Groove tonnage lifting method based on double-bar production line

Abstract

The invention relates to a method for increasing the tonnage of a rolling groove based on a double-bar production line, which specifically comprises the following steps of: 1, redesigning the shape of the rolling groove of the third sort, and increasing the width of the bottom of the rolling groove to 154mm under the condition that the height of the rolling groove of the third sort is kept at 88mm, and 2, increasing the width of the bottom of the rolling groove to 154mm according to the change of the shape of the rolling groove of the third sort. The roll gap value of the third sortie is increased from 12 mm to 18 mm; the red blank ruler is adjusted to be 147mm * 88mm in oval size; the ejection speed of the third sortie is adjusted to 0.56 m / s; 3, the roll gap value of the fourth sortie is increased to 14 mm from 13 mm, and the red blank ruler is adjusted to be in the oval size of 106 mm * 105 mm; the ejection speed of the fourth sortie is adjusted to be 0.76 m / s; 4, calculating an R factor according to the sectional area of the rolling groove hole of the third sortie and the R factor of each rolling groove of the first sortie to the fourth sortie. According to the method, the deformation of each sortie can be reasonably distributed, and the impact of the steel billet on the rolling grooves is reduced; the cooling level of the rolling groove is improved, and the abrasion of the rolling groove is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of bar production, and in particular relates to a method for increasing the rolling groove tonnage based on a double-bar production line. Background Art

[0002] In the steel production industry, the bar production line is one of the key equipment for manufacturing various types of bar-shaped steel products. In order to improve production efficiency and product quality, many enterprises have introduced advanced production equipment and processes from abroad. The company's existing double bar production line is a typical representative of such advanced equipment. The production line was completed and put into production in 2006. Each production line is equipped with 18 rolling mills, which adopt horizontal and vertical alternating layout to achieve non-twisting full continuous rolling. The designed annual output is 750,000 tons (two lines in total), and the maximum rolling speed can reach 18 meters per second, which can meet the market's large demand for high-quality bars.

[0003] However, during the production process, we encountered a significant technical problem: the wear resistance and service life of the rolling grooves were insufficient. In particular, when producing bars with raw material specifications of 160×160×12000mm and 150×150×12000mm, the 1-4# rolling mills in the rough rolling stage use a common pass type, and the rolling grooves are under great load during use. At present, the tonnages of 1-4# rolling grooves are 20,000 tons, 20,000 tons, 18,000 tons and 14,000 tons respectively, among which the 4# rolling groove is particularly prone to the situation that it does not reach the rated tonnage and needs to be replaced due to severe wear.

[0004] This frequent groove replacement brings about many adverse effects. First, it increases downtime and reduces the operating rate of the production line. The current production operating rate is only maintained at about 80%. Secondly, the replacement of the groove increases the labor intensity of employees, posing a challenge to production efficiency and employee health. What is more serious is that after each groove replacement, the tension between the rolling mills needs to be readjusted. This process is prone to produce defective products such as oversized, ears, and week errors, resulting in a low product qualification rate of only 98.70%. In addition, frequent groove changes cause frequent changes in the rolling state, increase the risk of steel pile accidents, and pose a threat to production safety and equipment stability.

[0005] Therefore, there is an urgent need for an effective method to increase the tonnage of the rolling groove, reduce the number of times the rolling groove is replaced, and improve the operating rate of the production line and the qualified rate of the product.

[0006] After in-depth research and analysis, we found that by changing the groove pass of the third run, reasonably allocating the reduction, and optimizing the size of the red billet of each run, the load of the groove can be effectively reduced, thereby achieving the goal of increasing the tonnage of the groove. The implementation of this method is expected to significantly improve the problems existing in the existing production line, improve production efficiency and product quality, and reduce production costs and safety risks. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a method for increasing the use tonnage of rolling grooves, reducing the number of times the rolling grooves are replaced, and improving the operation rate of the production line and the qualified rate of products. To this end, it involves a method for increasing the tonnage of rolling grooves based on a double bar production line.

