A control method for preventing steel pipe surface from sticking steel

Abstract

The present application relates to steel pipe production and processing technology field, disclose a kind of control method for preventing steel pipe surface stick steel, comprising the following steps: billet cleaning treatment, before billet enters rolling mill, billet is cleaned and treated, remove surface dirt, oxide and other impurities;Cooling water control, ensure that rolling mill cooling water system normal operation, provide sufficient cooling water volume and proper cooling water pressure;Adjust cooling water nozzle, and the number of continuous rolling roller cooling water nozzle is set to 3-5, and to avoid the intersection of two water nozzles cooling fan-shaped surface of groove bottom, the blowing angle of two cooling water nozzles in the middle of cooling water ring is adjusted to 13-15 °.By using this control method, the downtime and maintenance cost of steel pipe production line can be reduced.Compared with the traditional mechanical cleaning or spraying anti-sticking agent method, this method is more efficient, and frequent downtime operation or anti-sticking agent replenishment is not required, and since the control method reduces downtime and maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of steel pipe production and processing technology, specifically to a control method for preventing steel from sticking to the surface of steel pipes. Background Technology

[0002] Steel adhesion to the surface of steel pipes refers to the phenomenon where, during hot continuous rolling, due to the high stress on the rolling rolls, some metal from the steel pipe surface peels off and adheres to the surface of the work rolls, damaging the surface quality of both the rolls and the rolled material. In the production of seamless steel pipes, the phenomenon becomes more severe with increasing pipe diameter-to-wall ratio and rolling load. Steel adhesion leads to uneven and rough surfaces on the steel pipes, seriously affecting their quality and processing results. Currently, some methods and technologies have been proposed to address this problem, but these methods still have limitations.

[0003] Traditional methods for preventing steel adhesion to the surface of steel pipes mainly rely on mechanical cleaning or spraying anti-adhesion agents. However, these methods have certain limitations and shortcomings. Mechanical cleaning usually requires machine shutdown, increasing production line downtime and maintenance costs, while spraying anti-adhesion agents requires frequent replenishment and maintenance, increasing workload and costs. Furthermore, these traditional methods often fail to meet the special requirements of some special steels or high-speed production lines, resulting in unsatisfactory results. Therefore, those skilled in the art propose a control method to prevent steel adhesion to the surface of steel pipes to solve the above problems. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a control method for preventing steel from adhering to the surface of steel pipes. This method solves the problem that existing technologies require machine shutdown to prevent steel from adhering to the surface of steel pipes, which increases production line downtime, maintenance costs, and workload.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a control method for preventing steel from adhering to the surface of a steel pipe, comprising the following steps:

[0006] The billet is cleaned before entering the rolling mill to remove oil, oxides and other impurities from its surface.

[0007] Cooling water control ensures the normal operation of the rolling mill cooling water system, providing sufficient cooling water volume and appropriate cooling water pressure;

[0008] Adjust the cooling water nozzles to set the number of cooling water nozzles for the continuous rolling mill to 3 to 5. In order to avoid the cross-flow of the cooling fan-shaped water surface of the two water nozzles at the bottom of the trough, adjust the spray angle of the two cooling water nozzles at the bottom of the rolling mill in the middle of the cooling water ring to 13 to 15°.

[0009] Adjust the rolling parameters of the continuous rolling mill rolls to make the wall thickness of the first rolled steel pipe a few millimeters thicker, so as to reduce the "wall reduction" between each stand, reduce the force per unit area of ​​the rolls, and reduce the temperature rise per unit time.

[0010] Roll lubrication involves filling the roll surface with sufficient lubricant to reduce friction between the steel pipe and the roll.

[0011] Roll cooling is used to control the temperature of the rolls and prevent the roll surface from overheating during the operation of the rolling mill.

[0012] The descaling equipment is operated to remove the iron oxide scale from the surface of the tube by spraying high-pressure water, so as to prevent the steel from sticking to the surface of the rolls during the rolling process.

