CN112974519B - Economical welding endless rolled bar production line process arrangement and production method - Google Patents
Economical welding endless rolled bar production line process arrangement and production method Download PDFInfo
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
- B21B1/16—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling wire rods, bars, merchant bars, rounds wire or material of like small cross-section
- B21B1/18—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling wire rods, bars, merchant bars, rounds wire or material of like small cross-section in a continuous process
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B15/00—Arrangements for performing additional metal-working operations specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B15/0007—Cutting or shearing the product
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B15/00—Arrangements for performing additional metal-working operations specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B15/0085—Joining ends of material to continuous strip, bar or sheet
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
- B21B45/0203—Cooling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B45/04—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for de-scaling, e.g. by brushing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B15/00—Arrangements for performing additional metal-working operations specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B15/0007—Cutting or shearing the product
- B21B2015/0014—Cutting or shearing the product transversely to the rolling direction
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B15/00—Arrangements for performing additional metal-working operations specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
- B21B2015/0092—Welding in the rolling direction
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
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Abstract
The invention discloses a process arrangement and a production method of an economical welding endless rolled bar production line, belonging to the technical field of material processing, wherein the technical scheme comprises a rough rolling unit processing line and a finishing mill unit processing line, wherein the rough rolling unit processing line and the finishing mill unit processing line are transmitted and arranged through an intermediate billet turnover device; the middle finishing mill group processing line comprises a welding deburring device, a middle rolling mill group and a finishing mill group which are sequentially arranged; the production line of the rough rolling unit processing line and the middle finishing unit processing line are oppositely arranged; firstly, the quality of the square continuous casting billet produced by the multi-strand continuous casting machine cannot meet the requirement, so that the technical problem of welding endless rolling interruption is solved, secondly, the oxidation in the descaling welding process of the intermediate billet is solved, the welding quality and the product quality are influenced, and thirdly, the problems of overlong production line and large occupied area are solved.
Description
Technical Field
The invention belongs to the technical field of material processing, and particularly relates to process arrangement and a production method of an economical welding endless rolled bar production line.
Background
The traditional rolling technology is to heat a billet with a certain section and length to a rolling temperature, and send the billet into a rolling mill one at a time to roll the billet into products with required specifications. The rolling mill bites the billet repeatedly frequently, which inevitably causes repeated impact to the rolling mill, increases the steel stacking probability of rolled pieces, increases the working load of the rolling mill, aggravates the abrasion of the roller, shortens the service life of the roller, reduces the stability of the whole rolling process, and influences the increase of the fault rate of the rolling mill. In addition, in order for the subsequent finishing zone to proceed smoothly, a certain time interval must be left between the billets, since the effective rolling time of the billets is reduced.
The welding endless rolling is a process of welding billets in one period to enable the length of rolled pieces to be infinitely prolonged, thereby realizing uninterrupted rolling. The short length, the head cutting and the tail cutting in the single billet rolling process are greatly reduced by endless rolling, and the yield is improved; the pile steel in the rolling process is reduced, and the operation rate of steel rolling equipment is improved. Compared with the traditional rolling process, the endless rolling process has the advantages that impact load generated by biting and throwing out the rolled piece does not exist, the impact of the rolled piece on the rolling mill is reduced, the service lives of the roller and the guide position can be prolonged, the process equipment accidents and the consumption of spare parts due to continuous rolling are reduced, the rolled piece has no dimensional deviation caused by head-tail tension loss, the dimensional control precision of the rolled piece is improved, and the product quality is improved.
The endless rolling technology is newly built on a production line at present, continuous casting and rolling are used as technical targets, and the endless rolling is realized by adopting a billet welding endless rolling technology for the rolling technology of a cutting billet intermittent continuous rolling unit which is widely used worldwide.
Although the welding endless rolling technology is developed and popularized through a plurality of years of technology, the welding endless rolling technology is still in an individual production line test stage in the worldwide steel industry, and cannot be widely popularized and applied in the worldwide steel industry, and the reason is that the welding technology in the welding endless rolling technology can meet the long-period continuous welding requirement of the welding endless rolling although being a long progress, but the steelmaking continuous casting billet currently adopts a continuous production technology for multi-stream casting, and the difference of casting speed and section cooling strength of stream and stream causes larger difference of the appearance dimension of stream and stream casting billets, so that the geometric shape of the tapping end face is square, the end face is flat, and the billets are free from bending, slipping and twisting. The external dimension of the steel billet can not meet the requirements, so that the defects of steel billet welding dislocation, head lap joint, even cold joint and the like are caused after the steel billet is welded, the steel billet can not stably enter a rolling mill or the rolling process is interrupted, the continuous rolling operation is forced to be interrupted, and the operation rate of a welded endless rolling steel rolling production line is seriously influenced.
In addition, in the descaling welding process of the steel billet, oxygen in the air is in contact with the steel billet at high temperature to generate surface oxidation, particularly, in the welding process, a welding machine generates a large amount of heat to locally melt the end face of the steel billet, and the melted end face is subjected to butt welding to finish the welding. The partial surface of the steel billet is exposed in the air in the welding process, and is rapidly oxidized under the high-temperature condition, and if oxidized scales generated by oxidation are involved in a welding interface, the welding quality and the performance of a welding part of the steel bar are adversely affected.
CN 110116135A discloses a method for endless rolling production of rod and wire products, which comprises a square billet, a rectangular billet or round billet continuous casting machine, an electromagnetic induction heater, a blooming mill group, a roughing mill group, a middle rolling mill group, a finishing mill group and a finishing cooling collecting area; a water spray or water mist cooling device is arranged behind each rolling unit; each production device is connected with a control system to realize automatic control of endless rolling production of the rod and wire; the adopted endless rolling production method of the rod and wire comprises the following steps: continuous casting, temperature control, blooming and continuous rolling. The invention relates to a cast rolling endless rolling technology for continuous casting and rolling of billets.
CN201811342936.7 discloses a finishing mill group and a rolling method in ESP endless rolling, the finishing mill group in ESP endless rolling of the invention comprises a plurality of finishing mills arranged according to the sequence of the finishing process, and is characterized in that: one of the stands is a stand-by finishing mill for replacing the worn finishing mill; a finishing mill arranged in sequence in front of the standby finishing mill and the worn finishing mill, wherein a spray header is arranged in front of the finishing mill; the spray header sprays cold water to cool the strip and complete the austenite to ferrite transformation process. The invention relates to a finishing mill group in headless cast rolling and a rolling control technology.
CN201910894976.0 discloses a process equipment of a headless rolled bar production line, the invention provides a process equipment of a headless rolled bar production line, which comprises a steelmaking continuous casting unit, a middle rolling unit, a temperature control forming rolling unit and a finished product finishing treatment unit which are sequentially arranged; the steelmaking continuous casting unit comprises a set of pouring platform and a plurality of continuous casting guide mechanisms. The intermediate rolling unit comprises a first continuous rolling unit, a temperature control device and first shearing equipment which are sequentially arranged. The temperature control forming rolling unit comprises a second continuous rolling unit, a front temperature control device, a rear temperature control device and second shearing equipment. The finishing treatment equipment corresponds to an upstream parallel-arranged temperature control forming rolling unit and comprises a high-speed steel feeding device, a cooling bed, corresponding fixed-length shears, a checking bundling collection device. The invention relates to a cast rolling endless rolling technology for continuous casting and continuous rolling.
