Design method of water-saving descaling ring

Abstract

The invention discloses a water-saving descaling ring design method, which comprises the following steps of: calculating a contact part of a rolled piece and a roller in a rolling deformation process so as to judge a position needing to be descaled, arranging no descaling nozzle at the position needing not to be descaled according to a calculation result, and determining the position of the nozzle when the descaling ring is designed. And water is saved on the premise that the descaling requirement is met.

Description

Technical Field

[0001] The invention relates to a field, and in particular to a design method for a water-saving descaling ring. Background Art

[0002] In the production of hot-rolled bars and profiles, high-pressure water descaling of the rolled materials before entering the rolling mill is an important part of surface quality control. Descaling rings are common descaling devices for hot-rolled bars and profile production lines. In the design process of descaling rings, the nozzle striking distance and the spacing between adjacent nozzles are two main factors that affect the descaling effect. The nozzle striking distance directly affects the descaling striking force, while the nozzle spacing determines the overlap of the adjacent nozzle striking range. Reducing the descaling striking distance is conducive to improving the striking force, thereby obtaining a better descaling effect, but at the same time, after the striking distance is reduced, the coverage range of a single nozzle will be reduced accordingly, so the nozzle spacing must also be reduced accordingly to ensure that there is no striking blind area between adjacent nozzles. A reduction in the nozzle spacing will increase the number of nozzles, that is, the total water flow rate increases.

[0003] The increase in water volume will generate corresponding costs and place higher requirements on water pumps. Considering that during the hot rolling process of general bars and profiles, only two sides of the rolled pieces are in contact with the rolls when passing through a rolling mill stand (the upper and lower sides are in contact with the rolls for flat rolling; the side surfaces are in contact with the rolls for vertical rolling), the side surfaces of the rolled pieces do not contact the rolls when passing through the flat rolling stand, and the corresponding positions do not need to be descaled. The oxide scale can be removed by rolling deformation, so the number of nozzles can be reduced to achieve the purpose of water saving.

[0004] However, according to the hole type and reduction of the roll, a part of the side of the rolled piece near the corner will also contact the roll during the flat rolling process, and this part needs to be descaled. Therefore, it is necessary to develop a new descaling ring design method to calculate the contact part between the rolled piece and the roll during the rolling deformation process, so as to determine the position that needs to be descaled to achieve the purpose of water saving. Summary of the invention

[0005] Purpose of the invention: In view of the shortcomings and defects of the prior art, the present invention provides a water-saving descaling ring design method, which calculates the contact portion between the rolled piece and the rolling roller during the rolling deformation process to determine the position where descaling is required. According to the calculation results, descaling nozzles are not set at positions where descaling is not required. The nozzle position is determined when designing the descaling ring, thereby saving water while meeting the descaling requirements.

[0006] Technical solution: A water-saving descaling ring design method of the present invention is characterized by comprising the following steps:

[0007] 1) Determine the striking distance and nozzle spacing d of the descaling nozzle. 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 intervals of width d from both ends to the middle in the height direction until the remaining width at the center position is no greater than d; each interval represents the striking range of a nozzle; the number of intervals is n2;

[0009] 3) Establish rolling finite element model:

[0010] The model is a three-dimensional model, which contains three parts, namely the rolled material and the upper and lower rollers. In the finite element analysis software, the rollers are drawn according to the actual size.

[0011] Draw a three-dimensional model of the rolled material, and divide the rolled material into n2 domains along the longitudinal direction according to the division result of step 2); and divide it into 2 domains in the transverse direction; the whole rolled material is divided into 2n2 domains;

[0012] 4) Set material properties:

[0013] Set the material properties of the blank under working conditions; for the roll, set its properties to rigidity;

[0014] 5) Set initial conditions and boundary conditions:

[0015] Setting contact conditions: setting contact between the roller surface and the surface of the rolled material, and setting the friction coefficient of the contact surface;

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

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

[0018] 6) Splitting: using hexahedral units to split the rolled material;

[0019] 7) Carry out transient process calculation on the established model;

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

[0021] Extract the contact pressure of all nodes on the side of a domain in any 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 domain does not contact the roll during the rolling process, and the descaling nozzle does not need to be set at the corresponding position; if there is contact pressure, it means that the position will contact the roll during the rolling process, and the descaling nozzle needs to be set at the corresponding position;

[0022] The above operation is performed for all 2n2 domains; it is determined whether nozzles need to be set at corresponding positions to complete the design of water-saving descaling rings.

