Special-shaped brass bar and production process thereof

Abstract

The invention relates to the technical field of copper bar machining, in particular to a special-shaped brass bar and a production process thereof. The process comprises the following steps: firstly melting an electrolytic copper plate to obtain a copper melt, then adding a zinc ingot into the copper melt, and melting to obtain a copper-zinc alloy melt; continuously casting the copper-zinc alloy melt into a brass rod by adopting an up-drawing continuous casting process; continuously extruding the brass rod by adopting a continuous extruder with an eccentric hole extrusion die to obtain a brass rod; the brass rod is subjected to drawing machining under the lubricating condition; and the brass rod is subjected to stress relief annealing and straightening and shaping treatment. The method effectively solves the technical problems that in the prior art, a copper rod production process needs to roll the copper rod twice, the efficiency is low, and grains of the rolled copper rod generate anisotropy, so that the grains of the formed copper rod are coarse and low in hardness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper bar processing, and particularly relates to a special-shaped brass bar and a production process thereof. BACKGROUND

[0002] Copper has good mechanical processing performance, stable electrical conductivity and thermal conductivity, good corrosion resistance and wear resistance, and other advantages, and is one of the commonly used metal materials in the electronic and electrical fields. At present, when using copper to process oxygen-free copper bars for electronic vacuum devices, generally includes the steps of vacuum furnace smelting, ingot casting, heating, extrusion, drawing and slitting, and has large investment scale, low material yield, limited product length, low production efficiency, large energy consumption, and unstable oxygen content of the produced products.

[0003] To solve the above problems, a patent document with the authorization publication number CN107185994B discloses a production process of copper bars, which takes high-purity cathode copper as raw material to complete the production of copper bars through up-drawing continuous casting-continuous extrusion-first continuous rolling-annealing-second continuous rolling-drawing-slitting; the high-purity cathode copper is preheated and dried before being melted in a smelting device, charcoal and graphite scales are used to cover the surface of the copper liquid, and a traction unit is used to up-draw the copper rod in the crystallizer; the copper rod prepared by up-drawing continuous casting is used as raw material for continuous extrusion to prepare oxygen-free copper bars; the copper bars prepared by continuous extrusion are used as raw material for first continuous rolling, a two-roll mill with ten racks is used to roll the copper bars at a rolling speed of 0.15-0.25 m / s; the total processing rate of continuous rolling is greater than 80%; the copper bars are annealed in a protective atmosphere vacuum furnace at an annealing temperature of 370 degrees for 5 hours, and the grain size of the copper bars after annealing is 0.02-0.03 mm; a two-roll mill with ten racks is used for second continuous rolling of the copper bars at a rolling speed of 0.15-0.25 m / s; the total processing rate of continuous rolling is 30%-50%; a hydraulic drawing machine is used to stretch and deform the copper bars, one-pass stretch deformation is performed, the stretch deformation coefficient is 1.02, the die angle of the drawing die is 8°, and the die hole working belt length of the drawing die is 8 mm; the tensile strength of the copper bars after drawing is greater than 285 MPa, and the elongation is 5%-10%; the copper bars are cut according to the required length of the customer by using a cutting device.

[0004] The above-mentioned production process uses continuous extrusion, continuous rolling, and annealing to prepare copper rods, which improves the density of the copper rods and saves energy compared with traditional processes by eliminating the steps of ingot heating and hot extrusion. However, the above-mentioned production process still has the following problems in practical applications: 1. It requires two rolling processes on the copper rods using a rolling mill, which is cumbersome; 2. The process of changing and adjusting the rolling mill's pass is complex; 3. Defects such as flash and burrs are prone to appear on the surface of the rolled copper rods, and the grains are elongated along the rolling direction, forming a fibrous structure, which in turn causes anisotropy, resulting in coarse grains and reduced hardness. Summary of the Invention

[0005] This invention provides a production process for irregularly shaped brass rods to solve the technical problems in the prior art where the copper rod production process requires two rolling processes, resulting in low efficiency and anisotropy of the copper rod grains after rolling, leading to coarse grains and low hardness in the formed copper rods; the purpose of this invention is also to provide an irregularly shaped brass rod.

