Super duplex stainless steel round bar rolling equipment

Abstract

The invention solves the problem that a precipitated phase is easily generated in the rolling process of super duplex stainless steel, and relates to the technical field of rolling equipment, in particular to super duplex stainless steel round bar rolling equipment which comprises a round bar body arranged between two rollers of a finishing mill, an electromagnetic induction heating mechanism is installed on one side of the finishing mill, and an electromagnetic induction heating mechanism is installed on the other side of the finishing mill. The electromagnetic induction heating mechanism is coaxial with the circle center of the round bar body, a temperature measurer is installed at the position, close to the round bar body, of the finishing mill, and a water-cooling spraying system is installed on the side, close to the electromagnetic induction heating mechanism, of the finishing mill and comprises a collecting pipe installed at the top of the finishing mill. An inlet in the top of the collecting pipe is connected with a draw-off pump, and the inlet end of the draw-off pump is connected with a cooler located on one side of the finishing mill. The electromagnetic induction heating mechanism and the water-cooling spraying system are additionally arranged at the end of the finishing mill, so that the rolling process of the stainless steel round bar body can be remarkably improved, and the product quality and the production efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of rolling equipment technology, specifically to a super duplex stainless steel round bar rolling equipment. Background Technology

[0002] During the rolling process of super duplex stainless steel, improper temperature control can easily lead to the formation of precipitates, such as the σ phase. The formation of precipitates severely reduces the plasticity of the material, causing cracks on the surface and inside the material.

[0003] The conventional rolling method involves first roughing the billet on a roughing mill, then rolling it into the required round bars on a finishing mill, slitting it, and finally air-cooling it on a cooling bed. During this process, the final rolling temperature of the finishing mill has a significant impact on the formation of precipitates. Super duplex stainless steel will produce a large number of precipitates in a very short time within the temperature range of 800-950°C.

[0004] A common solution is to add an electromagnetic induction heating device between the roughing and finishing mills, raising the billet to a suitable temperature in advance based on the temperature drop during the finishing mill rolling process. High-temperature rolling causes the finished round steel to become coarse, which reduces the mechanical properties and impact toughness of the material to some extent. Although this method can increase the final rolling temperature of the finishing mill, the round steel will still remain in the temperature range where precipitates are generated on the cooling bed, and precipitates will still be produced. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a super duplex stainless steel round bar rolling equipment to solve the problem mentioned in the background art that super duplex stainless steel is prone to the generation of precipitates during the rolling process.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a super duplex stainless steel round bar rolling equipment, comprising a round bar body disposed between two rolls of a finishing mill, an electromagnetic induction heating mechanism installed on one side of the finishing mill, the electromagnetic induction heating mechanism being coaxial with the center of the round bar body, a temperature measuring device installed on the finishing mill near the round bar body, and a water-cooled spray system installed on the side of the finishing mill near the electromagnetic induction heating mechanism. The water-cooled spray system includes a collection pipe installed on the top of the finishing mill. An extraction pump is connected to the inlet at the top of the collection pipe. A cooler located on one side of the finishing mill is connected to the inlet of the extraction pump. Two rows of output structures arranged in a front-to-back mirror pattern are connected to the surface of the collection pipe. An adjustment component connected to the two rows of output structures is installed on the finishing mill. The adjustment component is used to control the distance between the outlet ends of the two rows of output structures and the central axis of the cylindrical bar.

[0007] Preferably, the outlet structure includes a branch pipe communicating with the manifold, and a wide, flat nozzle is connected to one end of the branch pipe away from the manifold, with the spraying end of the wide, flat nozzle facing the surface of the cylindrical body.

[0008] Preferably, the branch pipe is a silicone hose with a built-in metal wire mesh, the branch pipe is arranged in an arc shape, and the wide and flat nozzles in the two rows of outlet structures are arranged in a staggered manner.

[0009] Preferably, the adjustment assembly includes two connecting shafts that are respectively connected to the ends of the two rows of branch pipes near the wide flat nozzle. The connecting shafts have built-in sensors for monitoring the distance between them and the surface of the round bar. A guide frame is installed on one side of the finishing mill, and a drive structure is installed on the guide frame. The drive structure is used to control the synchronous movement of the two connecting shafts.