CN201910336344.2 discloses a short-flow long-material endless rolling production line and a rolling method thereof, the method comprises a steelmaking furnace, a continuous casting machine, a withdrawal and straightening machine, a rough rolling production line, a middle rolling production line, a finish rolling production line, a reducing and sizing production line and a cooling bed which are tightly connected in sequence, wherein the rough rolling production line comprises a rough rolling unit, an accident shear and cooling bed, a heat preservation device and a first head flying shear in sequence, the heat preservation device supplements the temperature of a casting blank after rough rolling, and the interval from an inlet of the withdrawal and straightening machine to an inlet of the rough rolling unit is 9-30 m; the middle rolling production line sequentially comprises a middle rolling unit, a water cooling tank and a second crop flying shear; the finish rolling production line sequentially comprises a finish rolling unit, a water cooling box and a third crop flying shear; the reducing sizing production line sequentially comprises a reducing sizing mill, a water cooling box and a sizing flying shear, the rolling production line is simple in process arrangement, the continuous casting and rough rolling mill set is small in distance, the rough rolling biting is facilitated, the heat preservation or temperature compensation after rough rolling is low in relative power consumption, and the cost is low. The difference with other patents is mainly to solve the problems that the production flow is long, the continuous casting billet temperature is excessively reduced, and the rolling requirement of a rolling mill cannot be met. The invention provides a short-flow continuous casting and rolling endless rolling production line and a rolling method thereof.
CN201910336344.2 discloses a method for endless rolling of sectional materials, bars and wires and a flexible connection device thereof, and the invention discloses a method for endless rolling of sectional materials, bars and wires and a flexible connection device thereof, which realize seamless connection and continuous forming of full-line rolled pieces from a crystallizer to finished products. The invention discloses a flexible connecting device for endless rolling of sectional materials and rod wires, which realizes seamless connection and continuous forming of all-line rolled pieces from a crystallizer to a finished product.
The patent is a continuous casting and rolling endless rolling production technology for a rod and a wire rod, which is formed by adopting a single-machine single-strand continuous casting machine and a rolling production line. The problem that the external dimension of a billet produced by a conventional wire and bar multi-strand continuous casting machine cannot meet the requirement of welding endless rolling cannot be solved.
Disclosure of Invention
The invention aims to provide a process arrangement and a production method of an economical welding endless rolling bar production line, which mainly solve the technical problems existing in the transformation of a conventional bar intermittent rolling production line into a welding endless rolling production line: firstly, the technical problem of welding endless rolling interruption is caused by that the shape quality of square continuous casting billets produced by a multi-strand continuous casting machine can not meet the requirement. Secondly, the problem that oxidation in the descaling welding process of the intermediate blank affects the welding quality and the product quality is solved; the running rolling direction of the heating furnace and the roughing mill is in reverse arrangement with the welding and intermediate finishing mill groups. Reduces the occupied area, saves the land resource and reduces the investment.
The first object of the present invention is achieved by comprising a roughing mill train machining line and a finishing mill train machining line, which are arranged in a transfer manner by means of an intermediate billet turning device; the middle finishing mill group processing line comprises a welding deburring device, a middle rolling mill group and a finishing mill group which are sequentially arranged; the roughing mill group machining line and the intermediate finishing mill group machining line are oppositely arranged.
The second object of the present invention is achieved by: heating a billet, namely heating the billet to 1160-1200 ℃ by adopting a square billet with 165-220-200 mm and 8000-14000 mm in length, preserving heat for 30-60 minutes, and discharging and rolling;
Step two: rough rolling, namely enabling the billet heated by the heating furnace to enter a rough rolling unit for rolling, enabling the billet to be subjected to 6-pass torsion-free rolling in the rough rolling unit to form an intermediate billet with the diameter of 130-145 mm and the external dimension of the diameter of the intermediate billet, wherein 4 frames of the intermediate billet are subjected to box-oval-round hole type rolling before rough rolling, and 2 frames of round-round hole type rolling after rough rolling further roll the round intermediate billet rolled by the front frame rolling mill into an intermediate billet with the diameter of 130-145 mm and the external dimension of the intermediate billet being highly accurate; the allowable deviation of the diameter of the intermediate blank is +/-0.30 mm, the out-of-roundness is less than or equal to 0.40mm, and the length is 77-113 m; the initial rolling temperature of the billet is 1020-1080 ℃, the rough rolling inlet speed is 0.26-0.3 m/s, the rough rolling outlet speed is 1.28-1.36 m/s, the water spray cooling is carried out after the intermediate billet is taken out of a rough rolling unit, and the surface temperature is controlled to be 980-1030 ℃;
Step three: the method comprises the steps of (1) sawing an intermediate round billet, wherein an intermediate billet turnover device with the length less than or equal to 115m is arranged between a rough rolling unit and an intermediate rolling unit in rolling, after rough rolling, the intermediate billet is fed into a turnover cooling bed through an outlet roller way and a sliding plate roller way with a friction braking sliding plate, the intermediate billet automatically rolls into an intermediate billet collecting groove formed by a guide rail with the inclination angle less than or equal to 40 degrees and a baffle plate on the turnover cooling bed by means of self weight, compression rollers and sawing machines are arranged at two ends of the collecting groove, the heads and the tails of the intermediate billet are tightly pressed on the guide rail of the collecting groove by the compression rollers, the sawing machines saw the heads and the tails rapidly in a static state, after the sawing time is 4-5 seconds, a rail baffle plate falls down, and the sawed intermediate billet automatically rolls into a welding rolling line by means of self weight;
Step four: the middle round billet is welded, the middle billet after head and tail removal reversely enters a welding line, the middle billet enters a descaling device under the clamping of a pinch roll, and the descaling device performs descaling on the tail part of the first middle billet and the head part of the next middle billet; the flash welding machine is arranged at the rear of the descaling device, the heads and the tails of the two intermediate blanks after descaling are welded on line, the welding is completed in 4-5 seconds under high current, and the burrs of the welding part are removed by the burr removing device after the intermediate blanks are welded;
The intermediate billet subjected to welding and burr cleaning enters an inlet roller way protected by a nitrogen heat-preserving cover with the length more than or equal to 115m, and the intermediate billet subjected to sawing head and tail, welding and burr removal stably enters a medium finish rolling continuous rolling mill group for rolling under the clamping of a pinch roll; the descaling, welding and burr cleaning device and the medium finish rolling continuous rolling unit are arranged on a medium finish rolling continuous rolling inlet roller way, and the length of the inlet roller way is more than or equal to 230 meters; during the descaling, welding and burr cleaning processes of the intermediate blank, nitrogen or other protective gases are adopted for protection, so that the surface of the high-temperature intermediate blank is prevented from being exposed in the air and being rapidly oxidized during the descaling process, and the influence of oxide skin on the welding quality and the performance of the welding part of the steel bar during the welding process is avoided;
Step five: rolling the intermediate round billet in an intermediate finish rolling continuous rolling unit at 950-1000 ℃, after intermediate rolling and cooling, feeding the intermediate round billet into the intermediate finish rolling continuous rolling unit at 940-980 ℃, wherein the intermediate rolling inlet speed is 1.32-1.42 m/s, and the finish rolling outlet speed is 5.4-13.8 m/s; the rolled piece is rolled into a bar finished product through finish rolling, the bar finished product is cooled by water mist and then is fed into a cooling bed, the surface temperature of the steel bar on the cooling bed is 840-930 ℃, and the surface temperature of the steel bar is reduced to below 360 ℃ and is collected and then cut to length, collected and bundled.
