A rough rolling mill pass for rolling H-beam

Abstract

The present invention belongs to the technical field of hot-rolled steel rolling, and in particular relates to a roughing mill pass for rolling H-shaped steel. It achieves high production and low consumption of H-shaped steel, greatly improving production efficiency. The mill pass is composed of the upper and lower horizontal rollers of the roughing mill. The mill pass includes a closed hole and a special-shaped hole located to the left of the closed hole. The closed hole includes a first closed hole and a second closed hole of identical structure, and the first closed hole and the second closed hole are connected by a first horizontal connecting hole. The special-shaped hole includes a first special-shaped hole and a second special-shaped hole of identical structure, and the first special-shaped hole and the second special-shaped hole are connected by a second horizontal connecting hole. The closed hole and the special-shaped hole are not connected.

Description

Technical Field

[0001] The invention belongs to the technical field of hot-rolled steel section rolling, and in particular relates to a rough rolling mill pass for rolling H-section steel. Background Art

[0002] H-beams are a new type of economical construction steel with widespread applications in numerous fields. Their cross-sectional shape is economical and rational, with excellent mechanical properties. During rolling, they achieve uniform cross-sectional extension and minimize internal stress. Compared to conventional I-beams, they offer a larger cross-sectional modulus, lighter weight, and reduced metal consumption, potentially reducing building structures by 30-40%. Their parallel inner and outer legs and right-angled ends allow them to be assembled into structural components, saving up to 25% on welding and riveting. They are commonly used in large buildings and prefabricated steel structures requiring high load-bearing capacity and cross-sectional stability.

[0003] When rolling H-beams, small H-beams are typically rolled using a fully continuous rolling arrangement, medium H-beams using a semi-continuous rolling arrangement, and large H-beams using a reversing rolling arrangement. Small lines typically roll square billets, medium lines use rectangular billets, and large lines use profiled billets. Regardless of the billet type being produced, heating furnace temperature and the number of roughing passes are bottlenecks limiting production efficiency. Therefore, effectively reducing heating furnace temperature, furnace time, and the number of rolling passes is crucial.

[0004] When rolling medium-sized H-beams from rectangular billets, the billet-to-finished product compression ratio should generally be above 4:1, and the billet height to finished product flange height should be above 1.6:1. Consequently, the billet height for rolling a 200mm flange must be above 320mm. Heating large rectangular billets in a reheating furnace requires high temperatures and long furnace times, requiring nine or seven rough rolling passes, significantly reducing production efficiency. Therefore, a mill pass structure is urgently needed to improve production efficiency. Summary of the Invention

[0005] The present invention aims to solve the defects in the prior art and provides a rough rolling mill pass for rolling H-shaped steel.

[0006] To achieve the above purpose, the present invention adopts the following technical solution, which is composed of the upper horizontal roll and the lower horizontal roll of the roughing mill, and the mill pass type includes a closed hole and a special-shaped hole located on the left side of the closed hole.

[0007] The closed holes include a first closed hole and a second closed hole with the same structure, and the first closed hole and the second closed hole are connected through a first horizontal connecting hole.

[0008] The special-shaped holes include a first special-shaped hole and a second special-shaped hole having the same structure, and the first special-shaped hole and the second special-shaped hole are connected through a second horizontal connecting hole.

[0009] The closed hole is not connected to the special-shaped hole.

[0010] Furthermore, a cavity channel with a closing point is provided between the closed hole and the special-shaped hole.

[0011] Furthermore, the cavity channel includes an arc segment and a horizontal segment; the arc segment is composed of two upper and lower line segments, and there is at least one contact point between the upper and lower line segments to form a closed point.

[0012] From above, closed hole:

[0013] Furthermore, the first closed hole and the second closed hole are both symmetrical images mirrored relative to the center line.

[0014] Furthermore, the first closed hole and the second closed hole both include a first side wall and a second side wall, and a top arc edge and a bottom arc edge are arranged between the first side wall and the second side wall; one side of the top arc edge is connected to the horizontal section, and the other side of the top arc edge is connected to the first horizontal connecting hole; one side of the bottom arc edge is connected to the first side wall through the first horizontal wing edge, and the other side of the bottom arc edge is connected to the second side wall through the second horizontal wing edge; the first end of the first side wall is connected to the horizontal section, and the second end of the first side wall is connected to the first horizontal wing edge; the first end of the second side wall is connected to the first horizontal connecting hole, and the second end of the second side wall is connected to the second horizontal wing edge.

