A segmented water cooling device for improving the metallographic structure and surface quality

Abstract

This invention provides a segmented water-cooling device for improving metallographic structure and surface quality, comprising two water-cooling sections with a slow-cooling section between them. In use, after the finished steel bars pass through the rolling mill, they first enter the first turbulent flow tube for initial water cooling, then the slow-cooling section warms the surface of the rolled piece, and finally the second turbulent flow tube for secondary water cooling to reach the final rolling temperature. This segmented cooling method solves the problem of unstable metallographic structure caused by uneven cooling in traditional methods, and also improves the surface rust caused by uneven cooling in traditional methods.

Description

Technical Field

[0001] This invention belongs to the field of steel rolling technology, specifically relating to a segmented water cooling device for improving metallographic structure and surface quality. Background Technology

[0002] In controlled cooling of steel sections, the finished rolled steel section immediately passes through a water-cooling device for forced cooling after being rolled out of the finishing mill. This controlled cooling after controlled rolling is generally referred to as primary cooling. Primary cooling typically employs water purging, which controls the microstructure of the deformed austenite through intense cooling, preventing grain growth or premature carbide precipitation, increasing the undercooling degree of phase transformation, and preparing the microstructure for the transformation of deformed austenite into ferrite, cementite, or pearlite. The cooling rate directly affects whether the desired microstructure can be obtained. When the surface temperature of the steel is below 500℃ after water purging, martensite will form, thus failing to meet the metallographic requirements of the GB / T 1499.2-2018 national standard for steel reinforcement. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides a segmented water-cooling device to improve metallographic structure and surface quality.

[0004] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0005] A segmented water-cooling device for improving metallographic structure and surface quality includes two water-cooling sections and a slow-cooling section between the two water-cooling sections.

[0006] Furthermore, the water-cooled section is a turbulent tube-type water-cooling device.

[0007] Furthermore, the length of the turbulent water-passing pipe in each water-cooling section is ≤2.5 meters, and the length of the slow-cooling section is greater than the length of the turbulent water-passing pipe.

[0008] Furthermore, the slow cooling section includes several slow cooling conduits arranged in a line, and the slow cooling conduits are equipped with an air blowing mechanism for blowing air onto the surface of the rolled piece.

[0009] Furthermore, the air blowing mechanism is located at both ends of the slow cooling duct. The air blowing mechanism is a ring structure with a passageway in the middle for the rolled piece to pass through. Several nozzles are evenly distributed around the passageway, and the nozzles are inclined towards the rolled piece.

[0010] Furthermore, the air blowing mechanism is provided with a ring-shaped pressurized air chamber, and the tail end of each nozzle is connected to the pressurized air chamber, which is externally connected to an air pump.

[0011] Furthermore, the nozzle is provided with a guide vane, which divides the nozzle into two flow channels. One side of the guide vane is a plane, and the other side is provided with a slope, wherein the side with the slope is relatively close to the workpiece. The guide vane can move back and forth along the nozzle to adjust the amount of the slope extending outside the nozzle. When the slope retracts inward, it will gradually reduce the opening of the flow channel on the slope side until it is completely closed.

[0012] Furthermore, the driving mechanism for driving the guide vane includes a turntable and a rack. The turntable surrounds the pressurized air chamber and has a groove. The distance from each point in the groove to the center of rotation of the turntable gradually decreases. The guide vane is slidably connected to the arc-shaped groove. The turntable has a section of arc teeth that mesh with the rack. The rack is slidably connected to the housing of the air blowing mechanism and can translate along a direction parallel to the axis of the air blowing mechanism. All racks in the air blowing mechanism are connected in series and move synchronously.

[0013] Furthermore, the outer side of the slow cooling conduit is covered by a cooling cover, and a sealed cavity for injecting coolant is formed between the cooling cover and the slow cooling conduit. The outer side of the cooling cover is connected to an inlet and an outlet.

[0014] Furthermore, the coolant flows in the opposite direction to the movement of the rolled piece.

[0015] The beneficial effects of this invention are as follows: (1) This invention provides a segmented water-cooling device for improving metallographic structure and surface quality. After the finished steel bars pass through the finished steel rolling mill, they first enter the first turbulent flow tube for preliminary water cooling, then use a slow cooling section to reheat the surface of the rolled piece, and finally enter the second turbulent flow tube for secondary water cooling to reach the final rolling temperature. Through the above segmented cooling method, the problem of unstable metallographic structure of the rolled piece caused by uneven water cooling in traditional methods is solved, and the surface rust caused by uneven cooling in traditional methods can also be improved.

