Water-saving descaling ring design method

Abstract

The application discloses a water-saving descaling ring design method. The method calculates the contact part of a rolled piece with a roller in a rolling deformation process, thereby judging the position requiring descaling. According to the calculation result, a descaling nozzle is not arranged at the position not requiring descaling, so that the nozzle position is determined in the design of the descaling ring, and water consumption is saved under the premise of meeting the descaling requirement.

Description

Technical Field

[0001] This invention relates to the field of water conservation, and more particularly to a water-saving descaling ring design method. Background Technology

[0002] In the production of hot-rolled bars and sections, high-pressure water descaling before entering the rolling mill is a crucial step in surface quality control. Descaling rings are common descaling devices in hot-rolled bar and section production lines. In the design of descaling rings, the nozzle striking distance and the spacing between adjacent nozzles are two main factors affecting the descaling effect. The nozzle striking distance directly affects the descaling impact force, while the nozzle spacing determines the overlap of the striking range of adjacent nozzles. Reducing the descaling striking distance helps to increase the impact force, thus achieving a better descaling effect. However, at the same time, with a reduced striking distance, the coverage area of ​​a single nozzle will correspondingly decrease. Therefore, the nozzle spacing must also be reduced accordingly to ensure that there are no blind spots between adjacent nozzles. Reducing the nozzle spacing increases the number of nozzles, i.e., increases the total water flow rate.

[0003] Increasing water volume will incur corresponding costs and place higher demands on water pumps. Considering that during the hot rolling process of bars and profiles, only two surfaces of the rolled piece contact the rolls when passing through a mill stand (the top and bottom surfaces of the rolled piece contact the rolls in flat rolling; the side surfaces of the rolled piece contact the rolls in vertical rolling), the side surfaces of the rolled piece do not contact the rolls when passing through a flat rolling mill stand. Therefore, descaling can be omitted at the corresponding positions, and the iron oxide scale can be removed by rolling deformation. This reduces the number of nozzles and achieves water conservation.

[0004] However, depending on the roll pass and reduction, a portion of the workpiece near the corner will also come into contact with the rolls during the flat rolling process, and this portion requires descaling. Therefore, a novel descaling ring design method needs to be developed to calculate the contact area between the workpiece and the rolls during the rolling deformation process, thereby determining the location where descaling is required and achieving water conservation. Summary of the Invention

[0005] Purpose of the invention: To address the shortcomings and defects of existing technologies, this invention provides a water-saving descaling ring design method. By calculating the contact area between the workpiece and the roll during the rolling deformation process, the location where descaling is required is determined. Based on the calculation results, descaling nozzles are not installed in locations where descaling is not required. This method is used to determine the nozzle position when designing the descaling ring, saving water while meeting the descaling requirements.

[0006] Technical solution: The present invention provides a water-saving descaling ring design method, characterized by comprising the following steps:

[0007] 1) Determine the striking distance and nozzle spacing d of the descaling nozzles. The width of the rolled piece is W, the height is H, and the number of nozzles n1 required in the transverse direction should satisfy n1d>W.

[0008] 2) Preset the nozzle position longitudinally, and gradually divide the height direction into intervals of width d from both ends toward the middle until the remaining width at the center position is no higher than d; each interval represents the hitting range of one nozzle; the number of intervals is n2;

[0009] 3) Establish a finite element model for rolling:

[0010] The model is a three-dimensional model containing three components: the rolled material and the upper and lower rolls. The rolls are drawn according to their actual dimensions in the finite element analysis software.

[0011] Draw a three-dimensional model of the rolled material. According to the result of step 2), divide the rolled material into n2 domains along the longitudinal direction; at the same time, divide it into 2 domains in the transverse direction; the entire rolled material is divided into 2n2 domains.

[0012] 4) Set material properties:

[0013] Set the material properties of the billet under operating conditions; for the roll, set its properties to rigid.

[0014] 5) Set initial and boundary conditions:

[0015] Set contact conditions: Set contact between the surface of the roll and the surface of the rolled material, and set the friction coefficient of the contact surface;

[0016] Set the boundary conditions for the rolls: set the displacement of the roll's rotation axis in all directions to 0, and set the rotational speed of the roll around the rotation axis;

[0017] Set the initial conditions for the billet: Set the initial speed of the billet before it enters the rolling mill;

[0018] 6) Perform splitting, using hexahedral elements to split the rolled material;

[0019] 7) Perform transient process calculations on the established model;

[0020] 8) After the calculation is completed, perform the following post-processing steps:

[0021] Extract the contact pressure of all nodes on the side of a certain region in any cross section of the rolled material during the rolling process. If the contact pressure of all nodes is close to 0, it is considered that the region does not contact the roll during the rolling process, and the corresponding position does not need to be equipped with a descaling nozzle; if there is contact pressure, it means that the position will contact the roll during the rolling process, and the corresponding position needs to be equipped with a descaling nozzle.