[0006] To solve the above problems, the production process of the irregularly shaped brass rods provided by this invention adopts the following technical solution: A manufacturing process for irregularly shaped brass rods includes the following steps: S1: Melt preparation: First, melt the electrolytic copper plate to obtain copper melt, then add zinc ingots to the copper melt and melt to obtain copper-zinc alloy melt; S2: Upward continuous casting: The copper-zinc alloy melt is continuously cast into brass rods using the upward continuous casting process; S3: Continuous extrusion: Brass rods are continuously extruded using a continuous extrusion press to obtain brass bars. The continuous extrusion press uses an eccentric hole extrusion die. The eccentric hole extrusion die includes a die body with a die hole. The center of the die body is coaxial with the feed port and the discharge port. The center of the die hole is offset from the center of the die body by 10mm to 20mm. S4: Hydraulic drawing: Drawing a brass bar under lubricated conditions; S5: Stress-relief annealing and straightening: The brass rod obtained in step S4 is subjected to stress-relief annealing, and then the brass rod is straightened and shaped.

[0007] The beneficial effects of the production process for irregularly shaped brass rods provided by this invention are: In the extrusion of brass rods, the present invention uses a continuous extrusion press to carry out continuous extrusion. The continuous extrusion press uses an eccentric hole extrusion die and an integrated deformation-recrystallization continuous extrusion process to replace the separate process of two rolling and one high-temperature annealing in the prior art.

[0008] Current rolling technology primarily employs unidirectional compression, where grains are only flattened and elongated along the rolling direction without effective fragmentation. While this can refine the microstructure to some extent, it also leads to fibrous grain extension, causing anisotropy in material properties. Therefore, subsequent high-temperature annealing (e.g., prolonged holding at 370℃) is necessary to trigger static recrystallization and restore the equiaxed structure. This process is lengthy, energy-intensive, and prone to softening the brass rod, requiring a second rolling process to harden it. This roundabout process of first damaging the microstructure, then rebuilding it, and finally strengthening it further limits both economic efficiency and effectiveness. Furthermore, in conventional horizontal extrusion, metal flow is primarily axially compressed during extrusion, resulting in relatively uniform deformation but insufficient shear force. This leads to grain elongation along the extrusion direction, forming a fibrous structure and significant anisotropy (large differences in longitudinal and transverse properties). Consequently, the extruded brass rod has a relatively coarse grain size (approximately 0.2mm–0.5mm), failing to adequately meet the requirements for hardness, strength, plasticity, and toughness.

[0009] This application employs a continuous extrusion press with an eccentric die to continuously extrude brass rods, offering two advantages: First, the misalignment between the central axes of the inlet and outlet and the die's orifice axis creates an asymmetrical force state at the die inlet, where the brass metal flow is compressed on one side and dragged on the other, generating a transverse shear force perpendicular to the extrusion direction. Under this shear force, the grains not only experience axial compression but are also torn and twisted. Due to the presence of grain boundaries and segregation zones within the coarse grains of cast brass, the shear force preferentially propagates along these weak areas, breaking down large grains into smaller ones and achieving initial grain refinement. Second, continuous extrusion is a high-strain (large deformation) and high-strain-rate processing procedure. The eccentric die introduces additional shear force during extrusion, causing a sharp increase in dislocation density within the brass rod and generating significant deformation heat. When dislocations accumulate to a critical value, dynamic recrystallization is triggered, which transforms the broken grain fragments into new crystal nuclei and grows into equiaxed fine grains (effectively eliminating performance anisotropy), rather than the elongated deformed grains in existing technologies. Ultimately, this achieves dual refinement through crushing and recrystallization, significantly reducing the grain size of brass rods and increasing their hardness.