[0008] The present invention is implemented as follows: a method for increasing the rolling groove tonnage based on a double bar production line, characterized in that:

[0009] Step 1: Redesign the groove pass of the third run. While maintaining the groove height of the third run at 88mm, increase the groove bottom width to 154mm.

[0010] Step 2: According to the change of the groove pass of the third run, the roll gap value of the third run is increased to 18 mm; the red billet size is adjusted to an elliptical size of 147 mm × 88 mm; the billet discharge speed of the third run is adjusted to 0.56 m / s;

[0011] Step 3: Increase the roll gap value of the 4th batch from 13mm to 14mm, adjust the red blank size to an elliptical size of 106mm×105mm; adjust the billet discharge speed of the 4th batch to 0.76m / s;

[0012] Step 4: Calculate the R factor based on the cross-sectional area of ​​the groove profile of the third run;

[0013]

[0014] The above table shows the roll gap, blank size, speed and R factor corresponding to each rolling groove in the 1st to 4th runs.

[0015] Further preferably, the spray angles of the cooling nozzles on the cooling main pipes of all the rolls are adjusted so that the spray angles of the cooling nozzles are arranged to gradually increase in the direction opposite to the rotation direction of the rolls.

[0016] Further preferably, each group of cooling nozzles includes two parallel nozzles with the same spray angle and a nozzle located below the two parallel nozzles.

[0017] Further preferably, the spray angle of the uppermost group of cooling nozzles is 15°; the spray angle gradually increases in the direction opposite to the rotation direction of the roller, and increases in increments of 8-15°.

[0018] The technical effects of the present invention are summarized as follows:

[0019] Optimization of the groove hole profile: By redesigning the groove hole profile of the third run and widening the groove bottom width, the bulge (ear) generated at the roll gap when the material fluctuates is effectively reduced, the impact on the arc of the 4# groove is reduced, deep grooves, block falling and other phenomena are avoided, and stable rolling is achieved.

[0020] Adjustment of rolling parameters: According to the changes in the rolling groove profile, the roll gap value, red billet size and billet discharge speed of the 3rd and 4th passes were adjusted to make the rolling process smoother and improve the rolling efficiency.

[0021] R-factor calculation and application: By calculating the R-factor of each batch, data support is provided for the optimization of the rolling process, which helps to further improve the rolling effect.

[0022] Extended service life of the rolling groove: As the material size of the rolling groove increases, the roll gap needs to be continuously pressed down to maintain its size. The design of enlarged roll gap can provide more sufficient space for pressing down, and increase the tonnage of the rolling groove (when the roll gap is pressed to 0, it cannot be pressed down and must be replaced). By redistributing the pressing amount of each batch, the deformation of the rolling groove of each batch is made more uniform. At the same time, the cooling system is optimized, the cooling effect of the rolling groove is improved, and the service life of the rolling groove is significantly increased, especially the service life of the 4# rolling groove is increased by 3 times.

[0023] Improved operating rate and qualified rate: The implementation of the present invention increases the operating rate to 91% and the qualified rate to 99.97%, greatly improving production efficiency and product quality.

[0024] In summary, the present invention significantly improves the service life, operation rate and qualified rate of the rolling groove by optimizing the rolling groove hole design, adjusting the rolling parameters, calculating the R factor and improving the cooling system, providing an effective method for improving the rolling groove tonnage of the double bar production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of the roller cooling main pipe of the present invention;

[0026] Figure 2 yes Figure 1 Middle AA section view;

[0027] Figure 3 yes Figure 1 Middle BB section view;

[0028] Figure 4 This is a schematic diagram of the installation position of the roller cooling main pipe.

[0029] In the figure, 1. Roller cooling main pipe; 2. Cooling nozzle. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] A method for increasing the rolling groove tonnage based on a double bar production line, characterized in that:

[0032] Step 1: Redesign the groove pass of the third run. While the groove height of the third run is maintained at 88mm, the groove bottom width is increased from 147mm to 154mm. The original pass design is easy to fill, and when the material fluctuates, it is easy to produce bulges (ears) at the roll gap, which impacts the arc of the 4# groove, accelerates wear, and causes deep grooves and block drop in severe cases. The newly designed pass completely absorbs the fluctuation of the pass, always reproduces the arc state in the widened part, is easy to bite into the 4# groove, and achieves stable rolling.