[0016] (2) In the water cooling device of the present invention, by setting air blowing mechanisms at both ends of the slow cooling conduit, high-pressure air is used to blow the surface of the rolled piece to accelerate the removal of residual moisture on the surface of the rolled piece and help the surface of the rolled piece to recover temperature; wherein the air blowing mechanism at the front end is mainly used to blow away the moisture on the surface of the rolled piece directly, while the air blowing mechanism at the rear end is mainly used to generate axial airflow inside the slow cooling conduit to blow the hotter air on the surface of the rolled piece at the rear end forward to assist the rolled piece at the front end to recover temperature.

[0017] (3) In the nozzle of the present invention, by setting a guide vane to change the nozzle flow channel, the nozzle coverage range can be adjusted more flexibly; the nozzle opening size can also be adjusted by the position of the guide vane.

[0018] (4) In this invention, the slow cooling conduit is provided with a sealed cavity for injecting coolant, which improves the heat dissipation capacity of the slow cooling conduit by liquid cooling, and avoids the slow cooling conduit from being baked by high-temperature rolled workpieces for a long time and thus failing or being damaged. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the segmented water-cooling device of the present invention; Figure 2 This is a structural diagram of the slow cooling section in this invention; Figure 3 This is a three-dimensional view of the slow-cooling conduit in this invention; Figure 4 This is a structural diagram of the air blowing mechanism on the slow cooling duct in this invention; Figure 5 This is a structural diagram of the nozzle in the air blowing mechanism of the present invention; Figure 6 This is a schematic diagram of the movement of the nozzle part of the present invention.

[0020] Figure label: 1-Water cooling section; 2-Slow cooling section; 3-Slow cooling duct; 31-Cooling shroud; 32-Sealed cavity; 33-Inlet; 34-Outlet; 4-Air blowing mechanism; 41-Nozzle; 42-Pressurized air chamber; 43-Guide vane; 44-Rotating disc; 45-Slide groove; 46-Rack; 47-Shell; 48-Intake pipe. Implementation

[0021] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein similar or identical reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0022] like Figure 1 The segmented water-cooling device shown includes two water-cooling sections 1, with a slow-cooling section 2 located between them. Specifically, water-cooling sections 1 employ a turbulent tube-type water-cooling device, with the length of the turbulent water-cooling tube in each section 1 ≤ 2.5 meters. The length of the slow-cooling section 2 must be greater than the length of the turbulent water-cooling tubes in each section. By improving the traditional water-cooling device to the above-mentioned segmented structure and reducing the length of each turbulent tube, the intensity and temperature drop of a single water-cooling cycle are reduced. A slow-cooling section 2 is added between the two water-cooling sections 1 to appropriately reheat the surface of the rolled piece. Ultimately, segmented water-cooling avoids the formation of low-temperature martensite in the bar metallographic structure, improving the bar's metallographic structure and surface quality.

[0023] like Figure 2 As shown, the slow cooling section 2 is equipped with multiple slow cooling conduits 3, which are arranged in a straight line with each other at intervals. The slow cooling conduits 3 are covered by a cooling shroud 31, and a sealed cavity 32 is formed between the cooling shroud 31 and the slow cooling conduits 3. The sealed cavity 32 is filled with coolant. The cooling shroud 31 has an inlet 33 and an outlet 34 on its outside. The coolant enters the sealed cavity 32 through the inlet 33 and then flows out through the outlet 34 in a circulation. The coolant flows in the opposite direction to the movement direction of the rolled piece within the sealed cavity 32.

[0024] like Figure 3 and Figure 4 As shown, each end of the slow-cooling conduit 3 is equipped with an air blowing mechanism 4. The air blowing mechanism 4 includes a ring-shaped protective shell 47. A passageway for the rolled piece to pass through is provided in the middle of the protective shell 47. Several nozzles 41 are provided on the protective shell 47, evenly arranged around the passageway and inclined towards the rolled piece. An annular air pipe is provided inside the protective shell 47, and an air inlet pipe 48 is provided outside the annular air pipe for connecting an external air pump. A pressurized air chamber 42 is provided inside the annular air pipe, and the tail ends of each nozzle 41 are respectively connected to the pressurized air chamber 42.