[0023] Wherein, in the step 3), when the roller is drawn according to the actual size, it is a rotating body with a certain hole shape.

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

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

[0026] Wherein, in the step 6), when the rolled material is split, the unit size of the split is not greater than d / 2.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: The present invention determines the position that needs descaling by calculating the contact portion between the rolled piece and the rolling roller during the rolling deformation process. According to the calculation result, no descaling nozzle is set at the position where descaling is not required. The nozzle position is determined when designing the descaling ring, which saves water while meeting the descaling requirements, thereby reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A schematic diagram of a roll pass structure of an embodiment of the present invention;

[0029] Figure 2 A cross-sectional domain diagram of an embodiment of the present invention;

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

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

[0032] Figure 5 This is a diagram of the maximum contact stress during the rolling process of an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0034] The present invention relies on the finite element calculation method to calculate the contact part between the rolled piece and the roller during the rolling deformation process, so as to determine the position that needs to be descaled. According to the calculation result, no descaling nozzle is set at the position on the side that does not need to be descaled, thereby realizing the design of a water-saving descaling ring.

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

[0036] 1) Determine the striking distance and nozzle spacing d of the descaling nozzle. 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 intervals of width d from both ends to the middle in the height direction until the remaining width at the center position is no greater than d; each interval represents the striking range of a nozzle; the number of intervals is n2;

[0038] 3) Establish rolling finite element model:

[0039] The model is a three-dimensional model, which contains three parts, namely the rolled material and the upper and lower rollers. In the finite element analysis software, the rollers are drawn according to the actual size, which are usually a rotating body with a certain hole shape.

[0040] Draw a three-dimensional model of the rolled material. The rolled material is usually a square or rectangular cross section. According to the result of the division in step 2), the rolled material is divided into n2 domains in the longitudinal direction; and 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 blank under working conditions, including density, elastic modulus, yield strength, Poisson's ratio and hardening function model; for the roll, set its properties to rigidity;

[0043] 5) Set initial conditions and boundary conditions:

[0044] Setting contact conditions: setting contact between the roller surface and the surface of the rolled material, and setting the friction coefficient of the contact surface;

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

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

[0047] 6) Perform segmentation, using hexahedral units to segment the rolled material, and the size of the segmented unit is not greater than d / 2;

[0048] 7) Carry out transient process calculation on the established model;

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

[0050] Extract the contact pressure of all nodes on the side of a domain in any 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 domain does not contact the roll during the rolling process, and the descaling nozzle does not need to be set at the corresponding position; if there is contact pressure, it means that the position will contact the roll during the rolling process, and the descaling nozzle needs to be set at the corresponding position;

[0051] The above operation is performed for all 2n2 domains; it is determined whether nozzles need to be set at corresponding positions to complete the design of water-saving descaling rings.

[0052] Example:

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

[0054] 1. The ideal striking distance of the descaling nozzle is 100mm. At this distance, the descaling nozzle spacing needs to be set to 50mm. The billet width is 350mm, the height is 250mm, the length is 1000mm, and the corner radius is 10mm. The roll pass is as follows Figure 1 The rolling process is horizontal rolling, the reduction is 45mm, and the roller speed is 50rpm.

[0055] 2. According to this parameter, the descaling ring needs to be equipped with 7 nozzles horizontally and divided into 5 sections of 50 mm in length vertically.

