A method of rolling a bar using a breakdown pass sequence

Abstract

The application discloses a method for rolling 170*190mm by using a bar billet mill pass system, and relates to the technical field of the billet mill. The method for rolling 170*190mm by using the bar billet mill pass system comprises a large push bed opening degree, a small push bed opening degree and a billet mill reduction, adopts 430*350mm raw material section 9-pass rolling to form a 170*190mm section; a first-pass pre-machine turn-over, K1 rolling reduction 75-95mm; a second-pass post-machine turn-over, K1 rolling reduction 50-70mm; a third-pass pre-machine turn-over, K2 rolling reduction 60-80mm; a fourth-pass post-machine turn-over, K2 rolling reduction 70-90mm; a fifth-pass pre-machine turn-over, K3 rolling reduction 55-75mm; a sixth-pass no turn-over, K3 rolling reduction 50-70mm; a seventh-pass pre-machine turn-over, K4 rolling reduction 55-75mm; an eighth-pass no turn-over, K3 rolling reduction 35-55mm; a ninth-pass pre-machine turn-over, K5 rolling reduction 50-70mm.

Description

Technical Field

[0001] This invention relates to the field of billet rolling mill technology, and in particular to a method for rolling bars using a billet rolling mill pass system. Background Technology

[0002] The main function of the billet mill is to reciprocate and roll the billet heated in the furnace into intermediate billets of a certain size for use by the continuous rolling mill. During the rolling process, the billet mill can automatically adjust the reduction according to the preset tool parameters and rolling program to achieve the desired rolling effect. However, the billet mill also has some disadvantages, such as low output, low yield, a large number of operators, and relatively outdated technology.

[0003] Existing patent publication number CN218340652U discloses a rolling mill pass system for rolling various cross-section billets using a single roll. The roll has three passes: roll pass four, roll pass three, and roll pass two. This rolling mill pass system for rolling φ60~φ250mm round steel using a single roll for various cross-section billets reduces the width of roll pass three and the width of the roller rings in the middle passes, and increases the number of passes from three to four, thereby reducing roll change time. It enables the production of Φ60-Φ250mm round steel and 140-200×170-240mm large-diameter electrode flat steel from billets with cross-sections of 240×240mm, 280×380mm, 320×415mm, and Φ200-Φ350mm. However, this pass system only has four passes. This patent does not exhibit low efficiency when rolling small cross-sections. Summary of the Invention

[0004] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide a method for rolling bar stock using a billet mill pass system, which can solve the above-mentioned problems.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a rolling mill pass system for bar stock, comprising five pass types: K5, K4, K3, K2, and K1;

[0006] The K5 slot is designed to be 380-400mm wide, with a bottom diameter of 350-360mm, a hole radius of 23-27mm, a r-angle of 23-27mm, a sidewall slope of 14-16°, and a slot height of 145-155mm.

[0007] The K4 slot opening is 330-340mm, the slot bottom is 295-305mm, the hole radius (R) is 23-27mm, the r angle is 23-27mm, the sidewall slope is 13-15°, and the slot height is 145-155mm.

[0008] The K3 slot opening is 270-280mm, the slot bottom is 235-245mm, the hole radius (R) is 28-32mm, the radius (r) is 23-27mm, the sidewall slope is 12-14°, and the slot height is 165-175mm.

[0009] The K2 slot opening is 225-235mm, the slot bottom is 195-200mm, the hole radius (R) is 28-32mm, the r angle is 23-27mm, the sidewall slope is 12-14°, and the slot height is 165-175mm.

[0010] The K1 slot opening is 200-210mm, the slot bottom is 165-175mm, the hole R angle is 28-32mm, the r angle is 23-27mm, the side wall slope is 12-14°, and the slot height is 165-175mm.

[0011] The billet rolling system includes the opening degree of the large pusher bed, the opening degree of the small pusher bed, and the billet reduction. It uses a 430*350mm raw material cross section to roll into a 170×190mm cross section in 9 passes.

[0012] The first pass of steel is turned over before rolling, and the K1 rolling reduction is 75-95mm.

[0013] After the second pass, the steel is turned over, and the K1 rolling reduction is 50-70mm.

[0014] The steel is turned over in the third pass, and the K2 rolling reduction is 60-80mm.

[0015] After the fourth pass, the steel is turned over, and the K2 rolling reduction is 70-90mm.

[0016] The steel is turned over before the fifth pass, and the K3 rolling reduction is 55-75mm.

[0017] The sixth pass does not involve turning over the steel; the K3 rolling reduction is 50-70mm.

