Ultrafine special-shaped steel wire drawing die and process

Abstract

The invention relates to the technical field of metal wire machining, and discloses a superfine special-shaped steel wire drawing die and process, the superfine special-shaped steel wire drawing die comprises a die sleeve, an inlet die, a reducing die, a transition die, a pre-forming die and a sizing die are arranged in an inner cavity of the die sleeve, and the inlet die, the reducing die, the transition die, the pre-forming die and the sizing die are sequentially arranged from left to right; the axis of the die sleeve coincides with the axis of the inlet die, the axis of the reducing die, the axis of the transition die, the axis of the pre-forming die and the axis of the sizing die. Through the arrangement of the inlet die, the reducing die, the transition die, the pre-forming die and the sizing die, when a reducing area, a transition area, a pre-forming area and a sizing area are abraded, the reducing die, the transition die and the pre-forming die are taken down from the die sleeve to be replaced, and then the problem that the reducing area, the transition area and the pre-forming area on an existing die are seriously abraded areas, and the size of the die is too large is solved. In the prior art, a die needs to be replaced regularly, a die sleeve and the die can be separated only in a high-temperature state, a large amount of electric energy needs to be consumed in the process, and the machining cost of steel wires is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal wire processing, in particular to a super-fine special-shaped steel wire drawing die and process. BACKGROUND

[0002] Special-shaped steel wire, i.e. non-circular cross-section steel wire, super-fine special-shaped steel wire has a wide range of applications in high-end fields such as aerospace, precision instruments and automobile manufacturing. For example, in the field of aerospace, super-fine special-shaped steel wire can be used to manufacture high-precision springs, connecting parts and the like, and its performance directly affects the safety and reliability of the aircraft; in the field of automobile manufacturing, super-fine special-shaped steel wire can be used to manufacture special springs of the engine and key components of the brake system, and plays an important role in improving the performance and quality of the automobile.

[0003] The existing drawing die is a cylindrical body with a hole, and some simple-shaped steel wires can be processed by this method. At the same time, the reducing zone, transition zone and preforming zone on the die are the most severely worn areas, so the die needs to be replaced regularly. When disassembling the die sleeve and the die, heating treatment is required, so that the die sleeve and the die need to be in a high temperature state to separate. A large amount of electric energy is consumed in this process, increasing the processing cost of the steel wire. SUMMARY

[0004] The present application provides a super-fine special-shaped steel wire drawing die and process, comprising a die sleeve, the inner cavity of the die sleeve is provided with an inlet die, a reducing die, a transition die, a preforming die and a sizing die, the inlet die, the reducing die, the transition die, the preforming die and the sizing die are sequentially sorted from left to right, the axis of the die sleeve coincides with the axes of the inlet die, the reducing die, the transition die, the preforming die and the sizing die. The outer edge of the inlet die is provided with an inlet zone, the outer edge of the sizing die is provided with an outlet zone, the outer edge of the reducing die is provided with a reducing zone, the outer edge of the transition die is provided with a transition zone, the outer edge of the preforming die is provided with a preforming zone, and the inner wall of the preforming zone is provided with a sizing zone.

[0005] As a preferred technical solution of the present application, a disassembly groove is formed in the outer wall of the die sleeve, a fixed cover is threadedly connected to the inner wall of the die sleeve, a disassembly hole is formed in the outer edge of the fixed cover, and the fixed cover is located on the left side of the inlet die.

[0006] As a preferred technical solution of the present application, a threaded hole is formed in the outer edge of the inlet die, a circular hole is formed in the outer edge of each of the reducing die, the transition die, the preforming die and the sizing die, a fixed bolt penetrates the inner cavity of the circular hole, and the fixed bolt is threadedly connected with the threaded hole in the inlet die.

[0007] As a preferred technical scheme of the present application, the outer wall of the entry die, the reducing die, the transition die, the preforming die and the sizing die is provided with a positioning groove, and the inner wall of the die sleeve is provided with a limiting strip, which is in sliding connection with the positioning groove.

[0008] As a preferred technical scheme of the present application, the connecting part of the preforming zone and the sizing zone is subjected to arc treatment, the shapes of the entry zone and the exit zone are horn-shaped structures, and the flaring angles of the entry zone and the exit zone are 30° and 45° respectively.

[0009] As a preferred technical scheme of the present application, the materials of the entry die, the reducing die, the transition die, the preforming die and the sizing die are polycrystalline diamond, and the diamond composite material comprises the following components in mass percentage: diamond particles 15%-25%, cobalt 5%-10%, copper 10%-15%, nickel 2%-5%, and the rest is graphite, and the surfaces of the entry zone, the reducing zone, the transition zone, the preforming zone, the sizing zone and the exit zone are provided with a titanium nitride nano coating with a thickness of 0.5-1.5 μm.