The beneficial effects of the invention are as follows:
1. in the invention, a columnar square billet is rolled into a round high-precision intermediate billet through a rough rolling reducing sizing mill, the external dimension of the round intermediate billet is high in precision, the non-roundness is small and flat, and the external dimensions of the square billet, the intermediate billet and the round steel are compared with each other as shown in Table 1; the centers and the outer circles of the front and rear intermediate blanks are overlapped in height, so that the on-line welding is facilitated. The problems of difficult welding, and dislocation of the section of the welding part caused by poor external dimensions such as square continuous casting billet dislocation, head bending, billet bending, torsion and the like are avoided. Continuous and stable welding of intermediate billets can be realized, and continuous and stable, efficient and long-period stable rolling of a rolling line is ensured.
2. In the invention, the intermediate billet overturning cooling bed with longer length is arranged between the roughing mill set and the intermediate mill set, and the intermediate billet forms a certain temperature drop in the air in the overturning and welding processes, thereby being beneficial to realizing low-temperature fine grain rolling, improving the strength and toughness of the steel bar, being beneficial to reducing the alloy content of the steel billet, and further realizing the reduction of the alloying cost of the steel billet. Alloy resources are saved, and production cost is reduced.
3. In the invention, the head and the tail of the intermediate blank are cut by adopting the sawing machine, the sections are flush, the quick alignment during welding is facilitated, and the welding speed and the welding quality are improved.
4. In the invention, the head and the tail of the intermediate blank are cut on the intermediate blank overturning cooling bed, and the head and the tail cutting do not influence the production rhythm of a welding finish rolling line.
5. According to the invention, the section of the rolled intermediate blank is reduced, so that the rapid and stable welding of the steel billet is facilitated, and the welding time is reduced from 8-10 seconds to 4-5 seconds. The welding time of the intermediate blank is reduced, namely the continuous operation time of the welding machine is reduced, so that the cooling of the welding machine is facilitated, and the long-term stable operation of the welding machine is facilitated.
6. In the invention, as the welding section is reduced, a welder with smaller rated power can be used, and a small welder hydraulic pump station and a small welding transformer can be used, thereby reducing the investment of the movable welder.
7. According to the invention, the intermediate billet is used for overturning the intermediate billet to a continuous intermediate rolling finish rolling line after rough rolling through the overturning mechanism, the square billet is formed into a round intermediate billet after rough rolling and enters a rough rolling outlet roller way, a steel overturning device is arranged on the outlet roller way, the intermediate billet can be pushed to a steel overturning slope formed by steel rails, and the intermediate billet rolls on the overturning slope to a collecting tank and a roller way on a welding continuous rolling line by virtue of self gravity, so that the method is rapid, accurate and stable, the equipment structure is simple, and the energy is saved.
8. According to the invention, the intermediate blank overturning slope steel rail and the baffle plate are utilized to form the collecting groove, and the compression roller is adopted to press the intermediate blank on the collecting groove, so that the stability is good, and the structure is simple.
9. According to the invention, before the intermediate billet enters the intermediate finishing mill group in the descaling, welding and burr cleaning processes and after welding, nitrogen or other protective gases are adopted for protection, so that the surface of the high-temperature intermediate billet is prevented from being exposed in the air in the descaling process and being rapidly oxidized, and the influence of oxide scale on the welding quality and the performance of the welded part of the steel bar in the welding process is avoided.
10. In the invention, the intermediate billet rolled by rough rolling has sufficient time for temperature conduction before entering the intermediate finish rolling, and the intermediate finish rolling is stable in deformation process due to uniform temperature and austenite grains, so that the occurrence of steel stacking accidents during rolling is greatly reduced, the rolling is smoother, and the appearance size and the performance of the rolled finished steel bar are stable and uniform.
11. The running rolling direction of the heating furnace roughing mill is opposite to the running direction of finish rolling in welding, the production line is arranged tightly, and the process is smooth. The compact arrangement enables the length of the production line to be obviously shortened, the occupied area to be reduced, the land resources to be saved, and the fixed asset investment limit to be greatly reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. Like elements or portions are generally identified by like reference numerals throughout the several figures. In the drawings, elements or portions thereof are not necessarily drawn to scale.
FIG. 1 is a diagram showing the construction and arrangement of a production line according to the present invention.
In the drawing, a 1-roughing mill group machining line, a 2-intermediate finishing mill group machining line, a 3-intermediate billet turnover device, a 4-welding deburring device, a 5-intermediate rolling mill group, a 6-finishing mill group, a 7-heating furnace, an 8-roughing mill group, 9-snap shears, a 10-water cooling device I, an 11-C collecting tank lifting baffle, a 12-fixed sawing machine, a 13-movable sawing machine, a 14-press roll, a 15-dephosphorization device, a 16-movable flash butt welding machine, a 17-burr cleaning device, an 18-gas protection conveying roller way, a 19-second snap shears, a 20-feeding roller, a 23-third snap shears, a 24-first water cooling device, a 25-second water cooling device, a 26-second double shear ruler and a 27-collecting cooling bed.
Detailed Description
Embodiments of the technical scheme of the present invention will be described in detail below with reference to the accompanying drawings. The following examples are only for more clearly illustrating the technical aspects of the present invention, and thus are merely examples, and are not intended to limit the scope of the present invention.
It is noted that unless otherwise indicated, technical or scientific terms used herein should be given the ordinary meaning as understood by one of ordinary skill in the art to which this application belongs.
The economical process arrangement of the welding endless rolled bar production line comprises a rough rolling unit processing line 1 and a finishing mill unit processing line 2, wherein the rough rolling unit processing line 1 and the middle finishing mill unit processing line 2 are in transmission arrangement through an intermediate billet turnover device 3; the middle finishing mill group machining line 2 comprises a welding deburring device 4, a middle rolling mill group 5 and a finishing mill group 6 which are sequentially arranged; the production line directions of the roughing mill group machining line 1 and the intermediate finishing mill group machining line 2 are opposite.
The roughing mill set machining line 1 comprises a heating furnace 7, a roughing mill set 8, a cutting shear 9 and a water cooling device I10 which are sequentially arranged; the rough rolling unit machining line 1 is higher than the middle finishing unit machining line 2, the height difference of the rough rolling unit machining line 1 higher than the middle finishing unit machining line 2 is 1.0-1.8 m, the rough rolling unit machining line 2 is arranged on one side of the middle finishing unit machining line 2, and the distance between the rough rolling unit machining line 1 and the middle finishing unit machining line 2 is 10-16m; the heating furnace tapping rail and the roughing mill are arranged on the same rolling line; and the welding deburring and intermediate finishing rolling continuous rolling unit (intermediate rolling unit and finishing rolling unit) is arranged on the other rolling line. And the rough rolling mill unit and the welding-medium finish rolling continuous rolling mill unit are not in the same rolling height, and the common height difference is 1.0-1.8 meters. And heating the rough rolling line and the finish rolling line in welding for a certain distance, wherein the distance between the rough rolling line and the finish rolling line in welding is 18-28 meters. And (5) reversely entering a medium finish rolling continuous rolling line to roll the welding intermediate billet into a finished product.
The intermediate blank turnover device 3 comprises a plurality of C-shaped collecting tank lifting baffles 11 which are sequentially arranged along the direction of a processing line, a fixed sawing machine 12 arranged on one side of the C-shaped collecting tank lifting baffles 11 and a movable sawing machine 13 arranged on the other side of the C-shaped collecting tank lifting baffles 11, and a compression roller 14 is arranged between the fixed sawing machine 12 and the movable sawing machine 13.
The welding deburring device 4 comprises a dephosphorization device 15, a movable flash butt welding machine 16, a deburring device 17 and a gas protection conveying roller way 18 which are sequentially arranged.