[0022] Perform the above operations on all 2n2 domains; determine whether nozzles need to be installed at the corresponding positions, and complete the design of the water-saving descaling ring.

[0023] In step 3), when drawing the roll according to the actual dimensions, it is a rotating body with a certain hole shape.

[0024] In step 3), when drawing the three-dimensional model of the rolled material, the rolled material has a square or rectangular cross-section.

[0025] In step 4), the material properties of the billet are set, including density, elastic modulus, yield strength, Poisson's ratio and hardening function model.

[0026] In step 6), when the rolled material is split, the size of the split unit is no greater than d / 2.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The present invention calculates the contact part between the workpiece and the roll during the rolling deformation process to determine the location where descaling is required. Based on the calculation results, descaling nozzles are not set in the locations where descaling is not required. This is used to determine the nozzle position when designing the descaling ring, saving water while meeting the descaling requirements and reducing production costs. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the roll pass structure according to an embodiment of the present invention;

[0029] Figure 2 This is a cross-sectional domain division diagram of an embodiment of the present invention;

[0030] Figure 3 This is a cross-sectional view of an embodiment of the present invention;

[0031] Figure 4 Post-rolling deformation diagram drawn for an embodiment of the present invention

[0032] Figure 5 This is a diagram showing the maximum contact stress during the rolling process in an embodiment of the present invention. Detailed Implementation

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] This invention relies on the finite element method to calculate the contact part between the workpiece and the roll during the rolling deformation process, thereby determining the location where descaling is required. Based on the calculation results, descaling nozzles are not set in the side positions where descaling is not required, thus realizing the design of a water-saving descaling ring.

[0035] The water-saving descaling ring design method of the present invention includes the following steps:

[0036] 1) Determine the striking distance and nozzle spacing d of the descaling nozzles. The width of the rolled piece is W, the height is H, and the number of nozzles n1 required in the transverse direction should satisfy n1d>W.

[0037] 2) Preset the nozzle position longitudinally, and gradually divide the height direction into intervals of width d from both ends toward the middle until the remaining width at the center position is no higher than d; each interval represents the hitting range of one nozzle; the number of intervals is n2;

[0038] 3) Establish a finite element model for rolling:

[0039] The model is a three-dimensional model containing three parts: the rolled material and the upper and lower rolls. In the finite element analysis software, the rolls are drawn according to the actual dimensions, which are usually rotating bodies with a certain type of hole.

[0040] Draw a three-dimensional model of the rolled material. The rolled material is usually square or rectangular in cross-section. According to the result of step 2), the rolled material is divided into n2 domains along the longitudinal direction; at the same time, it is further divided into 2 domains in the transverse direction; the entire rolled material is divided into 2n2 domains.

[0041] 4) Set material properties:

[0042] Set the material properties of the billet under operating conditions, including density, elastic modulus, yield strength, Poisson's ratio, and hardening function model; for the roll, set its properties to rigid.

[0043] 5) Set initial and boundary conditions:

[0044] Set contact conditions: Set contact between the surface of the roll and the surface of the rolled material, and set the friction coefficient of the contact surface;

[0045] Set the boundary conditions for the rolls: set the displacement of the roll's rotation axis in all directions to 0, and set the rotational speed of the roll around the rotation axis;

[0046] Set the initial conditions for the billet: Set the initial speed of the billet before it enters the rolling mill;

[0047] 6) Perform splitting: use hexahedral elements to split the rolled material, and the size of the split element shall not be greater than d / 2;

[0048] 7) Perform transient process calculations on the established model;

[0049] 8) After the calculation is completed, perform the following post-processing steps:

[0050] Extract the contact pressure of all nodes on the side of a certain region in any cross section of the rolled material during the rolling process. If the contact pressure of all nodes is close to 0, it is considered that the region does not contact the roll during the rolling process, and the corresponding position does not need to be equipped with a descaling nozzle; if there is contact pressure, it means that the position will contact the roll during the rolling process, and the corresponding position needs to be equipped with a descaling nozzle.

[0051] Perform the above operations on all 2n2 domains; determine whether nozzles need to be installed at the corresponding positions, and complete the design of the water-saving descaling ring.

[0052] Example:

[0053] This embodiment describes a water-saving descaling ring design method for a certain profile:

[0054] 1. The ideal impact distance for the descaling nozzles is 100mm, at which point the nozzle spacing needs to be set to 50mm. The billet width is 350mm, height is 250mm, length is 1000mm, and corner radius is 10mm. The roll pass shape is as follows: Figure 1 As shown. The rolling process is cross rolling, with a reduction of 45 mm. The roll speed is 50 rpm.

[0055] 2. According to these parameters, the descaling ring needs to be equipped with 7 nozzles in the horizontal direction and divided into 5 sections with a length of 50mm in the vertical direction.

[0056] 3. Draw the dimensions of the geometric object:

[0057] (a) Draw the upper and lower roll pass patterns in the finite element analysis software.

