked when sliding into the straightening plate material chute from the roller table, that is, the steel bars near the brake plate end are stacked above the steel bars near the roller table. During the operation of the steel bars in the second stage, firstly, multiple lengths of steel bars in the same tooth groove are turned over or even jump teeth, that is, the steel bars originally arranged side by side in the tooth groove are stacked; secondly, multiple lengths of steel bars are turned over and stacked when stepping from the last moving tooth groove of the roller table to the arrangement chain; thirdly, the diameter of multiple lengths of steel bars is greater than the distance moved to the next process by the arrangement chain, that is, the free steel receiving area of the arrangement chain is insufficient to accommodate the steel bars conveyed from the roller table, and the steel bars are stacked on the arrangement chain. When the multiple lengths of steel bars are cut to a fixed length, firstly, bending is prone to occur at the cutting position with a high temperature; secondly, the stacking of the multiple lengths of steel bars is not completely eliminated in the first and second stages, resulting in a bending head during cutting.

[0025] Embodiments of the present application provide a method for preventing bending head defects during cutting of split-rolled steel bars to a fixed length, comprising the following steps: During the process of sliding the multiple lengths of steel bars from the brake skirt plate to the straightening plate, the spatial freedom of the steel bars is limited by an adjustable limiting mechanism, so that the steel bars are orderly and single-layered when sliding into the straightening plate material chute; When the multiple lengths of steel bars are conveyed to the arrangement chain by the roller table, the step distance of the arrangement chain is accurately controlled by a displacement mechanism to control the gap between adjacent steel bars, and the head of the steel bar is directionally cooled; Before the multiple lengths of steel bars enter the cold shear, the stacking is eliminated by a roller pressing and guiding mechanism, and a temperature control device is arranged at the cutting position to control the temperature of the steel bar.

[0026] The present application prevents the stacking of multiple lengths of steel bars during cutting to a fixed length by the following three stages: preventing overturning by the first stage of pressing roller limiting in the process of controlling the running state of the multiple lengths of steel bars from the brake skirt plate to the cold shear, preventing multiple steel bars by the second stage of motor encoder distance control, and separating single steel bars by the third stage of guiding roller. The fixed length cutting position of the steel bar is supplemented by directional water cooling and final cooling temperature control, which solves the problem of plastic deformation caused by high temperature cutting, thereby preventing the bending head defects of the multiple lengths of steel bars during cutting to a fixed length due to stacking, high temperature and other reasons.

[0027] In an embodiment of the present application, the limiting of the spatial freedom of the steel bars by the adjustable limiting mechanism comprises: A pressing roller device is arranged between the brake skirt plate and the straightening plate, the pressing roller device is a free roller, the installation height of the pressing roller device is greater than the straightening plate inclined plane steel throwing point, the distance B between the pressing roller device and the straightening plate inclined plane is greater than the nominal diameter of the steel bar, and the inclination angle of the pressing roller device is greater than the inclination angle of the straightening plate.

[0028] Further, the pressing roller device is installed at the entrance of the cooling bed, and the number is one or more; the installation height of the pressing roller device is 10-15 mm higher than the steel throwing point of the straightening plate slope, the distance B between the pressing roller device and the straightening plate slope is set as B=nominal diameter of the steel bar+(3-5 mm), and the inclination angle of the pressing roller device is 1-3° larger than the inclination angle of the straightening plate slope.

[0029] In the embodiment, when the steel bars slide to the straightening plate at high speed from the brake skirt, the multiple steel bars are prone to overturn and stack in the material dropping groove of the straightening plate due to inertial impact and drop, which causes uneven stress and elbow during subsequent shearing. The multiple pressing roller devices are installed at the entrance of the cooling bed, and the installation height is 10-15 mm higher than the steel throwing point of the straightening plate slope, so as to ensure that the pressing roller covers the high point of the steel throwing track, avoids interference with the brake plate, and forces the steel bar to slide in a single layer. Then, the distance B between the pressing roller device and the straightening plate slope is set as B=nominal diameter of the steel bar+(3-5 mm), a dynamic limiting channel is formed, the stacking is prevented, and smooth passing is allowed. Finally, the inclination angle of the pressing roller device is 1-3° larger than the inclination angle of the straightening plate slope, so that the inclination angle of the pressing roller is steeper than that of the straightening plate, the steel bar obtains an additional gravity acceleration component, the air retention time is shortened, and the overturning opportunity is reduced.