The gas-shielded roller conveyor 18 is a nitrogen-shielded roller conveyor.
The middle rolling mill set 5 comprises a second breaking shear 19, a feeding roller 20, a plurality of rolling mills and a plurality of binding ways which are sequentially arranged.
A third snap shear 23 and a first water cooling device 24 are arranged between the finishing mill group 6 and the middle rolling mill group 5, the finishing mill group 6 comprises a plurality of rolling mills and a plurality of rolling ways, and the rolling mills and the rolling ways of the finishing mill group 6 are less than those of the middle rolling mill group 5.
The outlet end of the finishing mill group 6 is also provided with a second water cooling device 25, a second double shear ruler 26 and a collecting cooling bed 27 in sequence.
A production method for process arrangement of an economical welding endless rolled bar production line, comprising the following steps:
step one: heating a billet, namely heating the billet to 1160-1200 ℃ by adopting a square billet with 165-220-200 mm and 8000-14000 mm in length, preserving heat for 30-60 minutes, and discharging and rolling;
Step two: rough rolling, namely enabling the billet heated by the heating furnace to enter a rough rolling unit for rolling, enabling the billet to be subjected to 6-pass torsion-free rolling in the rough rolling unit to form an intermediate billet with the diameter of 130-145 mm and the external dimension of the diameter of the intermediate billet, wherein 4 frames of the intermediate billet are subjected to box-oval-round hole type rolling before rough rolling, and 2 frames of round-round hole type rolling after rough rolling further roll the round intermediate billet rolled by the front frame rolling mill into an intermediate billet with the diameter of 130-145 mm and the external dimension of the intermediate billet being highly accurate; the allowable deviation of the diameter of the intermediate blank is +/-0.30 mm, the out-of-roundness is less than or equal to 0.40mm, and the length is 77-113 m; the initial rolling temperature of the billet is 1020-1080 ℃, the rough rolling inlet speed is 0.26-0.3 m/s, the rough rolling outlet speed is 1.28-1.36 m/s, the water spray cooling is carried out after the intermediate billet is taken out of a rough rolling unit, and the surface temperature is controlled to be 980-1030 ℃;
Step three: the method comprises the steps of (1) sawing an intermediate round billet, wherein an intermediate billet turnover device with the length less than or equal to 115m is arranged between a rough rolling unit and an intermediate rolling unit in rolling, after rough rolling, the intermediate billet is fed into a turnover cooling bed through an outlet roller way and a sliding plate roller way with a friction braking sliding plate, the intermediate billet automatically rolls into an intermediate billet collecting groove formed by a guide rail with the inclination angle less than or equal to 40 degrees and a baffle plate on the turnover cooling bed by means of self weight, compression rollers and sawing machines are arranged at two ends of the collecting groove, the heads and the tails of the intermediate billet are tightly pressed on the guide rail of the collecting groove by the compression rollers, the sawing machines saw the heads and the tails rapidly in a static state, after the sawing time is 4-5 seconds, a rail baffle plate falls down, and the sawed intermediate billet automatically rolls into a welding rolling line by means of self weight;
Step four: the middle round billet is welded, the middle billet after head and tail removal reversely enters a welding line, the middle billet enters a descaling device under the clamping of a pinch roll, and the descaling device performs descaling on the tail part of the first middle billet and the head part of the next middle billet; the flash welding machine is arranged at the rear of the descaling device, the heads and the tails of the two intermediate blanks after descaling are welded on line, the welding is completed in 4-5 seconds under high current, and the burrs of the welding part are removed by the burr removing device after the intermediate blanks are welded;
The intermediate billet subjected to welding and burr cleaning enters an inlet roller way protected by a nitrogen heat-preserving cover with the length more than or equal to 115m, and the intermediate billet subjected to sawing head and tail, welding and burr removal stably enters a medium finish rolling continuous rolling mill group for rolling under the clamping of a pinch roll; the descaling, welding and burr cleaning device and the medium finish rolling continuous rolling unit are arranged on a medium finish rolling continuous rolling inlet roller way, and the length of the inlet roller way is more than or equal to 230 meters; during the descaling, welding and burr cleaning processes of the intermediate blank, nitrogen or other protective gases are adopted for protection, so that the surface of the high-temperature intermediate blank is prevented from being exposed in the air and being rapidly oxidized during the descaling process, and the influence of oxide skin on the welding quality and the performance of the welding part of the steel bar during the welding process is avoided;
Step five: rolling the intermediate round billet in an intermediate finish rolling continuous rolling unit at 950-1000 ℃, after intermediate rolling and cooling, feeding the intermediate round billet into the intermediate finish rolling continuous rolling unit at 940-980 ℃, wherein the intermediate rolling inlet speed is 1.32-1.42 m/s, and the finish rolling outlet speed is 5.4-13.8 m/s; the rolled piece is rolled into a bar finished product through finish rolling, the bar finished product is cooled by water mist and then is fed into a cooling bed, the surface temperature of the steel bar on the cooling bed is 840-930 ℃, and the surface temperature of the steel bar is reduced to below 360 ℃ and is collected and then cut to length, collected and bundled.
Rolling the blank to meet the size and precision of a finished product by a medium finish rolling continuous rolling unit and a rough rolling unit which are not in the same rolling line, and continuously performing tension-free rolling on a rolled piece through a loop between rolling mills; the horizontal and vertical convertible rolling mill is used horizontally during split rolling; a looper is arranged between each two frames of the finish rolling to perform torsion-free tension-free rolling on a rolled piece, a pre-water cooling tank is arranged in front of the finish rolling mill and used for controlling the temperature of the rolled piece entering the finish rolling unit to realize temperature control rolling, the rolled steel bars of the middle finish rolling unit are sent to a double-length flying shear to perform sectional shearing, ribbed steel bars of phi 12mm and phi 14mm are produced by adopting a four-splitting process, ribbed steel bars of phi 16 and phi 18mm are produced by adopting a three-splitting process, and ribbed steel bars of phi 20 and phi 22mm are produced by adopting a two-splitting process; the ribbed steel bars with phi 25 and phi 50mm are produced by adopting a single-wire rolling process.
The working principle and the working process of the invention are as follows:
The working principle and working process of the invention are described in combination with examples 1-6, and the specific operation is as follows:
Example 1
A. Billet heating
Adopting a square billet with 220 multiplied by 220mm section and 120000mm brand HRB500, heating to 1160 ℃ by a heating furnace, preserving heat for 60 minutes, and discharging and rolling.
B. rough rolling
After descaling the billet heated by the heating furnace, the billet enters a roughing mill unit consisting of 4 short-stress rolling mills with high rigidity and alternating in parallel and vertical and 2 reducing sizing mill units for rolling at 0.26m/s, and the billet is rolled into an intermediate billet with high accuracy in external dimension of 145mm diameter by 6-pass torsion-free micro-tension rolling in the roughing mill unit. The front 4 frames of rough rolling are rolled by adopting box-ellipse-circle-ellipse hole patterns, the rear 2 frames of circle-circle hole patterns further roll the round intermediate billet rolled by the front 4 frame rolling mill into an intermediate billet with 145mm diameter and high precision external dimension, the allowable deviation of the diameter is +/-0.3 mm, and the out-of-roundness is less than or equal to 0.4mm.