[0015] Furthermore, a first inner fillet R1 is provided at the connection between the top arc edge and the horizontal section, and a second inner fillet R2 is provided at the connection between the top arc edge and the first horizontal connecting hole; a third inner fillet R3 is provided at the connection between the bottom arc edge and the first horizontal wing edge, and a fourth inner fillet R4 is provided at the connection between the bottom arc edge and the second horizontal wing edge; a first outer fillet R7 is provided at the connection between the first side wall and the horizontal section, and a fifth inner fillet R5 is provided at the connection between the first side wall and the first horizontal wing edge; a second outer fillet R8 is provided at the connection between the second side wall and the first horizontal connecting hole, and a sixth inner fillet R6 is provided at the connection between the second side wall and the second horizontal wing edge.

[0016] Furthermore, the angle between the first side wall or the second side wall and the parting line is 95-110 degrees.

[0017] Furthermore, the top arc edge and the bottom arc edge are arranged opposite to each other, and the bending directions of the two arc edges are away from the parting line.

[0018] Furthermore, the arc radius of the top arc edge is 200MM-400MM.

[0019] Special-shaped hole: Furthermore, the first special-shaped hole and the second special-shaped hole both include flange holes on both sides and a web hole located between the two flange holes, and the top edge and the bottom edge of the web hole both adopt arc-shaped edges.

[0020] Furthermore, the arc-shaped top edge and the arc-shaped bottom edge are arranged opposite to each other, and the bending directions of the two arc-shaped edges are both away from the parting line.

[0021] Furthermore, the arc radius of the arc-shaped edge is 200MM-400MM.

[0022] Compared with the prior art, the present invention has beneficial effects.

[0023] The roughing mill pass for H-beam rolling in this invention improves upon the conventional pass system, lowering heating temperatures, reducing furnace time, and reducing the number of roughing passes, enabling three or five roughing passes. The new, efficient pass achieves high H-beam yields with low consumption, significantly improving production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention is further described below with reference to the accompanying drawings and specific embodiments. The scope of protection of the present invention is not limited to the following description.

[0025] Figure 1 It is a structural schematic diagram of the pass type of the rough rolling mill for rolling H-shaped steel in a specific embodiment.

[0026] Figure 2 It is a schematic diagram of the special-shaped hole structure.

[0027] Figure 3 It is a schematic diagram of closed pore structure.

[0028] Figure 4 It is a schematic diagram of the arc radius of the arc-shaped top edge and the arc-shaped bottom edge of the special-shaped hole.

[0029] Figure 5 It is a schematic diagram of metal flow in special-shaped holes.

[0030] Figure 6 It is a schematic diagram of the arc radius of the top arc edge and the inclination of the side wall of the closed hole.

[0031] Figure 7 It is a schematic diagram of closed hole metal flow.

[0032] In the figure, 1 is the upper horizontal roller, 2 is the lower horizontal roller, 3 is the first special-shaped hole, 4 is the second special-shaped hole, 5 is the first closed hole, 6 is the second closed hole, 7 is the first side wall, 8 is the second side wall, 9 is the first horizontal connecting hole, 10 is the second horizontal connecting hole, 11 is the top arc edge, 12 is the bottom arc edge, 13 is the cavity channel, 14 is the closing point, 15 is the parting line, 16 is the arc top edge, 17 is the arc bottom edge, 18 is the first horizontal wing edge, 19 is the second horizontal wing edge, 20 is the horizontal segment, and 21 is the arc segment. DETAILED DESCRIPTION

[0033] like Figure 1-7 As shown, a specific embodiment is formed by splicing the upper horizontal roller 1 and the lower horizontal roller 2 of the rough rolling mill, and the rolling mill pass includes a closed hole and a special-shaped hole located on the left side of the closed hole; the closed hole includes a first closed hole 5 and a second closed hole 6 with the same structure, and the first closed hole 5 and the second closed hole 6 are connected through a first horizontal connecting hole 9; the special-shaped hole includes a first special-shaped hole 3 and a second special-shaped hole 4 with the same structure, and the first special-shaped hole 3 and the second special-shaped hole 4 are connected through a second horizontal connecting hole 10; the closed hole and the special-shaped hole are not connected.

[0034] The invention comprises rough rolling holes, which include closed holes and special-shaped holes. The rough rolling holes are used to realize three-pass rolling or five-pass rolling.

[0035] Figure 1 The roll mill consists of an upper horizontal roll (1) and a lower horizontal roll (2). It utilizes a combination of closed and shaped holes, with two identical holes per hole pattern, effectively utilizing the rolls and doubling the steel throughput. This allows the rectangular billet to be formed into the prototype of the H-beam, or H-shaped billet. The shaped holes are slotted by the upper and lower rolls to create a symmetrical H-shape, preventing web center deviation in the finished H-beam.

