A graded aerosol cooling ring for hot-rolled H-beams

Abstract

This invention relates to a graded aerosol cooling ring for hot-rolled H-beams, designed to address problems such as uneven microstructure and properties caused by inhomogeneous cooling rates and phase transformations during H-beam cooling, as well as cracking due to residual stress. The graded aerosol cooling ring of this invention differs from existing water-mist cooling nozzles primarily in its wide air-to-water flow ratio (or simply air-to-water ratio) control range, adjustable arbitrarily from 40% to 0%. Furthermore, it can differentially cool different parts based on the CCT continuous cooling transformation curve characteristics of the H-beam and the requirements for controlling cooling process parameters, thereby effectively and accurately controlling the cooling rate at different locations of the hot-rolled H-beam. This results in the desired uniform microstructure and mechanical properties, thus solving the problems of uneven microstructure and properties caused by inhomogeneous cooling rates and phase transformations during H-beam cooling, as well as cracking due to residual stress.

Description

Technical Field

[0001] This invention relates to the field of steel rolling technology, and more particularly to a graded aerosol cooling ring for hot-rolled H-beams. Background Technology

[0002] For the past 20 years, my country's hot-rolled H-beams have been cooled using air cooling and QST quenching methods. While improving strength, this inevitably leads to problems such as high alloy costs, easy surface rust formation, poor shape, and susceptibility to cracking. H-beams have an asymmetrical cross-section; due to differences in thickness, deformation, and temperature at different locations, cooling rates vary. Conventional air cooling can cause bending, while QST quenching, with its large water volume, leads to severe localized water accumulation, resulting in uneven microstructure and poor shape. To improve the cooling efficiency of hot-rolled H-beams, enhance overall microstructure uniformity, and reduce post-rolling straightening, subsequent cooling needs to employ different cooling rates and paths for different locations to achieve uniform phase transformation, thereby improving the strength, plasticity, low-temperature toughness, and other mechanical properties, as well as the shape. Therefore, it is necessary to develop a method and device for hot-rolled H-beams that provides sufficient cooling capacity and rate while allowing for precise control of the cooling length at the final rolling temperature (800-1100℃). Water mist cooling, which involves mixing water and gas (air or nitrogen), offers advantages such as a large water volume and flexible arrangement and assembly (individual or in groups / sections), resulting in a wide cooling rate range. However, water mist nozzles, due to their large water volume and the requirement to control the air-to-water ratio (or simply air-to-water ratio) between 30 and 5, and the fact that most designed water mist nozzles are single units relying on internal mixing chambers for atomization, suffer from complex piping, difficult mixing chamber design and fabrication, and challenging maintenance, ultimately failing to meet practical needs. Summary of the Invention

[0003] Based on the above analysis, the present invention aims to provide a graded aerosol cooling ring for hot-rolled H-beams to solve problems such as uneven microstructure and properties caused by uneven cooling rate and phase transformation during the H-beam cooling process, as well as cracking caused by residual stress.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A graded aerosol cooling ring for hot-rolled H-beams includes a first flange and a second flange. The first flange and the second flange are respectively connected to an annular gas distribution box and an annular water distribution box through a central hole. The annular gas distribution box and the annular water distribution box are arranged parallel to each other along the cooling direction. 10-20 mixing chambers are provided between the annular gas distribution box and the annular water distribution box, and 10-20 nozzles are provided on each mixing chamber.

[0006] Furthermore, the outside of the mixing chamber is fixedly connected to the first mounting base, the second mounting base, the third mounting base, and the fourth mounting base by bolts, respectively. The first mounting base and the second mounting base are arranged opposite to each other, and the third mounting base and the fourth mounting base are arranged opposite to each other.

[0007] Furthermore, the first mounting base is connected to the annular air distribution box through an air inlet, and the second mounting base is connected to the annular water distribution box through a water inlet.

[0008] Furthermore, the annular gas distribution box and the annular water distribution box have the same shape, both being H-shaped structures.

[0009] Furthermore, the mixing chamber is provided with 10-20 water holes and 10-20 air holes, with the water holes and air holes being arranged in a one-to-one correspondence.

[0010] Furthermore, the cross-section of the mixing cavity is approximately ellipsoidal.

[0011] Furthermore, one side of the mixing chamber is connected to the annular water distribution box through a water hole, and the other side of the mixing chamber is connected to the annular air distribution box through an air hole.

[0012] Furthermore, the upper and lower sides of the mixing chamber are fixedly connected to the annular gas distribution box and the annular water distribution box, respectively.

