Method for forming a h-beam by rolling a shaped intermediate blank

Abstract

The application provides a forming method of shaped intermediate blank rolling H-shaped steel, and belongs to the technical field of rolling steel, which is used for rolling shaped intermediate blanks into H-shaped steel products by using a tandem reversible rolling mill group; the forming method comprises the following steps: determining the rolling pass number N according to the size of the H-shaped steel product and the size of the shaped intermediate blank, and the UR reduction, the ED reduction and the UF reduction of each rolling pass; the rolling piece is positively passed through the rolling mill group from the UR side to complete the first rolling pass; the rolling piece is reversely passed through the rolling mill group from the UF side to complete the second rolling pass; the rolling is repeated until the last rolling pass is positively completed; wherein, in at least the first rolling pass, the ED reduction is zero, and the ED reduction of each reversely completed rolling pass is non-zero. The forming method of shaped intermediate blank rolling H-shaped steel provided by the application can solve the bulging problem of the inner side of the flange of the rolling piece, thereby eliminating the abnormal wear of the side wall of the UF roller, and is beneficial to improving the service life of the roller.

Description

Technical Field

[0001] This invention belongs to the field of steel rolling technology, specifically relating to a method for forming H-beams from irregularly shaped intermediate billets. Background Technology

[0002] H-beams are irregularly shaped steel sections. During rolling, various factors such as irregular cross-sections, uneven temperature distribution, and uneven metal flow between the web and flanges can lead to significant uneven deformation in different sections. The H-beam rolling process typically uses a tandem reversible rolling mill (universal roughing mill UR, intermediate edging mill ED, and universal finishing mill UF arranged in sequence). Because the flanges of the irregularly shaped intermediate billet have a slope after roughing, metal bulges are easily formed on the inner side of the flanges when entering the ED pass. Subsequently, when passing through the UF pass, the flanges of the billet, in addition to bearing the predetermined reduction, also need to provide additional rolling for the bulges, resulting in abnormal wear of the sidewalls of the UF rolls and seriously affecting the service life of the UF rolls. Summary of the Invention

[0003] This invention provides a method for forming H-beams from irregularly shaped intermediate billets, aiming to reduce roll wear in finishing rolling passes and improve roll service life.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a forming method for rolling H-beams from irregularly shaped intermediate billets is provided, which is used to roll irregularly shaped intermediate billets, which are used as rolling works, into finished H-beams using a tandem reversible rolling mill. The irregularly shaped intermediate billet has a lug formed during the billet opening process in the middle of the outer side of the flange. The tandem reversible rolling mill includes a UR rolling mill, an ED rolling mill, and a UF rolling mill arranged sequentially along the conveyor roller table. The molding method includes the following steps: S100. Determine the number of rolling strokes N, UR reduction, ED reduction, and UF reduction for each rolling stroke based on the dimensions of the finished H-beam and the dimensions of the irregular intermediate billet. S200: The rolled piece is passed sequentially from the UR side through the UR rolling mill, ED rolling mill and UF rolling mill to complete the first rolling stroke in the forward direction; S300: The rolled piece is passed sequentially from the UF side through the UF rolling mill, ED rolling mill and UR rolling mill, and the second rolling stroke is completed in reverse. S400, repeat rolling until the Nth rolling stroke is completed in the forward direction, N≥3 and N is an odd number; Among them, the UR mill adopts the X rolling method and the UF mill adopts the H rolling method. At least in the first rolling stroke, the ED reduction is zero, and the ED reduction in each even-numbered rolling stroke is non-zero.

[0005] In one possible implementation, each rolling pass includes UR passes and UF passes, with a total of 2N rolling passes; step S100 includes: S101. According to the web reduction schedule, the web reduction rate for each pass is determined by working backward from the web thickness of the finished H-beam to the web thickness of the intermediate billet. The number of rolling passes N is then determined based on the web reduction rate for each pass. The web reduction schedule is as follows: the reduction rate for the first two passes is less than 20%, the reduction rate increases from the first to the third pass, and the reduction rate decreases from the third to the 2Nth pass.

[0006] In some embodiments, the web reduction procedure also includes: a web reduction rate of ≤32% per pass.