[0030] In an embodiment of the present application, the head of the steel bar is oriented and cooled, comprising: A water cooling device is arranged above the head of the steel bar at the end of the cooling bed, the spray head of the water cooling device cools the head of the steel bar in the form of spray, and the diameter of the spray head of the water cooling device is ≥30 mm and the covered length is ≥800 mm.

[0031] In the embodiment, the water mist focuses on the head of the steel bar in a range of ≥800 mm, and the temperature of the head of the steel bar is reduced from an average of 350℃ at the outlet of the cooling bed to ≤180℃. When the shearing temperature is ≤180℃, the yield strength of the steel is improved, the anti-shearing deformation ability is enhanced, and the occurrence rate of elbow is reduced.

[0032] In an embodiment of the present application, the step distance of the arrangement chain is accurately controlled through a displacement mechanism, comprising: The moving distance L of the arrangement chain is controlled through a motor and an encoder, wherein L≥nominal diameter of the steel bar×number of cutting+ (1-3 mm), so as to control the stacking of the multiple steel bars from the movable rack to the arrangement chain.

[0033] In the embodiment, the displacement of the arrangement chain is controlled through the motor and the encoder to build an isolation area, so as to ensure that the gap between the steel bars is constant>0. The encoder feedback replaces the time relay, the control accuracy of the step distance is improved, the periodic stacking caused by errors is eliminated, and the stacking transmission from the cooling bed to the cold shears is cut off.

[0034] In an embodiment of the present application, the stacking is eliminated through a roller pressure dredging mechanism, comprising: The relief pressure roller is arranged on the cold bed output roller way, and the relief pressure roller is a free roller. The gap D between the relief pressure roller and the output roller way is set as: D = nominal diameter of the steel bar + (3-5 mm).

[0035] In the embodiment, the relief pressure roller forces the double-steel-bar stack to separate into single bars. When the steel bars try to pass in double, the D value exceeds the upper limit, and the steel bars cannot pass. When the single bars pass, the upper steel bars fall due to gravity, but are blocked by the pressure roller due to the high gap. The stranded steel bars are rearranged into a single layer under the limitation of the pressure roller. After the bottom steel bars pass, the upper steel bars pass through the gap D in turn.

[0036] In one embodiment of the present application, the temperature control device is arranged at the shearing position to control the temperature of the steel bars, including: a fan or a water cooling device is arranged on the output roller way at the entrance of the cold shears, so that the temperature of the steel bars is ≤180 ℃ when shearing.

[0037] In the embodiment, the fan or the water cooling device is arranged at the entrance of the cold shears, so that the shearing temperature of the steel bars is strictly ≤180 ℃, and the yield strength and the shear deformation resistance of the steel are improved.

[0038] In one embodiment of the present application, the length of the roller body of the relief pressure roller is equal to or greater than the length of the roller body of the corresponding cold bed output roller, and the installation height of the relief pressure roller is adjustably arranged.

[0039] In the embodiment, the length of the roller body is greater than the length of the roller body of the output roller, so that the end of the steel bar is completely covered, and the risk of vibration and tilting of the suspended section is eliminated. The height is adjustably achieved by a screw rod lifting / electric push rod, and the gap D is quickly switched.

[0040] In summary, after reading the present application document, those skilled in the art can make other various corresponding transformation schemes according to the technical scheme and technical concept of the present application without creative mental labor, which all belong to the protection range of the present application.