[0013] When using products with low continuous rolling load, a certain number of products with low continuous rolling load should be arranged when new continuous rolling rolls are put into use to avoid the instantaneous high temperature generated by the relative movement between the workpiece and the rolls, which would reduce the yield strength of the rolls and cause steel sticking.

[0014] Quality inspection and control: Establish strict quality inspection and control measures, monitor and analyze key parameters in the production process, promptly identify and correct problems, and ensure that the surface quality of steel pipes meets the requirements.

[0015] Preferably, the specific steps in the billet cleaning process are as follows:

[0016] Mechanical cleaning: Using mechanical equipment, such as brushes, spray guns, spray systems or misting systems, to clean the surface of steel billets. Mechanical cleaning can be achieved by rotating brushes, spraying liquid or high-pressure water jets, etc., to remove oil, oxides and other impurities from the surface.

[0017] Rinsing: After mechanical cleaning, rinse with cooling water or cleaning solution to ensure thorough removal of any remaining impurities;

[0018] Drying: Similar to the steps in the pickling process, the surface of the billet is completely dried by using a drying oven or hot air drying.

[0019] Preferably, in the cooling water control step, the cooling water volume is adjusted to 30-350 m³ / h. 3 / h, cooling water pressure is 0.2~0.5MPa.

[0020] Preferably, in the step of adjusting the rolling parameters of the continuous rolling mill, the wall thickness of the first rolled steel pipe is increased by 3.2 to 3.6 mm.

[0021] Preferably, the rolling temperature in the roll cooling step is between 0 and 100°C.

[0022] Preferably, the specific steps in operating the phosphorus removal equipment are as follows:

[0023] S1. Preparation: Ensure that the phosphorus removal equipment and high-pressure water jet system are operating normally;

[0024] S2. Steel pipe positioning: The capillary tube to be treated is sent into the descaling equipment for surface treatment;

[0025] S3. High-pressure water jetting: Using a high-pressure water system, 12MPa high-pressure water is jetted onto the capillary surface to remove iron oxide scale.

[0026] S4. Scan the entire surface: Ensure that the high-pressure water jet covers the entire capillary surface and that each area is thoroughly cleaned;

[0027] S5. Surface inspection: After high-pressure water jetting is completed, inspect the surface to ensure that all iron oxide scale has been removed.

[0028] S6. Post-treatment: As needed, post-treatment can be carried out, such as neutralization treatment, rust removal treatment or other anti-corrosion measures, to protect the steel pipe surface from re-oxidation.

[0029] Preferably, the specific steps for using products with low continuous rolling load are as follows:

[0030] Roll installation preparation: Ensure that the installation and calibration of the new continuous rolls have been completed, and ensure that the rolls are precisely matched with the mill.

[0031] Select low-load products: Select a certain number of products with low continuous rolling load from the product inventory. The cross-sectional shape and size of these products should be similar to those of normally produced products, but with a lighter load.

[0032] Continuous rolling low-load products: Selected low-load products are fed into the continuous rolling production line for continuous rolling;

[0033] Promoting oxide film formation: During continuous rolling, localized oxidation and surface cooling measures are used to promote the formation of oxide films on the roll surface;

[0034] Roll hardening: The hardening effect on the surface of the roll is achieved by using cooling and pressure during the rolling process;

[0035] Roll surface inspection: After rolling low-load products, the roll surface is inspected to ensure that the surface hardness and oxide film formation meet the requirements.

[0036] Preferably, the specific steps for promoting localized oxidation in the formation of the oxide film are: during continuous rolling, oxygen is supplied or a specific localized oxidation device is used at a specific location.

[0037] Preferably, the high-pressure water jet intensity in the phosphorus removal equipment is 11.5–14 MPa.