[0013] Furthermore, the nozzle includes at least two spray angles: one nozzle has a spray angle of 30-90°, and the other nozzle has a spray angle of 90-150°.

[0014] Furthermore, taking the cooling direction of the H-beam steel plate as a reference, the installation angle of the nozzle is 30-150°.

[0015] Furthermore, the nozzle outlet has an orifice diameter of 0.5-8 mm and a cooling rate of 1-200℃ / s.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0017] (1) The graded air mist cooling ring of the present invention differs from the existing water mist cooling nozzles mainly in that the air-water flow ratio (or simply air-water ratio) has a wide control range, which can be adjusted at will from 40 to 0. It can also perform differential cooling according to the characteristics of the CCT continuous cooling transformation curve of H-beam and the requirements of controlling cooling process parameters, targeting the temperature gradient difference of different parts, thereby effectively and accurately controlling the cooling rate of different positions of hot-rolled H-beam, obtaining the required uniform microstructure and mechanical properties, thus solving the problems of uneven microstructure and properties caused by uneven cooling rate and phase transformation during the cooling process of H-beam and cracking caused by residual stress.

[0018] (2) The nozzles of the present invention are installed and applied in a grouped and segmented manner between the roughing mill and the finishing mill of hot-rolled H-beams or in the air mist cooling device arranged after the universal finishing mill. This effectively improves the heat exchange efficiency of hot-rolled H-beams and optimizes the cooling path of hot-rolled H-beams. While significantly improving the strength of hot-rolled H-beams, it not only avoids the uneven structure between the surface and core of the H-beams and the generation of surface red rust, but also ensures the plate shape and low residual stress after straightening.

[0019] (3) The graded mist cooling ring of the present invention vaporizes instantaneously in the high temperature zone (1050~700℃) of the final rolling temperature of hot-rolled H-beam when the water supply and air supply conditions reach the required water pressure, water volume, air pressure and air volume range, and carries away a large amount of latent heat of vaporization phase change, so that the hot-rolled H-beam can obtain uniform and rapid cooling.

[0020] (4) In this invention, the nozzle cross-section at different positions is selected by the area covered, so that the nozzle jet forms a fixed flat shape. On the one hand, the vertical direct spray fan shape uniformly covers the entire H-beam cross-section. On the other hand, by adjusting the installation angle, the coverage length of the fan-shaped mist along the rolling direction of the hot H-beam is increased. This not only reduces the attenuation and escape of the jet in the air caused by air-water mixing and atomization, but also concentrates the jet on the surface of the hot H-beam, maximizing the utilization of the atomized jet. Moreover, the cooling effect is more uniform, thereby enabling the hot-rolled H-beam to obtain a good, stable, and rapid cooling curve.

[0021] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0022] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0023] Figure 1 This is a partial physical diagram of the overall external structure of an aerosol ring according to the present invention;

[0024] Figure 2 This is a front view of an aerosol ring according to the present invention;

[0025] Figure 3 This is a top view of an aerosol ring according to the present invention;

[0026] Figure 4 This is a side view of an aerosol ring according to the present invention;

[0027] Figure 5 This is a schematic diagram showing the connection positions of the annular air distribution box, the annular water distribution box, and the mixing chamber in an aerosol ring according to the present invention.

[0028] Figure 6 This is a schematic diagram of the nozzle installation position in Embodiment 1 of the present invention;

[0029] Figure 7 This is a physical image of a nozzle according to the present invention;

[0030] Figure 8 This is a physical diagram showing the installation angle of the nozzle in Embodiment 1 of the present invention;

[0031] Figure 9 This is a diagram showing typical aerosol shape and size test data of the aerosol cooling ring of the present invention.

[0032] Figure label:

[0033] 1-First flange, 11-Air inlet, 2-Second flange, 21-Water inlet, 3-First mounting base, 31-First nozzle, 32-First and second nozzles, 4-Second mounting base, 41-Second nozzle, 42-Second and second nozzles, 5-Third mounting base, 51-Third nozzle, 52-Third and second nozzle, 53-Third and third nozzle, 54-Third and fourth nozzle, 55-Third and fifth nozzle, 6-Fourth mounting base, 61-Fourth nozzle, 62-Fourth and second nozzle, 63-Fourth and third nozzle, 64-Fourth and fourth nozzle, 65-Fourth and fifth nozzle, 7-Annular air distribution box, 71-Air hole, 8-Annular water distribution box, 81-Water hole, 9-Mixing chamber, 91-Protective cover, 10-Nozzle. Detailed Implementation

[0034] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0035] A specific embodiment of the present invention, such as Figure 1-8 As shown, a graded aerosol cooling ring for hot-rolled H-beams is disclosed, including a first flange 1 and a second flange 2. The first flange 1 and the second flange 2 are respectively connected to an annular air distribution box 7 and an annular water distribution box 8 through a central hole. The annular air distribution box 7 and the annular water distribution box 8 are arranged parallel to each other along the cooling direction. 10-20 mixing chambers 9 are arranged between the annular air distribution box 7 and the annular water distribution box 8. 10-20 nozzles 10 are arranged on the mixing chambers 9.