Claims

1. A method for preventing bending defects during the cutting of rolled steel bars to length, characterized in that, Includes the following steps: During the process of the long steel bars sliding from the brake skirt to the straightening plate, the spatial freedom of the steel bars is restricted by the adjustable limiting mechanism, so that the steel bars slide into the straightening plate drop chute in an orderly manner in a single layer. When the long steel bars are transported to the arrangement chain via the cooling bed, the stepping distance of the arrangement chain is precisely controlled by the displacement mechanism to control the gap between adjacent steel bars, while the head of the steel bars is directionally cooled. Before the long steel bars enter the cold shearing process, the stacking is eliminated by a roller pressing and guiding mechanism, and a temperature control device is set at the shearing position to control the temperature of the steel bars.

2. The method for preventing bending defects during the cutting of rolled steel bars to length according to claim 1, characterized in that, The method of restricting the spatial degrees of freedom of the reinforcing bars through an adjustable limiting mechanism includes: A pressure roller device is installed between the brake skirt and the straightening plate. The pressure roller device is a free roller. The installation height of the pressure roller device is greater than the steel throwing point on the inclined surface of the straightening plate. The distance B between the pressure roller device and the inclined surface of the straightening plate is greater than the nominal diameter of the steel bar. The inclination angle of the pressure roller device is greater than the inclination angle of the straightening plate.

3. The method for preventing bending defects during the cutting of rolled steel bars to length according to claim 2, characterized in that, The installation height of the pressure roller device exceeds the steel throwing point on the inclined surface of the straightening plate by 10-15mm. The distance B between the pressure roller device and the inclined surface of the straightening plate is set as: B = nominal diameter of the steel bar + (3-5mm), and the tilt angle of the pressure roller device is 1-3° larger than the angle of the inclined surface of the straightening plate.

4. The method for preventing bending defects during the cutting of rolled steel bars to length according to claim 1, characterized in that, The directional cooling of the steel bar head includes: A water-cooling device is installed above the head of a multiple-length steel bar at the end of the cooling bed, and the nozzle of the water-cooling device cools the head of the steel bar in the form of spray.

5. A method for preventing bending defects during the cutting of rolled steel bars to length, as described in claim 4, characterized in that, The precise control of the stepping distance of the arrangement chain through the displacement mechanism includes: The movement distance L of the arrangement chain is controlled by a motor and an encoder, where L ≥ nominal diameter of the steel bar × number of cuts + (1-3mm), so as to control the multiple length steel bars to be transported by the moving rack to the stacking on the arrangement chain.

6. The method for preventing bending defects during the cutting of rolled steel bars to length according to claim 1, characterized in that, The elimination of stacking by the roller pressing and guiding mechanism includes: A guide roller is installed on the output roller conveyor of the cooling bed. The guide roller is a free roller. The gap D between the guide roller and the output roller conveyor is set as: D = nominal diameter of the steel bar + (3-5mm).

7. A method for preventing bending defects during the cutting of rolled steel bars to length, as described in claim 6, characterized in that, The method of setting a temperature control at the shearing position to control the temperature of the reinforcing bar includes: A fan or water cooling device is installed on the output roller conveyor at the cold shear inlet to ensure that the temperature of the steel bar is ≤180℃ during shearing.

8. A method for preventing bending defects during the cutting of rolled steel bars to length, as described in claim 3, characterized in that, The pressure roller device is installed at the inlet of the cooling bed, and there are one or more of them.

9. A method for preventing bending defects during the cutting of rolled steel bars to length, as described in claim 5, characterized in that, The nozzle diameter of the water-cooling device is ≥30mm, and the coverage length is ≥800mm.

10. A method for preventing bending defects during the cutting of rolled steel bars to length, as described in claim 7, characterized in that, The length of the guide roller is equal to or greater than the length of the corresponding cooling bed output roller, and the installation height of the guide roller is adjustable.

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