[0038] Preferably, in the step of adjusting the rolling parameters of the continuous rolling roll, the bottom of the three grooves of the continuous rolling roll is first ground. The bottom of the grooves needs to be ground continuously and without gaps using a grinding wheel. The grinding depth is greater than 0.3mm, and the grinding width is required to correspond to the chord length of the bottom of the grooves not less than 200mm.

[0039] This invention provides a method for preventing steel from adhering to the surface of steel pipes. It has the following beneficial effects:

[0040] 1. This invention adjusts the rolling parameters of the continuous rolling mill rolls to make the wall thickness of the first rolled steel pipe 3.5mm thicker, thereby reducing the "wall reduction" between each stand, reducing the force per unit area of ​​the rolls, and lowering the temperature rise per unit time. In addition, it is combined with a descaling device to remove the iron oxide scale on the surface of the tube by spraying 12MPa high-pressure water, preventing the steel from sticking to the roll surface during the rolling process. This effectively prevents the phenomenon of steel sticking to the surface of the steel pipe, keeps the surface of the steel pipe uniform and smooth, and thus improves the quality and appearance of the product.

[0041] 2. By using this control method, the present invention can reduce downtime and maintenance costs of steel pipe production lines. Compared with traditional mechanical cleaning or anti-sticking agent spraying methods, this method is more efficient, does not require frequent downtime operations or replenishment of anti-sticking agent, and because this control method reduces downtime and maintenance costs, and eliminates the need for frequent purchase and application of consumables such as anti-sticking agent, it can reduce operating costs in the steel pipe production process. Detailed Implementation

[0042] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0043] Example:

[0044] This invention provides a method for preventing steel from sticking to the surface of a steel pipe, comprising the following steps:

[0045] Before entering the rolling mill, the steel billet undergoes a cleaning process to remove surface oil, oxides, and other impurities. Common surface treatment methods include rust removal, spraying with an anti-corrosion coating, or plating. These treatments form a protective layer that prevents the steel pipe surface from contacting other steel materials, thereby reducing the possibility of steel sticking.

[0046] Cooling water control ensures the normal operation of the mill's cooling water system, providing sufficient cooling water volume and appropriate cooling water pressure. This improves the cooling effect of the rolls, ensuring that the rolls can cool down quickly after each steel pipe is rolled, and preventing the rolls from remaining at a high temperature, which would cause steel sticking.

[0047] Adjust the cooling water nozzles to set the number of cooling water nozzles for the continuous rolling mill to 4. In order to avoid the cross-flow of the cooling fan-shaped water surface of the two nozzles at the bottom of the trough, adjust the spray angle of the two nozzles in the middle of the cooling water ring at the bottom of the rolling mill trough to 15°. This can effectively improve the cooling effect at the bottom of the rolling mill trough.

[0048] Adjust the rolling parameters of the continuous rolling mill rolls to make the wall thickness of the first steel pipe rolled a few millimeters thicker, so as to reduce the "wall reduction" between each stand, reduce the force per unit area of ​​the rolls, reduce the temperature rise per unit time, and avoid the rolls from being kept at a high temperature and causing steel sticking.

[0049] Roll lubrication involves filling the roll surface with sufficient lubricant to reduce friction between the steel pipe and the roll. The lubricant can be lubricating oil, grease, or coating, and can be applied to the roll surface by coating, spraying, or impregnation.

[0050] Roll cooling is used to control the temperature of the rolls during the operation of the rolling mill, prevent the roll surface from overheating, reduce the force per unit area of ​​the roll, and reduce the temperature rise per unit time.

[0051] The descaling equipment is operated to remove the iron oxide scale from the surface of the tube by spraying high-pressure water, so as to prevent the steel from sticking to the surface of the rolls during the rolling process.