[0036] Compared with the prior art, the graded aerosol cooling ring of the present invention is equipped with multiple nozzles on the mixing chamber 9. Each nozzle can adjust the cooling rate individually by adjusting the core process parameters such as the air-water flow ratio, outlet diameter, and outlet angle. This allows for differentiated cooling based on the temperature gradient difference at different locations of the H-beam according to the requirements of the controlled cooling process parameters. Combined with subsequent grouping and segmentation, the cooling path can be optimized, thereby obtaining the required uniform microstructure and mechanical properties. This solves the problems of uneven microstructure and properties caused by uneven cooling rate and phase transformation during the H-beam cooling process, as well as cracking caused by residual stress.

[0037] A physical diagram of a nozzle according to the present invention is shown below. Figure 7 As shown, the installation angle is as follows Figure 8 As shown.

[0038] In a specific implementation, such as Figure 2-3 As shown, the outside of the mixing chamber is fixedly connected to the first mounting base 3, the second mounting base 4, the third mounting base 5 and the fourth mounting base 6 respectively by T-bolts. The first mounting base 3 and the second mounting base 4 are arranged opposite to each other, and the third mounting base 5 and the fourth mounting base 6 are arranged opposite to each other.

[0039] The first mounting base 3 is connected to the annular air distribution box 7 through the air inlet 11, and the second mounting base 4 is connected to the annular water distribution box 8 through the water inlet 21.

[0040] In one specific embodiment, the annular air distribution box 7 and the annular water distribution box 8 have the same shape, both being H-shaped structures. The H-shaped steel passes through the middle of the air mist cooling ring for cooling.

[0041] In one specific embodiment, the mixing chamber 9 is provided with 10-20 water holes 81 and 10-20 air holes 71, with the water holes 81 and air holes 71 arranged in a one-to-one correspondence.

[0042] In a preferred embodiment, the cross-section of the mixing cavity 9 is approximately ellipsoidal.

[0043] In one specific embodiment, the mixing chamber 9 is provided with a spiral inspection hole, and a protective sleeve 91 is provided on the outside of the spiral inspection hole.

[0044] If an instruction manual is required, the purpose of the spiral inspection hole is to facilitate quick maintenance and repair. The spiral inspection holes in this invention are all existing technologies and will not be described in detail.

[0045] In one specific embodiment, one side of the mixing chamber 9 is connected to the annular water distribution box 8 through a water hole 81, and the other side of the mixing chamber is connected to the annular air distribution box 7 through an air hole 71.

[0046] In one specific embodiment, the upper and lower sides of the mixing chamber 9 are fixedly connected to the annular gas distribution box 7 and the annular water distribution box 8, respectively, for example, by means of O-ring gaskets and fixing bolts.

[0047] In one specific embodiment, the mist in the mixing chamber 9 is sprayed through nozzles onto the web, flanges, R-angle, and other parts of the H-beam for cooling.

[0048] In one specific embodiment, the nozzle includes at least two spray angles: one nozzle spray angle is 30-90°, and the other nozzle spray angle is 90-150°.

[0049] In one specific implementation, with the cooling direction of the H-beam steel plate as a reference, the installation angle of the nozzle is 30-150°.

[0050] In one specific embodiment, the nozzle outlet has an orifice diameter of 0.5-8 mm and a cooling rate of 1-200 °C / s.

[0051] It should be noted that the nozzle outlet diameter in this invention is set to 0.5-8mm, and by adjusting the pressure and flow rate of the air and water, a cooling rate of 1-200℃ / s can be obtained. The staged aerosol cooling ring of this invention, when the water and air supply conditions reach the required water pressure, water volume, air pressure, and air volume range, instantaneously vaporizes within the high-temperature zone (1050-700℃) of the final rolling temperature of the hot-rolled H-beam, carrying away a large amount of latent heat of vaporization phase transformation, thus enabling the hot-rolled H-beam to achieve highly efficient aerosol cooling.