[0018] The steel is turned over at the front of the seventh pass mill, and the K4 rolling reduction is 55-75mm.

[0019] The eighth pass does not involve turning over the steel; the K3 rolling reduction is 35-55mm.

[0020] The steel is turned over before the ninth pass, and the K5 rolling reduction is 50-70mm.

[0021] Preferably, the distance between the K5-K1 holes is 53mm.

[0022] Preferably, K1 is 100mm from the roller head and K5 is 100mm from the roller bottom.

[0023] Preferably, the upper roller has a diameter of 1100-1102 mm and the lower roller has a diameter of 1096-1098 mm.

[0024] Preferably, the eighth pass does not involve turning the steel back to the third hole for rolling, which provides a large reduction while reducing the number of rolling passes.

[0025] Preferably, the opening of the large pusher is 5-10 mm larger than the width of the rolled material, and the opening of the small pusher is 7-14 mm larger than the width of the rolled material in the subsequent rolling passes.

[0026] Preferably, a method for rolling 170×190mm bars using a billet mill includes the following specific steps:

[0027] S1 Rolling Preparation: Raw Material Preparation: Prepare raw steel billets of suitable size and quality, ensuring that the chemical composition and dimensional tolerances of the billets meet the requirements of the rolled product. Equipment Inspection: Inspect the mechanical components of the billet mill, such as rolls, bearings, and transmission systems, to ensure they are in good working condition. Inspect the electrical system to ensure normal power supply and stable control system. Inspect the lubrication system to ensure sufficient oil supply to all lubrication points. Roll Pass Inspection and Adjustment: Inspect the roll pass required for rolling, ensuring that the wear of the roll pass is within the allowable range. According to the product specification requirements of 170×190mm, precisely adjust the roll pass, including the height, width, and roll gap parameters.

[0028] S2 Heating and Charging: Heating involves placing the steel billet into the heating furnace and heating it according to a predetermined heating curve to bring the billet to a suitable rolling temperature, usually between 1100 and 1300°C, in order to ensure that the billet has good plasticity and low deformation resistance.

[0029] Loading: After the steel billet is heated to the specified temperature, a conveying device is used to smoothly feed the steel billet into the feed port of the billet mill;

[0030] S3 rolling process: In the roughing stage, the billet enters the first pass of the billet mill for preliminary rolling. Through repeated rolling several times, the cross-sectional size of the billet is gradually reduced, so that the shape and size of the billet are close to the prototype of the target specification.

[0031] In the intermediate rolling stage, the steel billet after rough rolling enters the intermediate rolling mill for further rolling, so as to further adjust the shape and size of the steel billet and improve dimensional accuracy and surface quality.

[0032] In the finishing rolling stage, based on the intermediate rolling, the steel billet enters the finishing rolling pass for final rolling, ensuring that the rolled product dimensions accurately meet the requirement of 170×190mm, while also ensuring that the surface quality of the product meets the specified standards.

[0033] S4 Post-rolling treatment: Cooling. After rolling, the product enters the cooling area through a conveyor and is cooled by natural cooling, air cooling or water cooling to ensure that the product's performance and structure meet the requirements.

[0034] Shearing and cutting to length: According to the product's usage requirements, the cooled rolled material is sheared and cut to the specified length.

[0035] Quality inspection involves measuring the dimensions, checking the surface quality, and testing the mechanical properties of the rolled products to ensure that the product quality meets relevant standards and customer requirements.

[0036] Products that have passed quality inspection are collected, bundled, or packaged, and then stored in designated warehouses or storage yards.

[0037] Compared with the prior art, the beneficial effects of the present invention are:

[0038] 1. The bar stock is rolled using a billet mill pass system with a large reduction: By returning to the third pass for rolling, a large reduction can be achieved in this pass, which helps to quickly reduce the cross-sectional area and length of the rolled piece, making it closer to the size of the final product. Reduced rolling passes: By increasing the reduction in the eighth pass, the number of subsequent rolling passes can be reduced, thereby improving the overall rolling efficiency.

[0039] 2. The bar stock is rolled using a roughing mill pass system. The roughing mill sidewall inclinations are similar. Sidewall inclination refers to the angle between the sidewall of the pass and the vertical line of the roll axis. It is used to describe the degree of inclination of the sidewall of the pass. It can be expressed as a percentage, the tangent of the angle, or directly as an angle. When the sidewall inclinations of different passes in the roughing mill pass system are similar, it usually means that these passes have similar characteristics in controlling metal flow and rolling force during the rolling process. This similarity helps to maintain the stability and consistency of the rolling process and improve rolling efficiency and product quality.

