Slitting and rolling method for flat wires with large width-to-thickness ratio

Abstract

The invention relates to the field of alloy wire machining, in particular to a large-width-to-thickness-ratio flat wire slitting rolling method which comprises the steps that a roughing mill unit, an intermediate mill unit and a finishing mill unit are adopted, and hole pattern system parameters and gradient distribution pass deformation of the three units are designed correspondingly; the wire with the circular cross section is rolled by the roughing mill unit, the intermediate mill unit and the finishing mill unit in sequence and finally rolled into two flat wires with the large width-to-thickness ratio, the cross section sizes and the shapes of the two flat wires are identical, the width-to-thickness ratio is larger than 7, and the technical problems that in the prior art, produced flat wires with the large width-to-thickness ratio are large in width size fluctuation and low in production efficiency are solved.

Description

Technical Field

[0001] The invention relates to the field of alloy wire processing, and in particular to a method for slitting and rolling flat wire with a large width-to-thickness ratio. Background Art

[0002] In recent years, with the continuous advancement of process technology and the upgrading of major equipment, the demand for quality flat wire in fields such as aviation, aerospace, and nuclear energy has gradually increased. Fasteners for high-efficiency and high-power equipment have placed more stringent requirements on the dimensional accuracy of flat wire materials. For example, the width of multiple specifications of flat wire used in spiral / elastic retaining rings of a certain equipment must be 6.20 to 9.63 mm, with a width dimensional accuracy of ±0.05 mm; the thickness must be 0.865 to 1.145 mm, with a thickness dimensional accuracy of ±0.02 mm. Under this dimensional accuracy, the width-to-thickness ratio of the flat wire is greater than 7, which is a high width-to-thickness ratio flat wire.

[0003] Currently, the main production methods for high width-to-thickness ratio flat wire include rolling, die drawing, roller drawing and wide plate slitting. However, each production method has defects to varying degrees, such as: ① The edge quality of the flat wire with large width-to-thickness ratio produced by the wide plate longitudinal shearing method is poor, and it is easy to produce defects such as burrs; ② The die-drawing method has problems such as difficulty in mold making, insufficient filling of corners, and lengthy production cycle; ③ The roller drawing method has the disadvantages of producing flat wires with large width-to-thickness ratios with significant size fluctuations and difficulty in precision control; ④ The width of the flat wire with large width-to-thickness ratio produced by the rolling method fluctuates too much, resulting in low yield and serious material waste. For example, when producing δ1.145 0 -0.045 mm×9.63 0 -0.2 Taking 1.5mm flat wire as an example, the measured width of the rolled product fluctuates between 9.3 and 9.7mm. Furthermore, conventional rolling methods for producing flat wire require precise calculation of the round wire dimensions based on the finished flat wire dimensions, a highly cumbersome process. Furthermore, the preparation of the finished round wire often requires multiple drawing, heat treatment, alkali boiling, pickling, and surface finishing processes, requiring multiple cycles. This results in long production cycles and low efficiency for conventional rolling methods of flat wire with large width-to-thickness ratios.

[0004] In summary, the current production process of large width-to-thickness ratio flat wire is cumbersome, the process is complicated, the production cycle is long, and the production efficiency is low; the width dimension of the large width-to-thickness ratio flat wire products produced has large fluctuations, poor edge quality, and low yield, which greatly increases production costs. Summary of the Invention

[0005] The purpose of the present invention is to address the corresponding shortcomings of the existing technology and provide a method for slitting and rolling flat wire with a large width-to-thickness ratio. By adopting three units, namely a roughing mill unit, an intermediate rolling mill unit and a finishing mill unit, and designing the hole system parameters of the three units and the gradient distribution of the deformation amount of the passes respectively, a wire with a circular cross-section is rolled in sequence by the roughing mill unit, the intermediate rolling mill unit and the finishing mill unit, and finally rolled into two flat wires with a large width-to-thickness ratio with a completely identical cross-sectional size and shape and a width-to-thickness ratio greater than 7, thereby overcoming the technical difficulties of the existing technology in producing flat wires with a large width-to-thickness ratio, such as large width dimensional fluctuations and low production efficiency.

[0006] The purpose of the present invention is to adopt the following scheme to achieve: A method for slitting and rolling flat wire with a large width-to-thickness ratio, comprising the following steps: 1) Rough rolling A roughing mill comprising a first rolling mill, a second rolling mill, and a third rolling mill is used to roll a wire material having a circular cross section into a flat rough billet in three passes, wherein the total reduction of the three passes is controlled at 40-60%, and the flat rough billet is annealed; 2) Medium rolling The annealed flat billet is pre-slit and rolled in three passes using an intermediate rolling mill comprising a fourth rolling mill, a fifth rolling mill, and a sixth rolling mill, so that the rolled billet is pre-slit into two parallel flat billets. The thickness of the parallel connection of the two flat billets is less than the thickness of the flat billets, forming a parallel critical state, forming a cross-section similar to "∞", and forming a cutting wedge arc on both sides of the parallel connection of the two flat billets. 3) Finish rolling A finishing rolling mill group including the seventh rolling mill, the eighth rolling mill, the ninth rolling mill, the tenth rolling mill and the eleventh rolling mill is used to split the two pre-cut parallel flat wire blanks through five passes to obtain two flat wires with the same cross-sectional size and shape and a width-to-thickness ratio greater than 7.

[0007] Preferably, the first rolling mill, the second rolling mill and the third rolling mill all use flat rolls, the roll diameter of the first rolling mill is 300-400 mm, the roll diameter of the second rolling mill is 250-350 mm, and the roll diameter of the third rolling mill is 200-300 mm.

[0008] Preferably, the single-pass reduction of the first rolling mill is controlled at 25-35%, the single-pass reduction of the second rolling mill is controlled at 15-25%, and the single-pass reduction of the third rolling mill is controlled at 5-15%.

[0009] Preferably, the fourth rolling mill, the fifth rolling mill and the sixth rolling mill all use pre-slitting rollers, and the middle section of the roller of each rolling mill is provided with an annular protrusion for slitting, and the annular protrusion includes a slitting wedge top angle (A), a slitting wedge top angle arc and a slitting wedge arc with concave arcs on both sides.