[0033] Step 2: According to the change of the groove pass of the third run, the roll gap value of the third run is increased from 12mm to 18mm; the red billet size is adjusted from the original 140mm×88mm circular size to 147mm×88mm elliptical size; the billet discharge speed of the third run is adjusted to 0.56m / s;

[0034] Step 3: Increase the roll gap value of the 4th batch from 13mm to 14mm, and adjust the red blank size from the original 105mm×105mm circular size to 106mm×105mm elliptical size; adjust the billet discharge speed of the 4th batch to 0.76m / s;

[0035] Step 4: Calculate the R factor based on the cross-sectional area of ​​the groove profile of the third run;

[0036]

[0037] The above table shows the roll gap, blank size, speed and R factor corresponding to each rolling groove in the 1st to 4th runs.

[0038] Preferably, the spray angles of the cooling nozzles 2 on the cooling main pipes 1 of all the rolls are adjusted so that the spray angles of the cooling nozzles are arranged gradually in the opposite direction of the roll rotation direction. Preferably, each group of cooling nozzles includes two parallel nozzles with the same spray angle and a nozzle located below the two parallel nozzles. The incremental arrangement uses a "double-single" alternating arrangement of the main water pipe nozzles to cool the rolling groove, increase the contact time between the cooling water and the roll, and reduce water splashing, greatly improving the cooling effect.

[0039] Further preferably, the spray angle of the uppermost group of cooling nozzles is 15°; the spray angle gradually increases in the direction opposite to the rotation direction of the roller, and increases in increments of 8-15°.

[0040] By analyzing the existing hole configuration and actual use of the rolling groove, the hole shape of the 3# rolling groove was redesigned, and the groove bottom was widened by 7mm to reduce the impact on the arc part of the 4# rolling groove; the reduction amount of each frame was redistributed to make the deformation of the rolling groove of each frame more uniform; the cooling system was redesigned to increase the contact time between the cooling water and the rollers, while reducing water splashing, greatly improving the cooling effect of the rolling groove.

[0041] To further optimize the cooling effect, a cooling and dust removal device for a rod and wire rolling production line recorded in the prior application CN202020423796.2 of the applicant is installed on the exit guide box, and is directly opposite to the gap between the exit guide box and the rolling groove; it includes a basic frame welded from a square tube with a hollow structure, and the basic frame includes a water inlet main pipe, an upper spray pipe, a lower spray pipe, and a bypass branch pipe; one end of the water inlet main pipe is connected to the water inlet connector, and two upper spray heads are symmetrically installed on the upper spray pipe; the lower spray pipe is connected to the water inlet main pipe through a bypass branch pipe, and two lower spray heads are installed on the lower spray pipe; the two upper spray heads and the two lower spray heads are inclined toward the gap between the exit guide box and the rolling groove.

[0042] Embodiment 1

[0043] Production specifications: Round Steel

[0044] Steel grade: 20, Q235B

[0045] Rolling mills in use: 1st to 12th

[0046] Table 1 Round steel rolling schedule

[0047]

[0048]

[0049] Continuous output: 45,000 tons

[0050] This rolling process uses 160mm steel produced by the company's steelmaking plant. 2×11400mm billet, in accordance with the standard YB / T2011-2014, is heated in the heating furnace to the rolling temperature of 1030-1050℃, and then goes through the rough rolling of the 1st to 6th rolling mills, and then goes through the 1# swing shear head and enters the 7th to 12th rolling mills for rolling, and finally produces the finished product size, and then goes through the 120-meter cooling bed for natural cooling, and is sheared to a fixed length of 9 meters and then packaged and collected in fixed bundles. During the production process, the tension of each batch is stable, and the test results of the produced round steel products are qualified, with a qualified rate of 99.97% and a finished product rate of 98.63%. The final statistics of the amount of steel passed in each rolling groove are as follows in Table 2:

[0051] Flights Rated tonnage (tons) Actual maximum tonnage of a single tank (tons) 1 20000 25000 2 20000 24000 3 16000 26000 4 14000 40100 5 12000 16000 6 11000 17000 7 12000 16500 8 10000 15700 9 9000 15700 10 8000 14650 11 5500 7200 12 4500 4430*

[0052] It can be seen from Table 2 that the actual tonnage of each unit has increased significantly compared with the rated tonnage, especially the tonnage of the four rolling mills has increased from 14,000 to 40,100 tons, an increase of more than 3 times.

[0053] *In order to ensure the surface quality of round steel products, it is stipulated that the finished product rolling groove is not allowed to exceed the rated tonnage.

[0054] Embodiment 2

[0055] Production specifications: Round Steel

[0056] Steel grade: 20, 45

[0057] Rolling mills in use: 1st to 10th

[0058] Table 3: Round steel rolling schedule

[0059]

[0060] Continuous output: 41,000 tons

[0061] This rolling process uses 160mm steel produced by the company's steelmaking plant. 2 ×11400mm billet, in accordance with the standard YB / T2011-2014, is heated in the heating furnace to the rolling temperature of 1030-1050℃, and then goes through the rough rolling of the 1st to 6th rolling mills, and then goes through the 1# swing shear head to the 7th to 12th rolling mills, and finally produces the finished product size, and then goes through the 120-meter cooling bed for natural cooling, and then cuts to length for 9 meters and then packs and collects in fixed bundles. During the production process, the tension of each batch is stable, and the test results of the produced round steel products are qualified, with a qualified rate of 99.98% and a finished product rate of 98.85%. The final statistics of the amount of steel passed in each rolling groove are as follows in Table 4:

[0062]

[0063]

[0064] It can be seen from Table 4 that the actual tonnage of each unit has increased significantly compared with the rated tonnage, especially the tonnage of the four rolling mills has increased from 14,000 to 41,000 tons, an increase of more than 3 times.

[0065] *In order to ensure the surface quality of round steel products, it is stipulated that the finished product rolling groove is not allowed to exceed the rated tonnage.

[0066] In summary, the present invention can reasonably distribute the deformation amount of each frame, reduce the impact of the steel billet on the rolling groove, improve the cooling level of the rolling groove, and reduce the wear of the rolling groove.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for increasing the rolling groove tonnage based on a double bar production line, characterized in that: The steps include: Step 1: Redesign the groove pass of the third run. While maintaining the groove height of the third run at 88mm, increase the groove bottom width to 154mm. Step 2: According to the change of the groove pass of the third run, the roll gap value of the third run is increased to 18 mm; the red billet size is adjusted to an elliptical size of 147 mm × 88 mm; the billet discharge speed of the third run is adjusted to 0.56 m / s; Step 3: Increase the roll gap value of the 4th batch from 13mm to 14mm, adjust the red blank size to an elliptical size of 106mm×105mm; adjust the billet discharge speed of the 4th batch to 0.76m / s; Step 4: Calculate the R factor based on the cross-sectional area of ​​the groove profile of the third run. The above table shows the roll gap, blank size, speed and R factor corresponding to each rolling groove in the 1st to 4th runs.

2. The method for increasing the rolling groove tonnage based on a double bar production line according to claim 1, characterized in that: Adjust the spray angles of the cooling nozzles on the cooling main pipes of all the rolls so that the spray angles of the cooling nozzles are gradually increased and arranged in the opposite direction of the roll rotation direction.

3. The method for increasing the rolling groove tonnage based on a double bar production line according to claim 2, characterized in that: Each group of cooling nozzles includes two parallel nozzles with the same spray angle and a nozzle located below the two parallel nozzles.

4. The method for increasing the rolling groove tonnage based on a double bar production line according to claim 2, characterized in that: The spray angle of the cooling nozzles at the top is 15°; the spray angle gradually increases in the opposite direction of the roller rotation direction, increasing by 8-15°.

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