[0007] In some embodiments, step S100 further includes: S102. Determine the flange reduction ratio for each track according to the flange reduction ratio specification; wherein, the flange reduction ratio specification is: satisfy the web reduction ratio specification, and the flange reduction ratio for each track is greater than the web reduction ratio.

[0008] For example, the difference between the flange reduction ratio and the web reduction ratio in each pass is 2% to 4%.

[0009] In one possible implementation, step S100 further includes: S103. Except for the ED reduction of zero, the reduction of the ED in all other ED courses is greater than the reduction of the flange in the previous course.

[0010] For example, the flange reduction of the ED pass is 2-7 mm greater than that of the previous pass.

[0011] In some embodiments, the horizontal rolls of the UR mill have a side slope that gradually thins from the center to the edge, and the roll diameter of the vertical rolls of the UR mill gradually decreases from the center to both ends to form a circumferential slope; wherein, the middle part of the circumferential surface of the vertical rolls of the UR mill is rolled on a lug, and the side slope is smaller than the inner slope of the flange of the irregular intermediate billet.

[0012] For example, the side slope is 2 to 5 degrees less than the slope of the inner side of the flange of the rolled piece.

[0013] For example, a UF mill is equipped with a cooling water channel that sprays cooling water toward the sides of its horizontal rolls.

[0014] The beneficial effects of the forming method for rolling H-beams from irregularly shaped intermediate billets provided by the present invention are as follows: Compared with the prior art, the forming method for rolling H-beams from irregularly shaped intermediate billets of the present invention uses a tandem reversible rolling mill to roll the irregularly shaped intermediate billet. During the rolling process, the UR rolling mill adopts the X rolling method, which only presses down the web and the root of the flange. The flange ends are in an unconstrained and freely extending state. At the same time, it can also apply directional extrusion force to the lug area of ​​the irregularly shaped intermediate billet, forcing the metal in the lug area to extend evenly to the upper and lower sides along the flange height direction. The plastic deformation of the lug area is completely concentrated in the outer flange area, thereby reducing the accumulation of metal at the root where the flange and web meet.

[0015] Based on this, the first rolling pass eliminates the forced pressing of the flange ends by the ED, which allows the metal at the flange ends to flow freely along the flange height direction. This avoids bulging on the inner side of the flange of the rolled piece caused by the ED pass. Subsequent UF passes only need to use the H rolling method for shaping, without the need for additional forced flattening of the bulge. As a result, not only can abnormal wear on the sidewalls of the UF rolls be eliminated and the service life of the UF rolls be improved, but it is also beneficial to improve the uniformity of the flange cross-section deformation, thereby improving the forming quality of H-beam products. Attached Figure Description

[0016] Figure 1 A step-by-step flowchart of the method for forming H-beams from irregularly shaped intermediate billets provided in this embodiment of the invention. Figure 1 ; Figure 2 A step-by-step flowchart of the method for forming H-beams from irregularly shaped intermediate billets provided in this embodiment of the invention. Figure 2 ; Figure 3 A schematic diagram of the roll structure of a tandem reversible rolling mill used in the forming method of rolling H-beams from irregularly shaped intermediate billets provided in the embodiments of the present invention; Figure 4 A schematic diagram of the cooperation structure between the rolls of the UR mill and the shaped intermediate billet in the forming method of rolling H-beams from shaped intermediate billets provided in the embodiments of the present invention; Figure 5 A schematic diagram of the rolling process for the forming method (five-pass rolling) of H-beams from irregularly shaped intermediate billets provided in an embodiment of the present invention; Figure 6 A schematic diagram of the reduction rate for the forming method (five rolling passes) of rolling H-beams from irregularly shaped intermediate billets provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of the rolling process of H-beams in the prior art; Figure 8 To adopt Figure 5 The diagram shows a bulge appearing on the inner side of the flange of the rolled piece during the rolling process.