[0010] Preferably, the included angles of the cutting wedge top angles of the rolls of each rolling mill are different and are calculated according to the following formula:

[0011] Where, f is the friction coefficient between the roller and the workpiece, α is the included angle of the cutting wedge top angle of the roll of the fourth rolling mill, β is the included angle of the cutting wedge top angle of the roll of the fifth rolling mill, θ It is the included angle of the cutting wedge top angle of the roll of the sixth rolling mill.

[0012] Preferably, the radius of the cutting wedge arc of the rollers of each rolling mill is different and is calculated according to the following formula:

[0013] Where, R i For the middle rolling mill i The radius of the cutting wedge arc of the rolling mill roll, H i For the middle rolling mill i The thickness of the rolled product after rolling on the rolling mill.

[0014] Preferably, the fourth rolling mill only pre-cuts the incoming material, the radius of the wedge angle arc of the cutting roller of the fourth rolling mill is 0.4-0.6 mm, and the thickness of the flat wire blanks at the parallel connection after cutting is controlled to be 2.0-2.5 times the thickness of the finished flat wire; the single-pass reduction of the fifth rolling mill is controlled to be 20-40%, the radius of the wedge angle arc of the cutting roller of the fifth rolling mill is 0.1-0.2 mm, and the thickness of the flat wire blanks at the parallel connection after cutting is controlled to be 1.5-2.0 times the thickness of the finished flat wire; the single-pass reduction of the sixth rolling mill is controlled to be 10-20%, the radius of the wedge angle arc of the cutting roller of the sixth rolling mill is 0.05-0.15 mm, and the thickness of the flat wire blanks at the parallel connection after cutting is controlled to be 1.0-1.5 times the thickness of the finished flat wire.

[0015] Preferably, the seventh rolling mill in the finishing mill group uses slit rolls, the eighth rolling mill uses flat rolls, the ninth rolling mill uses grooved rolls, and the tenth rolling mill and the eleventh rolling mill both use flat rolls.

[0016] Preferably, the finishing mill group is arranged in the following manner: S1) Determine the included angle of the cutting wedge top angle of the seventh rolling mill roll and the distance between the corresponding centers of the cutting wedge arcs by the following formulas:

[0017] Where, ψ is the included angle of the cutting wedge top angle of the roll of the seventh rolling mill, αis the included angle of the cutting wedge top angle of the roll of the fourth rolling mill, L 4 is the distance between the centers of the wedge arcs of the seventh rolling mill rolls, H 4 is the thickness of the rolled piece; S2) The single-pass reduction of the eighth rolling mill is controlled at 30-40%; S3) The ninth rolling mill is arranged vertically, and the pass height of the pass rollers of the ninth rolling mill is 1.0 to 1.1 times the thickness of the flat wire, and the pass width of the pass rollers is 0.4 to 0.45 times the width of the flat wire; S4) Determine the arc radius of the groove bottom of the grooved roller of the ninth rolling mill by the following formula:

[0018] Where, R 5 is the arc radius at the bottom of the ninth mill pass, h is the groove height of the grooved rolls of the ninth rolling mill; S5) The single-pass reduction of the tenth rolling mill is controlled at 10-20%; S6) The single-pass reduction of the eleventh rolling mill is controlled at 5-10%.

[0019] Preferably, the annealing treatment is performed in a protective atmosphere continuous annealing furnace or a vacuum heat treatment furnace.

[0020] The beneficial effects of the present invention are as follows: A method for slitting and rolling flat wire with a large width-to-thickness ratio, comprising the following steps: 1) Rough rolling A roughing mill comprising a first rolling mill, a second rolling mill, and a third rolling mill is used to roll a wire material having a circular cross section into a flat rough billet in three passes, wherein the total reduction of the three passes is controlled at 40-60%, and the flat rough billet is annealed; 2) Medium rolling The annealed flat billet is pre-slit and rolled in three passes through an intermediate rolling mill comprising a fourth rolling mill, a fifth rolling mill, and a sixth rolling mill, so that the rolled billet is pre-slit into two parallel flat billets. The parallel connection of the two flat billets is in a critical parallel state, forming a cross-section similar to "∞", and a dividing wedge arc is formed on both sides of the parallel connection of the two flat billets. 3) Finish rolling A finishing rolling mill group including the seventh rolling mill, the eighth rolling mill, the ninth rolling mill, the tenth rolling mill and the eleventh rolling mill is used to split the two pre-cut parallel flat wire blanks through five passes to obtain two flat wires with the same cross-sectional size and shape and a width-to-thickness ratio greater than 7.

[0021] The present invention utilizes a roughing mill to roll a round wire into a flat rough billet, which can quickly reduce the thickness of the wire material and perform an annealing and softening treatment, so that the billet state of the flat rough billet is suitable for subsequent pre-slitting and finishing rolling; then, an intermediate rolling mill and a finishing rolling mill are used to sequentially perform multiple passes of rolling and slitting on the flat rough billet, so that the flat rough billet can be rolled into two flat wires with a large aspect ratio of more than 7 and having completely identical cross-sectional dimensions and shapes.

[0022] Preferably, the seventh rolling mill in the finishing mill group uses slit rolls, the eighth rolling mill uses flat rolls, the ninth rolling mill uses grooved rolls, and the tenth rolling mill and the eleventh rolling mill both use flat rolls.

[0023] Preferably, the finishing mill group is arranged in the following manner: S1) Determine the included angle of the cutting wedge top angle of the seventh rolling mill roll and the distance between the corresponding centers of the cutting wedge arcs by the following formulas:

[0024] Where, ψ is the included angle of the cutting wedge top angle of the roll of the seventh rolling mill, α is the included angle of the cutting wedge top angle of the roll of the fourth rolling mill, L 4 is the distance between the centers of the wedge arcs of the seventh rolling mill rolls, H 4 is the thickness of the rolled piece; S2) The single-pass reduction of the eighth rolling mill is controlled at 30-40%; S3) The ninth rolling mill is arranged vertically, and the pass height of the pass rollers of the ninth rolling mill is 1.0 to 1.1 times the thickness of the flat wire, and the pass width of the pass rollers is 0.4 to 0.45 times the width of the flat wire; S4) Determine the arc radius of the groove bottom of the grooved roller of the ninth rolling mill by the following formula:

[0025] Where, R 5 is the arc radius at the bottom of the ninth mill pass, h is the groove height of the grooved rolls of the ninth rolling mill; S5) The single-pass reduction of the tenth rolling mill is controlled at 10-20%; S6) The single-pass reduction of the eleventh rolling mill is controlled at 5-10%.