[0010] Furthermore, the eccentric hole extrusion die has its die hole center offset from the die body center by 10mm to 20mm, which enables the brass metal flow to form a stable asymmetric force field at the die entrance. This avoids insufficient transverse shear force due to excessively small eccentricity, resulting in grains being compressed only axially and difficult to break. It also prevents excessively large eccentricity from causing metal flow segregation and local stress concentration, which would lead to increased die wear. Combined with the high strain characteristics of continuous extrusion, it can efficiently break down large grains along weak areas such as grain boundaries and segregation zones of cast brass grains, providing sufficient fragment nuclei for subsequent dynamic recrystallization, and ultimately achieving a significant reduction in grain size.

[0011] In summary, the present invention effectively solves the technical problems in the existing copper rod production process, which requires two rolling processes, resulting in low efficiency and anisotropy of the rolled copper rod grains, leading to coarse grains and low hardness in the formed copper rods.

[0012] Furthermore, in step S1, zinc ingots and pure copper scrap are first packaged into blocks, with the zinc ingots placed in the middle of the pure copper scraps. Then, the blocks are added into the copper melt and melted to obtain a copper-zinc alloy melt.

[0013] Beneficial effects: Encasing zinc ingots in pure copper allows the pure copper to melt first in the high-temperature molten copper, creating a gradual heating zone for the zinc ingot. This prevents the zinc ingot from being directly exposed to the copper molten metal, which has a boiling point far exceeding its own, thus suppressing violent boiling and vaporization of zinc. This keeps zinc volatilization loss to a very low level, improving zinc utilization and saving raw material costs in brass rod production. At the same time, reducing zinc volatilization also ensures that the zinc content of the final melt is highly consistent with the designed ratio, avoiding compositional fluctuations caused by zinc burn-off. This improves the stability and reliability of the mechanical properties, electrical conductivity, corrosion resistance, and other properties of the final brass rods produced.

[0014] Further, in step S1, an electrolytic copper plate and zinc ingot are melted using a smelting device. The smelting device includes a smelting furnace and a holding furnace. The temperature of the smelting furnace is 1010℃~1210℃, and the temperature of the holding furnace is 1000℃~1200℃.

[0015] Furthermore, in step S2, the casting speed of the upward continuous casting is 5 m / min to 10 m / min.

[0016] Furthermore, in step S3, the extrusion speed of the continuous extruder is 7 r / min to 12 r / min.

[0017] Furthermore, in step S3, the thickness of the mold body is 20mm to 25mm, the length of the sizing band of the mold body is 3mm to 6mm, and the feeding angle of the brass rod entering the eccentric hole extrusion mold is 2° to 5°.

[0018] Beneficial effects: A die thickness of 20mm to 25mm ensures that the metal flow has sufficient deformation buffer space within the die, avoiding excessively fast metal flow and uneven structure due to excessive thickness, or increased extrusion resistance and energy consumption due to excessive thickness (>25mm); while a feed angle of 2° to 5° guides the metal flow to enter the die orifice smoothly, reducing the generation of eddies and pores at the inlet, while reducing frictional wear between the die and the metal, balancing forming accuracy and processing efficiency, and avoiding the accumulation of dimensional deviations caused by multiple processing passes in traditional rolling.

[0019] The sizing band length is 3mm to 6mm, which allows for precise shaping and calibration of the extruded brass bars. This prevents the bar cross-section from becoming too short, resulting in excessive roundness and large dimensional fluctuations, while avoiding excessive friction between the metal and the die and increased surface roughness caused by an excessively long sizing band. At the same time, the continuous slight deformation during the sizing process can further eliminate local structural defects, improve the hardness consistency and isotropy of the brass bars, reduce the machining allowance in subsequent hydraulic drawing and shaping processes, and lower overall production energy consumption and costs.