[0010] An ultra-fine special-shaped steel wire drawing process based on an ultra-fine special-shaped steel wire drawing die, and the specific steps are as follows: S1: selecting a steel wire blank, performing surface rust removal treatment, removing surface oxide scale by pickling, rinsing clean and drying after pickling, and then performing annealing treatment on the blank, with an annealing temperature of 700-800 ℃ and a holding time of 2-3 h, and furnace cooling to room temperature; S2: preheating the drawing die in a heating device, with a preheating temperature of 120-150 ℃ and a holding time of 30-40 min, and at the same time, preparing a drawing lubricant, which is composed of the following components in mass percentage: base oil 60%-70%, extreme pressure agent 5%-10%, anti-wear agent 3%-5%, emulsifier 2%-4%, anti-rust agent 1%-3%, and the rest is water; uniformly applying the prepared lubricant on the inner walls of the working areas of the entry zone, the reducing zone, the transition zone, the preforming zone, the sizing zone and the exit zone and the surface of the pretreated steel wire blank; S3: using the preheated die to perform multi-pass drawing on the steel wire blank, with 8-12 drawing passes, and the deformation amount between adjacent two passes being controlled within 8%-12%; the drawing speed increases with the pass, with a first-pass drawing speed of 2-3 m / s and a last-pass drawing speed of 8-10 m / s; the die temperature is kept stable at 100-130 ℃ during the drawing process, and the die temperature is adjusted by a circulating cooling system; S4: after the 4th-5th drawing pass and the 8th-9th drawing pass, the steel wire is subjected to intermediate heat treatment, respectively; the intermediate heat treatment comprises normalizing and tempering, the normalizing temperature is 850-900 DEG C, the holding time is 1-1.5 h, and the air cooling is to room temperature; the tempering temperature is 400-450 DEG C, the holding time is 1.5-2 h, and the furnace cooling is to room temperature; S5: after the last drawing pass, the steel wire is sent to a straightening machine for straightening treatment, and the straightening speed is 5-6 m / s; after the straightening, the steel wire is cleaned and dried, and then subjected to size precision detection, surface quality detection and mechanical property detection, and the qualified product is the finished product of the ultra-fine special-shaped steel wire.

[0011] As a preferred technical scheme of the present application, the acid solution used in the pickling in step S1 is a hydrochloric acid solution with a mass concentration of 15%-20%, the pickling temperature is 40-50 DEG C, and the pickling time is 10-15 min.

[0012] As a preferred technical scheme of the present application, the extreme pressure agent in step S2 is sulfided isobutylene, the anti-wear agent is zinc dialkyldithiophosphate, the emulsifier is Span-80, and the rust inhibitor is benzotriazole.

[0013] As a preferred technical scheme of the present application, the circulating cooling system in step S3 uses heat conducting oil as the cooling medium, the flow rate of the cooling medium is 0.8-1.2 m / s, the mold temperature is monitored in real time by a temperature sensor, and when the mold temperature exceeds 130 DEG C, the flow rate of the cooling medium is automatically increased.

[0014] The present application has the following beneficial effects: 1. The ultra-fine special-shaped steel wire drawing die and process, through the setting of the entry die, the reducing die, the transition die, the preforming die and the sizing die, when the reducing zone, the transition zone, the preforming zone and the sizing zone are worn, the reducing die, the transition die and the preforming die can be taken off from the die sleeve and replaced, thereby solving the problem that the reducing zone, the transition zone and the preforming zone of the existing die are severely worn, the die needs to be replaced regularly, the die sleeve and the die need to be separated under high temperature, and a large amount of electric energy is consumed in the process, increasing the steel wire processing cost.

[0015] 2. The ultra-fine special-shaped steel wire drawing die and process, through the setting of the entry die, the reducing die, the transition die, the preforming die and the sizing die, the setting of the entry die, the reducing die, the transition die, the preforming die and the sizing die can reduce the processing cost of the steel wire, facilitate the processing of the entry zone, the reducing zone, the transition zone, the preforming zone, the sizing zone and the exit zone, and solve the problem that the surface structure of the existing special-shaped steel wire is complex, the die opening process is more, and the die production cost is increased.

[0016] 3、The superfine special-shaped steel wire drawing die and process, through the combination of the entry die, the reducing die, the transition die, the preforming die and the sizing die, the combined split design decomposes the deformation function, the preforming die bears the main deformation, and the sizing die only finishes the finishing, the wear of the sizing die is greatly reduced, the stress concentration is avoided by the multi-section transition zone, the wear is more uniform, the service life of the die is improved by more than 3 times, and the product size precision can reach ±0.001 mm. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a front perspective structural schematic view of the present application. Figure 2 It is a back perspective structural schematic view of the present application. Figure 3 It is a transverse cross-sectional structural schematic view of the present application. Figure 4 It is a vertical cross-sectional structural schematic view of the present application. Figure 5 It is an inner die structural schematic view of the present application. Figure 6 It is a reducing zone, transition zone and preforming zone position schematic view of the present application. Figure 7 It is a fixed cover and die sleeve schematic view of the present application. Figure 8 It is an inner die unfolded structural schematic view of the present application.