[0040] 3. The bar is rolled using a billet rolling mill pass system. The radius (R) of the billet rolling mill pass system K1 / K2 is smaller than that of K3 / K4 / K5. In the initial stage of rolling (such as K1 / K2), a smaller radius is required to better control the flow and shape of the metal. In the subsequent stage (such as K3 / K4 / K5), as the metal gradually deforms and compresses, a larger radius is required to reduce rolling force and energy consumption.

[0041] 4. A method for rolling 170×190mm bars using a billet mill. This step has the following effects: it is highly systematic. From pre-rolling preparation, heating and loading, rolling process to post-rolling treatment, it covers the entire rolling production process. Each link is closely connected, forming a complete production system, which helps to ensure the continuity and stability of production.

[0042] Quality Assurance: Before rolling, the equipment, roll pattern and raw materials are strictly inspected and prepared. During the rolling process, roughing, intermediate rolling and finishing stages are set up to gradually and accurately control the shape, size and surface quality of the product. After rolling, quality inspection is carried out. Multi-stage control of product quality can effectively improve the product qualification rate and quality stability.

[0043] Efficiency Improvement: A well-planned heating and charging process, along with a phased rolling process, helps improve production efficiency. By rationally dividing tasks and ensuring coordination at each stage, downtime and waiting time are reduced, making the entire rolling process smoother and more efficient.

[0044] High flexibility: The method has a certain degree of flexibility in terms of equipment inspection and orifice adjustment. It can be adjusted and optimized according to different production requirements, raw material characteristics and equipment conditions to adapt to different production scenarios and needs. Attached Figure Description

[0045] The present invention will be further described below with reference to the accompanying drawings and embodiments:

[0046] Figure 1 This is the rolling program table for the billet mill of the present invention;

[0047] Figure 2 This is a schematic diagram of the cross-sectional dimensions of the spring flat steel of the present invention. Detailed Implementation

[0048] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0049] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, and right, are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0050] In the description of this invention, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0051] In the description of this invention, unless otherwise explicitly defined, the terms "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0052] Please see Figure 1-2 The present invention provides a technical solution: a rolling mill pass system for bar stock, including five pass types: K5, K4, K3, K2, and K1;

[0053] The K5 slot is designed to be 380-400mm wide, with a bottom diameter of 350-360mm, a hole radius of 23-27mm, a r-angle of 23-27mm, a sidewall slope of 14-16°, and a slot height of 145-155mm.

[0054] The K4 slot opening is 330-340mm, the slot bottom is 295-305mm, the hole radius (R) is 23-27mm, the r angle is 23-27mm, the sidewall slope is 13-15°, and the slot height is 145-155mm.

[0055] The K3 slot opening is 270-280mm, the slot bottom is 235-245mm, the hole radius (R) is 28-32mm, the radius (r) is 23-27mm, the sidewall slope is 12-14°, and the slot height is 165-175mm.

[0056] The K2 slot opening is 225-235mm, the slot bottom is 195-200mm, the hole radius (R) is 28-32mm, the r angle is 23-27mm, the sidewall slope is 12-14°, and the slot height is 165-175mm.

[0057] The K1 slot opening is 200-210mm, the slot bottom is 165-175mm, the hole radius (R) is 28-32mm, the r angle is 23-27mm, the sidewall slope is 12-14°, and the slot height is 165-175mm.

[0058] Furthermore, the distance between the K5 and K1 apertures is 53mm;

[0059] Furthermore, K1 is 100mm from the roller head and K5 is 100mm from the roller bottom; at the same time, in this bushing system, the upper roller diameter is 1100-1102mm and the lower roller diameter is 1096-1098mm.

[0060] The billet rolling system includes the opening degree of the large pusher bed, the opening degree of the small pusher bed, and the billet reduction. It uses a 430*350mm raw material cross section to roll into a 170×190mm cross section in 9 passes.

[0061] The first pass of steel is turned over before rolling, and the K1 rolling reduction is 75-95mm.

[0062] After the second pass, the steel is turned over, and the K1 rolling reduction is 50-70mm.

[0063] The steel is turned over in the third pass, and the K2 rolling reduction is 60-80mm.

[0064] After the fourth pass, the steel is turned over, and the K2 rolling reduction is 70-90mm.

[0065] The steel is turned over before the fifth pass, and the K3 rolling reduction is 55-75mm.