[0020] Furthermore, in step S4, the deformation coefficient of the hydraulic drawing is 1.15 to 1.25, the feed angle of the drawing die is 10° to 15°, the drawing speed is 15 m / min to 20 m / min, and the emulsion concentration is 5% to 10%.

[0021] Furthermore, in step S5, an annealing process is performed using a forklift furnace, which is equipped with a blower to ensure uniform temperature within the furnace.

[0022] Furthermore, the annealing temperature of the forklift furnace is 200℃~300℃, and the holding time is 2h~3h.

[0023] To solve the above problems, the irregularly shaped brass rod provided by the present invention adopts the following technical solution: A type of irregularly shaped brass rod is manufactured using the aforementioned production process for irregularly shaped brass rods.

[0024] The beneficial effects of the irregularly shaped brass rods provided by this invention are: The high-performance irregular-shaped brass rod provided by this invention uses a continuous extrusion press to continuously extrude the brass rod during the production process. The continuous extrusion press uses an eccentric hole extrusion die and an integrated deformation-recrystallization continuous extrusion process to replace the separate process of two rolling and one high-temperature annealing in the prior art.

[0025] Current technology for producing brass bars primarily involves unidirectional compression during rolling. The grains are only flattened and elongated along the rolling direction without effective fragmentation. While this can refine the microstructure to some extent, it also leads to fibrous grain extension, causing anisotropy in material properties. Therefore, subsequent high-temperature annealing (such as holding at 370°C for an extended period) is necessary to trigger static recrystallization and restore the equiaxed nature of the microstructure. This process is lengthy, energy-intensive, and prone to softening the brass bars, requiring a second rolling process to re-harden them. This roundabout process of first damaging the microstructure, then rebuilding it, and finally strengthening it further limits both economic efficiency and effectiveness.

[0026] This invention employs a continuous extrusion press with an eccentric die to continuously extrude brass rods, offering two key advantages: First, the misalignment between the central axes of the inlet and outlet and the die's orifice axis creates an asymmetrical force distribution at the die inlet, resulting in compression on one side and dragging on the other. This generates a transverse shear force perpendicular to the extrusion direction. Under this shear force, the grains not only experience axial compression but are also torn and twisted. Due to the presence of grain boundaries and segregation zones within the coarse grains of cast brass, the shear force preferentially propagates along these weak areas, breaking down large grains into smaller ones and achieving initial grain refinement. Second, continuous extrusion is a high-strain (large deformation) and high-strain-rate process. The eccentric die introduces additional shear force during extrusion, causing a sharp increase in dislocation density within the brass rod and generating significant deformation heat. When dislocations accumulate to a critical value, dynamic recrystallization is triggered, which transforms the broken grain fragments into new crystal nuclei and grows into equiaxed fine grains (effectively eliminating performance anisotropy), rather than the elongated deformed grains in existing technologies. Ultimately, this achieves dual refinement through crushing and recrystallization, significantly reducing the grain size of brass rods and increasing their hardness.

[0027] In summary, the present invention effectively solves the technical problems in the existing copper rod production process, which requires two rolling processes, resulting in low efficiency and anisotropy of the rolled copper rod grains, leading to coarse grains and low hardness in the formed copper rods. Attached Figure Description

[0028] The above and other objects, features, and advantages of exemplary embodiments of the present invention will become readily apparent upon reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of the invention are illustrated by way of example and not limitation, and like or corresponding reference numerals denote like or corresponding parts, wherein: Figure 1 A flowchart illustrating the manufacturing process of the irregularly shaped brass rods provided by this invention; Figure 2 This is an exploded view of the continuous extrusion press used in this invention.

[0029] Explanation of reference numerals in the attached figures: 1. Cavity; 11. Expansion cavity; 12. Feed inlet; 13. Screw hole; 2. Cavity cover; 21. Discharge port; 22. Locking hole; 3. Eccentric hole extrusion die; 31. Die body; 32. Die hole. Detailed Implementation

[0030] The principles and spirit of the present invention will be explained in detail below with reference to several representative embodiments.