[0017] In the figure: 10, UR mill; 11, horizontal rolls of UR mill; 12, vertical rolls of UR mill; 20, ED mill; 30, UF mill; 40, irregular intermediate billet; 41, lug. Detailed Implementation

[0018] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0019] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0020] It should be understood that UR, ED, and UF mentioned in this application refer to the corresponding rolling mill types, which are specific names for rolling mills in this field and should not be construed as having any other meaning. Specifically, UR (abbreviation for Universal Roughing) is a universal roughing mill, which is the core of a tandem reversible rolling mill unit. It is equipped with a pair of active horizontal rolls and a pair of driven vertical rolls, and is mainly responsible for rough rolling to reduce the web thickness and flange thickness of irregularly shaped intermediate billets, completing the preliminary section forming. ED (abbreviation for Edge-Dressing) is an edge-dressing mill, which is a two-roll structure, specifically used for trimming the flange ends of H-beams to precisely control the flange height of the rolled piece. UF (abbreviation for Universal Finishing) is a universal finishing mill, which is also composed of horizontal and vertical rolls, and is responsible for the final high-precision shaping of the rolled piece to ensure that the web and flange dimensions of the finished H-beams meet the requirements.

[0021] It should be noted that a rolling pass is considered to be completed when a workpiece passes through a UR or UF rolling mill once, and a rolling stroke is considered to be completed when a workpiece passes through a tandem reversible rolling mill group once. Therefore, a rolling stroke includes two rolling passes: UR and UF.

[0022] It should be understood that both reduction amount and reduction rate reflect the degree of rolling. Specifically, pass reduction amount refers to the dimensional difference of the workpiece before and after passing through a single pass, while pass reduction rate refers to the percentage of pass reduction amount relative to the workpiece's original size before passing through that pass. Similarly, rolling stroke reduction amount refers to the dimensional difference of the workpiece before and after passing through a single rolling stroke, while rolling stroke reduction rate refers to the percentage of rolling stroke reduction amount relative to the workpiece's original size before passing through that rolling stroke.

[0023] In addition, during the rolling process of irregularly shaped intermediate billets, since the total reduction of the web and the total reduction of the flange are not the same, the reduction of the web and the reduction of the flange can vary for each rolling stroke and even for each pass, so as to ensure that the dimensions of the web and the flange meet the requirements at the same time after the last pass.

[0024] It should be noted that during the process of rough rolling red steel into irregularly shaped intermediate billets, metal flows into the roll gap of the rolling mill rolls. Therefore, the two outer sides of the irregularly shaped intermediate billet have a raised lug, which is a lug. The outer side of the flange of the finished H-beam is a smooth plane. Therefore, during the rolling process of the irregularly shaped intermediate billet, it is necessary to flatten the lug area.

[0025] It should be noted that X-rolling refers to the process of using the shapes of horizontal and vertical rolls to drive the rolled piece into a shape close to "X", while H-rolling uses the forced constraints of horizontal and vertical rolls to drive the rolled piece into an "H" shape. Both X-rolling and H-rolling are commonly used processes in this field and will not be elaborated further here.

[0026] In related technologies, the process of rolling irregular intermediate billets into H-beam products usually adopts a tandem reversible rolling mill (UR, ED, UF in series). UR uses the X rolling method, and UF uses the H rolling method, forming an overall X-H rolling process. The ED between UR and UF is used to apply pressure to the flange ends to limit the flange height.

[0027] Because H-beams are irregularly shaped sections, the temperature distribution across the cross-section is uneven during rolling, and the metal flow between the web and flanges is also uneven. Therefore, uneven deformation is inevitable in various parts during the forming process. In particular, the inner slope of the flange of the irregularly shaped intermediate billet is greater than the side slope of the horizontal rolls of the UR rolls. When the workpiece first bites into the UR rolls, the sides of the rolls do not effectively constrain the flange ends. Figure 4 As shown, therefore, during the subsequent ED edge rolling, when there is a large rolling pressure, a noticeable bulge area will appear on the inner side of the flange of the rolled piece, such as... Figure 8 As shown; subsequently, when the rolled piece with bulges enters the UF mill, the horizontal rolls of the UF mill, in addition to pressing down the flange ends, also need to use the sides of the horizontal rolls to perform an additional pressing action on the bulge area, which leads to abnormal wear on the sidewalls of the UF rolls. Unlike the wear of the roll body circumference, which can be repaired by turning the roll diameter, the wear of the roll sidewalls cannot be restored to its shape by re-turning. Therefore, sidewall wear has a significant impact on roll life.