[0066] The sixth pass does not involve turning over the steel; the K3 rolling reduction is 50-70mm.

[0067] The steel is turned over at the front of the seventh pass mill, and the K4 rolling reduction is 55-75mm.

[0068] The eighth pass does not involve turning over the steel; the K3 rolling reduction is 35-55mm.

[0069] The steel is turned over at the front of the ninth pass mill, and the K5 rolling reduction is 50-70mm.

[0070] Among them, the eighth pass does not turn the steel back to the third hole for rolling, which provides a large reduction while reducing the number of rolling passes;

[0071] Among them, the opening of the large pusher bed is 5-10 mm larger than the width of the rolled material, and the opening of the small pusher bed is 7-14 mm larger than the width of the rolled material in the subsequent rolling passes.

[0072] In this invention, the diameter of the upper roll is larger than that of the lower roll. This configuration is called "upper pressure rolling" because it allows the upper roll to generate greater pressure relative to the lower roll, which helps to improve bite conditions, increase reduction, and improve billet opening capacity.

[0073] The radius (R) of the rolling mill pass system K1 / K2 is smaller than that of K3 / K4 / K5. In the initial stage of rolling (such as K1 / K2), a smaller radius is needed to better control the flow and shape of the metal. In the subsequent stage (such as K3 / K4 / K5), as the metal gradually deforms and compresses, a larger radius is needed to reduce rolling force and energy consumption.

[0074] Similar sidewall inclinations in the roughing mill system indicate that the sidewall inclination is similar to the angle between the sidewall of the roll pass and the vertical line of the roll axis. It describes the degree of inclination of the roll pass sidewall and can be expressed as a percentage, the tangent of the angle, or directly as an angle. When the sidewall inclinations of different roll passes in the roughing mill system are similar, it usually means that these roll passes have similar characteristics in controlling metal flow and rolling force during the rolling process. This similarity helps to maintain the stability and consistency of the rolling process and improve rolling efficiency and product quality.

[0075] Large reduction: By returning to the third pass for rolling, a larger reduction can be achieved in this pass, which helps to quickly reduce the cross-sectional area and length of the rolled piece, making it closer to the size of the final product. Reduced rolling passes: By increasing the reduction in the eighth pass, the number of subsequent rolling passes can be reduced, thereby improving the overall rolling efficiency.

[0076] The billet rolling program table in this embodiment is as follows: Figure 1 As shown;

[0077] A method for rolling 170×190mm bars using a billet mill includes the following specific steps.

[0078] Preparation before S1 rolling: Raw material preparation: Prepare raw steel billets of suitable size and quality, ensuring that the chemical composition and dimensional tolerances of the billets meet the requirements of the rolled product. Equipment inspection: Inspect the mechanical components of the billet mill, such as rolls, bearings, and transmission systems, to ensure they are in good working condition; inspect the electrical system to ensure normal power supply and stable control system; inspect the lubrication system to ensure sufficient oil supply to all lubrication points. Pass inspection and adjustment: Inspect the pass required for rolling, ensuring that the wear of the pass is within the allowable range. Based on the product specification of 170×190mm, precisely adjust the pass, including the height, width, and roll gap parameters.

[0079] S2 Heating and Charging: Heating involves placing the steel billet into the heating furnace and heating it according to a predetermined heating curve to bring the billet to a suitable rolling temperature, usually between 1100 and 1300°C, in order to ensure that the billet has good plasticity and low deformation resistance.

[0080] Loading: After the steel billet is heated to the specified temperature, a conveying device is used to smoothly feed the steel billet into the feed port of the billet mill;

[0081] S3 rolling process: In the roughing stage, the billet enters the first pass of the billet mill for preliminary rolling. Through repeated rolling several times, the cross-sectional size of the billet is gradually reduced, so that the shape and size of the billet are close to the prototype of the target specification.

[0082] In the intermediate rolling stage, the steel billet after rough rolling enters the intermediate rolling mill for further rolling, so as to further adjust the shape and size of the steel billet and improve dimensional accuracy and surface quality.

[0083] In the finishing rolling stage, based on the intermediate rolling, the steel billet enters the finishing rolling pass for final rolling, ensuring that the rolled product dimensions accurately meet the requirement of 170×190mm, while also ensuring that the surface quality of the product meets the specified standards.

[0084] S4 Post-rolling treatment: Cooling. After rolling, the product enters the cooling area through a conveyor and is cooled by natural cooling, air cooling or water cooling to ensure that the product's performance and structure meet the requirements.