The initial rough rolling temperature is 1040 ℃, water spray cooling is carried out after the intermediate billet is taken out of a rough rolling unit, and the surface temperature is cooled to 1000 ℃;
C. Sawing of intermediate round blanks
The rough rolled intermediate billet is sent into a turnover cooling bed by an outlet roller way and a sliding plate roller way with a friction braking sliding plate, the intermediate billet automatically rolls into an intermediate billet collecting groove sawing position formed by the guide rail and a baffle plate by the self weight on the turnover cooling bed by a guide rail with an inclination angle not more than 30 degrees, the head and the tail of the intermediate billet are pressed on the collecting groove guide rail by a compression roller, and the head and the tail of the intermediate billet are cut off by a sawing machine in a static state. Sawing time is 5 seconds, and head and tail sawing is completed. After the completion, the rail baffle falls down, and the sawed intermediate billet automatically rolls into a welding rolling line by means of self weight.
D. welding process of middle round blank
The intermediate blanks after head and tail sawing reversely enter a welding line, are clamped and held by a pinch roll and run at the speed of 1.28m/s, are subjected to online descaling in a nitrogen environment and are welded for 5 seconds under a large amount of flow to form longer intermediate blanks, and after the burrs of the intermediate blanks are removed after the welding, the intermediate blanks are sent into a medium finish rolling continuous rolling mill for rolling through a nitrogen protection roller way.
E. Rolling process of medium finish rolling continuous rolling mill unit
The intermediate billet after head and tail removal is welded by a flash welder welding unit to form a longer billet, the longer billet enters a middle finish rolling continuous rolling unit for rolling, single-line rolling is adopted for finish rolling, 4 steps are adopted for middle rolling by using 4 racks, 2 steps are adopted for finish rolling by using 2 racks, and a finished product of hot rolled ribbed steel bars with the diameter of 50mmHRB500,500 is formed.
The intermediate round billet enters a rolling temperature of 970 ℃ of a medium finish rolling continuous rolling unit, the speed of a medium rolling inlet is 1.32m/s, the temperature of the finish rolling inlet is 940 ℃ after the medium rolling is cooled, and the speed of a finish rolling outlet is 5.4m/s; the intermediate blank is rolled into a finished product of a bar with the diameter of 50mm by adopting a single wire, the bar is cooled by water mist and then is put on a cooling bed, the surface temperature of the bar on the cooling bed is 920 ℃, the bar is put on the cooling bed, and the bar is collected after the surface temperature of the bar on the cooling bed is reduced to below 360 ℃ and is cut to length, collected and bundled.
Example 2
A. Billet heating
Adopting square billets with 200X 200mm sections and 120000mm brands of HRB500, heating to 1040 ℃ by a heating furnace, preserving heat for 60 minutes, and discharging and rolling.
B. rough rolling
After descaling the billet heated by the heating furnace, the billet enters a roughing mill unit consisting of 4 short-stress rolling mills with high rigidity and alternating in parallel and vertical and 2 reducing sizing mill units for rolling at 0.26m/s, and the billet is rolled into an intermediate billet with high accuracy in external dimension of 145mm diameter by 6-pass torsion-free micro-tension rolling in the roughing mill unit. The front 4 frames of rough rolling are rolled by adopting box-ellipse-circle-ellipse hole patterns, the rear 2 frames of circle-circle hole patterns further roll the round intermediate billet rolled by the front 4 frame rolling mill into an intermediate billet with 145mm diameter and high precision external dimension, the allowable deviation of the diameter is +/-0.3 mm, and the out-of-roundness is less than or equal to 0.4mm.
The initial rough rolling temperature is 1040 ℃, water spray cooling is carried out after the intermediate billet is taken out of a rough rolling unit, and the surface temperature is cooled to 1010 ℃;
C. Sawing of intermediate round blanks
The rough rolled intermediate billet is sent into a turnover cooling bed by an outlet roller way and a sliding plate roller way with a friction braking sliding plate, the intermediate billet automatically rolls into an intermediate billet collecting groove sawing position formed by the guide rail and a baffle plate by the self weight on the turnover cooling bed by a guide rail with an inclination angle not more than 30 degrees, the head and the tail of the intermediate billet are pressed on the collecting groove guide rail by a compression roller, and the head and the tail of the intermediate billet are cut off by a sawing machine in a static state. Sawing time is 5 seconds, and head and tail sawing is completed. After the completion, the rail baffle falls down, and the sawed intermediate billet automatically rolls into a welding rolling line by means of self weight.
D. welding process of middle round blank
The intermediate blanks after head and tail sawing reversely enter a welding line, are clamped and held by a pinch roll and run at the speed of 1.36m/s, are subjected to online descaling in a nitrogen environment and are welded for 5 seconds under a large amount of flow to form longer intermediate blanks, and after the intermediate blanks are welded, burrs are removed, the intermediate blanks are sent into a medium finish rolling continuous rolling mill for rolling through a nitrogen protection roller way.
E. Rolling process of medium finish rolling continuous rolling mill unit
The intermediate billet after head and tail removal is welded by a flash welder welding unit to form a longer billet, the longer billet enters a middle finish rolling continuous rolling unit for rolling, single-line rolling is adopted for finish rolling, 6 frames are adopted for middle rolling for 6 passes, 2 frames are adopted for finish rolling for 2 passes, and a finished product of hot rolled ribbed steel bars with the diameter of 40mmHRB500,500 is formed.
The intermediate round billet enters a rolling temperature 980 ℃ of a medium finish rolling continuous rolling unit, the medium rolling inlet speed is 1.36m/s, the medium rolling is cooled, the finish rolling temperature is 965 ℃, and the finish rolling outlet speed is 7.4m/s; the intermediate blank is rolled into a finished product of a bar with the diameter of 40mm by adopting a single wire, the bar is cooled by water mist and then is put on a cooling bed, the surface temperature of the steel bar on the cooling bed is 930 ℃, the bar is put on the cooling bed, and the bar is collected after the surface temperature of the steel bar on the cooling bed is reduced to below 350 ℃ and is cut to length, collected and bundled.
Example 3
A. Billet heating
Adopting a square billet with 220 multiplied by 220mm section and 120000mm brand HRB500, heating to 1200 ℃ by a heating furnace, preserving heat for 50 minutes, and discharging and rolling.
B. rough rolling
After descaling the billet heated by the heating furnace, the billet enters a roughing mill unit consisting of 4 short stress rolling mills with high rigidity and alternating in parallel and vertical and 2 reducing sizing mill units for rolling at 0.3m/s, and the billet is rolled into an intermediate billet with high accuracy in external dimension of 145mm diameter by 6-pass torsion-free micro-tension rolling in the roughing mill unit. The front 4 frames of rough rolling are rolled by adopting box-ellipse-circle-ellipse hole patterns, the rear 2 frames of circle-circle hole patterns further roll the round intermediate billet rolled by the front 4 frame rolling mill into an intermediate billet with 145mm diameter and high precision external dimension, the allowable deviation of the diameter is +/-0.3 mm, and the out-of-roundness is less than or equal to 0.4mm.
The initial rough rolling temperature is 1080 ℃, the intermediate billet is cooled by spraying water after being discharged from a rough rolling unit, and the surface temperature is cooled to 1030 ℃;
C. Sawing of intermediate round blanks
The rough rolled intermediate billet is sent into a turnover cooling bed by an outlet roller way and a sliding plate roller way with a friction braking sliding plate, the intermediate billet automatically rolls into an intermediate billet collecting groove sawing position formed by the guide rail and a baffle plate by the self weight on the turnover cooling bed by a guide rail with an inclination angle not more than 30 degrees, the head and the tail of the intermediate billet are pressed on the collecting groove guide rail by a compression roller, and the head and the tail of the intermediate billet are cut off by a sawing machine in a static state. Sawing time is 5 seconds, and head and tail sawing is completed. After the completion, the rail baffle falls down, and the sawed intermediate billet automatically rolls into a welding rolling line by means of self weight.