[0026] In the finishing mill group adopted by the present invention, the seventh rolling mill is a slitting mill, the purpose of which is to split the workpiece into two independent workpieces. By calculating the wedge top angle and center distance of the seventh rolling mill, the tensile stress on the connecting belt can be maximized, and the two parallel workpieces can be completely separated and disconnected; the eighth rolling mill is a flat roll mill, the purpose of which is to cause large compression deformation of the workpiece. According to the metal flow deformation characteristics of flat roll rolling, the single-pass reduction control of the eighth rolling mill is set to ensure that the workpiece has a large width expansion in the width direction, thereby eliminating defects such as "ears and lace" formed by slitting to the greatest extent; the ninth rolling mill is a hole-type rolling mill, which can cause the workpiece to be compressed and deformed in the width direction, and further eliminate the residual "ears" problem that may not have been eliminated by the previous rolling mill, with the purpose of making the arcs on both sides of the workpiece symmetrical; the tenth rolling mill and the eleventh rolling mill are both flat roll rolling, which can make the two flat wire workpieces finally rolled out have the same cross-sectional size and shape.

[0027] The advantages of the present invention are as follows: ① By designing pass parameters and optimizing the distribution of deformation per pass, the present invention effectively combines the wide plate slitting method (the fourth to seventh rolling mills incorporate the "slicing" concept of the wide plate slitting method) with the rolling method (each rolling mill on the production line). This allows the production of high-width-ratio flat wire to combine the advantages of both wide plate slitting and rolling methods. This results in not only excellent wire surface quality but also stable and highly precise external dimensions. This overcomes the problems of large width dimensional fluctuations and poor edge quality associated with the prior art in producing high-width-ratio flat wire, significantly improving the yield rate of high-width-ratio flat wire. ② The high-width-thickness-ratio flat wire produced by the present invention possesses all the advantages of the high-width-thickness-ratio flat wire produced by conventional rolling methods. The edges of the high-width-thickness-ratio flat wire produced are arc-shaped, and the probability of defects such as burrs and cracks is low. Under large tensile stress conditions, the high-width-thickness-ratio flat wire is not prone to cracks and other failure sources. It has high strength, plasticity, and deep-drawing properties, as well as excellent fatigue resistance, and has excellent overall performance. In addition, the present invention has fewer production steps, a shorter cycle, and higher efficiency than conventional rolling methods: conventional rolling methods can only produce a single high-width-thickness-ratio flat wire at a time, while the present invention can simultaneously produce two high-width-thickness-ratio flat wires with the same cross-sectional size and appearance, resulting in higher production efficiency; the round wire (i.e., wire with a circular cross-section) used in the slitting and rolling of the present invention is larger in size than the round wire used in conventional rolling methods, and the number of preliminary processes involved, such as drawing, heat treatment, alkali boiling, pickling, and surface finishing, is fewer, that is, the present invention has fewer preliminary steps and a shorter cycle; ③ Existing slit rolling technologies (for example, for slit rolling of rebar or bars (round steel)) are all hot rolling, meaning the incoming material must be heated before rolling. The slit rolling technology employed in this invention, however, is cold rolling. This eliminates the need for heating the incoming material (i.e., round cross-section wire) and allows rolling at room temperature, resulting in fewer production steps and lower energy consumption. Crucially, flat wire used in elastic components requires cold rolling to ensure high strength and elasticity, as conventional hot-rolled materials do not meet performance requirements.

[0028] Glossary: Flat wire: A type of shaped wire. Shaped wire refers to a metal wire with a non-circular cross section, and flat wire is a metal wire with a flat cross section. High aspect ratio flat wire usually refers to a flat wire with a width-to-thickness ratio greater than 5.

[0029] The intermediate rolling mill plays a crucial role in this invention, adjusting the size of the workpiece entering the finishing mill and ensuring a stable finishing process. Although the workpiece has been initially shaped after rough rolling, it is still relatively large. The intermediate rolling mill uses multiple rolling passes to gradually reduce the cross-sectional dimensions of the workpiece, bringing it closer to the specifications of the finished product. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the planar layout of the entire production line of the present invention; Figure 2 It is a structural schematic diagram of the 4H rolling mill pass of the present invention; Figure 3 It is a structural schematic diagram of the 5H rolling mill pass of the present invention; Figure 4 It is a structural schematic diagram of the 6H rolling mill pass of the present invention; Figure 5 It is a structural schematic diagram of the 7H rolling mill pass of the present invention; Figure 6 It is a structural schematic diagram of the 9H rolling mill pass of the present invention; Figure 7 It is a cross-sectional diagram of the critical state of two parallel rolled pieces being cut; Figure 8 It is a schematic diagram of the distance between the centers of the wedge arcs of the rolling mill; Figure 9 This is a schematic structural diagram of the 4H rolling mill roll of the present invention; Figure 10 This is a schematic structural diagram of a 5H rolling mill roll according to the present invention; Figure 11 It is a schematic structural diagram of the 6H rolling mill roller of the present invention. DETAILED DESCRIPTION

[0031] like Figures 1 to 11As shown, a method for slitting and rolling flat wire with a large width-to-thickness ratio comprises the following steps: 1) Rough rolling A roughing mill comprising a first rolling mill (i.e., a 1H rolling mill), a second rolling mill (i.e., a 2H rolling mill), and a third rolling mill (i.e., a 31H rolling mill) is used to roll a wire having a circular cross section into a flat rough billet in three passes, wherein the total reduction of the three passes is controlled at 40-60%, and the flat rough billet is annealed; Specifically, the 1H rolling mill, 2H rolling mill and 3H rolling mill all use flat rolls, and the diameter of each flat roll (i.e., roll diameter) decreases successively. The roll diameter of the 1H rolling mill is 300-400mm, the roll diameter of the 2H rolling mill is 250-350mm, and the roll diameter of the 3H rolling mill is 200-300mm.