[0056] 3. Draw the size of the geometry:

[0057] (a) In the finite element analysis software, draw the upper and lower roll pass shapes.

[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 with a length of 1000 mm. Divide the cross section into 10 domains using the above method and name them Domain 1 to Domain 10. Figure 2 The lateral positions corresponding to these 10 domains are potential locations where descaling nozzles may be set.

[0059] 4. Set material properties:

[0060] (a) The density of the blank is set to 7400 kg / m 3 ; Elastic modulus 1.00GPa; Poisson's ratio 0.3; Using ideal plasticity model, yield strength 30MPa.

[0061] (b) The rollers are set rigid.

[0062] 5. Set initial conditions and boundary conditions:

[0063] (a) Contact is set up as above, with the friction coefficient set to 0.6.

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

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

[0066] 6. The blank is segmented, where the size of the P region d0 is set to 10 mm. The mesh after segmentation is as follows: Figure 3 shown.

[0067] 7. Calculate the model. The duration of the transient model is 5s.

[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 shown.

[0070] (b) Extract the maximum value of the contact stress of the side nodes of each domain during the rolling process from the calculation results, such as Figure 5 As shown in the figure, it can be seen that, except for domain 1, domain 2 and domain 4, the contact stress of the remaining domains is always 0, indicating that the corresponding side surfaces at these positions will not contact the roller during the rolling process. That is, among the 10 side surface positions, only the side surface positions corresponding to domain 1, domain 2 and domain 4 need to be provided with nozzles, and the remaining 7 positions do not need to be provided with nozzles.

[0071] The present invention determines the position where descaling is required by calculating the contact portion between the rolled piece and the rolling roller during the rolling deformation process. According to the calculation result, no descaling nozzle is set at the position where descaling is not required. The nozzle position is determined when designing a descaling ring, and water is saved while meeting the descaling requirements, thereby reducing production costs.

Claims

1. A water-saving descaling ring design method, characterized in that: The steps include: 1) Determine the impact distance and nozzle spacing d of the descaling nozzle. 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 intervals of width d from both ends to the middle in the height direction until the remaining width at the center position is no greater than d; each interval represents the striking range of a nozzle; the number of intervals is n2; 3) Establish rolling finite element model: The model is a three-dimensional model, which contains three parts, namely the rolled material and the upper and lower rollers. In the finite element analysis software, the rollers are drawn according to the actual size. Draw a three-dimensional model of the rolled material, and divide the rolled material into n2 domains along the longitudinal direction according to the division result of step 2); and divide it into 2 domains in the transverse direction; the whole rolled material is divided into 2n2 domains; 4) Set material properties: Set the material properties of the blank under working conditions; for the roll, set its properties to rigidity; 5) Set initial conditions and boundary conditions: Setting contact conditions: setting contact between the roller surface and the surface of the rolled material, and setting the friction coefficient of the contact surface; Set the roller boundary conditions: set the displacement of the roller's rotation axis in all directions to 0, and set the roller's rotation speed around the rotation axis; Set the initial conditions of the billet: set the initial speed of the billet before it enters the rolling mill; 6) Splitting: using hexahedral units to split the rolled material; 7) Carry out transient process calculation on the established model; 8) After the calculation is completed, the following post-processing steps are performed: Extract the contact pressure of all nodes on the side of a domain in any 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 domain does not contact the roll during the rolling process, and the descaling nozzle does not need to be set at the corresponding position; if there is contact pressure, it means that the position will contact the roll during the rolling process, and the descaling nozzle needs to be set at the corresponding position; The above operation is performed for all 2n2 domains; it is determined whether nozzles need to be set at corresponding positions to complete the design of water-saving descaling ring.

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

3. The water-saving descaling ring design method according to claim 1 is characterized in that: In the 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 is characterized in that: In the step 4), the blank material properties 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 is characterized in that: In the step 6), when the rolled material is split, the unit size of the split is not greater than d / 2.

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