D. welding process of middle round blank
The intermediate blanks after head and tail sawing reversely enter a welding line, are clamped and held by a pinch roll and run at the speed of 1.28m/s, are subjected to online descaling in a nitrogen environment and are welded for 5 seconds under a large amount of flow to form longer intermediate blanks, and after the burrs of the intermediate blanks are removed after the welding, the intermediate blanks are sent into a medium finish rolling continuous rolling mill for rolling through a nitrogen protection roller way.
E. Rolling process of medium finish rolling continuous rolling mill unit
The intermediate billet after head and tail removal is welded by a flash welder welding unit to form a longer billet, the longer billet enters a single-line rolling unit of a medium finish rolling continuous rolling unit, 6 steps are adopted for medium rolling by using 6 stand rolls, 2 steps are adopted for finish rolling by using 2 stand rolls, and a finished product of the hot rolled ribbed steel bar with the diameter of 25mmHRB500,500 is formed.
The intermediate round billet enters a rolling temperature of 1000 ℃ of a medium finish rolling continuous rolling mill, the medium rolling inlet speed is 1.38m/s, the medium rolling is cooled, the finish rolling temperature is 980 ℃, and the finish rolling outlet speed is 13.8m/s; the intermediate blank is rolled into a finished product of phi 25mm bar by single wire, and the finished product is cooled by water mist, and then the surface temperature is 910 ℃ and the finished product is put on a cooling bed. And (5) cutting to length, collecting and bundling after the surface temperature of the steel bars on the cooling bed is reduced to 330 ℃.
Example 4
A. Billet heating
Adopting square billets with 200X 200mm sections and 120000mm brands of HRB500, heating to 1160 ℃ by a heating furnace, preserving heat for 50 minutes, and discharging and rolling.
B. rough rolling
After descaling the billet heated by the heating furnace, the billet enters a roughing mill unit consisting of 4 short-stress rolling mills with high rigidity and alternating in parallel and vertical and 2 reducing sizing mill units for rolling at 0.3m/s, and the billet is rolled into an intermediate billet with high accuracy in external dimension and diameter of 140mm by 6-pass torsion-free micro-tension rolling in the roughing mill unit. The front 4 frames of rough rolling are rolled by adopting box-ellipse-circle-ellipse hole patterns, the rear 2 frames of circle-circle hole patterns further roll the round intermediate billet rolled by the front 4 frame rolling mill into an intermediate billet with the diameter of 140mm and the external dimension highly accurate, the allowable deviation of the diameter is +/-0.3 mm, and the out-of-roundness is less than or equal to 0.4mm. The initial rough rolling temperature is 1070 ℃, water spray cooling is carried out after the intermediate billet is taken out of a rough rolling unit, and the surface temperature is cooled to 1000 ℃;
C. Sawing of intermediate round blanks
The rough rolled intermediate billet is sent into a turnover cooling bed by an outlet roller way and a sliding plate roller way with a friction braking sliding plate, the intermediate billet automatically rolls into an intermediate billet collecting groove sawing position formed by the guide rail and a baffle plate by the self weight on the turnover cooling bed by a guide rail with an inclination angle not more than 30 degrees, the head and the tail of the intermediate billet are pressed on the collecting groove guide rail by a compression roller, and the head and the tail of the intermediate billet are cut off by a sawing machine in a static state. Sawing time is 5 seconds, and head and tail sawing is completed. After the completion, the rail baffle falls down, and the sawed intermediate billet automatically rolls into a welding rolling line by means of self weight.
D. welding process of middle round blank
The intermediate blanks after head and tail sawing reversely enter a welding line, are clamped and held by a pinch roll and run at the speed of 1.32m/s, are subjected to online descaling in a nitrogen environment and are welded for 5 seconds under a large amount of flow to form longer intermediate blanks, and after the burrs of the intermediate blanks are removed after the welding, the intermediate blanks are sent into a medium finish rolling continuous rolling mill for rolling through a nitrogen protection roller way.
E. Rolling process of medium finish rolling continuous rolling mill unit
And welding the intermediate blanks after the head and the tail are cut off on line by a flash welding machine welding unit to form longer billets, rolling the longer billets by a middle finish rolling continuous rolling unit, rolling 8 passes by using 8 stand, rolling 4 passes by using 4 stand for finish rolling, and finishing rolling into two-cut rolling to obtain a finished product of the hot rolled ribbed steel bar with the diameter of 22mmHRB500 after finishing finish rolling.
The intermediate round billet enters a rolling temperature of 970 ℃ of a medium finish rolling continuous rolling unit, the speed of a medium rolling inlet is 1.4m/s, the temperature of the finish rolling inlet is 950 ℃ after the medium rolling is cooled, and the speed of a finish rolling outlet is 13 m/s; and (3) performing finish rolling on the intermediate blank, namely performing two-segmentation rolling on the intermediate blank to obtain a finished product of the bar with the diameter of 22mm, cooling the intermediate blank by water mist, cooling the intermediate blank by using the water mist, and collecting the intermediate blank after the surface temperature of the bar on the cooling bed is reduced to below 320 ℃, and performing fixed-length shearing, collecting and bundling.
Example 5
A. Billet heating
Adopting a section of 165X 165mm, heating a square billet with the billet length of 120000mm and the brand of HRB500 to 1180 ℃ by a heating furnace, preserving heat for 40 minutes, and discharging and rolling.
B. rough rolling
After descaling the billet heated by the heating furnace, entering a roughing mill unit consisting of 2 high-rigidity rolling mill short-stress rolling mills with 0.3m/s in a horizontal-vertical alternating mode and 2 reducing sizing mill units for rolling, and rolling the billet into an intermediate billet with the external dimension of 130mm diameter and high accuracy by 6-pass torsion-free micro-tension rolling in the roughing mill unit. The front 4 frames of rough rolling are rolled by adopting box-ellipse-circle-ellipse hole patterns, the rear 2 frames of circle-circle hole patterns further roll the round intermediate blank rolled by the front 4 frame rolling mill into an intermediate blank with 130mm diameter and high precision external dimension, the allowable deviation of the diameter is +/-0.3 mm, and the non-roundness is less than or equal to 0.4mm.
The initial rolling temperature of rough rolling is 1060 ℃, water spray cooling is carried out after the intermediate billet is taken out of a rough rolling unit, and the surface temperature is cooled to 1010 ℃;
C. Sawing of intermediate round blanks
The rough rolled intermediate billet is sent into a turnover cooling bed by an outlet roller way and a sliding plate roller way with a friction braking sliding plate, the intermediate billet automatically rolls into an intermediate billet collecting groove sawing position formed by the guide rail and a baffle plate by the self weight on the turnover cooling bed by a guide rail with an inclination angle not more than 30 degrees, the head and the tail of the intermediate billet are pressed on the collecting groove guide rail by a compression roller, and the head and the tail of the intermediate billet are cut off by a sawing machine in a static state. Sawing time is 4 seconds, and head and tail sawing is completed. After the completion, the rail baffle falls down, and the sawed intermediate billet automatically rolls into a welding rolling line by means of self weight.
D. welding process of middle round blank
The intermediate blanks after head and tail sawing reversely enter a welding line, are clamped and held by a pinch roll and run at the speed of 1.42m/s, are subjected to online descaling in a nitrogen environment and are welded for 4 seconds under a large amount of flow to form longer intermediate blanks, and after the burrs of the intermediate blanks are removed after the welding, the intermediate blanks are sent into a medium finish rolling continuous rolling mill for rolling through a nitrogen protection roller way.