[0085] Shearing and cutting to length: According to the product's usage requirements, the cooled rolled material is sheared and cut to the specified length.

[0086] Quality inspection involves measuring the dimensions, checking the surface quality, and testing the mechanical properties of the rolled products to ensure that the product quality meets relevant standards and customer requirements.

[0087] Collection and storage: Products that have passed quality inspection are collected, bundled or packaged, and then stored in designated warehouses or storage yards.

[0088] Furthermore, this step has the following effects: it is highly systematic. From pre-rolling preparation, heating and loading, rolling process to post-rolling treatment, it covers the entire rolling production process. Each link is closely connected, forming a complete production system, which helps to ensure the continuity and stability of production.

[0089] Quality Assurance: Before rolling, the equipment, roll pattern and raw materials are strictly inspected and prepared. During the rolling process, roughing, intermediate rolling and finishing stages are set up to gradually and accurately control the shape, size and surface quality of the product. After rolling, quality inspection is carried out. Multi-stage control of product quality can effectively improve the product qualification rate and quality stability.

[0090] Efficiency Improvement: A well-planned heating and charging process, along with phased rolling process planning, helps improve production efficiency. By rationally dividing tasks and ensuring collaborative work at each stage, downtime and waiting time are reduced, making the entire rolling process smoother and more efficient.

[0091] High flexibility: The method has a certain degree of flexibility in terms of equipment inspection and orifice adjustment. It can be adjusted and optimized according to different production requirements, raw material characteristics and equipment conditions to adapt to different production scenarios and needs.

[0092] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for rolling bars using a billet mill pass system, characterized in that: It includes five hole types: K5, K4, K3, K2, and K1; The K5 slot is designed to be 380-400mm wide, with a bottom diameter of 350-360mm, a hole radius of 23-27mm, a r-angle of 23-27mm, a sidewall slope of 14-16°, and a slot height of 145-155mm. The K4 slot opening is 330-340mm, the slot bottom is 295-305mm, the hole radius (R) is 23-27mm, the r angle is 23-27mm, the sidewall slope is 13-15°, and the slot height is 145-155mm. The K3 slot opening is 270-280mm, the slot bottom is 235-245mm, the hole radius (R) is 28-32mm, the radius (r) is 23-27mm, the sidewall slope is 12-14°, and the slot height is 165-175mm. The K2 slot opening is 225-235mm, the slot bottom is 195-200mm, the hole radius (R) is 28-32mm, the r angle is 23-27mm, the sidewall slope is 12-14°, and the slot height is 165-175mm. The K1 slot opening is 200-210mm, the slot bottom is 165-175mm, the hole R angle is 28-32mm, the r angle is 23-27mm, the side wall slope is 12-14°, and the slot height is 165-175mm. The billet rolling system includes the opening degree of the large pusher bed, the opening degree of the small pusher bed, and the billet reduction. It uses a 430*350mm raw material cross section to roll into a 170×190mm cross section in 9 passes. The first pass of steel is turned over before rolling, and the K1 rolling reduction is 75-95mm. After the second pass, the steel is turned over, and the K1 rolling reduction is 50-70mm. The steel is turned over in the third pass, and the K2 rolling reduction is 60-80mm. After the fourth pass, the steel is turned over, and the K2 rolling reduction is 70-90mm. The steel is turned over before the fifth pass, and the K3 rolling reduction is 55-75mm. The sixth pass does not involve turning over the steel; the K3 rolling reduction is 50-70mm. The steel is turned over at the front of the seventh pass mill, and the K4 rolling reduction is 55-75mm. The eighth pass does not involve turning over the steel. The K3 rolling reduction is 35-55mm. The eighth pass does not involve turning over the steel and returns it to the third hole for rolling, which provides a large reduction while reducing the number of rolling passes. The steel is turned over at the front of the ninth pass mill, and the K5 rolling reduction is 50-70mm. The upper roller has a diameter of 1100-1102mm, and the lower roller has a diameter of 1096-1098mm.

2. The method for rolling bars using a roughing mill pass system according to claim 1, characterized in that: The distance between the K5-K1 holes is 53mm.

3. The method for rolling bars using a roughing mill pass system according to claim 1, characterized in that: K1 is 100mm from the roller head, and K5 is 100mm from the roller bottom.

4. A method for rolling bars using a roughing mill pass system according to claim 1, characterized in that: The opening of the large pusher bed is 5-10 mm larger than the width of the rolled material, and the opening of the small pusher bed is 7-14 mm larger than the width of the rolled material in the next rolling pass.

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