[0032] Rough rolling refers to the use of a rough rolling mill group including a 1H rolling mill (i.e., a rolling mill numbered 1H), a 2H rolling mill, and a 3H rolling mill to roll a wire with a circular cross-section into a flat rough billet through three passes, with the single-pass reduction of the 1H rolling mill controlled at 25-35%, the single-pass reduction of the 2H rolling mill controlled at 15-25%, and the single-pass reduction of the 3H rolling mill controlled at 5-15%, and the total reduction of the three passes controlled at 40-60%, and the flat rough billet is annealed and softened, and the annealing and softening treatment is carried out in a protective atmosphere continuous annealing furnace or a vacuum heat treatment furnace.

[0033] 2) Medium rolling The annealed flat billet is pre-slit and rolled in three passes using an intermediate rolling mill comprising a fourth rolling mill, a fifth rolling mill, and a sixth rolling mill, so that the rolled billet is pre-slit into two parallel flat billets. The thickness of the parallel connection of the two flat billets is less than the thickness of the flat billets, forming a parallel critical state, forming a cross-section similar to "∞", and forming a cutting wedge arc on both sides of the parallel connection of the two flat billets. Specifically, the 4H, 5H, and 6H mills all use pre-slit rollers. Each mill features an annular protrusion around the middle of the rollers for slitting. This annular protrusion includes a slitting wedge angle A, a slitting wedge angle arc, and a slitting wedge arc with concave arcs on either side. It's worth noting that the slitting wedge angle arc is the arc of slitting wedge angle A, and the slitting wedge arc is the slitting wedge arc formed on both sides of the parallel connection of the flat wire blanks slit using the slitting wedge angle.

[0034] like Figures 9-11 As shown in the figure, the included angle of the cutting wedge top angle of each rolling mill is different and is calculated according to the following formula:

[0035] Where, f is the friction coefficient between the roller and the workpiece, αis the included angle of the cutting wedge top angle of the roll of the 4H rolling mill, β is the included angle of the cutting wedge top angle of the roll of the 5H rolling mill, θ It is the included angle of the cutting wedge top angle of the roll of the 6H rolling mill.

[0036] The radius of the cutting wedge arc of the rolls of each rolling mill is different and is calculated according to the following formula:

[0037] Where, R i For the middle rolling mill i The radius of the cutting wedge arc of the rolling mill roll, H i For the middle rolling mill i The thickness of the rolled product after rolling in the rolling mill; In this embodiment, the radius of the cutting wedge arc of the rollers of each rolling mill calculated by the above formula is mainly used to provide a rolling reference for the finishing rolling group, so that when the finishing rolling group rolls the other end (free end) of the flat wire billet, it can roll the end into an arc that is exactly the same as the "cutting wedge arc formed on both sides of the parallel connection", which can make the surface of the flat wire finally rolled more uniform and the dimensional accuracy higher.

[0038] like Figures 2-4 As shown, the 4H rolling mill only pre-cuts the incoming material, and the radius r1 of the cutting wedge angle arc of the roller of the 4H rolling mill is 0.4~0.6mm. The thickness of the parallel connection of the flat wire blank after cutting is controlled to be 2.0~2.5 times the thickness of the finished flat wire; the single-pass reduction of the 5H rolling mill is controlled to be 20~40%, and the radius r2 of the cutting wedge angle arc of the roller of the 5H rolling mill is 0.1~0.2mm. The thickness of the parallel connection of the flat wire blank after cutting is controlled to be 1.5~2.0 times the thickness of the finished flat wire; the single-pass reduction of the 6H rolling mill is controlled to be 10~20%, and the radius r3 of the cutting wedge angle arc of the roller of the 6H rolling mill is 0.05~0.15mm. The thickness of the parallel connection of the flat wire blank after cutting is controlled to be 1.0~1.5 times the thickness of the finished flat wire. The thickness of the two sides of the parallel connection of the flat wire billet after cutting is the thickness of the flat wire, which is controlled by the single-pass reduction of each rolling mill.

[0039] Intermediate rolling means that the flat rough billet after annealing and softening treatment is pre-cut and rolled by the intermediate rolling mill group including 4H rolling mill, 5H rolling mill and 6H rolling mill in three passes, so that the rolled billet is pre-cut into two parallel flat wire billets. The parallel connection of the two flat wire billets is in a parallel critical state, forming a cross-section similar to "∞". The two flat wire billets are formed on both sides of the parallel connection of the two flat wire billets. Figure 7 As shown; 3) Finish rolling A finishing rolling mill group including the seventh rolling mill, the eighth rolling mill, the ninth rolling mill, the tenth rolling mill and the eleventh rolling mill is used to split the two pre-cut parallel flat wire blanks through five passes to obtain two flat wires with the same cross-sectional size and shape and a width-to-thickness ratio greater than 7.

[0040] Specifically, in the finishing mill group, the 7H mill uses split rolls, the 8H mill uses flat rolls, the 9H mill uses grooved rolls, and the 10H and 11H mills both use flat rolls. Each mill is set up as follows: S1) Determine the included angle of the cutting wedge top angle of the 7H rolling mill roll and the distance between the corresponding centers of the cutting wedge arcs by the following formulas:

[0041] Where, ψ is the included angle of the cutting wedge top angle of the roll of the 7H rolling mill, α is the included angle of the cutting wedge top angle of the roll of the 4H rolling mill, L 4 is the distance between the centers of the wedge arcs of the rollers of the 7H rolling mill (e.g. Figure 8 shown), H 4 is the thickness of the rolled piece; S2) The single-pass reduction of the 8H rolling mill is controlled at 30-40%; S3) The 9H rolling mill is arranged vertically, and the pass height of the pass roller of the 9H rolling mill is 1.0 to 1.1 times the thickness of the flat wire, and the pass width of the pass roller is 0.4 to 0.45 times the width of the flat wire; S4) Determine the arc radius of the groove bottom of the 9H mill groove roll by the following formula:

[0042] Where, R 5 is the arc radius at the bottom of the 9H mill pass, h is the groove height of the groove roll of the 9H rolling mill; S5) The single-pass reduction of the 10H rolling mill is controlled at 10-20%; S6) The single-pass reduction of the 11H rolling mill is controlled at 5-10%.