[0018] In the figure: 1, die sleeve; 2, entry die; 3, reducing die; 4, transition die; 5, preforming die; 6, sizing die; 7, fixed cover; 8, dismounting hole; 9, dismounting groove; 10, round hole; 11, threaded hole; 12, fixed bolt; 13, positioning groove; 14, limiting strip; 21, entry zone; 31, reducing zone; 41, transition zone; 51, preforming zone; 52, sizing zone; 61, exit zone. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the present application. EMBODIMENT

[0020] Please refer to Figures 1-8The utility model provides an ultra -fine special -shaped steel wire drawing die, including die sleeve 1, the inner chamber of die sleeve 1 is equipped with inlet die 2, reducing die 3, transition die 4, preforming die 5 with sizing die 6, inlet die 2, reducing die 3, transition die 4, preforming die 5 with sizing die 6 are sequentially arranged from left to right, and the axis of die sleeve 1 coincides with the axis of inlet die 2, reducing die 3, transition die 4, preforming die 5 with sizing die 6. The outer edge of inlet die 2 is provided with an inlet area 21, the outer edge of sizing die 6 is provided with an outlet area 61, the outer edge of the reducing die 3 is provided with a reducing area 31, the outer edge of the transition die 4 is provided with a transition area 41, and the outer edge of the preforming die 5 is provided with a preforming area 51. The inner wall of the preforming area 51 is provided with a sizing area 52.

[0021] In the above structure, by the setting of inlet die 2, reducing die 3, transition die 4, preforming die 5 and sizing die 6, since the reducing area 31, the transition area 41 and the preforming area 51 are the main shaping areas, the wear is larger here, and when serious wear occurs, it will cause scratches, fuzzing and early fracture on the surface of the steel wire. Therefore, by the combined design of inlet die 2, reducing die 3, transition die 4, preforming die 5 and sizing die 6, the reducing die 3, the transition die 4 and the preforming die 5 can be replaced. The die can be replaced regularly according to the process, which greatly improves the wire drawing efficiency of the steel wire and improves the qualified rate of the product.

[0022] In a preferred embodiment, the outer wall of the die sleeve 1 is provided with a dismounting groove 9, the inner wall of the die sleeve 1 is threadedly connected with a fixing cover 7, the outer edge of the fixing cover 7 is provided with a dismounting hole 8, and the fixing cover 7 is located on the left side of the inlet die 2.

[0023] In the above structure, by the setting of the dismounting groove 9, the dismounting groove 9 on the die sleeve 1 is clamped in the groove on the steel plate, at this time the die sleeve 1 cannot be rotated, then the fixing cover 7 is unscrewed from the die sleeve 1, then the inlet die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 can be knocked off from the die sleeve 1, so that the inlet die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 can be separated from the die sleeve 1.

[0024] In a preferred embodiment, the outer edge of the inlet die 2 is provided with a threaded hole 11, the outer edges of the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are all provided with a round hole 10, the inner cavity of the round hole 10 penetrates a fixing bolt 12, and the fixing bolt 12 is threadedly connected with the threaded hole 11 on the inlet die 2.

[0025] In the structure, the surfaces of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are treated before assembly, then the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are combined, the fixing bolt 12 is inserted into the fixing bolt 12 and the threaded hole 11 on the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6, then the fixing bolt 12 is tightened, the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are assembled to form a whole, and the whole is installed in the die sleeve 1.

[0026] In a preferred embodiment, the outer walls of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are provided with positioning grooves 13, and the inner wall of the die sleeve 1 is provided with a limiting strip 14, and the limiting strip 14 is in sliding connection with the positioning grooves 13.

[0027] In the structure, the positioning grooves 13 and the limiting strip 14 are used in cooperation, and the cooperation of the positioning grooves 13 and the limiting strip 14 plays a positioning role, so that the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 cannot rotate in the die sleeve 1, but can only move in the die sleeve 1, thereby improving the stability of the movement of the steel wire on the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6.

[0028] In a preferred embodiment, the connection between the preforming area 51 and the sizing area 52 is treated with a circular arc, and the shapes of the entry area 21 and the exit area 61 are horn-shaped structures, and the flaring angles of the entry area 21 and the exit area 61 are 30° and 45° respectively.