[0058] (b) Draw a cuboid with a length of 1000 mm, a width of 350 mm, and a height of 200 mm. Add fillets with a radius of 10 to the four sides of the 1000 mm length. Divide the cross-section into 10 regions using the method described above, naming them Region 1 to Region 10 respectively. Figure 2 As shown. The side positions corresponding to these 10 domains are potential locations where descaling nozzles may need to be installed.

[0059] 4. Set material properties:

[0060] (a) The density of the billet is set to 7400 kg / m³. 3 Elastic modulus 1.00 GPa; Poisson's ratio 0.3; Yield strength 30 MPa using an ideal plastic model.

[0061] (b) The rolls are set to be rigid.

[0062] 5. Set initial and boundary conditions:

[0063] (a) Set the contact as described above, with the coefficient of friction set to 0.6.

[0064] (b) The displacement of the rotation axis of the roll in all directions is set to 0, and the roll speed is set to 50 rpm.

[0065] (e) The initial velocity of the billet is set to 1 m / s.

[0066] 6. Divide the billet into sections, where the size of region P (d0) is set to 10mm. The resulting mesh is as follows: Figure 3 As shown.

[0067] 7. Perform calculations on the model. The duration of the transient model is 5 seconds.

[0068] 8. Perform data post-processing:

[0069] (a) Select any section perpendicular to the rolling direction and draw the deformation after rolling, such as... Figure 4 As shown.

[0070] (b) Extract the maximum value of the contact stress over time at the side nodes of each domain during the rolling process from the calculation results, such as... Figure 5 As shown, except for domains 1, 2, and 4, the contact stress in the other domains is always 0, indicating that the corresponding sides at these locations will not contact the rolls during the rolling process. That is, only the side positions corresponding to domains 1, 2, and 4 need to be equipped with nozzles, while the other 7 positions do not need to be equipped with nozzles.

[0071] This invention calculates the contact area between the workpiece and the roll during the rolling deformation process to determine the location where descaling is required. Based on the calculation results, descaling nozzles are not installed in locations where descaling is not required. This invention is used to determine the nozzle position when designing the descaling ring, saving water while meeting descaling requirements and reducing production costs.

Claims

1. A water-saving descaling ring design method, characterized in that: Includes the following steps: 1) Determine the striking distance and nozzle spacing d of the descaling nozzles. The width of the rolled piece is W, the height is H, and the number of nozzles n1 required in the transverse direction should satisfy n1d>W. 2) Preset the nozzle position longitudinally, and gradually divide the height direction into intervals of width d from both ends toward the middle until the remaining width at the center position is no higher than d; each interval represents the hitting range of one nozzle; the number of intervals is n2; 3) Establish a finite element model for rolling: The model is a three-dimensional model containing three components: the rolled material and the upper and lower rolls. The rolls are drawn according to their actual dimensions in the finite element analysis software. Draw a three-dimensional model of the rolled material. According to the result of step 2), divide the rolled material into n2 domains along the longitudinal direction; at the same time, divide it into 2 domains in the transverse direction; the entire rolled material is divided into 2n2 domains. 4) Set material properties: Set the material properties of the billet under operating conditions; for the roll, set its properties to rigid. 5) Set initial and boundary conditions: Set contact conditions: Set contact between the surface of the roll and the surface of the rolled material, and set the friction coefficient of the contact surface; Set the boundary conditions for the rolls: set the displacement of the roll's rotation axis in all directions to 0, and set the rotational speed of the roll around the rotation axis; Set the initial conditions for the billet: Set the initial speed of the billet before it enters the rolling mill; 6) Perform splitting, using hexahedral elements to split the rolled material; 7) Perform transient process calculations on the established model; 8) After the calculation is completed, perform the following post-processing steps: Extract the contact pressure of all nodes on the side of a certain region in any cross section of the rolled material during the rolling process. If the contact pressure of all nodes is close to 0, it is considered that the region does not contact the roll during the rolling process, and the corresponding position does not need to be equipped with a descaling nozzle; if there is contact pressure, it means that the position will contact the roll during the rolling process, and the corresponding position needs to be equipped with a descaling nozzle. Perform the above operations on all 2n2 domains; determine whether nozzles need to be installed at the corresponding positions, and complete the design of the water-saving descaling ring.

2. The water-saving descaling ring design method according to claim 1, characterized in that: In step 3), when drawing the roll according to the actual dimensions, it is a rotating body with a certain hole shape.

3. The water-saving descaling ring design method according to claim 1, characterized in that: In step 3), when drawing the three-dimensional model of the rolled material, the rolled material has a square or rectangular cross-section.

4. The water-saving descaling ring design method according to claim 1, characterized in that: In step 4), the material properties of the billet are set, including density, elastic modulus, yield strength, Poisson's ratio, and hardening function model.

5. The water-saving descaling ring design method according to claim 1, characterized in that: In step 6), when the rolled material is split, the size of the split unit is no greater than d / 2.

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