[0043] Finishing rolling refers to the use of a finishing rolling mill group including a 7H rolling mill, an 8H rolling mill, a 9H rolling mill, a 10H rolling mill, and an 11H rolling mill to split two pre-cut parallel flat wire billets through five passes to obtain two flat wires with the same cross-sectional size and shape and a width-to-thickness ratio greater than 7.

[0044] According to the above method, the following examples are made: First, a fully automatic production line for slitting and rolling flat wire with large width-to-thickness ratio is formed by using roughing mill, intermediate rolling mill and finishing mill. Figure 1 In this production line, the roughing mill group is arranged at the wire feeding place, the discharge port of the roughing mill group is aligned with the feed port of the intermediate rolling mill group, and the discharge port of the intermediate rolling mill group is aligned with the feed port of the finishing mill group. The various rolling mills in each rolling mill group are arranged as follows: Roughing mill group: The feed port of the 1H rolling mill is the feed port of the roughing mill group, the discharge port of the 1H rolling mill is aligned with the feed port of the 2H rolling mill, the discharge port of the 2H rolling mill is aligned with the feed port of the 3H rolling mill, and the discharge port of the 3H rolling mill is the discharge port of the roughing mill group.

[0045] Intermediate rolling mill group: The feed port of the 4H rolling mill is the feed port of the intermediate rolling mill group, the discharge port of the 4H rolling mill is aligned with the feed port of the 5H rolling mill, the discharge port of the 5H rolling mill is aligned with the feed port of the 6H rolling mill, and the discharge port of the 6H rolling mill is the discharge port of the intermediate rolling mill group.

[0046] Finishing mill group: The feed port of the 7H rolling mill serves as the feed port of the finishing mill group, and the discharge port of the 7H rolling mill is aligned with the feed port of the 8H rolling mill, the discharge port of the 8H rolling mill is aligned with the feed port of the 9H rolling mill, the discharge port of the 9H rolling mill is aligned with the feed port of the 10H rolling mill, the discharge port of the 10H rolling mill is aligned with the feed port of the 11H, and the discharge port of the 11H serves as the discharge port of the finishing mill group. Example

[0047] 1) Rough rolling A rough rolling mill group including a 1H rolling mill (i.e., a rolling mill numbered 1H), a 2H rolling mill, and a 3H rolling mill is used to roll a wire with a circular cross-section into a flat rough billet in three passes. The single-pass reduction of the 1H rolling mill is controlled at 25%, the single-pass reduction of the 2H rolling mill is controlled at 15%, and the single-pass reduction of the 3H rolling mill is controlled at 5%. The total reduction of the three passes is controlled at 40%, and the flat rough billet is annealed and softened, and the annealing and softening treatment is carried out in a protective atmosphere continuous annealing furnace or a vacuum heat treatment furnace.

[0048] In this embodiment, the 1H rolling mill, the 2H rolling mill, and the 3H rolling mill all use flat rolls, and the diameter of each flat roll (i.e., the roll diameter) decreases successively. The roll diameter of the 1H rolling mill is 300 mm, the roll diameter of the 2H rolling mill is 250 mm, and the roll diameter of the 3H rolling mill is 200 mm.

[0049] 2) Medium rolling The flat rough billet after annealing and softening treatment is pre-cut and rolled in three passes by a medium rolling mill group including a 4H rolling mill, a 5H rolling mill and a 6H rolling mill, so that the rolled billet is pre-cut into two parallel flat wire billets. The parallel connection of the two flat wire billets is in a parallel critical state, forming a cross-section similar to "∞". A cutting wedge arc is formed on both sides of the parallel connection of the two flat wire billets, such as Figure 7 As shown; In this embodiment, the 4H rolling mill, the 5H rolling mill, and the 6H rolling mill all use pre-slit rollers. The middle section of the roller of each rolling mill is provided with an annular protrusion for slitting. The annular protrusion includes a slitting wedge top angle A, a slitting wedge top angle arc, and a slitting wedge arc with concave arcs on both sides, such as Figures 9-11 As shown in the figure, the included angle of the cutting wedge top angle of each rolling mill is different and is calculated according to the following formula:

[0050] Where, f is the friction coefficient between the roller and the workpiece, α is the included angle of the cutting wedge top angle of the roll of the 4H rolling mill, β is the included angle of the cutting wedge top angle of the roll of the 5H rolling mill, θ It is the included angle of the cutting wedge top angle of the roll of the 6H rolling mill.

[0051] The radius of the cutting wedge arc of the rolls of each rolling mill is different and is calculated according to the following formula:

[0052] Where, R i For the middle rolling mill i The radius of the cutting wedge arc of the rolling mill roll, H i For the middle rolling mill i The thickness of the rolled product after rolling in the rolling mill; like Figures 2-4 As shown, the 4H rolling mill only pre-cuts the incoming material, the radius r1 of the cutting wedge angle arc of the roller of the 4H rolling mill is 0.4mm, and the thickness of the flat wire blanks in parallel after cutting is controlled at 2.0 times the thickness of the finished flat wire; the single-pass reduction of the 5H rolling mill is controlled at 20%, the radius r2 of the cutting wedge angle arc of the roller of the 5H rolling mill is 0.1mm, and the thickness of the flat wire blanks in parallel after cutting is controlled at 1.5 times the thickness of the finished flat wire; the single-pass reduction of the 6H rolling mill is controlled at 10%, the radius r3 of the cutting wedge angle arc of the roller of the 6H rolling mill is 0.05mm, and the thickness of the flat wire blanks in parallel after cutting is controlled at 1.0 times the thickness of the finished flat wire.

[0053] 3) Finish rolling A finishing rolling mill group including 7H rolling mill, 8H rolling mill, 9H rolling mill, 10H rolling mill and 11H rolling mill is used to split the two pre-cut parallel flat wire billets through five passes to obtain two flat wires with the same cross-sectional size and shape and a width-to-thickness ratio of 8.04 / 1.04=7.73.