[0052] It should be noted that the nozzle cross-section at different locations is selected based on the coverage area, ensuring that the nozzle jet forms a fixed flat shape. On one hand, the vertically directed fan-shaped jet uniformly covers the entire H-beam cross-section. On the other hand, adjusting the installation angle increases the coverage length of the fan-shaped atomization along the rolling direction of the hot H-beam. This not only reduces the attenuation and escape of the jet in the air caused by air-water mixing and atomization, but also concentrates the jet on the surface of the hot H-beam, maximizing the utilization of the atomized jet. Furthermore, the cooling effect is more uniform, resulting in a good, stable, and rapid cooling curve for the hot-rolled H-beam.

[0053] It is worth noting that the number of nozzles in this invention is not specifically limited, as long as the surface of the hot H-beam can be fully cooled. Those skilled in the art can adjust the installation angle according to the size of the H-beam to ensure that the curved surface of the hot H-beam is fully cooled. Furthermore, the aerosol ring of this invention is not limited to cooling H-beams, but is also suitable for cooling structural steel, plates, strips, pipes, etc.

[0054] In this invention, the impact force of each nozzle is 0.8–100 kg / mm. 2 This can effectively prevent the formation of red rust and the damage of iron oxide scale on the surface of H-beams, and delay rusting.

[0055] The aerosol cooling ring described in this invention can operate at air pressures of 0.1–1.8 MPa and temperatures of 50–1000 Nm. 3 Within the flow rate range, the area of ​​aerosol particle size distribution can be flexibly adjusted to achieve an aerosol size of 30–500 μm. Typical aerosol shape and size test data of the aerosol cooling ring in this invention are shown in the figure below. Figure 9 As shown. The aerosol cooling ring of the present invention enables hot-rolled H-beams to increase the proportion of vaporization cooling in mixed cooling (including contact cooling, film boiling cooling, and vaporization cooling) to varying degrees under the same initial conditions of final rolling temperature, thereby obtaining different heat exchange efficiencies and cooling rates.

[0056] The nozzles of this invention are installed and applied in groups and segments in the air mist cooling device arranged between the roughing and finishing mills of hot-rolled high-strength H-beams or after the universal finishing mill. This effectively improves the heat exchange efficiency of hot-rolled H-beams and optimizes the cooling path of hot-rolled H-beams. While significantly improving the strength of hot-rolled H-beams, it not only avoids the uneven structure between the surface and core of the H-beam (formation of martensite rings on the surface of the H-beam cross-section) and the formation of surface red rust, but also inhibits the precipitation of carbides in high-carbon steel and ensures the shape of the straightened plate and low residual stress.

[0057] The aerosol cooling ring described in this invention can achieve three modes: single-air, single-water, and water-vapor mixture. It also provides different cooling intensities for different cooling zones, with a total water flow rate of 100-10000 t / h and a total air flow rate of 100-4000 m³ / h. 3 / h, air-to-water ratio 40~0, heat transfer coefficient 500~20000W / (℃*m) 2 The cooling rate can be adjusted within the range of 1-200℃ / s.

[0058] The technical effects of the present invention will be further explained below with reference to specific embodiments.

[0059] Example 1

[0060] This embodiment uses a 300*300mm H-beam as an example. A total of 14 nozzles and 14 mixing chambers are provided. Figure 2-6 As shown, the first nozzle 31, the first second nozzle 32, the second first nozzle 41, the second second nozzle 42, the third first nozzle 51, the third third nozzle 53, the third fifth nozzle 55, the fourth first nozzle 61, the fourth third nozzle 63, and the fourth fifth nozzle 65 all have a spray angle of 100°, spraying out at a pressure of 0.4 MPa, with a total water flow rate of 100 t / h and a total air flow rate of 3000 m³ / h. 3 The air-to-water ratio is 30, and the injection angles of the third and second nozzles (52, 54, 62, and 64) are all 60°. The water is injected at a pressure of 0.7 MPa, with a total water flow rate of 10000 t / h and a total air flow rate of 100 m³ / h. 3 / h, air-to-water ratio 0.1.

[0061] Based on the cooling direction of the H-beam steel plate, the installation angles of the first nozzle 31, the second nozzle 32, the second nozzle 41, the second nozzle 42, the third nozzle 51, the third nozzle 52, the third nozzle 53, the third nozzle 54, the third nozzle 55, the fourth nozzle 61, the fourth nozzle 62, the fourth nozzle 63, the fourth nozzle 64, and the fourth nozzle 65 are all 90°.