[0052] When using products with low continuous rolling load, a certain number of products with low continuous rolling load should be arranged when new continuous rolling rolls are put into use. This avoids the reduction of the yield strength of the rolls due to the instantaneous high temperature generated by the relative movement between the workpiece and the rolls, which would cause steel sticking. At the same time, it promotes the oxidation of the roll surface, so that a dense oxide film is formed on the roll surface. Through rolling hardening, the surface hardness of the roll is improved, and the steel sticking on the roll surface is alleviated.

[0053] Quality inspection and control: Establish strict quality inspection and control measures, monitor and analyze key parameters in the production process, promptly identify and correct problems, and ensure that the surface quality of steel pipes meets the requirements.

[0054] The specific steps in the billet cleaning process are as follows:

[0055] Mechanical cleaning: Using mechanical equipment, such as brushes, spray guns, spray systems or misting systems, to clean the surface of steel billets. Mechanical cleaning can be achieved by rotating brushes, spraying liquid or high-pressure water jets, etc., to remove oil, oxides and other impurities from the surface.

[0056] Rinsing: After mechanical cleaning, rinse with cooling water or cleaning solution to ensure thorough removal of any remaining impurities;

[0057] Drying: Similar to the steps in the pickling process, the surface of the billet is completely dried by using a drying oven or hot air drying.

[0058] In the cooling water control procedure, the cooling water flow rate is adjusted to 350m³. 3 / h, cooling water pressure is 0.5MPa.

[0059] In the step of adjusting the rolling parameters of the continuous rolling mill, the wall thickness of the first rolled steel pipe is increased by 3.5mm.

[0060] The rolling temperature during the roll cooling process is 90℃.

[0061] The specific steps for operating the phosphorus removal equipment are as follows:

[0062] S1. Preparation: Ensure that the phosphorus removal equipment and high-pressure water jet system are operating normally, and check the safety and reliability of the equipment. Ensure that the water supply system and power system are working normally.

[0063] S2. Steel pipe positioning: The capillary tube to be treated is sent into the descaling equipment for surface treatment, ensuring the stability and accurate positioning of the steel pipe so that high-pressure water jets can cover the entire surface.

[0064] S3. High-Pressure Water Spray: Utilizing a high-pressure water system, 12MPa high-pressure water is sprayed onto the capillary surface to remove iron oxide scale. The nozzle selection and settings can be adjusted according to specific circumstances to achieve the best cleaning effect. High-pressure nozzles and appropriate water flow and spray angles are typically used to ensure that the iron oxide scale is effectively flushed and removed.

[0065] S4. Scan the entire surface: Ensure that the high-pressure water jet covers the entire capillary surface and that each area is thoroughly cleaned. Maintain a certain spray distance and speed during spraying to ensure uniform cleaning results.

[0066] S5. Surface Inspection: After high-pressure water jetting, inspect the surface to ensure that all iron oxide scale has been removed. Visual inspection or other relevant equipment can be used to assess the cleanliness of the surface.

[0067] S6. Post-treatment: As needed, post-treatment can be carried out, such as neutralization treatment, rust removal treatment or other anti-corrosion measures, to protect the steel pipe surface from re-oxidation.

[0068] The specific steps for using products with low continuous rolling load are as follows:

[0069] Roll installation preparation: Ensure that the installation and calibration of the new continuous rolls have been completed, and ensure that the rolls are precisely matched with the mill.

[0070] Select low-load products: Select a certain number of products with low continuous rolling load from the product inventory. The cross-sectional shape and size of these products should be similar to those of normally produced products, but with a lighter load.

[0071] Continuous rolling low-load products: Selected low-load products are fed into the continuous rolling production line for continuous rolling;

[0072] Adjusting mill parameters: Based on the characteristics of low-load products, adjust the mill parameters, including mill speed, roll gap, and roll gap control system, to adapt to the rolling requirements of low-load products.

[0073] Temperature control: Monitor the frictional heat between the rolls and the workpiece to ensure that the temperature rise does not exceed the yield strength of the rolls. Control the frictional heat between the rolls and the workpiece by adjusting the mill parameters, cooling system and lubrication system.