[0010] Preferably, the drive structure includes a servo motor installed on the side of the guide frame away from the finishing mill, two lead screws are rotatably installed inside the guide frame, and the two lead screws are respectively connected to two connecting shafts through sliders. A gear transmission group connecting the output end of the servo motor and the ends of the two lead screws is provided in the middle of the guide frame.

[0011] Preferably, the guide frame consists of a vertical cavity plate detachably mounted on the extended end of the outer wall of the finishing mill and two sliding groove plates on the surface of the vertical cavity plate, with the gear transmission assembly located inside the vertical cavity plate.

[0012] Preferably, the angle between the two slide plates is between 60° and 120°. Two elongated slots arranged in a front-to-back mirror pattern are provided on both sides of the finishing mill. The end of the connecting shaft passes through the elongated slot and connects to the slider on the lead screw. The inclination angle of the elongated slot is consistent with that of the slide plate.

[0013] Preferably, a water storage frame is installed at the bottom of the finishing mill, the water storage frame contains a filter, and the water outlet of the water storage frame is connected to the cooler.

[0014] By employing the above technical solution, the present invention provides a super duplex stainless steel round bar rolling equipment, which has at least the following beneficial effects: 1. This invention significantly improves the rolling process of stainless steel round bars by adding an electromagnetic induction heating mechanism and a water-cooled spray system to the end of the finishing mill, thereby improving product quality and production efficiency.

[0015] 2. The present invention makes the distance between the wide and flat nozzles of the two rows of outlet structures that discharge coolant and the central axis of the round bar adjustable by adjusting the components, so as to achieve the precise temperature control target of changing the diameter of the rolled round bar without changing the cooling effect.

[0016] 3. In this invention, the coolant sprayed onto the cylindrical rod through two rows of wide, flat nozzles first contacts the upper surface of the cylindrical rod, and then flows downward along the arc-shaped upper surface of the cylindrical rod. This prolongs the contact time between the coolant and the surface of the cylindrical rod, so that the coolant forms a continuous liquid film heat exchange layer on the surface of the cylindrical rod, rather than discrete dripping impacts. Heat can be efficiently transferred through both conduction and convection, which can quickly reduce the surface and subsurface temperatures of the cylindrical rod. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the installation structure of the water-cooled spray system of the present invention; Figure 3 This is a schematic diagram of the distribution of the derived structure of the present invention; Figure 4 This is a schematic diagram of the derived structure and adjustment components of the present invention; Figure 5 This is a schematic diagram of the guide frame of the present invention.

[0018] In the picture: 1. Finishing mill; 101. Long trough; 2. Round rod; 3. Electromagnetic induction heating mechanism; 301. Temperature measuring instrument; 4. Water-cooled spray system; 401. Manifold; 402. Extraction pump; 403. Cooler; 404. Outlet structure; 4041. Branch pipe; 4042. Wide flat nozzle; 5. Adjustment assembly; 501. Connecting shaft; 502. Guide frame; 5021. Vertical cavity plate; 5022. Slide plate; 503. Drive structure; 5031. Servo motor; 5032. Lead screw; 5033. Gear transmission group; 6. Water storage frame; 601. Filter. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. In the description of the present invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0020] Example 1 Please see Figures 1-5 This application discloses a super duplex stainless steel round bar rolling equipment that can effectively avoid the formation of precipitates. The stainless steel round bar rolling equipment includes a finishing mill 1 consistent with existing technology. The round bar 2 to be rolled is placed between two rolls of the finishing mill 1. An electromagnetic induction heating mechanism 3 is installed on one side of the finishing mill 1, coaxial with the center of the round bar 2. A temperature measuring device 301 is installed on the finishing mill 1 near the round bar 2. The electromagnetic induction heating mechanism 3 uses an alternating electromagnetic field through the roll seat of the finishing mill 1 to generate eddy currents inside the round bar 2, thereby rapidly heating it. This facilitates raising the round bar 2 to the required temperature in a short time, saving power consumption. Furthermore, since the electromagnetic induction heating mechanism 3 can precisely control the heating temperature, it is convenient to keep the round bar 2 within the optimal temperature range during rolling. In this embodiment, it is only necessary to heat the round bar 2 to the normal solution temperature of about 1050°C, which will not cause coarse grains inside the material. Based on this, a water-cooled spray system 4 is installed on the side of the finishing mill 1 near the electromagnetic induction heating mechanism 3. The water-cooled spray system 4 is used to uniformly cool the periphery of the round bar 2, rapidly reducing the temperature of the round bar 2 to below 600℃, so that it quickly leaves the precipitation phase temperature range. In addition, the temperature measuring device 301 is electrically connected to both the electromagnetic induction heating mechanism 3 and the water-cooled spray system 4. The temperature measuring device 301 monitors the temperature of the round bar 2 in real time and adjusts the heating power of the electromagnetic induction heating mechanism 3 and the flow rate of the cooling water in real time.