[0028] Actual production data shows that the annual downtime for roll wear repair accounts for 0.64% of the total production time, with an average monthly repair time of about 335 minutes, involving more than forty roll specifications, which seriously affects production efficiency and roll life.

[0029] For information on abnormal wear of UF rolls, please refer to the following: Figures 1 to 8 The forming method for rolling H-beams from a shaped intermediate billet 40 provided by the present invention will now be described. The forming method for rolling H-beams from a shaped intermediate billet 40 involves using a tandem reversible rolling mill to roll the shaped intermediate billet 40, which serves as a workpiece, into a finished H-beam. The shaped intermediate billet 40 has a lug 41 formed during the initial billet opening at the center of its outer flange. The tandem reversible rolling mill includes a UR rolling mill 10, an ED rolling mill 20, and a UF rolling mill 30 arranged sequentially along the conveyor roller table.

[0030] The forming method for rolling H-beams from irregularly shaped intermediate billets provided in this embodiment includes the following steps: S100. Determine the number of rolling strokes N, UR reduction, ED reduction, and UF reduction for each rolling stroke based on the dimensions of the finished H-beam and the dimensions of the irregular intermediate billet 40. S200: The rolled piece is passed sequentially from the UR side through the UR rolling mill 10, the ED rolling mill 20 and the UF rolling mill 30 to complete the first rolling stroke in the forward direction; S300, the rolled piece is passed sequentially from the UF side through the UF rolling mill 30, the ED rolling mill 20 and the UR rolling mill 10, and the second rolling stroke is completed in reverse; S400, repeat rolling until the Nth rolling stroke is completed in the forward direction, N≥3 and N is an odd number; Among them, the UR mill 10 adopts the X rolling method, and the UF mill 30 adopts the H rolling method. At least in the first rolling stroke, the ED reduction is zero, and the ED reduction in each even-numbered rolling stroke is non-zero.

[0031] It should be noted that, for the number of rolling passes N, firstly, N should be an odd number to ensure that the last rolling pass is completed in the forward direction, and the UF pass ensures the dimensional accuracy of the H-beam product; secondly, the value of N should be selected based on the total reduction, with a minimum selection of three, that is, the complete rolling process should have no less than two forward rolling passes and one reverse rolling pass. Of course, the larger the total reduction, the higher the value of N. In most cases, five or seven rolling passes are usually sufficient to ensure that each pass can obtain the ideal reduction / reduction rate.

[0032] In this embodiment, if N=3, then only the ED reduction in the first rolling pass is zero. If N≥5, then the ED reduction in both the first and third rolling passes is zero. Zero ED reduction can be understood as the roll gap being completely open when the workpiece passes through the ED mill 20, with no contact between the rolls and the workpiece. In all even-numbered rolling passes, such as the second and fourth passes, and in odd-numbered rolling passes (which are the last), the ED reduction is non-zero; that is, in these rolling passes, the ED mill 20 performs edge rolling on the workpiece according to a determined ED reduction.

[0033] Since the workpiece in even-numbered rolling passes first passes through the UF mill 30 and then the ED mill 20, which is a reverse rolling process, and the UF mill 30 has a shaping effect on the flange of the workpiece, unlike the UR mill 10 where the roll side does not contact the flange edge, when passing through the UF mill 30, the flange slope of the workpiece can be eliminated because the roll gap is H-shaped. When the workpiece passes through the ED mill 20, the flange is only deformed in the height direction and will not bulge on the side. Therefore, all even-numbered rolling passes can properly edge the workpiece, thereby preventing the excessive flange reduction per pass due to too few ED passes.