[0029] In the structure, the connection between the preforming area 51 and the sizing area 52 is treated with a circular arc, so that the connection between the preforming area 51 and the sizing area 52 has no edges, which facilitates the transition of the steel wire to the sizing area 52, and the preforming area 51 and the sizing area 52 are formed by one whole die, so that the connection between the preforming area 51 and the sizing area 52 also has no joint after the rounding, thereby further improving the quality of wire drawing; the horn-shaped structure of the entry area 21 is to prevent the steel wire surface from being cut or scratched by the sharp die port and produce scratch defects in the case of slight shaking, bending or uneven lubrication.

[0030] In a preferred embodiment, the materials of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are polycrystalline diamond, and the diamond composite material includes the following components by mass percentage: diamond particles 15%, cobalt 5%, copper 10%, nickel 2%, and the rest is graphite, and the surfaces of the entry area 21, the reducing area 31, the transition area 41, the preforming area 51, the sizing area 52 and the exit area 61 are provided with a titanium nitride nano coating with a thickness of 0.8 μm.

[0031] In the above structure, by setting the materials of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 to be polycrystalline diamond, when drawing high-carbon steel, stainless steel and other high-hardness and high-strength steel wires, the die hole size is extremely stable, the wear is extremely slow, the die life is greatly improved, and the long-term consistency and ultra-high precision of the product size are directly ensured, and the die changing downtime is reduced; the titanium nitride nano coating itself has a low friction coefficient, and the surface is smooth and dense, reducing energy consumption and allowing the equipment to operate at higher efficiency, reducing the deformation zone temperature from the source, preventing high-temperature failure of the lubricant, and allowing smoother sliding between the steel wire and the die, greatly reducing the generation of surface scratches, fuzz and bonding nodules, and making the steel wire surface brighter.

[0032] An ultra-fine special-shaped steel wire drawing process based on an ultra-fine special-shaped steel wire drawing die, the specific steps are as follows: S1: Selecting a steel wire blank, performing surface rust removal treatment, removing surface oxide scale by pickling, rinsing clean with clean water after pickling and drying, then annealing the blank, annealing temperature is 750 DEG C, holding time is 3h, furnace cooling to room temperature; S2: Preheat the drawing die in the heating device, preheat temperature is 120 DEG C, holding for 40min, at the same time, prepare the drawing lubricant, the drawing lubricant is composed of the following components in mass percentage: base oil 60%, extreme pressure agent 5%, anti-wear agent 3%, emulsifier 2%, anti-rust agent 1%, and the rest is water; evenly apply the prepared lubricant on the inner wall of the working area of the entry zone 21, reducing zone 31, transition zone 41, preforming zone 51, sizing zone 52 and exit zone 61, and the surface of the pretreated steel wire blank; S3: Using the preheated die to draw the steel wire blank in multiple passes, the drawing pass is 9, the deformation between adjacent two passes is controlled at 8%; the drawing speed increases with the pass, the first pass drawing speed is 2m / s, and the last pass drawing speed is 8m / s; keep the die temperature stable at 100 DEG C during drawing, and adjust the die temperature through the circulating cooling system; S4: After the 4th pass and the 8th pass, respectively, the steel wire is subjected to intermediate heat treatment; the intermediate heat treatment includes normalizing and tempering, the normalizing temperature is 900 DEG C, the holding time is 1h, and the air cooling is to room temperature; the tempering temperature is 400 DEG C, the holding time is 1.2h, and the furnace cooling is to room temperature; S5: After the last pass drawing is completed, the steel wire is sent into the straightening machine for straightening treatment, the straightening speed is 5m / s; after the straightened steel wire is cleaned and dried, the size precision detection, surface quality detection and mechanical property detection are performed, and the qualified product is the ultra-fine special-shaped steel wire finished product.

[0033] In a preferred embodiment, the acid solution used in the acid pickling in step S1 is a hydrochloric acid solution with a mass concentration of 15%-20%, the acid pickling temperature is 40°C, and the acid pickling time is 10 min.

[0034] In a preferred embodiment, the extreme pressure agent in step S2 is sulfurized isobutylene, the anti-wear agent is zinc dialkyldithiophosphate, the emulsifier is Span-80, and the rust inhibitor is benzotriazole.

[0035] In a preferred embodiment, the circulating cooling system in step S3 uses heat-conducting oil as the cooling medium, the flow rate of the cooling medium is 0.8 m / s, the mold temperature is monitored in real time by a temperature sensor, and when the mold temperature exceeds 130°C, the flow rate of the cooling medium is automatically increased. Embodiment

[0036] An ultra-fine special-shaped steel wire drawing die comprises a die sleeve 1, the inner cavity of the die sleeve 1 is provided with an entry die 2, a reducing die 3, a transition die 4, a preforming die 5 and a sizing die 6, the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are sequentially arranged from left to right, and the axis of the die sleeve 1 coincides with the axes of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6. The outer edge of the entry die 2 is provided with an entry zone 21, the outer edge of the sizing die 6 is provided with an exit zone 61, the outer edge of the reducing die 3 is provided with a reducing zone 31, the outer edge of the transition die 4 is provided with a transition zone 41, the outer edge of the preforming die 5 is provided with a preforming zone 51, and the inner wall of the preforming zone 51 is provided with a sizing zone 52.