[0062] The orifice diameter of the outlets of the first nozzle 31, the first second nozzle 32, the second first nozzle 41, the second second nozzle 42, the third first nozzle 51, the third second nozzle 52, the third third nozzle 53, the third fourth nozzle 54, the third fifth nozzle 55, the fourth first nozzle 61, the fourth second nozzle 62, the fourth third nozzle 63, the fourth fourth nozzle 64, and the fourth fifth nozzle 65 is 5mm. The cooling rate of the aerosol cooling ring in this embodiment is 10℃ / s.

[0063] This embodiment describes a graded air mist cooling ring for hot-rolled H-beams, comprising a first flange 1 and a second flange 2. The first flange 1 is connected to an annular air distribution box 7 and an annular water distribution box 8 through a central hole.

[0064] Specifically, the outside of the mixing chamber 9 is fixedly connected to the first mounting base 3, the second mounting base 4, the third mounting base 5, and the fourth mounting base 6 respectively by T-bolts. The first mounting base 3 and the second mounting base 4 are arranged opposite to each other, and the third mounting base 5 and the fourth mounting base 6 are arranged opposite to each other.

[0065] The annular air distribution box 7, the annular water distribution box 8, and the mixing chamber 9 are identical in shape and have an H-shaped structure. The mixing chamber 9 is provided with 14 water holes 81 and 14 air holes 71, with each water hole 81 and air hole 71 corresponding to the previous one. The cross-section of the mixing chamber 9 is approximately ellipsoidal.

[0066] In a further technical solution, a spiral inspection hole is provided on the mixing chamber 9, and a protective sleeve 91 is provided on the outside of the spiral inspection hole.

[0067] like Figure 5 As shown, one side of the mixing chamber 9 is connected to the annular water distribution box 8 through a water hole 81, and the other side of the mixing chamber is connected to the annular air distribution box 7 through an air hole 71.

[0068] Specifically, the mixing chamber 9 is externally fixedly connected to the first mounting base 3, the second mounting base 4, the third mounting base 5, and the fourth mounting base 6 by T-bolts.

[0069] The upper and lower sides of the mixing chamber 9 are fixedly connected to the annular gas distribution box 7 and the annular water distribution box 8, respectively, for example, by means of O-ring gaskets and fixing bolts.

[0070] The mist in the mixing chamber 9 is sprayed through nozzles onto the web, flanges, R-angle, and other parts of the H-beam for cooling.

[0071] 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 changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A graded aerosol cooling ring for hot-rolled H-beams, characterized in that, It includes a first flange and a second flange, which are respectively connected to an annular gas distribution box and an annular water distribution box through a central hole. The annular gas distribution box and the annular water distribution box are arranged parallel to each other along the cooling direction. 10-20 mixing chambers are arranged between the annular gas distribution box and the annular water distribution box. 10-20 nozzles are arranged on each mixing chamber. The cross-section of each mixing chamber is approximately ellipsoidal. The annular gas distribution box and the annular water distribution box are the same, both being H-shaped structures; The mixing chamber is provided with 10-20 water holes and 10-20 air holes, and the water holes and air holes are provided in a one-to-one correspondence. The nozzle includes at least two spray angles: one nozzle spray angle is 30-90°, and the other nozzle spray angle is 90-150°. Based on the cooling direction of the H-beam steel plate, the installation angle of the nozzle is 30-150°. The orifice diameter of the nozzle outlet is 0.5-8mm, and the cooling rate is 1-200℃ / s. The air-to-water flow ratio of the aerosol cooling ring is adjustable from 40 to 0.

2. The graded atomizing cooling ring for hot-rolled H-beams according to claim 1, characterized in that, The mixing chamber is fixedly connected to the first mounting base, the second mounting base, the third mounting base and the fourth mounting base by bolts. The first mounting base and the second mounting base are arranged opposite to each other, and the third mounting base and the fourth mounting base are arranged opposite to each other.

3. A graded aerosol cooling ring for hot-rolled H-beams according to claim 2, characterized in that, The first mounting base is connected to the annular air distribution box through an air inlet, and the second mounting base is connected to the annular water distribution box through a water inlet.

4. A graded aerosol cooling ring for hot-rolled H-beams according to claim 1, characterized in that, One side of the mixing chamber is connected to the annular water distribution box through a water hole, and the other side of the mixing chamber is connected to the annular air distribution box through an air hole.

5. A graded aerosol cooling ring for hot-rolled H-beams according to claim 1, characterized in that, The upper and lower sides of the mixing chamber are fixedly connected to the annular gas distribution box and the annular water distribution box, respectively.

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