[0021] Previously, the proportion of precipitated phases in the super duplex stainless steel S32750 round bars exceeded 10%, and there were microcracks and disordered structure; while the round bar 2 rolled using this embodiment has uniform austenite and ferrite inside, and there are no precipitated phases.

[0022] The following is a comparison of the impact toughness of Super Duplex Stainless Steel S32750 at -46℃: Both sets of tests selected the same batch of raw materials. Sample 1 was tested without the electromagnetic induction heating mechanism 3 and the water-cooled spray system 4. Sample 2 was heated to 1080℃ by the electromagnetic induction heating mechanism 3 and then rapidly cooled to below 600℃ by the water-cooled spray system 4.

[0023] Example 2 The water-cooled spray system 4 includes a manifold 401 installed on top of the finishing mill 1. An extraction pump 402 is connected to the inlet at the top of the manifold 401. A cooler 403 located on one side of the finishing mill 1 is connected to the inlet of the extraction pump 402. The cooler 403 can stably control the coolant temperature within a preset low-temperature range, preventing a decrease in cooling efficiency due to coolant overheating. Two rows of mirror-arranged outlet structures 404 are connected to the surface of the manifold 401. Each outlet structure 404 includes a branch pipe 4041 communicating with the manifold 401. A wide, flat nozzle 4042 is connected to the end of the branch pipe 4041 away from the manifold 401, with the spraying end of the wide, flat nozzle 4042 facing the surface of the cylindrical bar 2. The coolant in the cooler 403 is drawn by the pump 402 and then sprayed evenly from multiple positions on the front and rear sides of the cylindrical bar 2 through the wide and flat nozzles 4042 of the two rows of outlet structures 404. This makes the surface temperature field of the cylindrical bar 2 uniform, effectively suppresses defects such as bending and cracks, and thus improves its surface smoothness.

[0024] The cooling intensity of the coolant is negatively correlated with the distance between the spray outlet and the surface of the rolled piece: if the distance is too small, the coolant will contact the surface of the round bar 2 directly under high pressure, and the cooling rate will be too fast, which will cause the surface temperature of the stainless steel to drop sharply, which will easily induce martensitic phase transformation and embrittlement. At the same time, it will generate large thermal stress, causing defects such as surface cracks and uneven internal structure of the round bar 2. Conversely, if the distance is too large, the spray range of the coolant will spread, the impact force will be weakened, and some coolant will splash away without contacting the round bar 2, resulting in a significant decrease in cooling efficiency. It will be unable to remove the plastic deformation heat generated by the finishing rolling in time, resulting in the temperature of the round bar 2 being too high, which will easily lead to problems such as thickening of the surface oxide scale and loss of dimensional accuracy.

[0025] In order to avoid the above problems when rolling cylindrical bars of different diameters, such as Figure 1 , Figures 3-5As shown, an adjustment assembly 5 connected to two rows of guide structures 404 is installed on the finishing mill 1. The adjustment assembly 5 connects the two rows of branch pipes 4041 near the wide flat nozzles 4042 via two connecting shafts 501. The connecting shafts 501 have built-in sensors to monitor the distance between the connecting shafts 501 and the surface of the round bar 2 when the connecting shafts 501 are moved. A guide frame 502 is installed on one side of the finishing mill 1. A drive structure 503 is installed on the guide frame 502. The drive structure 503 includes a servo motor 5031 installed on the side of the guide frame 502 away from the finishing mill 1. Two lead screws 5032 are rotatably installed inside the guide frame 502. The two lead screws 5032 are respectively connected to the two connecting shafts 501 via sliders. A gear transmission group 5033 is provided in the middle of the guide frame 502, connecting the output end of the servo motor 5031 and the ends of the two lead screws 5032. In this embodiment, a servo motor 5031 is used as the drive source. Through a gear transmission group 5033, rotational power is simultaneously transmitted to two lead screws 5032, causing them to rotate synchronously. This controls the movement of two connecting shafts 501 along the guide of the lead screws 5032, thereby adjusting the distance between the wide flat nozzle 4042 and the surface of the cylindrical bar 2. When rolling a large-diameter cylindrical bar 2, the distance between the wide flat nozzle 4042 and the central axis of the large-diameter cylindrical bar 2 is appropriately increased; when rolling a small-diameter cylindrical bar 2, the distance is appropriately decreased. This achieves the precise temperature control goal of maintaining a constant cooling effect despite changes in the diameter of the rolled cylindrical bar 2.