[0054] In this embodiment, the 7H mill in the finishing mill group uses split rolls, the 8H mill uses flat rolls, the 9H mill uses grooved rolls, and the 10H and 11H mills both use flat rolls. Each mill is arranged as follows: S1) Determine the included angle of the cutting wedge top angle of the 7H rolling mill roll and the distance between the corresponding centers of the cutting wedge arcs by the following formulas:

[0055] Where, ψ is the included angle of the cutting wedge top angle of the roll of the 7H rolling mill, α is the included angle of the cutting wedge top angle of the roll of the 4H rolling mill, L 4 is the distance between the centers of the wedge arcs of the rollers of the 7H rolling mill (e.g. Figure 8 shown), H 4 is the thickness of the rolled piece; S2) The single-pass reduction of the 8H rolling mill is controlled at 30%; S3) The 9H rolling mill is arranged vertically, and the pass height of the pass roller of the 9H rolling mill is 1.0 to 1.1 times the thickness of the flat wire, and the pass width of the pass roller is 0.4 times the width of the flat wire; S4) Determine the arc radius of the groove bottom of the 9H mill groove roll by the following formula:

[0056] Where, R 5 is the arc radius at the bottom of the 9H mill pass, h is the groove height of the groove roll of the 9H rolling mill; S5) The single-pass reduction of the 10H rolling mill is controlled at 10%; S6) The single-pass reduction of the 11H rolling mill is controlled at 5%. Example

[0057] 1) Rough rolling A rough rolling mill group including a 1H rolling mill (i.e., a rolling mill numbered 1H), a 2H rolling mill, and a 3H rolling mill is used to roll a wire with a circular cross-section into a flat rough billet in three passes. The single-pass reduction of the 1H rolling mill is controlled at 30%, the single-pass reduction of the 2H rolling mill is controlled at 20%, and the single-pass reduction of the 3H rolling mill is controlled at 10%. The total reduction of the three passes is controlled at 50%, and the flat rough billet is annealed and softened, and the annealing and softening treatment is carried out in a protective atmosphere continuous annealing furnace or a vacuum heat treatment furnace.

[0058] In this embodiment, the 1H rolling mill, the 2H rolling mill, and the 3H rolling mill all use flat rolls, and the diameter of each flat roll (i.e., the roll diameter) decreases successively. The roll diameter of the 1H rolling mill is 350 mm, the roll diameter of the 2H rolling mill is 300 mm, and the roll diameter of the 3H rolling mill is 250 mm.

[0059] 2) Medium rolling The flat rough billet after annealing and softening treatment is pre-cut and rolled in three passes by a medium rolling mill group including a 4H rolling mill, a 5H rolling mill and a 6H rolling mill, so that the rolled billet is pre-cut into two parallel flat wire billets. The parallel connection of the two flat wire billets is in a parallel critical state, forming a cross-section similar to "∞". A cutting wedge arc is formed on both sides of the parallel connection of the two flat wire billets, such as Figure 7 As shown; In this embodiment, the 4H rolling mill, the 5H rolling mill, and the 6H rolling mill all use pre-slit rollers. The middle section of the roller of each rolling mill is provided with an annular protrusion for slitting. The annular protrusion includes a slitting wedge top angle A, a slitting wedge top angle arc, and a slitting wedge arc with concave arcs on both sides, such as Figures 9-11 As shown in the figure, the included angle of the cutting wedge top angle of each rolling mill is different and is calculated according to the following formula:

[0060] Where, f is the friction coefficient between the roller and the workpiece, α is the included angle of the cutting wedge top angle of the roll of the 4H rolling mill, β is the included angle of the cutting wedge top angle of the roll of the 5H rolling mill, θ It is the included angle of the cutting wedge top angle of the roll of the 6H rolling mill.

[0061] The radius of the cutting wedge arc of the rolls of each rolling mill is different and is calculated according to the following formula:

[0062] Where, R i For the middle rolling mill i The radius of the cutting wedge arc of the rolling mill roll, H i For the middle rolling milli The thickness of the rolled product after rolling in the rolling mill; like Figures 2-4 As shown, the 4H rolling mill only pre-cuts the incoming material, and the radius r1 of the cutting wedge angle arc of the roller of the 4H rolling mill is 0.5mm. The thickness of the flat wire blanks at the parallel connection after cutting is controlled at 2.25 times the thickness of the finished flat wire; the single-pass reduction of the 5H rolling mill is controlled at 30%, and the radius r2 of the cutting wedge angle arc of the roller of the 5H rolling mill is 0.15mm. The thickness of the flat wire blanks at the parallel connection after cutting is controlled at 1.75 times the thickness of the finished flat wire; the single-pass reduction of the 6H rolling mill is controlled at 15%, and the radius r3 of the cutting wedge angle arc of the roller of the 6H rolling mill is 0.10mm. The thickness of the flat wire blanks at the parallel connection after cutting is controlled at 1.25 times the thickness of the finished flat wire.

[0063] 3) Finish rolling A finishing rolling mill group including 7H rolling mill, 8H rolling mill, 9H rolling mill, 10H rolling mill and 11H rolling mill is used to split the two pre-cut parallel flat wire billets through five passes to obtain two flat wires with the same cross-sectional size and shape and a width-to-thickness ratio of 14.28 / 1.42=10.06.

[0064] In this embodiment, the 7H mill in the finishing mill group uses split rolls, the 8H mill uses flat rolls, the 9H mill uses grooved rolls, and the 10H and 11H mills both use flat rolls. Each mill is arranged as follows: S1) Determine the included angle of the cutting wedge top angle of the 7H rolling mill roll and the distance between the corresponding centers of the cutting wedge arcs by the following formulas:

[0065] Where, ψ is the included angle of the cutting wedge top angle of the roll of the 7H rolling mill, α is the included angle of the cutting wedge top angle of the roll of the 4H rolling mill, L 4 is the distance between the centers of the wedge arcs of the rollers of the 7H rolling mill (e.g. Figure 8 shown), H 4 is the thickness of the rolled piece; S2) The single-pass reduction of the 8H rolling mill is controlled at 35%; S3) The 9H rolling mill is arranged vertically, and the pass height of the pass roller of the 9H rolling mill is 1.0 to 1.1 times the thickness of the flat wire, and the pass width of the pass roller is 0.425 times the width of the flat wire; S4) Determine the arc radius of the groove bottom of the 9H mill groove roll by the following formula:

[0066] Where, R5 is the arc radius at the bottom of the 9H mill pass, h is the groove height of the groove roll of the 9H rolling mill; S5) The single-pass reduction of the 10H rolling mill is controlled at 15%; S6) The single-pass reduction of the 11H rolling mill is controlled at 7.5%. Example

[0067] 1) Rough rolling A rough rolling mill group including a 1H rolling mill (i.e., a rolling mill numbered 1H), a 2H rolling mill, and a 3H rolling mill is used to roll a wire with a circular cross-section into a flat rough billet in three passes. The single-pass reduction of the 1H rolling mill is controlled at 35%, the single-pass reduction of the 2H rolling mill is controlled at 25%, and the single-pass reduction of the 3H rolling mill is controlled at 15%. The total reduction of the three passes is controlled at 60%, and the flat rough billet is annealed and softened, and the annealing and softening treatment is carried out in a protective atmosphere continuous annealing furnace or a vacuum heat treatment furnace.