[0036] Preferably, a cavity channel 13 having a closing point 14 is provided between the closed hole and the irregular hole. The cavity channel 13 includes an arc segment 21 and a horizontal segment 20; the arc segment 21 is composed of two upper and lower line segments, and there is at least one contact point between the upper and lower line segments, forming the closing point 14.

[0037] From the above, the closed hole: the first closed hole 5 and the second closed hole 6 are both symmetrical images mirrored relative to the center line. The first closed hole 5 and the second closed hole 6 each include a first side wall 7 and a second side wall 8, with a top arc edge 11 and a bottom arc edge 12 provided between the first side wall 7 and the second side wall 8; one side of the top arc edge 11 is connected to the horizontal section 20, and the other side of the top arc edge 11 is connected to the first horizontal connecting hole 9; one side of the bottom arc edge 12 is connected to the first side wall 7 via a first horizontal wing 18, and the other side of the bottom arc edge 12 is connected to the second side wall 8 via a second horizontal wing 19; the first end of the first side wall 7 is connected to the horizontal section 20, and the second end of the first side wall 7 is connected to the first horizontal wing 18; the first end of the second side wall 8 is connected to the first horizontal connecting hole 9, and the second end of the second side wall 8 is connected to the second horizontal wing 19.

[0038] Preferred option 1: A first inner fillet R1 is provided at the connection between the top arc edge 11 and the horizontal section 20, and a second inner fillet R2 is provided at the connection between the top arc edge 11 and the first horizontal connecting hole; a third inner fillet R3 is provided at the connection between the bottom arc edge 12 and the first horizontal wing 18, and a fourth inner fillet R4 is provided at the connection between the bottom arc edge 12 and the second horizontal wing 19; a first outer fillet R7 is provided at the connection between the first side wall 7 and the horizontal section 20, and a fifth inner fillet R5 is provided at the connection between the first side wall 7 and the first horizontal wing 18; a second outer fillet R8 is provided at the connection between the second side wall 8 and the first horizontal connecting hole 9, and a sixth inner fillet R6 is provided at the connection between the second side wall 8 and the second horizontal wing 19.

[0039] Preferred solution two: The angle between the first side wall 7 or the second side wall 8 and the parting line 15 is 95-110 degrees. The closed hole adopts a large side wall slope to effectively flow the metal to the flange and compensate for the low compression ratio of the flange. The side wall slope is between 95-110 degrees, and is usually designed to be generally below 95 degrees (existing technology). The large side wall slope design reduces the deformation resistance, greatly reduces the energy consumption of metal deformation, and allows the metal to flow effectively to the flange. Through such closed hole rolling, the coarse grains in the casting state are broken, casting defects are reduced or eliminated, and the cast structure is transformed into a deformed structure, effectively improving the insufficient proportion of the original billet, reducing the problem of stress concentration, and having a good effect on enhancing product performance.

[0040] Preferred solution three: the top arc edge 11 and the bottom arc edge 12 are arranged opposite to each other, and the curvature directions of the two arc edges are both away from the parting line 15. The arc radius of the top arc edge 11 is 200MM-400MM.

[0041] Irregular-shaped holes: Both the first irregular-shaped hole 3 and the second irregular-shaped hole 4 include flange holes on either side and a web hole located between the two flange holes. The flange holes have the same hole shape as conventional flange holes. One improvement is that the top and bottom edges of the web holes are both curved. The curved top edge 16 and the curved bottom edge 17 are positioned opposite each other, and the curvature of both curved edges points away from the parting line 15. The radius of the curved edges is 200mm-400mm.

[0042] Both types of holes use a large arc transition (i.e., arc edge); the arc radius is between 200-400mm, which effectively allows the metal on the web to flow to the flange, so that the flange is completely filled with the hole.

[0043] Working process:

[0044] Step 1: The present invention is a semi-continuous rolling rough rolling pass, which is suitable for H-shaped steel with a web height of 400 mm and a flange width of 200 mm or less.

[0045] Step 2: Select a ratio of billet height to finished flange height of about 1.15:1 to optimize the billet and reduce the number of rolling passes. For example, for a 200mm flange width, select a 230mm billet.

[0046] Step 3: Heat the rectangular billet to 1260-1300°C in a heating furnace.