[0031] Example 1 of the manufacturing process for irregularly shaped brass rods provided by this invention: like Figure 1 As shown, the manufacturing process of irregularly shaped brass rods includes the following steps: S1: Melt preparation: First, melt the electrolytic copper plate to obtain copper melt, then add zinc ingots to the copper melt and melt to obtain copper-zinc alloy melt; S2: Upward continuous casting: The copper-zinc alloy melt is continuously cast into brass rods using the upward continuous casting process; S3: Continuous extrusion: Brass rods are continuously extruded using a continuous extrusion press to obtain brass bars. The continuous extrusion press uses an eccentric hole extrusion die. The eccentric hole extrusion die includes a die body with a die hole. The center of the die body is coaxial with the feed port and the discharge port. The center of the die hole is offset from the center of the die body by 10mm to 20mm. S4: Hydraulic drawing: Drawing a brass bar under lubricated conditions; S5: Stress-relief annealing and straightening: The brass rod obtained in step S4 is subjected to stress-relief annealing, and then the brass rod is straightened and shaped.

[0032] In step S1, zinc ingots and pure copper scrap are first packaged into blocks, with the zinc ingots placed in the middle of the pure copper scraps. Then, the blocks are added to the copper melt and melted to obtain a copper-zinc alloy melt. Electrolytic copper plates and zinc ingots are melted using a smelting device, which includes a smelting furnace and a holding furnace. The temperature of the smelting furnace is 1010℃~1210℃, and the temperature of the holding furnace is 1000℃~1200℃. The casting speed of the upward continuous casting is 5m / min~10m / min. After the upward continuous casting, the grain size of the brass rod is 2mm~8mm, and the hardness is 45HB~65HB.

[0033] In step S3, the extrusion speed of the continuous extruder is 7 r / min to 12 r / min; the thickness of the die body is 20 mm to 25 mm, the feed angle is 2° to 5°, and the sizing band length is 3 mm to 6 mm; after continuous extrusion, the grain size of the brass rod is 0.02 mm to 0.05 mm, and the hardness is 90 HB to 120 HB.

[0034] In step S4, the deformation coefficient of the hydraulic drawing is 1.15 to 1.25, the feed angle of the drawing die is 10° to 15°, the drawing speed is 15 m / min to 20 m / min, and the emulsion concentration is 5% to 10%.

[0035] In step S5, a forklift furnace is used for annealing. A blower is installed inside the forklift furnace to ensure uniform temperature inside the furnace. The annealing temperature of the forklift furnace is 200℃~300℃, and the holding time is 2h~3h. After annealing, the hardness of the brass rod increases by 5%~10%.

[0036] In step S5, a straightening machine is used to straighten the brass rod after stress relief annealing, so that the flatness of the brass rod is less than 0.3 mm per meter and the straightness is less than 0.5 mm per meter.

[0037] In this embodiment, in step S1, the smelting furnace and the holding furnace are covered with charcoal and graphite flakes. The temperature of the smelting furnace is 1110℃, the temperature of the holding furnace is 1100℃, the diameter of the upward continuous casting brass rod is 20mm, the casting speed is 6m / min, and finally the material is collected into a coil. After the upward continuous casting, the grain size of the brass rod is 2mm~8mm, and the hardness is 45HB~65HB.

[0038] In this embodiment, in step S3, a 400 copper continuous extrusion press is used to extrude brass rods at an extrusion speed of 9 r / min. In the eccentric hole extrusion die, the center of the die hole is 10 mm away from the center of the die, the die thickness is 23 mm, the feed angle is 3°, and the sizing band length is 4 mm. After continuous extrusion, the grain size of the brass rod is 0.02 mm to 0.05 mm, and the hardness is 90 HB to 110 HB.