[0034] The forming method for rolling H-beams from the irregular intermediate billet 40 provided in this embodiment, compared with the prior art, uses a tandem reversible rolling mill to roll the irregular intermediate billet 40. During the rolling process, the UR rolling mill 10 adopts the X rolling method, which only presses down the web and flange root, leaving the flange end in an unconstrained free extension state. At the same time, it can also apply directional extrusion force to the lug 41 area of ​​the irregular intermediate billet 40, forcing the metal in the lug 41 area to extend evenly to the upper and lower sides along the flange height direction. The plastic deformation of the lug 41 area is completely concentrated in the outer flange area, thereby reducing the accumulation of metal at the root where the flange and web meet.

[0035] Based on this, the first rolling pass eliminates the forced pressing of the flange ends by the ED, which allows the metal at the flange ends to flow freely along the flange height direction. This avoids bulging on the inner side of the flange of the rolled piece caused by the ED pass. Subsequent UF passes only need to use the H rolling method for shaping, without the need for additional forced flattening of the bulge. As a result, not only can abnormal wear on the sidewalls of the UF rolls be eliminated and the service life of the UF rolls be improved, but it is also beneficial to improve the uniformity of the flange cross-section deformation, thereby improving the forming quality of H-beam products.

[0036] In some embodiments, see Figure 2 and Figure 6 Each rolling pass includes UR passes and UF passes, with a total of 2N rolling passes; step S100 includes: S101. According to the web reduction procedure, the web thickness of the finished H-beam is used to extrapolate to the web thickness of the shaped intermediate billet 40 to determine the web reduction rate for each pass, and the number of rolling passes N is determined based on the web reduction rate for each pass. The web reduction procedure is as follows: the reduction rate for the first two passes is less than 20%, the reduction rate increases from the first pass to the third pass, and the reduction rate decreases from the third pass to the 2Nth pass.

[0037] The first two passes are mainly used to correct the dimensional deviation of the incoming material. To ensure that the incoming material can be bitten in smoothly, the reduction rate should not be too large, especially for the first pass, where the reduction rate can be selected in the range of 5% to 10%. The second pass can be appropriately increased, with a reduction rate higher than that of the first pass but lower than 20%. The 2Nth pass, as the last pass, is mainly used to obtain the molded size. To ensure accuracy, the reduction rate should not be too large, and it can be selected to be below 10%. The intermediate passes are mainly responsible for shaping.

[0038] After determining the reduction rates for the first, second, and 2Nth passes, the value of N is determined. Then, starting from the 2N-1th pass to the third pass, the reduction rates of each intermediate pass are distributed in reverse order based on the web reduction schedule. The reduction rate decreases from the third pass as the highest point, thus forming a process in which the prototype of the irregular intermediate billet 40 gradually changes into an H-shape, which is beneficial to improving the uniformity of metal flow during the rolling process.

[0039] It should be noted that, in this embodiment, the above-mentioned web reduction procedure also includes: a web reduction rate of ≤32% per pass. If the web reduction rate is too high, it will not only easily lead to bite difficulties, but also easily cause morphological defects such as side bending, deflection, and torsion of the rolled piece. At the same time, it will also cause serious wear on the rolls, resulting in a decrease in roll life. Therefore, in this embodiment, the maximum value of the web reduction rate is controlled below 32% to improve rolling stability, product quality, and roll life.

[0040] In some embodiments, such as Figure 6 As shown, step S100 above further includes: S102. Determine the flange reduction ratio for each track according to the flange reduction ratio specification; wherein, the flange reduction ratio specification is: satisfy the web reduction ratio specification, and the flange reduction ratio for each track is greater than the web reduction ratio.

[0041] The flange reduction rate for each pass should first follow the above-mentioned web reduction procedure, mainly the constraint of the above-mentioned web reduction procedure on the reduction rate of each pass. On this basis, considering that the total reduction of the flange is higher than the total reduction of the web during the forming process, the difference between the total reduction of the web and the flange is evenly distributed to each pass. This ensures that the flange and the web are formed synchronously, which is conducive to improving the uniformity of metal flow during the forming process, thereby improving the quality of the finished product.

[0042] Specifically, in step S102, the difference between the flange reduction ratio and the web reduction ratio for each pass is 2% to 4%. The flange reduction ratio and web reduction ratio for each pass can be set to the same difference or different differences, but the minimum difference should not be less than 2% and the maximum difference should not exceed 4%. Here, it is possible to make the flange reduction ratio for each pass 3% higher than the web reduction ratio.