[0047] Step 4: Send the heated rectangular billet to the die of the present invention for reciprocating rolling at a rolling temperature of 1150-1250° C. First, roll it in BD-1K for 2-3 passes, and then move it to BD-2K for 1-2 passes.

[0048] Step 5: The rolled H-shaped steel is sent to the subsequent process for continuous rolling (finishing rolling).

[0049] Specifically, rough rolling only requires these two pass rollings. The advantage of going through two processes is that the number of rolling passes can be effectively reduced. Rough rolling can be completed in 3 or 5 passes, which can effectively improve the production rhythm and effectively ensure the starting temperature of continuous rolling.

[0050] The purpose of the first BD-1K rolling is to deform the rectangular billet unevenly, force it to widen, and initially roll it into an H-shape that is asymmetric in the upper and lower parts and symmetrical in the left and right parts. The height and width of the H-shape are also limited to obtain the required height and width dimensions of the H-beam model to be rolled.

[0051] The purpose of the second BD-2K rolling is to make it deform evenly, transform the asymmetric H-shape into an H-shape that is symmetrical up and down and left and right, form the prototype of the H-shaped steel, and provide qualified billets for continuous rolling (finishing rolling).

[0052] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the scope of protection of the present invention.

Claims

1. A roughing mill pass for rolling H-beam, formed by combining the upper and lower horizontal rolls of a roughing mill, characterized in that: The mill pass profile includes a closed hole and a special-shaped hole located on the left side of the closed hole; The closed holes include a first closed hole and a second closed hole with the same structure, and the first closed hole and the second closed hole are connected through a first horizontal connecting hole; The special-shaped holes include a first special-shaped hole and a second special-shaped hole with the same structure, and the first special-shaped hole and the second special-shaped hole are connected through a second horizontal connecting hole; The closed hole and the special-shaped hole are not connected; A cavity channel with a closing point is provided between the closed hole and the special-shaped hole; The first closed hole and the second closed hole are both symmetrical images mirrored relative to the center line; The first closed hole and the second closed hole each include a first side wall and a second side wall, and a top arc edge and a bottom arc edge are provided between the first side wall and the second side wall; One side of the top arc edge is connected to the horizontal section, and the other side of the top arc edge is connected to the first horizontal connecting hole; One side of the bottom arc edge is connected to the first side wall via a first horizontal wing edge, and the other side of the bottom arc edge is connected to the second side wall via a second horizontal wing edge; The first end of the first side wall is connected to the horizontal section, and the second end of the first side wall is connected to the first horizontal wing; the first end of the second side wall is connected to the first horizontal connecting hole, and the second end of the second side wall is connected to the second horizontal wing; A first inner fillet R1 is provided at the connection between the top arc edge and the horizontal section, and a second inner fillet R2 is provided at the connection between the top arc edge and the first horizontal connecting hole; A third inner fillet R3 is provided at the connection between the bottom arc edge and the first horizontal wing edge, and a fourth inner fillet R4 is provided at the connection between the bottom arc edge and the second horizontal wing edge; A first outer fillet R7 is provided at the connection between the first side wall and the horizontal section, and a fifth inner fillet R5 is provided at the connection between the first side wall and the first horizontal wing edge; A second outer fillet R8 is provided at a connection between the second side wall and the first horizontal connecting hole, and a sixth inner fillet R6 is provided at a connection between the second side wall and the second horizontal wing edge.

2. The rough rolling mill pass for rolling H-beam according to claim 1, characterized in that: The cavity channel includes an arc segment and a horizontal segment; the arc segment is composed of two upper and lower line segments, and there is at least one contact point between the upper and lower line segments to form a closed point.

3. The rough rolling mill pass for rolling H-beam according to claim 1, characterized in that: The included angle between the first side wall or the second side wall and the parting line is 95-110 degrees.

4. The rough rolling mill pass for rolling H-beam according to claim 1, characterized in that: The top arc edge and the bottom arc edge are arranged opposite to each other, and the bending directions of the two arc edges are both away from the parting line; the arc radius of the top arc edge is 200mm-400mm.

5. The rough rolling mill pass for rolling H-beam according to claim 1, characterized in that: The first special-shaped hole and the second special-shaped hole both include flange holes on both sides and a web hole located between the two flange holes, and the top edge and the bottom edge of the web hole are both arc-shaped edges.

6. The rough rolling mill pass for rolling H-beam according to claim 5, characterized in that: The arc-shaped top edge and the arc-shaped bottom edge are arranged opposite to each other, and the bending directions of the two arc-shaped edges are both away from the parting line; the arc radius of the arc-shaped edges is 200mm-400mm.

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