E. Rolling process of medium finish rolling continuous rolling mill unit
The intermediate billet is welded by a flash welder welding unit to form a longer billet, the longer billet enters a middle finish rolling continuous rolling unit for rolling, 8 stand rolling passes are used for middle rolling, 6 stand rolling passes are used for finish rolling, three-split rolling is used for finish rolling, and a finished product of the hot rolled ribbed steel bar with the diameter of 22mmHRB500 is formed after finish rolling is completed.
The intermediate round billet enters a rolling temperature 990 ℃ of a medium finish rolling continuous rolling mill, the medium rolling inlet speed is 1.42m/s, the medium rolling cooling is carried out, the finish rolling temperature is 960 ℃, and the finish rolling outlet speed is 12.8m/s; the intermediate blank is rolled into a finished product of bars with phi 18mm by three-cutting, the surface temperature of the steel bar is reduced to 850 ℃ after the water mist cooling, and the steel bar is placed on a cooling bed. And (5) cutting to length, collecting and bundling after the surface temperature of the steel bars on the cooling bed is reduced to below 290 ℃.
Example 6
A. Billet heating
Adopting a section of 165X 165mm, heating a square billet with the billet length of 120000mm and the brand of HRB500 to 1200 ℃ by a heating furnace, preserving heat for 30 minutes, and discharging and rolling.
B. rough rolling
After descaling the billet heated by the heating furnace, entering a roughing mill unit consisting of 3 short-stress rolling mills with high rigidity and alternating in parallel and vertical mode and 2 reducing sizing mill units at 0.3m/s for rolling, and rolling the billet into an intermediate billet with high accuracy in external dimension and diameter of 130mmmm by 5-pass torsion-free micro-tension rolling in the roughing mill unit. The front 4 frames of rough rolling are rolled by adopting box-elliptic-circular-elliptic hole patterns, the rear 2 frames of circular-circular hole patterns further roll the circular intermediate blank rolled by the front 3 frame rolling mill into an intermediate blank with the diameter of 130mm and the external dimension highly accurate, the allowable deviation of the diameter is +/-0.30 mm, and the non-roundness is less than or equal to 0.4mm.
The initial rough rolling temperature is 1070 ℃, water spray cooling is carried out after the intermediate billet is taken out of a rough rolling unit, and the surface temperature is cooled to 1000 ℃;
C. Sawing of intermediate round blanks
The rough rolled intermediate billet is sent into a turnover cooling bed by an outlet roller way and a sliding plate roller way with a friction braking sliding plate, the intermediate billet automatically rolls into an intermediate billet collecting groove sawing position formed by the guide rail and a baffle plate by the self weight on the turnover cooling bed by a guide rail with an inclination angle not more than 35 degrees, the head and the tail of the intermediate billet are pressed on the collecting groove guide rail by a compression roller, and the head and the tail of the intermediate billet are cut off by a sawing machine in a static state. Sawing time is 4 seconds, and head and tail sawing is completed. After the completion, the rail baffle falls down, and the sawed intermediate billet automatically rolls into a welding rolling line by means of self weight.
D. welding process of middle round blank
The intermediate blanks after head and tail sawing reversely enter a welding line, are clamped and held by a pinch roll and run at the speed of 1.42m/s, are subjected to online descaling in a nitrogen environment and are welded for 4 seconds under a large amount of flow to form longer intermediate blanks, and after the burrs of the intermediate blanks are removed after the welding, the intermediate blanks are sent into a medium finish rolling continuous rolling mill for rolling through a nitrogen protection roller way.
E. Rolling process of medium finish rolling continuous rolling mill unit
The intermediate billet is welded by a flash welder welding unit to form a longer billet, the longer billet enters a middle finish rolling continuous rolling unit for rolling, 8 stand rolling passes are used for middle rolling, 6 stand rolling passes are used for finish rolling, the finish rolling is four-segment rolling, and the finished product of the hot rolled ribbed steel bar with the diameter of 12mmHRB500,500 after finish rolling is finished.
The intermediate round billet enters a medium finish rolling continuous rolling unit to be rolled at 1000 ℃, the medium rolling inlet speed is 1.42m/s, the medium rolling is cooled, the finish rolling temperature is 970 ℃, and the finish rolling outlet speed is 12m/s; the intermediate blank is rolled into a finished product of bars with phi 12mm by four-cutting, the surface temperature of the steel bar is reduced to 840 ℃ after the water mist cooling, and the steel bar is placed on a cooling bed. Cutting, collecting and bundling the steel bars on cooling bed after the surface temperature of the steel bars is reduced to below 280 DEG C
TABLE 1 comparison of the external dimensions of square billets, intermediate billets and round steels
The HRB400 hot rolled ribbed steel bar produced by the process has the performance shown in the following table 2, the composition shown in the table 3, and the steel bar performance, metallographic structure and hardness are all national standard GB/T1499.2-2016 (section 2 of steel for reinforced concrete): hot rolled ribbed bars.
TABLE 2 HRB500 Rebar Performance Components in examples 1-6
TABLE 3 HRB500 Reinforcement composition in examples 1-6
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention, and are intended to be included within the scope of the appended claims and description.
Claims (6)
1. The economical welding endless rolled bar production line process arrangement comprises a roughing mill group machining line (1) and a middle finishing mill group machining line (2), and is characterized in that the roughing mill group machining line (1) and the middle finishing mill group machining line (2) are in transmission arrangement through an intermediate billet turnover device (3); the middle finishing mill group machining line (2) comprises a welding deburring device (4), a middle rolling mill group (5) and a finishing mill group (6) which are sequentially arranged, wherein the middle rolling group (5) and the finishing mill group (6) form a middle finishing mill continuous rolling group; the production line direction of the rough rolling unit machining line (1) and the middle finishing mill unit machining line (2) is opposite; the roughing mill unit machining line (1) comprises a heating furnace (7), a roughing mill unit (8), a cutting shear (9) and a water cooling device I (10) which are sequentially arranged, wherein the water cooling device I (10) is a turnover cooling bed; the rough rolling unit machining line (1) is higher than the middle finishing mill unit machining line (2), the height difference of the rough rolling unit machining line (1) higher than the middle finishing mill unit machining line (2) is 1.0-1.8 m, the rough rolling unit machining line (2) is arranged on one side of the middle finishing mill unit machining line (2), and the distance between the rough rolling unit machining line (1) and the middle finishing mill unit machining line (2) is 10-16 m; the intermediate blank overturning device (3) comprises a plurality of C-shaped collecting groove lifting baffles (11) which are sequentially arranged along the direction of a processing line, a fixed sawing machine (12) arranged on one side of the C-shaped collecting groove lifting baffles (11) and a movable sawing machine (13) arranged on the other side of the C-shaped collecting groove lifting baffles (11), a compression roller (14) is arranged between the fixed sawing machine (12) and the movable sawing machine (13), and the fixed sawing machine (12) and the movable sawing machine (13) form a sawing machine; the welding burr removal device (4) comprises a phosphorus removal device (15), a mobile flash butt welding machine (16), a burr cleaning device (17) and a gas protection conveying roller way (18) which are sequentially arranged; the gas protection conveying roller way (18) is a nitrogen protection roller way.
2. The economical welding endless rolled bar production line process arrangement according to claim 1, characterized in that the intermediate rolling train (5) comprises a second snap shear (19), a feeding roller (20), a plurality of rolling mills and a plurality of rolling lanes arranged in sequence.