[0074] Promoting oxide film formation: During continuous rolling, the formation of oxide film on the roll surface is promoted through local oxidation and surface cooling measures. This can be achieved by using oxidants, oxide film generating agents, or controlling mill parameters.

[0075] Roll hardening: The rolling process utilizes cooling and pressure to harden the roll surface, resulting in higher hardness and wear resistance, and reducing the possibility of steel sticking.

[0076] Roll surface inspection: After rolling low-load products, the roll surface is inspected to ensure that the surface hardness and oxide film formation meet the requirements.

[0077] The specific steps to promote localized oxidation in the formation of oxide films are as follows: during continuous rolling, oxygen is supplied or a specific localized oxidation device is used at a specific location.

[0078] The high-pressure water jet intensity in the phosphorus removal equipment is 13.5 MPa.

[0079] The machined continuous rolling rolls have tiny "stripes" left on the circumferential surface due to machining, and the roll surface does not have an oxide film formed after high-temperature treatment. When the new rolls are put into operation to roll seamless steel pipes with large diameter-to-wall ratio and high load, the surface of the rolls is prone to sticking to the workpiece, causing local foreign matter accumulation and steel sticking to the roll surface. Therefore, the bottom of the three slots must be ground before the new rolls are put into operation. In the process of adjusting the rolling parameters of the continuous rolling rolls, the bottom of the three slots of the continuous rolling rolls must be ground first. The bottom of the slots must be ground continuously and without gaps using a grinding wheel. The grinding depth is greater than 0.3mm, and the grinding width is required to correspond to the chord length of the slot bottom of not less than 200mm.

[0080] In summary, this invention adjusts the initial rolling parameters of the continuous rolling mill rolls to increase the wall thickness of the first rolled steel pipe by 3.5mm, thereby reducing the "wall reduction" between stands, decreasing the stress per unit area of ​​the rolls, and lowering the temperature rise per unit time. Furthermore, in conjunction with a descaling device, 12MPa high-pressure water is sprayed to remove iron oxide scale from the surface of the tube, preventing steel adhesion during rolling. This effectively prevents steel adhesion on the pipe surface, maintaining a uniform and smooth surface, thus improving product quality and appearance. Moreover, this control method reduces downtime and maintenance costs in the steel pipe production line. Compared to traditional mechanical cleaning or anti-adhesion spraying methods, this method is more efficient, requiring less frequent downtime or replenishment of anti-adhesion agents. Because this control method reduces downtime and maintenance costs, and eliminates the need for frequent purchases and application of consumables such as anti-adhesion agents, it can lower operating costs in the steel pipe production process.

[0081] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preventing steel from sticking to the surface of a steel pipe, characterized in that, Includes the following steps: The billet is cleaned before entering the rolling mill to remove oil, oxides and other impurities from its surface. Cooling water control ensures the normal operation of the rolling mill cooling water system, providing sufficient cooling water volume and appropriate cooling water pressure; Adjust the cooling water nozzles to set the number of cooling water nozzles for the continuous rolling mill to 3 to 5. In order to avoid the crossover of the cooling fan-shaped water surfaces of the two nozzles at the bottom of the trough, adjust the spray angle of the two cooling water nozzles at the bottom of the trough in the middle of the cooling water ring to 13 to 15 degrees. Adjust the rolling parameters of the continuous rolling mill to make the wall thickness of the first rolled steel pipe 3.2 to 3.6 mm thicker, so as to reduce the "wall reduction" between each stand, reduce the force per unit area of ​​the rolling mill, and reduce the temperature rise per unit time. Roll lubrication involves filling the roll surface with sufficient lubricant to reduce friction between the steel pipe and the roll. Roll cooling is used to control the temperature of the rolls and prevent the roll surface from overheating during the operation of the rolling mill. The descaling equipment is operated to remove the iron oxide scale from the surface of the tube by spraying high-pressure water, so as to prevent the steel from sticking to the surface of the rolls during the rolling process. When using products with low continuous rolling load, a certain number of products with low continuous rolling load should be arranged when new continuous rolling rolls are put into use to avoid the instantaneous high temperature generated by the relative movement between the workpiece and the rolls, which would reduce the yield strength of the rolls and cause steel sticking. Quality inspection and control: Establish strict quality inspection and control measures, monitor and analyze key parameters in the production process, promptly identify and correct problems, and ensure that the surface quality of steel pipes meets the requirements.