[0025] like Figure 5 and Figure 6 As shown, a guide vane 43 is provided inside the nozzle 41, dividing the nozzle 41 into two flow channels. The end of the guide vane 43 extends outward from the end of the nozzle 41; one side of the exposed portion is flat, and the other side is sloped, with the sloped side being relatively closer to the workpiece. The guide vane 43 is driven by a drive mechanism and can move back and forth along the nozzle, thereby adjusting the amount of the slope extending out of the nozzle; when the guide vane 43 retracts inward, the opening of the flow channel on the sloped side will gradually decrease until it is completely closed.

[0026] The aforementioned driving mechanism includes a turntable 44 and a rack 46, wherein the turntable 44 is rotatably positioned around the outside of the annular air tube. A groove 45 is provided on the turntable 44. The groove 45 has an arc-shaped structure, and the distance from each point within the groove 45 to the center of rotation of the turntable 44 gradually decreases. A guide vane 43 is slidably connected to this arc-shaped groove 45; thus, when the turntable 44 rotates, the guide vane 43 will extend and retract via the groove 45. A section of arc-shaped teeth is provided on the turntable 44, which meshes with the rack 46. The rack 46 is slidably connected to the protective shell 47 and translates along a direction parallel to the axis of the air blowing mechanism 4. All racks 46 within the same air blowing mechanism 4 are connected in series via connecting rods to achieve synchronous movement.

[0027] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0028] This invention is not limited to the above-described embodiments. Any obvious improvements, substitutions, or modifications that can be made by those skilled in the art without departing from the essence of this invention are within the scope of protection of this invention.

Claims

1. A segmented water-cooling device for improving metallographic structure and surface quality, characterized in that: It includes two water-cooled sections (1), and a slow-cooling section (2) is provided between the two water-cooled sections (1). The slow cooling section (2) includes several slow cooling conduits (3) arranged in a line, and the slow cooling conduits (3) are provided with an air blowing mechanism (4) for blowing air onto the surface of the rolled piece; The air blowing mechanism (4) is located at both ends of the slow cooling conduit (3). The air blowing mechanism (4) is a ring structure with a passage for the rolled piece to pass through in the middle. Several nozzles (41) are evenly distributed around the passage. The nozzles (41) are inclined towards the rolled piece. The nozzle (41) is provided with a guide vane (43), which divides the nozzle (41) into two flow channels. One side of the guide vane (43) is a plane, and the other side is provided with a slope. The side with the slope is relatively close to the workpiece. The guide vane (43) can move back and forth along the nozzle (41) to adjust the amount of the slope extending outside the nozzle (41). When the slope retracts inward, it will gradually reduce the opening of the flow channel on the slope side until it is completely closed.

2. The segmented water-cooling device for improving metallographic structure and surface quality according to claim 1, characterized in that: The water-cooled section (1) is a turbulent tube-type water-cooling device.

3. The segmented water-cooling device for improving metallographic structure and surface quality according to claim 2, characterized in that: The length of the turbulent water pipe in each water-cooling section (1) is ≤2.5 meters, and the length of the slow-cooling section (2) is greater than the length of the turbulent water pipe.

4. The segmented water-cooling device for improving metallographic structure and surface quality according to claim 1, characterized in that: The air blowing mechanism (4) is provided with a ring-shaped pressurized air chamber (42), and the tail end of the nozzle (41) is connected to the pressurized air chamber (42). The pressurized air chamber (42) is connected to an air pump.

5. The segmented water-cooling device for improving metallographic structure and surface quality according to claim 1, characterized in that: The driving mechanism for driving the guide vane (43) includes a turntable (44) and a rack (46). The turntable (44) surrounds the pressurized air chamber (42). The turntable (44) is provided with a groove (45). The distance from each point in the groove (45) to the center of rotation of the turntable (44) gradually shortens. The guide vane (43) is slidably connected to the groove (45). The turntable (44) is provided with a section of arc teeth, which mesh with the rack (46) through the arc teeth. The rack (46) is slidably connected to the protective shell (47) of the air blowing mechanism (4) and can translate along a direction parallel to the axis of the air blowing mechanism (4). All racks (46) in the air blowing mechanism (4) are connected in series and move synchronously.

6. The segmented water-cooling device for improving metallographic structure and surface quality according to claim 1, characterized in that: The slow cooling conduit (3) is covered with a cooling cover (31) on the outside. A sealed cavity (32) for injecting coolant is formed between the cooling cover (31) and the slow cooling conduit (3). An inlet (33) and an outlet (34) are respectively connected to the outside of the cooling cover (31).

7. The segmented water-cooling device for improving metallographic structure and surface quality according to claim 6, characterized in that: The coolant flows in the opposite direction to the movement of the rolled piece.

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