Rolling method for 22 round bar with size exceeding one set of precision

Abstract

The invention relates to the technical field of rolling, and discloses a 22 round bar rolling method with the size exceeding one set of precision, which comprises the following specific steps: 1, raw material preparation, 2, heating, 3, rough rolling, 4, intermediate rolling, 5, finish rolling, 6, cooling, 7, cold shearing, and 8, finishing and packaging. According to the rolling method for the 22 round bar with the size exceeding the one-set precision, the size precision can be remarkably improved, the requirement that the size of the 22 round bar exceeds the one-set precision can be met by accurately controlling the rolling reduction, the rolling speed, the roller gap and the rolling force of each rolling stage, the size deviation is strictly controlled within the specified range, and the rolling quality is improved. By means of the method, the size precision and consistency of products are effectively improved, the requirement for high-precision bars in the high-end application field is met, the product quality can be improved, through reasonable heating temperature and time control, it is ensured that steel billets are heated evenly, the overheating and overburning phenomena are avoided, and internal defects of materials are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of rolling, in particular to a method for rolling a 22-round bar with a size exceeding one group of precision. Background Art

[0002] In modern industrial production, 22 round bar, as an important basic material, is widely used in machinery manufacturing, construction engineering, automobile industry and other fields. However, in the traditional 22 round bar rolling process, due to the influence of various factors such as raw materials, rolling equipment, process parameters, etc., it is often difficult to achieve a set of precision dimensional requirements.

[0003] In the traditional rolling method, the temperature control is not precise enough in the raw material heating process, which can easily lead to uneven heating of the steel billet, local overheating or overburning, thus affecting the subsequent rolling quality and dimensional accuracy. During the rolling process, the setting of the rolling mill's reduction and rolling speed is not reasonable, which can easily cause uneven deformation of the rolled piece and large dimensional fluctuations. In addition, the imperfect cooling and straightening process will also cause internal stress in the rolled piece during the cooling process, resulting in dimensional deformation, or in the straightening process, due to improper straightening force and straightening method, the rolled piece will have surface damage and dimensional deviation.

[0004] As the industrial field continues to increase the requirements for the size accuracy of 22 round bars, the traditional rolling method has been unable to meet the market demand. Therefore, the development of an improved version of the 22 round bar size super-precision rolling method is of great significance for improving product quality, reducing production costs, and enhancing corporate competitiveness. Summary of the invention

[0005] 1. Technical issues to be resolved In view of the shortcomings of the prior art, the present invention provides a method for rolling 22 round bars with a size exceeding one set of precision, which has the advantages of high rolling accuracy and solves the problem that the setting of the reduction amount and rolling speed of each pass of the rolling mill is not reasonable, which easily causes uneven deformation of the rolled piece and large dimensional fluctuations.

[0006] (II) Technical solution To achieve the above object, the present invention provides the following technical solution: a method for rolling 22 round bars with a size exceeding one group of precision, comprising the following specific method steps: the first step is raw material preparation, selecting high-quality continuous casting billets as raw materials, requiring the chemical composition of the billets to be uniform and stable, and meeting the product standards of 22 round bars, performing surface inspection on the billets, and removing billets with defects such as surface cracks, slag inclusions, and bubbles; The second step is heating. The qualified billets are sent to the heating furnace for heating. The heating furnace adopts a walking beam heating furnace. The heating time is determined according to the size of the billet and the amount of furnace loading to ensure that the billet is heated evenly and reaches the temperature required for rolling. The third step is rough rolling. The heated billet first enters the rough rolling unit, which consists of 2-4 rolling mills. The billet is rolled into an intermediate billet with a diameter of about 50-60mm. The fourth step is intermediate rolling. The intermediate billet after rough rolling enters the intermediate rolling mill, which consists of 3-5 rolling mills. The intermediate billet is rolled into a pre-finished billet with a diameter of about 30-35mm. The fifth step is finishing rolling. After the intermediate rolling, the pre-finished billet enters the finishing rolling unit. The finishing rolling unit consists of 4-6 rolling mills. By accurately adjusting the roll gap and rolling force of the rolls, the pre-finished billet is rolled into a round bar with a diameter of 22mm, and the size deviation is controlled within ±0.1mm. The sixth step is cooling. The 22 round bars after fine rolling are rapidly cooled in the water cooling section. The cooling rate is controlled at 50-100℃ / s to obtain good organizational properties and dimensional accuracy. The cooled bars enter the slow cooling zone for slow cooling. The slow cooling time is 2-3h to eliminate the residual stress inside the bars. The seventh step is cold shearing. Cold shearing usually consists of a shearing mechanism, a conveying mechanism and a control system. The shearing mechanism is used to shear the rolled piece, the conveying mechanism is used to convey the rolled piece to the shearing position, and the control system is used to control the operation of the cold shearing. After rolling, the rolled piece is conveyed to the cold shearing position by the conveying mechanism. At the cold shearing position, the shearing mechanism shears the rolled piece and cuts the rolled piece into the required length. During the cold shearing process, the rolled piece will be cooled to control the temperature and performance of the rolled piece. The eighth step is finishing and packaging. The cooled 22 round bars are straightened by a straightening machine. The surface quality of the straightened bars is checked, and the bars with surface defects are removed. The qualified 22 round bars are cut to length and bundled for storage.