[0037] In a preferred embodiment, the outer wall of the die sleeve 1 is provided with a dismounting groove 9, the inner wall of the die sleeve 1 is threadedly connected with a fixing cover 7, the outer edge of the fixing cover 7 is provided with a dismounting hole 8, and the fixing cover 7 is located at the left side of the entry die 2.

[0038] In a preferred embodiment, the outer edge of the entry die 2 is provided with a threaded hole 11, the outer edges of the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are all provided with round holes 10, the inner cavities of the round holes 10 are penetrated by fixing bolts 12, and the fixing bolts 12 are threadedly connected with the threaded hole 11 on the entry die 2.

[0039] In a preferred embodiment, the outer walls of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are all provided with positioning grooves 13, and the inner wall of the die sleeve 1 is provided with a limiting strip 14 which is slidingly connected with the positioning grooves 13.

[0040] In a preferred embodiment, the connection between the preforming zone 51 and the sizing zone 52 is arc-processed, the shapes of the entry zone 21 and the exit zone 61 are horn-shaped structures, and the flaring angles of the entry zone 21 and the exit zone 61 are 30° and 45°, respectively.

[0041] In a preferred embodiment: the material of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 is polycrystalline diamond, and the diamond composite comprises the following components in mass percentage: diamond particles 20%, cobalt 8%, copper 12%, nickel 3%, and the rest is graphite; the surfaces of the entry zone 21, the reducing zone 31, the transition zone 41, the preforming zone 51, the sizing zone 52 and the exit zone 61 are provided with a titanium nitride nano coating with a thickness of 1 μm.

[0042] A superfine profiled steel wire drawing process based on a superfine profiled steel wire drawing die, and the specific steps are as follows: S1: selecting a steel wire blank, performing surface rust removal treatment, removing the surface oxide scale by pickling, rinsing clean with clean water and drying after pickling, and then performing annealing treatment on the blank, the annealing temperature being 800 DEG C, the holding time being 2.5 h, and furnace cooling to room temperature; S2: preheating the drawing die in a heating device, the preheating temperature being 130 DEG C, holding for 35 min, while preparing a drawing lubricant, the drawing lubricant being composed of the following components in mass percentage: base oil 65%, extreme pressure agent 8%, anti-wear agent 4%, emulsifier 3%, anti-rust agent 2%, and the rest being water; uniformly applying the prepared lubricant on the inner walls of the working areas of the entry zone 21, the reducing zone 31, the transition zone 41, the preforming zone 51, the sizing zone 52 and the exit zone 61 and the surface of the pretreated steel wire blank; S3: performing multi-pass drawing on the steel wire blank by using the preheated die, the drawing pass being 8-12, the deformation amount between adjacent two passes being controlled at 10%; the drawing speed increases with the pass, the first pass drawing speed being 3 m / s, and the last pass drawing speed being 9 m / s; maintaining the die temperature at 110 DEG C during drawing, and adjusting the die temperature by a circulating cooling system; S4: after the 5th pass drawing and the 9th pass drawing, respectively performing intermediate heat treatment on the steel wire; the intermediate heat treatment includes normalizing and tempering, the normalizing temperature being 900 DEG C, the holding time being 1.3 h, and air cooling to room temperature; the tempering temperature being 450 DEG C, the holding time being 1.5 h, and furnace cooling to room temperature; S5: after the last pass drawing is completed, feeding the steel wire into a straightening machine for straightening treatment, the straightening speed being 6 m / s; after the straightened steel wire is cleaned and dried, performing size precision detection, surface quality detection and mechanical property detection, and the qualified product is the superfine profiled steel wire finished product.

[0043] In a preferred embodiment: the acid solution used for pickling in step S1 is a hydrochloric acid solution with a mass concentration of 18%, the pickling temperature is 45 DEG C, and the pickling time is 12 min.

[0044] In a preferred embodiment: the extreme pressure agent in step S2 is sulfurized isobutylene, the anti-wear agent is zinc dialkyldithiophosphate, the emulsifier is Span-80, and the anti-rust agent is benzotriazole.