[0039] In this embodiment, in step S4, the deformation coefficient is 1.18, the feed angle of the drawing die is 12.5°, the drawing speed is 15m / min, and an 8% concentration emulsion is used as the drawing lubricant.

[0040] In this embodiment, in step S5, the annealing temperature of the forklift furnace is 230°C and the holding time is 3 hours. After annealing, the hardness of the brass rod increases by 5% to 7%.

[0041] like Figure 2As shown, the continuous extrusion press includes a cavity 1, a cavity cover 2, and an eccentric hole extrusion die 3. The cavity 1 has an expansion cavity 11 at its center and a feed inlet 12 at its bottom. The expansion cavity 11 accommodates the eccentric hole extrusion die 3, which includes a die body 31 and die holes 32 formed on the die body. The bottom of the expansion cavity 11 communicates with the feed inlet 12. The cavity cover 2 has a discharge outlet 21 at its center. Multiple locking holes 22 are spaced apart on the outer periphery of the discharge outlet 21 on the cavity cover 2. Multiple screw holes 13 are spaced apart on the outer periphery of the expansion cavity 11 on the cavity 1. The number and position of the screw holes 13 correspond to the number and position of the locking holes 22. The cavity cover 2 is fixed to the cavity 1 by bolts that pass through the locking holes 22 and are screwed into the screw holes 13. The feed inlet 12 and the discharge outlet 21 are vertically aligned, and the die holes 32 are offset from the feed inlet 12 and the discharge outlet 21.

[0042] In conventional horizontal extrusion, the metal flow in the brass rod is mainly axial compression, resulting in relatively uniform deformation but insufficient shear force. This causes the grains to be elongated along the extrusion direction, forming a fibrous structure and producing obvious anisotropy. Consequently, the grain size of the extruded brass rod is relatively coarse (approximately 0.2 mm to 0.5 mm).

[0043] This invention employs a continuous extrusion press with an eccentric die to extrude brass bars. This creates an asymmetrical force state at the die inlet, where the brass metal flow is subjected to compression on one side and dragging on the other. This generates a transverse shear force perpendicular to the extrusion direction, causing a sharp increase in dislocation density within the brass bar and generating significant deformation heat. When dislocations accumulate to a critical value, dynamic recrystallization is triggered, transforming the broken grain fragments into new nuclei that grow into equiaxed fine grains. Ultimately, this achieves dual refinement through both crushing and recrystallization, significantly reducing the grain size of the brass bar and improving its hardness and other properties.

[0044] Example 2 of the manufacturing process for irregularly shaped brass rods provided by the present invention: Its main difference from Example 1 is: In Example 1, in step S1, the temperature of the melting furnace is 1110℃, the temperature of the holding furnace is 1100℃, and the casting speed is 6m / min; in step S3, in the eccentric hole extrusion die, the center of the die hole is offset from the center of the die by 10mm; in step S4, the deformation coefficient is 1.18; in step S5, the annealing temperature of the forklift furnace is 230℃, and the holding time is 3h.

[0045] In this embodiment, in step S1, the temperature of the melting furnace is 1210℃, the temperature of the holding furnace is 1200℃, and the casting speed is 8m / min; in step S3, in the eccentric hole extrusion die, the center of the die hole is offset from the center of the die by 20mm; in step S4, the deformation coefficient is 1.25; in step S5, the annealing temperature of the forklift furnace is 300℃, and the holding time is 2.5h.

[0046] In this embodiment, the hardness of the brass rod obtained in step S2 is 45HB to 65HB; in step S3, the grain size of the brass rod obtained is 0.02mm to 0.04mm, and the hardness is 90HB to 116HB; in step S5, the hardness of the brass rod is increased by 5% to 10% after annealing.