[0068] In this embodiment, the 1H rolling mill, the 2H rolling mill, and the 3H rolling mill all use flat rolls, and the diameter of each flat roll (i.e., the roll diameter) decreases successively. The roll diameter of the 1H rolling mill is 400 mm, the roll diameter of the 2H rolling mill is 350 mm, and the roll diameter of the 3H rolling mill is 300 mm.

[0069] 2) Medium rolling The flat rough billet after annealing and softening treatment is pre-cut and rolled in three passes by a medium rolling mill group including a 4H rolling mill, a 5H rolling mill and a 6H rolling mill, so that the rolled billet is pre-cut into two parallel flat wire billets. The thickness of the parallel connection of the two flat wire billets is less than the thickness of the flat wire billets, and they are in a parallel critical state, forming a cross-section similar to "∞". A cutting wedge arc is formed on both sides of the parallel connection of the two flat wire billets, such as Figure 7 As shown; In this embodiment, the 4H rolling mill, the 5H rolling mill, and the 6H rolling mill all use pre-slit rollers. The middle section of the roller of each rolling mill is provided with an annular protrusion for slitting. The annular protrusion includes a slitting wedge top angle A, a slitting wedge top angle arc, and a slitting wedge arc with concave arcs on both sides, such as Figures 9-11 As shown in the figure, the included angle of the cutting wedge top angle of each rolling mill is different and is calculated according to the following formula:

[0070] Where, f is the friction coefficient between the roller and the workpiece, α is the included angle of the cutting wedge top angle of the roll of the 4H rolling mill, β is the included angle of the cutting wedge top angle of the roll of the 5H rolling mill, θ It is the included angle of the cutting wedge top angle of the roll of the 6H rolling mill.

[0071] The radius of the cutting wedge arc of the rolls of each rolling mill is different and is calculated according to the following formula:

[0072] Where, R i For the middle rolling mill i The radius of the cutting wedge arc of the rolling mill roll, H i For the middle rolling mill i The thickness of the rolled product after rolling in the rolling mill; like Figures 2-4 As shown, the 4H rolling mill only pre-cuts the incoming material, and the radius r1 of the cutting wedge angle arc of the roller of the 4H rolling mill is 0.6mm. The thickness of the flat wire blanks at the parallel connection after cutting is controlled to be 2.5 times the thickness of the finished flat wire; the single-pass reduction of the 5H rolling mill is controlled at 40%, and the radius r2 of the cutting wedge angle arc of the roller of the 5H rolling mill is 0.2mm. The thickness of the flat wire blanks at the parallel connection after cutting is controlled to be 2.0 times the thickness of the finished flat wire; the single-pass reduction of the 6H rolling mill is controlled at 20%, and the radius r3 of the cutting wedge angle arc of the roller of the 6H rolling mill is 0.15mm. The thickness of the flat wire blanks at the parallel connection after cutting is controlled to be 1.5 times the thickness of the finished flat wire.

[0073] 3) Finish rolling A finishing rolling mill group including 7H rolling mill, 8H rolling mill, 9H rolling mill, 10H rolling mill and 11H rolling mill is used to split the two pre-cut parallel flat wire billets through five passes to obtain two flat wires with the same cross-sectional size and shape and a width-to-thickness ratio of 24.6 / 1.84=13.37.

[0074] In this embodiment, the 7H mill in the finishing mill group uses split rolls, the 8H mill uses flat rolls, the 9H mill uses grooved rolls, and the 10H and 11H mills both use flat rolls. Each mill is arranged as follows: S1) Determine the included angle of the cutting wedge top angle of the 7H rolling mill roll and the distance between the corresponding centers of the cutting wedge arcs by the following formulas:

[0075] Where, ψ is the included angle of the cutting wedge top angle of the roll of the 7H rolling mill, α is the included angle of the cutting wedge top angle of the roll of the 4H rolling mill, L 4 is the distance between the centers of the wedge arcs of the rollers of the 7H rolling mill (e.g. Figure 8 shown), H 4 is the thickness of the rolled piece; S2) The single-pass reduction of the 8H rolling mill is controlled at 40%; S3) The 9H rolling mill is arranged vertically, and the pass height of the pass roller of the 9H rolling mill is 1.0 to 1.1 times the thickness of the flat wire, and the pass width of the pass roller is 0.45 times the width of the flat wire; S4) Determine the arc radius of the groove bottom of the 9H mill groove roll by the following formula:

[0076] Where, R 5 is the arc radius at the bottom of the 9H mill pass, h is the groove height of the groove roll of the 9H rolling mill; S5) The single-pass reduction of the 10H rolling mill is controlled at 20%; S6) The single-pass reduction of the 11H rolling mill is controlled at 10%.

[0077] Thus, the present invention effectively combines the wide plate slitting method with the rolling method to establish a fully automated production line for slitting and rolling high-width-to-thickness ratio flat wire. The roughing, intermediate, and finishing mills in this production line sequentially roll and slit a circular cross-sectional wire, simultaneously producing two flat wires with identical cross-sectional dimensions and appearance. Comparative experiments (i.e., Examples 1-3) show that the flat wires rolled according to the present invention all have aspect ratios between 7 and 15, with width dimensional accuracy of ±0.02 mm and thickness dimensional accuracy of ±0.005 mm. These wires not only have excellent surface quality but also have stable and highly accurate external dimensions. This completely overcomes the problems of large width dimensional fluctuations and poor edge quality associated with the prior art production of high-width-to-thickness ratio flat wires, significantly improving the yield rate of high-width-to-thickness ratio flat wires.