[0045] In a preferred embodiment: the circulating cooling system in step S3 uses heat conducting oil as the cooling medium, the flow rate of the cooling medium is 1.2 m / s, the mold temperature is monitored in real time by a temperature sensor, and when the mold temperature exceeds 130℃, the flow rate of the cooling medium is automatically increased. Example

[0046] An ultra-fine shaped steel wire drawing die comprises a die sleeve 1, the inner cavity of the die sleeve 1 is provided with an entry die 2, a reducing die 3, a transition die 4, a preforming die 5 and a sizing die 6, the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are sequentially arranged from left to right, and the axis of the die sleeve 1 coincides with the axes of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6. The outer edge of the entry die 2 is provided with an entry zone 21, the outer edge of the sizing die 6 is provided with an exit zone 61, the outer edge of the reducing die 3 is provided with a reducing zone 31, the outer edge of the transition die 4 is provided with a transition zone 41, the outer edge of the preforming die 5 is provided with a preforming zone 51, and the inner wall of the preforming zone 51 is provided with a sizing zone 52.

[0047] In a preferred embodiment: the outer wall of the die sleeve 1 is provided with a disassembly groove 9, the inner wall of the die sleeve 1 is threadedly connected with a fixing cover 7, the outer edge of the fixing cover 7 is provided with a disassembly hole 8, and the fixing cover 7 is located on the left side of the entry die 2.

[0048] In a preferred embodiment: the outer edge of the entry die 2 is provided with a threaded hole 11, the outer edges of the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are all provided with round holes 10, the inner cavities of the round holes 10 are penetrated by fixing bolts 12, and the fixing bolts 12 are threadedly connected with the threaded hole 11 on the entry die 2.

[0049] In a preferred embodiment: the outer walls of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 are all provided with positioning grooves 13, and the inner wall of the die sleeve 1 is provided with a limiting strip 14 which is slidingly connected with the positioning grooves 13.

[0050] In a preferred embodiment: the connection between the preforming zone 51 and the sizing zone 52 is treated with a circular arc, the shapes of the entry zone 21 and the exit zone 61 are horn-shaped structures, and the flaring angles of the entry zone 21 and the exit zone 61 are 30° and 45°, respectively.

[0051] In a preferred embodiment: the material of the entry die 2, the reducing die 3, the transition die 4, the preforming die 5 and the sizing die 6 is polycrystalline diamond, and the diamond composite comprises the following components in mass percentage: diamond particles 22%, cobalt 6%, copper 11%, nickel 2%, and the rest is graphite; the surfaces of the entry zone 21, the reducing zone 31, the transition zone 41, the preforming zone 51, the sizing zone 52 and the exit zone 61 are provided with a titanium nitride nano coating with a thickness of 1.4 μm.

[0052] A superfine profiled steel wire drawing process based on a superfine profiled steel wire drawing die, the specific steps are as follows: S1: select the steel wire blank, carry out surface rust removal treatment, adopt pickling method to remove surface oxide scale, after pickling, rinse clean with clean water and dry, then carry out annealing treatment on the blank, annealing temperature is 770 DEG C, holding time is 2.8 h, furnace cooling to room temperature; S2: put the drawing die into the heating device for preheating, preheating temperature is 140 DEG C, holding for 38 min, at the same time, prepare the drawing lubricant, the drawing lubricant is composed of the following components in mass percentage: base oil 68%, extreme pressure agent 8%, anti-wear agent 5%, emulsifier 4%, anti-rust agent 2%, and the rest is water; evenly apply the prepared lubricant on the inner wall of the working area of the entry zone 21, the reducing zone 31, the transition zone 41, the preforming zone 51, the sizing zone 52 and the exit zone 61 and the surface of the pretreated steel wire blank; S3: adopt the preheated die to carry out multi-pass drawing on the steel wire blank, drawing pass is 10, the deformation amount between adjacent two passes is controlled at 10%; the drawing speed increases with the pass, the first pass drawing speed is 2.5 m / s, the last pass drawing speed is 10 m / s; keep the die temperature stable at 110 DEG C during drawing, adjust the die temperature through the circulating cooling system; S4: after the 4th pass drawing and the 9th pass drawing, carry out intermediate heat treatment on the steel wire respectively; the intermediate heat treatment includes normalizing and tempering, the normalizing temperature is 880 DEG C, holding time is 1.5 h, air cooling to room temperature; the tempering temperature is 440 DEG C, holding time is 2 h, furnace cooling to room temperature; S5: after the last pass drawing is completed, send the steel wire into the straightening machine for straightening treatment, the straightening speed is 6 m / s; after the straightened steel wire is cleaned and dried, carry out size precision detection, surface quality detection and mechanical property detection, and the qualified product is the superfine profiled steel wire finished product.

[0053] In a preferred embodiment: the acid solution adopted for pickling in step S1 is hydrochloric acid solution with mass concentration of 18%, pickling temperature is 45 DEG C, pickling time is 15 min.