[0007] Preferably, the reduction in the rough rolling stage is relatively large, generally [specific reduction 1], and the rolling speed is controlled at [specific speed 1]. The size of the rolled piece after rough rolling is approximately [specific size 1], and there should be no obvious defects such as cracks and folds on the surface.

[0008] Preferably, the reduction in the intermediate rolling stage is gradually reduced, generally [specific reduction 2], the rolling speed is gradually increased and controlled at [specific speed 2], the size of the rolled piece after intermediate rolling is approximately [specific size 2], the shape and size should meet the process requirements, and the surface quality is good.

[0009] Preferably, the reduction in the finishing rolling stage is small, generally [specific reduction 3], and the rolling speed is high, controlled at [specific speed 3]. During the finishing rolling process, the size and shape of the rolled piece are precisely controlled by adjusting the roll gap and rolling force of the rolling rollers to ensure that the dimensional accuracy of the rolled piece exceeds a set of accuracy requirements.

[0010] Preferably, the straightness of the straightened bar is controlled at 1-2 mm / m.

[0011] Preferably, the heating temperature is controlled at 1100-1200°C.

[0012] (III) Beneficial effects Compared with the prior art, the present invention provides a method for rolling 22 round bars with a precision exceeding one group, which has the following beneficial effects: 1. The 22 round bar size exceeds a group of precision rolling methods. This scheme can significantly improve the dimensional accuracy. By accurately controlling the reduction amount, rolling speed, roll gap and rolling force in each rolling stage, the 22 round bar size exceeds a group of precision requirements can be achieved. The dimensional deviation is strictly controlled within the specified range, effectively improving the dimensional accuracy and consistency of the product, and meeting the needs of high-end application fields for high-precision bars.

[0013] 2. The 22 round bar size exceeds a set of precision rolling methods. This method can improve product quality. Through reasonable heating temperature and time control, it ensures uniform heating of the billet, avoids overheating and overburning, and reduces the generation of internal defects in the material; precise rolling parameter control and optimized cooling and straightening processes help reduce the internal stress and surface defects of the rolled piece, so that the product has better surface quality and mechanical properties, and improves the overall quality and reliability of the product.

[0014] 3. The 22 round bars have a set of over-size precision rolling methods. This method can improve production efficiency. The optimized rolling process parameters and processes make the rolling process more stable and efficient, reduce scrap and rework caused by quality problems such as over-size, improve production efficiency, reduce production costs, and enhance market competitiveness. The 22 round bars produced by the improved rolling method have higher dimensional accuracy and better product quality, which can meet customer demand for high-quality bars, improve the company's competitiveness in the market, expand market share, and bring better economic benefits to the company. DETAILED DESCRIPTION