2. The control method for preventing steel from sticking to the surface of a steel pipe according to claim 1, characterized in that, The specific steps in the billet cleaning process are as follows: Mechanical cleaning: Using mechanical equipment, such as brushes, spray systems, or misting systems, to clean the surface of the steel billet and remove oil, oxides, and other impurities. Rinsing: After mechanical cleaning, rinse with cooling water or cleaning solution to ensure thorough removal of any remaining impurities; Drying: The surface of the steel billet is completely dried by using a drying oven or hot air drying.

3. The control method for preventing steel from sticking to the surface of a steel pipe according to claim 1, characterized in that, In the cooling water control step, the cooling water flow rate is adjusted to 30-350 m³ / h, and the cooling water pressure is 0.2-0.5 MPa.

4. The control method for preventing steel from sticking to the surface of a steel pipe according to claim 1, characterized in that, During the roll cooling step, the roll temperature is between 0 and 100°C.

5. The control method for preventing steel from sticking to the surface of a steel pipe according to claim 1, characterized in that, The specific steps for operating the phosphorus removal equipment are as follows: S1. Preparation: Ensure that the phosphorus removal equipment and high-pressure water jet system are operating normally; S2. Steel pipe positioning: The capillary tube to be treated is sent into the descaling equipment for surface treatment; S3. High-pressure water jetting: Using a high-pressure water system, 12MPa high-pressure water is jetted onto the capillary surface to remove iron oxide scale. S4. Scan the entire surface: Ensure that the high-pressure water jet covers the entire capillary surface and that each area is thoroughly cleaned; S5. Surface inspection: After high-pressure water jetting is completed, inspect the surface to ensure that all iron oxide scale has been removed. S6. Post-treatment: As needed, perform post-treatment to protect the steel pipe surface from re-oxidation.

6. The control method for preventing steel from sticking to the surface of a steel pipe according to claim 1, characterized in that, The specific steps for using products with low continuous rolling load are as follows: Roll installation preparation: Ensure that the installation and calibration of the new continuous rolls have been completed, and ensure that the rolls are precisely matched with the mill. Select low-load products: Select a certain number of products with low continuous rolling load from the product inventory. The cross-sectional shape and size of these products should be similar to those of normally produced products, but with a lighter load. Continuous rolling low-load products: Selected low-load products are fed into the continuous rolling production line for continuous rolling; Promoting oxide film formation: During continuous rolling, localized oxidation and surface cooling measures are used to promote the formation of oxide films on the roll surface; Roll hardening: The hardening effect on the surface of the roll is achieved by using cooling and pressure during the rolling process; Roll surface inspection: After rolling low-load products, the roll surface is inspected to ensure that the surface hardness and oxide film formation meet the requirements.

7. The control method for preventing steel from sticking to the surface of a steel pipe according to claim 1, characterized in that, The high-pressure water jet intensity in the phosphorus removal equipment is 11.5–14 MPa.

8. The control method for preventing steel from sticking to the surface of a steel pipe according to claim 1, characterized in that, In the step of adjusting the rolling parameters of the continuous rolling roll, the bottom of the three grooves of the continuous rolling roll is first ground. The bottom of the groove needs to be ground continuously and without gaps using a grinding wheel, and the grinding depth is greater than 0.3mm.