[0054] In a preferred embodiment: the extreme pressure agent in step S2 is sulfurized isobutylene, the anti-wear agent is zinc dialkyldithiophosphate, the emulsifier is Span-80, and the anti-rust agent is benzotriazole.

[0055] In a preferred embodiment: the circulating cooling system in step S3 uses heat conducting oil as the cooling medium, the flow rate of the cooling medium is 1.2 m / s, the mold temperature is monitored in real time by a temperature sensor, and when the mold temperature exceeds 130℃, the flow rate of the cooling medium is automatically increased.

[0056] The working principle is as follows: the inlet die 2, the reducing die 3, the transition die 4, the preforming die 5, and the sizing die 6 are sequentially stacked, then the fixing bolts 12 are inserted into the sizing die 6, the preforming die 5, the transition die 4, the reducing die 3, and the inlet die 2, and the fixing bolts 12 are tightened, at this time, the positioning grooves 13 on the sizing die 6, the preforming die 5, the transition die 4, the reducing die 3, and the inlet die 2 are on the same horizontal line, the positioning grooves 13 correspond to the limiting strips 14 on the mold sleeve 1, then the inlet die 2, the reducing die 3, the transition die 4, the preforming die 5, and the sizing die 6 are inserted into the mold sleeve 1, and the fixing cover 7 is screwed on the mold sleeve 1, the outer walls of the inlet die 2, the reducing die 3, the transition die 4, the preforming die 5, and the sizing die 6 tightly fit the inner wall of the mold sleeve 1, the inlet die 2, the reducing die 3, the transition die 4, the preforming die 5, and the sizing die 6 need to be hammered into the mold sleeve 1 several times during assembly, at this time, the entire mold is installed, and the head of the steel wire needs to be treated before drawing to enable the head of the steel wire to pass through the sizing area 52, then the steel wire is pulled, the steel wire is first deformed at the reducing area 31, at this time, the circular cross-section steel wire is initially reduced to a size close to the circumscribed circle size of the target special-shaped cross-section, when the steel wire passes through the transition area 41, the cross-sectional shape of the steel wire smoothly and gradually evolves from a circle to a similar shape of the target special-shaped profile, the curve in this area is designed based on the optimal streamline type of finite element simulation to ensure uniform metal flow, the steel wire passes through the sizing area 52 to make the steel wire cross-section accurately reach a special-shaped shape slightly larger than the final target size, and shape molding is completed, when the inlet die 2, the reducing die 3, the transition die 4, the preforming die 5, and the sizing die 6 need to be replaced, the fixing cover 7 is unscrewed from the mold sleeve 1, and then the inlet die 2, the reducing die 3, the transition die 4, the preforming die 5, and the sizing die 6 are knocked out of the mold sleeve 1.

[0057] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the same general inventive concepts embodied by the described embodiments. That is, although the present application is described in terms of particular embodiments and illustrative figures, it should be apparent that the scope of the present application is not limited to these specific embodiments.

[0058] While the embodiments of the application have been shown and described herein, it will be understood by those skilled in the art that many changes, modifications, substitutions and alterations to these embodiments can be made without departing from the principles and spirits of the application, and it is intended that the scope of the application be limited solely by the scope of the appended claims and the equivalents thereof.

Claims

1. A drawing die for ultra-fine irregular steel wire, comprising a die sleeve (1), characterized in that: The inner cavity of the mold sleeve (1) is provided with an inlet mold (2), a reducing mold (3), a transition mold (4), a preforming mold (5), and a sizing mold (6). The inlet mold (2), the reducing mold (3), the transition mold (4), the preforming mold (5), and the sizing mold (6) are arranged from left to right in sequence. The axis of the mold sleeve (1) coincides with the axis of the inlet mold (2), the reducing mold (3), the transition mold (4), the preforming mold (5), and the sizing mold (6). The outer edge of the inlet mold (2) is provided with an inlet area (21), the outer edge of the sizing mold (6) is provided with an outlet area (61), the outer edge of the reducing mold (3) is provided with a reducing area (31), the outer edge of the transition mold (4) is provided with a transition area (41), the outer edge of the preforming mold (5) is provided with a preforming area (51), and the inner wall of the preforming area (51) is provided with a sizing area (52).

2. The ultra-fine shaped steel wire drawing die according to claim 1, characterized in that: The outer wall of the mold sleeve (1) is provided with a disassembly groove (9), and the inner wall of the mold sleeve (1) is threaded with a fixing cover (7). The outer edge of the fixing cover (7) is provided with a disassembly hole (8), and the fixing cover (7) is located on the left side of the inlet mold (2).