[0015] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0016] The present invention provides a technical solution, specifically a method for rolling 22 round bars with a size exceeding one group of precision, including the following specific method steps: the first step is raw material preparation, selecting high-quality continuous casting billets as raw materials, requiring the chemical composition of the billets to be uniform and stable, and meet the product standards of 22 round bars, and performing surface inspection on the billets to remove billets with defects such as surface cracks, slag inclusions, and bubbles; The second step is heating. The qualified billets are sent to the heating furnace for heating. The heating furnace adopts a walking beam heating furnace. The heating temperature is controlled at 1100-1200℃. The heating time is determined according to the size of the billet and the amount of furnace loading to ensure that the billet is heated evenly and reaches the temperature required for rolling. The third step is rough rolling. The heated billet first enters the rough rolling unit, which consists of 2-4 rolling mills. In the rough rolling stage, a large reduction is used for rolling, with a reduction of 10-20 mm per pass and a rolling speed of 0.5-1 m / s to roll the steel billet into an intermediate billet with a diameter of about 50-60 mm. Among them, the reduction in the rough rolling stage is relatively large, generally [specific reduction 1], and the rolling speed is controlled at [specific speed 1]. The size of the rolled piece after rough rolling is about [specific size 1], and there should be no obvious cracks, folds and other defects on the surface; The fourth step is intermediate rolling. The intermediate billet after rough rolling enters the intermediate rolling mill group, which consists of 3-5 rolling mills. The reduction in the intermediate rolling stage is gradually reduced, and the reduction in each pass is 5-10mm. The rolling speed is increased to 1-2m / s, and the intermediate billet is rolled into a pre-finished billet with a diameter of about 30-35mm. Among them, the reduction in the intermediate rolling stage gradually decreases, generally [specific reduction 2], the rolling speed gradually increases, and is controlled at [specific speed 2]. The size of the rolled piece after intermediate rolling is about [specific size 2]. The shape and size should meet the process requirements and have good surface quality. The fifth step is finishing rolling. After the intermediate rolling, the pre-finished billet enters the finishing rolling unit. The finishing rolling unit consists of 4-6 rolling mills. In the finishing rolling stage, a smaller reduction is used for rolling. The reduction per pass is 1-3mm, and the rolling speed is 2-3m / s. By accurately adjusting the roll gap and rolling force of the rolls, the pre-finished billet is rolled into a round bar with a diameter of 22mm, and the size deviation is controlled within ±0.1mm. Among them, the reduction in the finishing rolling stage is small, generally [specific reduction 3], and the rolling speed is high, controlled at [specific speed 3]. During the finishing rolling process, the size and shape of the rolled piece are precisely controlled by adjusting the roll gap and rolling force of the rolls to ensure that the dimensional accuracy of the rolled piece meets a set of accuracy requirements. The sixth step is cooling. The 22 round bars after fine rolling are rapidly cooled in the water cooling section. The cooling rate is controlled at 50-100℃ / s to obtain good organizational properties and dimensional accuracy. The cooled bars enter the slow cooling zone for slow cooling. The slow cooling time is 2-3h to eliminate the residual stress inside the bars. The seventh step is cold shearing. Cold shearing usually consists of a shearing mechanism, a conveying mechanism and a control system. The shearing mechanism is used to shear the rolled piece, the conveying mechanism is used to convey the rolled piece to the shearing position, and the control system is used to control the operation of the cold shearing. After rolling, the rolled piece is conveyed to the cold shearing position by the conveying mechanism. At the cold shearing position, the shearing mechanism shears the rolled piece and cuts the rolled piece into the required length. During the cold shearing process, the rolled piece will be cooled to control the temperature and performance of the rolled piece. The eighth step is finishing and packaging. The cooled 22 round bars are straightened by a straightening machine. The straightness of the straightened bars is controlled at 1-2mm / m. The surface quality of the straightened bars is checked, and the bars with surface defects are removed. The qualified 22 round bars are cut to length and bundled for storage.

[0017] Furthermore, this solution can significantly improve dimensional accuracy. By accurately controlling the reduction amount, rolling speed, roll gap and rolling force in each rolling stage, it can achieve a set of precision requirements for 22 round bars. The dimensional deviation is strictly controlled within the specified range, effectively improving the dimensional accuracy and consistency of the product and meeting the demand for high-precision bars in high-end application fields.

[0018] Furthermore, the method can improve product quality by ensuring uniform heating of the billet through reasonable heating temperature and time control, thus avoiding overheating and overburning and reducing the occurrence of internal defects in the material. Precise rolling parameter control and optimized cooling and straightening processes help reduce the internal stress and surface defects of the rolled piece, giving the product better surface quality and mechanical properties, and improving the overall quality and reliability of the product.