[0043] In some possible implementations, step S100 above also includes: S103. Except for the ED reduction of zero, the reduction of the ED reduction of all other ED reductions is greater than the reduction of the wing edge of the previous ED reduction. Specifically, the reduction of the wing edge of the ED reduction is 2-7 mm greater than the reduction of the wing edge of the previous ED reduction.

[0044] For passes where the ED reduction is non-zero, considering that the ED mill 20 in the first rolling pass fully opens the roll gap, the ED reduction needs to be compensated. Therefore, the flange reduction of the ED pass is increased by 2-7 mm based on the flange reduction of the previous pass. Of course, considering that the flange of the rolled piece can freely extend its height dimension in the UR pass, that is, the UR pass has no constraint on the flange height dimension, the flange reduction of the rolled piece in the ED passes of each odd-numbered rolling pass is 2-7 mm, while in the ED passes of even-numbered rolling passes, the flange reduction is increased by 2-7 mm based on the flange reduction of the previous UF pass. In this way, the risk of bulging on the inner side of the flange can be reduced by using a smaller ED reduction in the forward rolling pass, while the lag in the flange height dimension formation of the rolled piece can be compensated by using a larger ED reduction in the reverse rolling pass.

[0045] It needs to be explained that, see Figure 4 In this embodiment, the horizontal rolls 11 of the UR mill have a side slope that gradually thins from the center to the edge, and the roll diameter of the vertical rolls 12 of the UR mill gradually decreases from the center to both ends to form a circumferential slope; wherein, the middle part of the circumferential surface of the vertical rolls 12 of the UR mill is rolled on the lug 41, and the side slope of the horizontal rolls 11 of the UR mill is smaller than the inner slope of the flange of the irregular intermediate billet 40.

[0046] The side slope of the horizontal rolls 11 of the UR mill, combined with the circumferential slope of the vertical rolls 12 of the UR mill, can form a roll gap close to an X-shape. As a result, the central part of the circumferential surface of the vertical rolls 12 of the UR mill rolls the lug 41 on the outer side of the flange of the workpiece, driving the metal in the lug 41 area to flow towards the flange end, thereby gradually eliminating the lug 41. The side slope of the horizontal rolls 11 of the UR mill can make the corner area where the web and flange of the workpiece meet form a smooth transition, avoiding the problem of crack defects in this area caused by directly rolling into a 90-degree corner.

[0047] It should be noted that the aforementioned side slope is 2-5° smaller than the slope of the inner flange of the rolled piece. It should be understood that for H-beam rolling, the upper and lower rolls of the horizontal pair of rolls 11 in the UR rolling mill are convex rolls. The roll side refers to the connection surface between the large-diameter middle part of the roll body and the small-diameter parts on both sides of that part. During the rolling process, in order to allow the metal in the web-flange junction area to flow towards the flange end, the side slope is made 2-5° smaller than the slope of the inner flange of the rolled piece. This creates a gap between the sides of the upper and lower rolls of the horizontal pair of rolls 11 of the UR rolling mill and the inner flange of the rolled piece, providing conditions for the uniform flow of metal in the flange area.

[0048] The size of the side slope is related to the size of the workpiece. Generally, the smaller the size of the workpiece, the smaller the difference between the side slope and the slope of the inner side of the workpiece flange. The larger the size of the workpiece, the larger the difference between the side slope and the slope of the inner side of the workpiece flange should be. This ensures that there is sufficient metal flow space between the sides of the upper and lower rolls of the horizontal roll 11 of the UR mill and the inner side of the workpiece flange.

[0049] In some embodiments, to further reduce roll wear, the UF mill 30 is provided with cooling water channels (not shown) that spray cooling water toward the sides of its horizontal rolls. By providing cooling water channels to spray cooling water onto the horizontal rolls, especially the sides of the horizontal rolls, it helps to slow down roll wear and improve roll service life.

[0050] Specifically, the cooling water path sprays cooling water onto the UF rolls through multiple rows of staggered spray nozzles arranged longitudinally on the pipeline. By staggering the nozzles, the interference between the spray ranges of adjacent nozzles can be reduced, thereby improving the uniformity and effectiveness of roll cooling.