[0026] Furthermore, the adjustable spacing between the outlet ends of the two rows of outlet structures 404 and the central axis of the cylindrical rod 2 ensures that the outlet ends of the two rows of outlet structures 404 always maintain a consistent gap with the surface of the cylindrical rod 2, ensuring that the coolant evenly coats the circumference of the cylindrical rod 2 and eliminating cooling blind spots.

[0027] Example 3 Branch pipe 4041 is a silicone hose with built-in metal mesh, which allows it to maintain its bending shape under external force. Branch pipe 4041 is arranged in an arc shape to avoid obstructing the movement of the connecting shaft 501 when the spacing is reduced or increased. The distance between two adjacent transversely arranged wide and flat nozzles 4042 is no greater than the spray width of the wide and flat nozzle 4042. The wide and flat nozzles 4042 in the two rows of outlet structures 404 are staggered, which allows the two rows of fan-shaped water flows to form complementary overlap. The circumferential area not covered by the row of wide and flat nozzles 4042 on the front side of the cylindrical body 2 can be filled by the coolant sprayed by the row of wide and flat nozzles 4042 on the rear side of the cylindrical body 2, ultimately achieving a 360° full-coverage spray on the cylindrical body without dead angles.

[0028] Example 4 The core characteristic of the wide-flat nozzle 4042 is its flat, fan-shaped water flow, and its cooling effect is highly dependent on the contact angle between the water flow and the surface of the cylindrical bar 2. If the wide-flat nozzle 4042 only moves horizontally when adjusting the spacing, the outlet direction of the wide-flat nozzle 4042 will deviate from the surface of the cylindrical bar 2 as the spacing changes. As the required diameter of the cylindrical bar 2 increases, the coolant sprayed by the wide-flat nozzle 4042 may drip instantly after contacting the surface of the cylindrical bar 2. The contact time between the coolant and the cylindrical bar 2 is extremely short, only able to remove a small amount of surface heat, resulting in limited cooling depth and efficiency, and inability to effectively control the internal temperature of the cylindrical bar 2. To effectively extend the contact time between the coolant and the surface of the cylindrical bar 2, such as... Figure 4 and Figure 5 As shown, the guide frame 502 consists of a vertical cavity plate 5021 detachably mounted on the extended end of the outer wall of the finishing mill 1 and two sliding plates 5022 on the surface of the vertical cavity plate 5021. The gear transmission assembly 5033 is located inside the vertical cavity plate 5021. The angle between the two sliding plates 5022 is between 60° and 120°. As the servo motor 5031 drives the two lead screws 5032 to rotate synchronously, it ultimately controls the two connecting shafts 501 to move along the path of the inclined sliding plates 5022, so that the outlet ends of the two rows of wide flat nozzles 4042 are always aligned with the upper surface of the round bar 2. The water sprayed by the wide flat nozzles 4042 onto the upper surface of the round bar 2 flows downward along the arc-shaped upper surface of the round bar 2, which can prolong the contact time between the coolant and the surface of the round bar 2. During this process, the coolant forms a continuous liquid film heat exchange layer on the surface of the cylindrical bar 2, rather than discrete dripping impacts. Heat can be efficiently transferred through both conduction and convection, which can quickly reduce the surface and subsurface temperatures of the cylindrical bar 2, stabilize the finishing rolling temperature of the cylindrical bar 2 within the optimal range, and avoid performance degradation of the cylindrical bar 2 caused by high temperature.

[0029] Following the above, two elongated slots 101 arranged in a front-to-back mirror configuration are provided on both sides of the finishing mill 1. The end of the connecting shaft 501 passes through the elongated slot 101 and connects to the slider on the lead screw 5032. The inclination angle of the elongated slot 101 is consistent with that of the slide plate 5022. The elongated slot 101 is used to support the connecting shaft 501 and prevent the connecting shaft 501 from tilting excessively under the action of gravity.