3. The economical welding endless rolled bar production line process arrangement according to claim 2, characterized in that a third snap shear (23) and a first water cooling device (24) are arranged between the finishing train (6) and the intermediate mill train (5), the finishing train (6) comprising a plurality of rolling mills and a plurality of rolling tracks, the rolling mills and rolling tracks in the finishing train (6) being fewer than the rolling mills and rolling tracks in the intermediate mill train (5).
4. A saving type welded endless rolled bar production line process arrangement according to claim 3, characterized in that the outlet end of the finishing mill group (6) is further provided with a second water cooling device (25), a second double shear ruler (26) and a collecting cooling bed (27) in sequence.
5. A method of producing an economical welded endless rolled bar production line process arrangement according to claim 4, comprising the steps of:
step one: heating a billet, namely heating the billet to 1160-1200 ℃ by adopting a square billet with 165-220-200 mm and 8000-14000 mm in length, preserving heat for 30-60 minutes, and discharging and rolling;
Step two: rough rolling, namely enabling the billet heated by the heating furnace to enter a rough rolling unit for rolling, enabling the billet to be subjected to 6-pass torsion-free rolling in the rough rolling unit to form an intermediate billet with the diameter of 130-145 mm and the external dimension of the diameter of the intermediate billet, wherein 4 frames of the intermediate billet are subjected to box-oval-round hole type rolling before rough rolling, and 2 frames of round-round hole type rolling after rough rolling further roll the round intermediate billet rolled by the front frame rolling mill into an intermediate billet with the diameter of 130-145 mm and the external dimension of the intermediate billet being highly accurate; the allowable deviation of the diameter of the intermediate blank is +/-0.30 mm, the out-of-roundness is less than or equal to 0.40mm, and the length is 77-113 m; the initial rolling temperature of the billet is 1020-1080 ℃, the rough rolling inlet speed is 0.26-0.3 m/s, the rough rolling outlet speed is 1.28-1.36 m/s, the water spray cooling is carried out after the intermediate billet is taken out of a rough rolling unit, and the surface temperature is controlled to be 980-1030 ℃;
Step three: the method comprises the steps of (1) sawing an intermediate round billet, wherein an intermediate billet turnover device with the length less than or equal to 115m is arranged between a rough rolling unit and an intermediate rolling unit in rolling, after rough rolling, the intermediate billet is fed into a turnover cooling bed through an outlet roller way and a sliding plate roller way with a friction braking sliding plate, the intermediate billet automatically rolls into an intermediate billet collecting groove formed by a guide rail with the inclination angle less than or equal to 40 degrees and a baffle plate on the turnover cooling bed by means of self weight, compression rollers and sawing machines are arranged at two ends of the collecting groove, the heads and the tails of the intermediate billet are tightly pressed on the guide rail of the collecting groove by the compression rollers, the sawing machines saw the heads and the tails rapidly in a static state, after the sawing time is 4-5 seconds, a rail baffle plate falls down, and the sawed intermediate billet automatically rolls into a welding rolling line by means of self weight;
Step four: the middle round billet is welded, the middle billet after head and tail removal reversely enters a welding line, the middle billet enters a descaling device under the clamping of a pinch roll, and the descaling device performs descaling on the tail part of the first middle billet and the head part of the next middle billet; the movable flash butt welding machine is arranged behind the descaling device, the heads and the tails of two intermediate blanks after descaling are welded on line, the welding is completed in 4-5 seconds under high current, and the burrs of the welding part are removed by the burr removing device after the intermediate blank is welded;
The intermediate billet subjected to welding and burr cleaning enters an inlet roller way protected by a nitrogen heat-preserving cover with the length more than or equal to 115m, and the intermediate billet subjected to sawing head and tail, welding and burr removal stably enters a medium finish rolling continuous rolling mill group for rolling under the clamping of a pinch roll; the descaling, welding and burr cleaning device and the medium finish rolling continuous rolling unit are arranged on a medium finish rolling continuous rolling inlet roller way, and the length of the inlet roller way is more than or equal to 230 meters; during the descaling, welding and burr cleaning processes of the intermediate blank, nitrogen or other protective gases are adopted for protection, so that the surface of the high-temperature intermediate blank is prevented from being exposed in the air and being rapidly oxidized during the descaling process, and the influence of oxide skin on the welding quality and the performance of the welding part of the steel bar during the welding process is avoided;
Step five: rolling the intermediate round billet in an intermediate finish rolling continuous rolling unit at 950-1000 ℃, after intermediate rolling and cooling, feeding the intermediate round billet into the intermediate finish rolling continuous rolling unit at 940-980 ℃, wherein the intermediate rolling inlet speed is 1.32-1.42 m/s, and the finish rolling outlet speed is 5.4-13.8 m/s; the rolled piece is rolled into a bar finished product through finish rolling, the bar finished product is cooled by a first water cooling device and then is put into a second water cooling device, the surface temperature of a cooling bed of the second water cooling device is 840-930 ℃, and the bar surface temperature is reduced to below 360 ℃ and is collected and then cut to length, collected and bundled.
6. The method according to claim 5, wherein the rolling of the intermediate rolling mill and the rough rolling mill are not performed on the same rolling line, the blank is rolled to meet the size and the precision of the finished product, and the rolling piece is continuously and tensionless rolled through the inter-rolling mill loopers; the horizontal and vertical convertible rolling mill is used horizontally during split rolling; a looper is arranged between each two frames of the finish rolling to perform torsion-free tension-free rolling on a rolled piece, a pre-water cooling box is arranged in front of the finish rolling mill and used for controlling the temperature of the rolled piece entering the finish rolling unit to realize temperature control rolling, the rolled steel bars of the middle finishing rolling unit are sent to a second double shear ruler to be sheared in sections, ribbed steel bars of phi 12mm and phi 14mm are produced by adopting a four-splitting process, ribbed steel bars of phi 16 and phi 18mm are produced by adopting a three-splitting process, and ribbed steel bars of phi 20 and phi 22mm are produced by adopting a two-splitting process; the ribbed steel bars with phi 25 and phi 50mm are produced by adopting a single-wire rolling process.
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| GB472804A (en) * | 1937-03-24 | 1937-09-30 | Julius Doubs | Improvements in and relating to the hot rolling of wide metallic bands |
| IT1288849B1 (en) * | 1996-02-12 | 1998-09-25 | Danieli Off Mecc | PERFECTED PROCEDURE FOR THE LAMINATION OF LONG PRODUCTS AND THE LAMINATION LINE THAT PERFORMS THIS PROCEDURE |
| DE19618437A1 (en) * | 1996-05-08 | 1997-11-13 | Schloemann Siemag Ag | Method for operating a roll stand system |
| EP0893168B1 (en) * | 1997-07-23 | 2002-05-22 | SMS Demag AG | Method for producing hot strip of 0.5 mm thickness in a hot strip mill |
| CN1883835A (en) * | 2005-06-20 | 2006-12-27 | 中冶东方工程技术有限公司 | Method for producing coiled sheet by continuous casting and tandem rolling of regular slab |
| CN102247981B (en) * | 2011-06-01 | 2013-06-26 | 中冶赛迪工程技术股份有限公司 | Structural steel rolling production line and production process thereof |
| WO2013046345A1 (en) * | 2011-09-28 | 2013-04-04 | 三菱日立製鉄機械株式会社 | Hot rolling facility |
| AT512399B1 (en) * | 2012-09-10 | 2013-08-15 | Siemens Vai Metals Tech Gmbh | Method for producing a microalloyed tubular steel in a cast-rolled composite plant and microalloyed tubular steel |
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