[0047] Example 3 of the manufacturing process for irregularly shaped brass rods provided by the present invention: Its main difference from Example 1 is: In Example 1, in step S1, the temperature of the melting furnace is 1110℃, the temperature of the holding furnace is 1100℃, and the casting speed is 6m / min; in step S3, in the eccentric hole extrusion die, the center of the die hole is offset from the center of the die by 10mm; in step S4, the deformation coefficient is 1.18; in step S5, the annealing temperature of the forklift furnace is 230℃, and the holding time is 3h.

[0048] In this embodiment, in step S1, the temperature of the melting furnace is 1010℃, the temperature of the holding furnace is 1000℃, and the casting speed is 5m / min; in step S3, the center of the die hole in the extrusion die deviates from the center of the die by 0mm; in step S4, the deformation coefficient is 1.15; in step S5, the annealing temperature of the forklift furnace is 260℃, and the holding time is 2h.

[0049] In this embodiment, the hardness of the brass rod obtained in step S2 is 45HB to 65HB; in step S3, the grain size of the brass rod obtained is 0.1mm to 0.2mm, and the hardness is 90HB to 120HB; in step S5, the hardness of the brass rod increases by 4% to 6% after annealing.

[0050] Example 4 of the manufacturing process for irregularly shaped brass rods provided by the present invention: Its main difference from Example 1 is: In Example 1, in step S1, the temperature of the melting furnace is 1110℃, the temperature of the holding furnace is 1100℃, and the casting speed is 6m / min; in step S3, in the eccentric hole extrusion die, the center of the die hole is offset from the center of the die by 10mm; in step S4, the deformation coefficient is 1.18; in step S5, the annealing temperature of the forklift furnace is 230℃, and the holding time is 3h.

[0051] In this embodiment, in step S1, the temperature of the melting furnace is 1210℃, the temperature of the holding furnace is 1200℃, and the casting speed is 10m / min; in step S3, the center of the die hole in the extrusion die deviates from the center of the die by 0mm; in step S4, the deformation coefficient is 1.25; in step S5, the annealing temperature of the forklift furnace is 260℃, and the holding time is 2h.

[0052] In this embodiment, the hardness of the brass rod obtained in step S2 is 45HB to 65HB; in step S3, the grain size of the brass rod obtained is 0.1mm to 0.2mm, and the hardness is 90HB to 100HB; in step S5, the hardness of the brass rod increases by 4% to 6% after annealing.

[0053] Example 5 of the manufacturing process for irregularly shaped brass rods provided by the present invention: Its main difference from Example 1 is: In Example 1, in step S1, the temperature of the melting furnace is 1110℃, the temperature of the holding furnace is 1100℃, and the casting speed is 6m / min; in step S3, in the eccentric hole extrusion die, the center of the die hole is offset from the center of the die by 10mm; in step S4, the deformation coefficient is 1.18; in step S5, the annealing temperature of the forklift furnace is 230℃, and the holding time is 3h.

[0054] In this embodiment, in step S1, the temperature of the melting furnace is 1010℃, the temperature of the holding furnace is 1000℃, and the casting speed is 5m / min; in step S3, in the eccentric hole extrusion die, the center of the die hole is offset from the center of the die by 20mm; in step S4, the deformation coefficient is 1.15; in step S5, the annealing temperature of the forklift furnace is 230℃, and the holding time is 3h.

[0055] In this embodiment, the hardness of the brass rod obtained in step S2 is 45HB to 65HB; in step S3, the grain size of the brass rod obtained is 0.02mm to 0.04mm, and the hardness is 100HB; in step S5, the hardness of the brass rod increases by 4% to 6% after annealing.

[0056] As can be seen from Examples 1 to 5, the melting temperature and holding temperature only affect the casting speed. The higher the melting temperature and holding temperature, the faster the casting speed. The hardness change after stress-relief annealing is affected by the deformation coefficient and annealing temperature. The larger the deformation coefficient and the higher the annealing temperature, the greater the hardness change after stress-relief annealing. Within the range of 10mm to 20mm between the die hole center and the die center of the eccentric extrusion die, the larger the eccentricity of the extrusion die, the finer the grain size of the brass rod.