[0051] 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 within the protection scope of the present invention.

Claims

1. A method for forming H-beams from irregularly shaped intermediate billets, characterized in that, This method is used to roll a shaped intermediate billet into an H-beam using a tandem reversible rolling mill. The shaped intermediate billet has a lug formed during the initial billet preparation on the outer center of its flange. The tandem reversible rolling mill includes a UR mill, an ED mill, and a UF mill arranged sequentially along the conveyor roller table. The forming method includes the following steps: S100. Determine the number of rolling strokes N, UR reduction, ED reduction, and UF reduction for each rolling stroke based on the dimensions of the finished H-beam and the dimensions of the irregular intermediate billet. S200: The rolled piece is passed sequentially from the UR side through the UR rolling mill, the ED rolling mill, and the UF rolling mill to complete the first rolling stroke in the forward direction; S300, The rolled piece is passed sequentially from the UF side through the UF rolling mill, the ED rolling mill and the UR rolling mill, and the second rolling stroke is completed in reverse; S400, repeat rolling until the Nth rolling stroke is completed in the forward direction, N≥3 and N is an odd number; The UR mill uses the X rolling method, the UF mill uses the H rolling method, and the ED reduction is zero at least in the first rolling stroke, while the ED reduction is non-zero in each even-numbered rolling stroke.

2. The forming method for rolling H-beams from irregularly shaped intermediate billets as described in claim 1, characterized in that, Each rolling pass includes UR passes and UF passes, with a total of 2N rolling passes; step S100 includes: S101. According to the web reduction schedule, the web thickness of the H-beam finished product is used to deduce the web thickness of the irregular intermediate billet, and the web reduction rate of each pass is determined. The number of rolling passes N is determined based on the web reduction rate of each pass. The web reduction schedule is as follows: the reduction rate of the first two passes is less than 20%, the reduction rate of the first to the third pass increases, and the reduction rate of the third to the 2Nth pass decreases.

3. The forming method for rolling H-beams from irregularly shaped intermediate billets as described in claim 2, characterized in that, The web reduction procedure also includes: a single pass web reduction rate of ≤32%.

4. The forming method for rolling H-beams from irregularly shaped intermediate billets as described in claim 2, characterized in that, Step S100 further includes: S102. Determine the flange reduction ratio for each pass according to the flange reduction procedure; wherein the flange reduction procedure is: satisfying the web reduction procedure, and the flange reduction ratio for each pass is greater than the web reduction ratio.

5. The forming method for rolling H-beams from irregularly shaped intermediate billets as described in claim 4, characterized in that, The difference between the flange reduction rate and the web reduction rate for each pass is 2% to 4%.

6. The forming method for rolling H-beams from irregularly shaped intermediate billets as described in claim 1, characterized in that, Step S100 further includes: S103. Except for the ED reduction of zero, the reduction of the remaining ED reduction is greater than the flange reduction of the previous reduction.

7. The forming method for rolling H-beams from irregularly shaped intermediate billets as described in claim 6, characterized in that, The wing reduction of the ED pass is 2-7 mm greater than that of the previous pass.

8. The method for forming H-beams from irregularly shaped intermediate billets as described in any one of claims 1-7, characterized in that, The horizontal rolls of the UR mill have a side slope that gradually thins from the center to the edge, and the vertical rolls of the UR mill have a roll diameter that gradually decreases from the center to both ends to form a circumferential slope; wherein, the middle part of the circumferential surface of the vertical rolls of the UR mill is rolled onto the lug, and the side slope is smaller than the inner slope of the flange of the irregular intermediate billet.

9. The forming method for rolling H-beams from irregularly shaped intermediate billets as described in claim 8, characterized in that, The slope of the side is 2-5° less than the slope of the inner side of the flange of the rolled piece.

10. The method for forming H-beams from irregularly shaped intermediate billets as described in any one of claims 1-7, characterized in that, The UF mill is equipped with a cooling water channel that sprays cooling water onto the sides of its horizontal rollers.

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