[0078] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made to the present invention by those skilled in the art without departing from the spirit of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A method for slitting and rolling flat wire with a large width-to-thickness ratio, characterized in that: The following steps are involved: 1) Rough rolling A roughing mill comprising a first rolling mill, a second rolling mill, and a third rolling mill is used to roll a wire material having a circular cross section into a flat rough billet in three passes, wherein the total reduction of the three passes is controlled at 40-60%, and the flat rough billet is annealed. 2) Medium rolling The annealed flat billet is pre-slit and rolled in three passes using an intermediate rolling mill comprising a fourth rolling mill, a fifth rolling mill, and a sixth rolling mill, so that the rolled billet is pre-slit into two parallel flat billets. The thickness of the parallel connection of the two flat billets is less than the thickness of the flat billets, forming a parallel critical state, forming a cross-section similar to "∞", and forming a cutting wedge arc on both sides of the parallel connection of the two flat billets. 3) Finish rolling A finishing rolling mill group including the seventh rolling mill, the eighth rolling mill, the ninth rolling mill, the tenth rolling mill and the eleventh rolling mill is used to split the two pre-cut parallel flat wire blanks through five passes to obtain two flat wires with the same cross-sectional size and shape and a width-to-thickness ratio greater than 7.

2. The method for slitting and rolling flat wire with a large width-to-thickness ratio according to claim 1, characterized in that: The first rolling mill, the second rolling mill and the third rolling mill all use flat rolls. The roll diameter of the first rolling mill is 300-400 mm, the roll diameter of the second rolling mill is 250-350 mm, and the roll diameter of the third rolling mill is 200-300 mm.

3. The method for slitting and rolling flat wire with a large width-to-thickness ratio according to claim 1, characterized in that: The single-pass reduction of the first rolling mill is controlled within 25-35%, the single-pass reduction of the second rolling mill is controlled within 15-25%, and the single-pass reduction of the third rolling mill is controlled within 5-15%.

4. The method for slitting and rolling flat wire with a large width-to-thickness ratio according to claim 1, wherein: The fourth, fifth and sixth rolling mills all use pre-slitting rollers, and the middle section of the roller of each rolling mill is provided with an annular protrusion for slitting. The annular protrusion includes a slitting wedge top angle (A), a slitting wedge top angle arc and a slitting wedge arc with concave arcs on both sides.

5. The method for slitting and rolling flat wire with a large width-to-thickness ratio according to claim 4, characterized in that: The included angle of the cutting wedge top angle of each rolling mill is different and is calculated according to the following formula: β＝α-(10°～20°) α>θ>β; Where f is the friction coefficient between the roll and the workpiece, α is the angle of the cutting wedge top angle of the roll of the fourth rolling mill, β is the angle of the cutting wedge top angle of the roll of the fifth rolling mill, and θ is the angle of the cutting wedge top angle of the roll of the sixth rolling mill.

6. The method for slitting and rolling flat wire with a large width-to-thickness ratio according to claim 4, characterized in that: The radius of the cutting wedge arc of the rolls of each rolling mill is different and is calculated according to the following formula: R i =(0.5~0.6)H i ; Where R i H is the radius of the cutting wedge arc of the roll of the i-th rolling mill in the rolling mill group, i It is the thickness of the rolled product after rolling by the i-th rolling mill in the intermediate rolling mill group.

7. The method for slitting and rolling flat wire with a large width-to-thickness ratio according to claim 1, characterized in that: The fourth rolling mill only pre-slits the incoming material. The radius of the wedge angle arc of the fourth rolling mill roller is 0.4-0.6 mm. The thickness of the parallel connection of the flat wire blank after slitting is controlled to be 2.0-2.5 times the thickness of the finished flat wire. The single-pass reduction of the fifth rolling mill is controlled to be 20-40%. The radius of the wedge angle arc of the fifth rolling mill roller is 0.1-0.2 mm. The thickness of the parallel connection of the flat wire blank after slitting is controlled to be 1.5-2.0 times the thickness of the finished flat wire. The single-pass reduction of the sixth rolling mill is controlled to be 10-20%. The radius of the wedge angle arc of the sixth rolling mill roller is 0.05-0.15 mm. The thickness of the parallel connection of the flat wire blank after slitting is controlled to be 1.0-1.5 times the thickness of the finished flat wire.

8. The method for slitting and rolling flat wire with a large width-to-thickness ratio according to claim 1, characterized in that: In the finishing mill group, the seventh rolling mill adopts slit rolls, the eighth rolling mill adopts flat rolls, the ninth rolling mill adopts grooved rolls, and the tenth rolling mill and the eleventh rolling mill both adopt flat rolls.

9. The method for slitting and rolling flat wire with a large width-to-thickness ratio according to claim 1, characterized in that: The finishing mill group is arranged in the following manner: S1) Determine the angle of the cutting wedge top angle of the rollers of the seventh rolling mill and the distance between the corresponding centers of the cutting wedge arcs by the following formulas: ψ=α L4>2H4; Where, ψ is the angle of the cutting wedge top angle of the rolls of the seventh rolling mill, α is the angle of the cutting wedge top angle of the rolls of the fourth rolling mill, L4 is the distance between the corresponding centers of the cutting wedge arcs of the rolls of the seventh rolling mill, and H4 is the thickness of the rolled product; S2) The single-pass reduction of the eighth rolling mill is controlled at 30-40%; S3) the ninth rolling mill is arranged vertically, and the pass height of the pass rollers of the ninth rolling mill is 1.0 to 1.1 times the thickness of the flat wire, and the pass width of the pass rollers is 0.4 to 0.45 times the width of the flat wire; S4) determining the arc radius of the groove bottom of the groove roll of the ninth rolling mill by the following formula: R5=(0.5:0.6)·h; Where, R5 is the arc radius of the bottom of the ninth mill pass, and h is the pass height of the ninth mill pass roll; S5) The single-pass reduction of the tenth rolling mill is controlled at 10-20%; S6) The single-pass reduction of the eleventh rolling mill is controlled at 5-10%.

10. The method for slitting and rolling flat wire with a large width-to-thickness ratio according to claim 1, characterized in that: The annealing treatment is performed in a protective atmosphere continuous annealing furnace or a vacuum heat treatment furnace.

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