[0057] Examples of irregularly shaped brass rods provided by the present invention: The irregularly shaped brass rods are manufactured using the aforementioned production process.

[0058] Based on the above description in this specification, those skilled in the art will also understand that the following terms, such as "upper," "lower," "front," "rear," "left," "right," "width," "horizontal," "top," "bottom," "inner," and "outer," which indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings of this specification. They are only for the purpose of facilitating the explanation of the present invention and simplifying the description, and do not explicitly or implicitly suggest that the device or element involved must have the specific orientation, or be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms should not be understood or interpreted as limitations on the present invention.

[0059] In addition, in the description of this specification, "multiple" means at least two, such as two, three or more, etc., unless otherwise expressly and specifically defined.

Claims

1. A manufacturing process for irregularly shaped brass rods, characterized in that, Includes the following steps: S1: Melt preparation: First, melt the electrolytic copper plate to obtain copper melt, then add zinc ingots to the copper melt and melt to obtain copper-zinc alloy melt; S2: Upward continuous casting: The copper-zinc alloy melt is continuously cast into brass rods using the upward continuous casting process; S3: Continuous extrusion: Brass rods are continuously extruded using a continuous extrusion press to obtain brass bars. The continuous extrusion press uses an eccentric hole extrusion die. The eccentric hole extrusion die includes a die body with a die hole. The center of the die body is coaxial with the feed port and the discharge port. The center of the die hole is offset from the center of the die body by 10mm to 20mm. S4: Hydraulic drawing: Drawing of brass bars under lubricated conditions; S5: Stress-relief annealing and straightening: The brass rod obtained in step S4 is subjected to stress-relief annealing, and then the brass rod is straightened and shaped.

2. The production process of the irregularly shaped brass rod according to claim 1, characterized in that, In step S1, zinc ingots and pure copper scrap are first packaged into blocks, with the zinc ingots placed in the middle of the pure copper scraps. Then, the blocks are added into the copper melt and melted to obtain a copper-zinc alloy melt.

3. The production process of irregularly shaped brass rods according to claim 1 or 2, characterized in that, In step S1, an electrolytic copper plate and zinc ingot are melted using a smelting device. The smelting device includes a smelting furnace and a holding furnace. The temperature of the smelting furnace is 1010℃~1210℃, and the temperature of the holding furnace is 1000℃~1200℃.

4. The production process of irregularly shaped brass rods according to claim 1 or 2, characterized in that, In step S2, the casting speed of the upward continuous casting is 5m / min to 10m / min.

5. The production process of irregularly shaped brass rods according to claim 1 or 2, characterized in that, In step S3, the extrusion speed of the continuous extruder is 7 r / min to 12 r / min.

6. The production process of the irregularly shaped brass rod according to claim 5, characterized in that, In step S3, the thickness of the mold body is 20mm to 25mm, the length of the sizing band of the mold body is 3mm to 6mm, and the feeding angle of the brass rod entering the eccentric hole extrusion mold is 2° to 5°.

7. The production process of irregularly shaped brass rods according to claim 1 or 2, characterized in that, In step S4, the deformation coefficient of the hydraulic drawing is 1.15 to 1.25, the feed angle of the drawing die is 10° to 15°, the drawing speed is 15 m / min to 20 m / min, and the emulsion concentration is 5% to 10%.

8. The manufacturing process for irregularly shaped brass rods according to claim 1 or 2, characterized in that, In step S5, an annealing process is performed using a forklift furnace, which is equipped with a blower to ensure uniform temperature inside the furnace.

9. The production process of the irregularly shaped brass rod according to claim 8, characterized in that, The annealing temperature of the forklift furnace is 200℃~300℃, and the holding time is 2h~3h.

10. A shaped brass rod, characterized in that, It is manufactured using the production process of the irregularly shaped brass rod as described in any one of claims 1 to 9.

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