3. The ultra-fine shaped steel wire drawing die according to claim 1, characterized in that: The outer edge of the inlet mold (2) is provided with a threaded hole (11). The outer edges of the reducing mold (3), transition mold (4), preforming mold (5) and sizing mold (6) are all provided with round holes (10). The inner cavity of the round hole (10) is provided with a fixing bolt (12). The fixing bolt (12) is threadedly connected to the threaded hole (11) on the inlet mold (2).

4. The ultra-fine shaped steel wire drawing die according to claim 1, characterized in that: The outer walls of the inlet mold (2), the reducing mold (3), the transition mold (4), the preforming mold (5) and the sizing mold (6) are all provided with positioning grooves (13), and the inner wall of the mold sleeve (1) is provided with a limiting strip (14), which is slidably connected to the positioning groove (13).

5. The ultra-fine shaped steel wire drawing die according to claim 1, characterized in that: The connection between the preforming area (51) and the sizing area (52) is rounded. The inlet area (21) and the outlet area (61) are horn-shaped structures, and the flaring angles of the inlet area (21) and the outlet area (61) are 30° and 45°, respectively.

6. The ultra-fine shaped steel wire drawing die according to claim 1, characterized in that: The materials of the inlet mold (2), the reducing mold (3), the transition mold (4), the preforming mold (5) and the sizing mold (6) are polycrystalline diamond, and the diamond composite material includes the following components by mass percentage: 15%-25% diamond particles, 5%-10% cobalt, 10%-15% copper, 2%-5% nickel, and the remainder is graphite. The surfaces of the inlet area (21), the reducing area (31), the transition area (41), the preforming area (51), the sizing area (52) and the outlet area (61) are provided with a titanium nitride nano-coating with a thickness of 0.5-1.5 μm.

7. A drawing process for ultra-fine irregular-shaped steel wire, characterized in that: Based on the ultra-fine shaped steel wire drawing die according to claim 6, the specific steps are as follows: S1: Select steel wire billet, perform surface rust removal treatment, use pickling to remove surface oxide scale, rinse with clean water after pickling and dry, then anneal the billet at a temperature of 700-800℃ for 2-3 hours, and cool it to room temperature in the furnace. S2: Place the drawing die in a heating device for preheating. The preheating temperature is 120-150℃. Keep it warm for 30-40 minutes. At the same time, prepare the drawing lubricant. The drawing lubricant is composed of the following components by mass percentage: 60%-70% base oil, 5%-10% extreme pressure agent, 3%-5% anti-wear agent, 2%-4% emulsifier, 1%-3% rust inhibitor, and the remainder is water. Apply the prepared lubricant evenly to the inner walls of the working areas of the inlet area (21), the diameter reduction area (31), the transition area (41), the preforming area (51), the sizing area (52), and the outlet area (61), as well as to the surface of the pretreated steel wire blank. S3: The preheated die is used to draw the steel wire billet in multiple passes, with 8-12 passes. The deformation between two adjacent passes is controlled at 8%-12%. The drawing speed increases with each pass, with the first pass drawing speed at 2-3 m / s and the last pass drawing speed at 8-10 m / s. During the drawing process, the die temperature is kept stable at 100-130℃, and the die temperature is regulated by a circulating cooling system. S4: After the 4th-5th drawing pass and after the 8th-9th drawing pass, the steel wire is subjected to intermediate heat treatment. The intermediate heat treatment includes normalizing and tempering. The normalizing temperature is 850-900℃, the holding time is 1-1.5h, and it is air-cooled to room temperature. The tempering temperature is 400-450℃, the holding time is 1.5-2h, and it is furnace-cooled to room temperature. S5: After the final drawing process, the steel wire is fed into a straightening machine for straightening at a speed of 5-6 m / s. After straightening, the steel wire is cleaned and dried, and then subjected to dimensional accuracy testing, surface quality testing, and mechanical property testing. Qualified products are finished ultra-fine shaped steel wires.

8. The ultra-fine shaped steel wire drawing process according to claim 7, characterized in that: In step S1, the acid used for pickling is a hydrochloric acid solution with a mass concentration of 15%-20%, the pickling temperature is 40-50℃, and the pickling time is 10-15 minutes.

9. The ultra-fine shaped steel wire drawing process according to claim 7, characterized in that: In step S2, the extreme pressure agent is isobutylene sulfide, the anti-wear agent is zinc dialkyl dithiophosphate, the emulsifier is Span-80, and the rust inhibitor is benzotriazole.

10. The ultra-fine shaped steel wire drawing process according to claim 7, characterized in that: In step S3, the circulating cooling system uses heat transfer oil as the cooling medium, and the flow rate of the cooling medium is 0.8-1.2 m / s. The temperature of the mold is monitored in real time by a temperature sensor. When the temperature of the mold exceeds 130°C, the flow rate of the cooling medium is automatically increased.

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