[0019] Furthermore, the method can improve production efficiency. The optimized rolling process parameters and processes make the rolling process more stable and efficient, reduce scrap and rework caused by quality problems such as dimensional tolerance, improve production efficiency, reduce production costs, and enhance market competitiveness. The 22-round bars produced by the improved rolling method have higher dimensional accuracy and better product quality, which can meet customer demand for high-quality bars, improve the company's competitiveness in the market, expand market share, and bring better economic benefits to the company.

[0020] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for rolling 22 round bars with a size exceeding one group of precision, characterized in that: The method includes the following specific steps: the first step is raw material preparation, selecting high-quality continuous casting billets as raw materials, requiring the chemical composition of the billets to be uniform and stable and meet the product standard of 22 round bars, performing surface inspection on the billets, and removing billets with defects such as surface cracks, slag inclusions, bubbles, etc.; The second step is heating. The qualified billets are sent to the heating furnace for heating. The heating furnace adopts a walking beam heating furnace. The heating time is determined according to the size of the billet and the amount of furnace loading to ensure that the billet is heated evenly and reaches the temperature required for rolling. The third step is rough rolling. The heated billet first enters the rough rolling unit, which consists of 2-4 rolling mills. The billet is rolled into an intermediate billet with a diameter of about 50-60mm. The fourth step is intermediate rolling. The intermediate billet after rough rolling enters the intermediate rolling mill, which consists of 3-5 rolling mills. The intermediate billet is rolled into a pre-finished billet with a diameter of about 30-35mm. The fifth step is finishing rolling. After the intermediate rolling, the pre-finished billet enters the finishing rolling unit. The finishing rolling unit consists of 4-6 rolling mills. By accurately adjusting the roll gap and rolling force of the rolls, the pre-finished billet is rolled into a round bar with a diameter of 22mm, and the size deviation is controlled within ±0.1mm. The sixth step is cooling. The 22 round bars after fine rolling are rapidly cooled in the water cooling section. The cooling rate is controlled at 50-100℃ / s to obtain good organizational properties and dimensional accuracy. The cooled bars enter the slow cooling zone for slow cooling. The slow cooling time is 2-3h to eliminate the residual stress inside the bars. The seventh step is cold shearing. Cold shearing usually consists of a shearing mechanism, a conveying mechanism and a control system. The shearing mechanism is used to shear the rolled piece, the conveying mechanism is used to convey the rolled piece to the shearing position, and the control system is used to control the operation of the cold shearing. After rolling, the rolled piece is conveyed to the cold shearing position by the conveying mechanism. At the cold shearing position, the shearing mechanism shears the rolled piece and cuts the rolled piece into the required length. During the cold shearing process, the rolled piece will be cooled to control the temperature and performance of the rolled piece. The eighth step is finishing and packaging. The cooled 22 round bars are straightened by a straightening machine. The surface quality of the straightened bars is checked, and the bars with surface defects are removed. The qualified 22 round bars are cut to length and bundled for storage.

2. A method for rolling round bars with a size exceeding one group of precision according to claim 1, characterized in that: The reduction in the rough rolling stage is relatively large, generally [specific reduction 1], and the rolling speed is controlled at [specific speed 1]. The size of the rolled piece after rough rolling is approximately [specific size 1], and there should be no obvious defects such as cracks and folds on the surface.

3. A method for rolling 22 round bars with a precision exceeding one group according to claim 1, characterized in that: The reduction in the intermediate rolling stage gradually decreases, generally to [specific reduction 2], and the rolling speed gradually increases and is controlled at [specific speed 2]. The size of the rolled piece after intermediate rolling is approximately [specific size 2], and the shape and size should meet the process requirements and have good surface quality.

4. A method for rolling round bars with a size exceeding one group of precision according to claim 1, characterized in that: The reduction in the finishing rolling stage is relatively small, generally [specific reduction 3], and the rolling speed is relatively high, controlled at [specific speed 3]. During the finishing rolling process, the size and shape of the rolled piece are precisely controlled by adjusting the roll gap and rolling force of the rolls to ensure that the dimensional accuracy of the rolled piece meets a set of precision requirements.

5. A method for rolling 22 round bars with a precision exceeding one group according to claim 1, characterized in that: The straightness of the straightened bar is controlled at 1-2 mm / m.

6. A method for rolling 22 round bars with a size exceeding one group of precision according to claim 1, characterized in that: The heating temperature is controlled at 1100-1200°C.