[0030] Example 5 In conjunction with the above embodiment 2, a water storage frame 6 is installed at the bottom of the finishing mill 1. The water storage frame 6 contains a filter 601, and the outlet of the water storage frame 6 is connected to the cooler 403. After the coolant droplets sprayed onto the surface of the cylindrical bar 2 by several wide flat nozzles 4042 fall off, they will collect inside the water storage frame 6. The filter 601 will filter out the impurities, and the filtered liquid will return to the cooler 403, thus forming a water cycle, which can save water resources to a certain extent.

[0031] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A super duplex stainless steel round bar rolling equipment, comprising a round bar (2) disposed between two rolls of a finishing mill (1), characterized in that: An electromagnetic induction heating mechanism (3) is installed on one side of the finishing mill (1). The electromagnetic induction heating mechanism (3) is coaxial with the center of the round bar (2). A temperature measuring device (301) is installed on the finishing mill (1) near the round bar (2). A water-cooled spray system (4) is installed on the side of the finishing mill (1) near the electromagnetic induction heating mechanism (3). The water-cooled spray system (4) includes a collection pipe (401) installed on the top of the finishing mill (1). The inlet of the top of the collection pipe (401) is connected to a pump (402). The inlet of the pump (402) is connected to a cooler (403) located on one side of the finishing mill (1). Two rows of outgoing structures (404) arranged in a front-to-back mirror arrangement are connected to the surface of the collection pipe (401). An adjustment component (5) connected to the two rows of outgoing structures (404) is installed on the finishing mill (1). The adjustment component (5) is used to control the distance between the outlet end of the two rows of outgoing structures (404) and the central axis of the round bar (2).

2. The super duplex stainless steel round bar rolling equipment according to claim 1, characterized in that: The outgoing structure (404) includes a branch pipe (4041) connected to the manifold (401), and a wide flat nozzle (4042) is connected to one end of the branch pipe (4041) away from the manifold (401), with the spraying end of the wide flat nozzle (4042) facing the surface of the cylindrical body (2).

3. The super duplex stainless steel round bar rolling equipment according to claim 2, characterized in that: The branch pipe (4041) is a silicone hose with built-in metal wire mesh. The branch pipe (4041) is arranged in an arc shape, and the wide and flat nozzles (4042) in the two rows of outlet structures (404) are arranged in a staggered manner.

4. The super duplex stainless steel round bar rolling equipment according to claim 1, characterized in that: The adjustment assembly (5) includes two connecting shafts (501) that are respectively connected to the ends of the two rows of branch pipes (4041) near the wide flat nozzle (4042). The connecting shafts (501) have built-in sensors for monitoring the distance between them and the surface of the round bar (2). A guide frame (502) is installed on one side of the finishing mill (1). A drive structure (503) is installed on the guide frame (502). The drive structure (503) is used to control the synchronous movement of the two connecting shafts (501).

5. The super duplex stainless steel round bar rolling equipment according to claim 4, characterized in that: The drive structure (503) includes a servo motor (5031) installed on the side of the guide frame (502) away from the finishing mill (1). Two lead screws (5032) are rotatably installed inside the guide frame (502). The two lead screws (5032) are respectively connected to two connecting shafts (501) through sliders. A gear transmission group (5033) is provided in the middle of the guide frame (502) to connect the output end of the servo motor (5031) and the ends of the two lead screws (5032).

6. The super duplex stainless steel round bar rolling equipment according to claim 5, characterized in that: The guide frame (502) consists of a vertical cavity plate (5021) detachably mounted on the extended end of the outer wall of the finishing mill (1) and two sliding groove plates (5022) on the surface of the vertical cavity plate (5021), and the gear transmission group (5033) is located inside the vertical cavity plate (5021).

7. The super duplex stainless steel round bar rolling equipment according to claim 6, characterized in that: The angle between the two slide plates (5022) is between 60° and 120°. Two long slots (101) arranged in a front-to-back mirror pattern are opened on both sides of the finishing mill (1). The end of the connecting shaft (501) passes through the long slot (101) and connects to the slider on the lead screw (5032). The inclination angle of the long slot (101) is consistent with that of the slide plate (5022).

8. The super duplex stainless steel round bar rolling equipment according to claim 1, characterized in that: The bottom of the finishing mill (1) is equipped with a water storage frame (6), which contains a filter (601). The water outlet of the water storage frame (6) is connected to the cooler (403).

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