A method for near-net-shape production of high-silicon steel wire

Abstract

The application belongs to the technical field of metal material preparation, and particularly relates to a near-net-shape preparation method of high-silicon steel wire material. The near-net-shape preparation method of high-silicon steel wire material comprises the following steps: S1, mother material preparation: taking pure iron and pure silicon as raw materials, mixing, smelting, casting, and forging and blooming to obtain an alloy mother material slab; S2, cutting into a narrow strip: cutting the alloy mother material slab into a narrow strip, and cleaning to obtain an alloy narrow strip; S3, melting the alloy narrow strip: adjusting the feeding speed of the alloy narrow strip, starting induction heating and laser, melting the alloy narrow strip, and flowing into a molten pool crucible after the alloy is melted, and protective gas is introduced into the molten pool crucible; S4, rapid solidification fine wire: dipping liquid alloy, and drawing out the molten pool to obtain high-silicon steel fine wire; and S5, coiling: coiling the high-silicon steel fine wire to obtain high-silicon steel wire material. The preparation method has the advantages of fast melting speed, high efficiency, continuous provision of the alloy mother material narrow strip, no size limitation, and continuous preparation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal material preparation, and particularly relates to a near-net-shape preparation method of high-silicon steel wire. BACKGROUND

[0002] Silicon steel is an important soft magnetic material, and accounts for more than 90% of the total amount of magnetic materials. Silicon steel plays a key role in the generation, conversion, transmission and use of electric energy, and can be used to manufacture generators, motors, transformers, mutual inductors, relays and other devices, and is widely used in the fields of electric power, electricity and communication. High-silicon steel generally refers to silicon steel with a silicon content of more than 3.5% (by weight, the same below). Compared with ordinary low-silicon steel, high-silicon steel, especially high-silicon steel with a silicon content of 6.5%, can increase the resistivity to 82 μΩ·cm, which is about twice that of 3wt.% Si silicon steel, and the alternating current loss is greatly reduced, and the magnetostriction coefficient is reduced to nearly zero. High-silicon steel is praised as "super core", and is an ideal material for the high efficiency, miniaturization and ultra-low noise of motors. However, due to the increase of the silicon content, 6.5% high-silicon steel has B2 and D03 ordered structures after cooling, and the room temperature plasticity is sharply reduced compared with low-silicon steel. It is very difficult to prepare and process by using the conventional hot rolling and cold rolling method, which seriously hinders the progress of industrialization. In order to avoid the brittle processing range of high-silicon steel, people use chemical vapor deposition siliconizing method and rapid solidification near-net-shape method to prepare high-silicon steel. The chemical vapor deposition method is to infiltrate silicon on ordinary silicon steel sheets with a silicon content of about 3%, and then perform homogenization treatment, so as to finally obtain gradient high-silicon steel sheets or pure 6.5% high-silicon steel. The rapid solidification near-net-shape method can rapidly solidify liquid metal into a shape, and the rapid cooling of liquid metal can significantly inhibit the brittle ordered phase of high-silicon steel, so that the order degree is reduced, and the structure is relatively fine, and the elongation is increased. The rapid solidification near-net-shape method mainly includes the preparation of thin strips, such as planar flow casting rapid solidification method, and the preparation of high-silicon steel filaments, such as rotating water spinning method and melt drawing method. High-silicon steel wire can be wound into a core material to manufacture transformers and mutual inductors and other devices.

[0003] Chinese patent CN105522128A discloses a "method for preparing high-silicon steel wire in a short process", which comprises: I. selecting high-silicon steel with a silicon content of more than 3.5% to make a rod; II. fixing a quartz tube provided with the rod; III. forming a rotating water layer by using a rotating drum; IV. melting the rod by high-frequency induction heating; V. spraying the molten steel into the rotating water layer to rapidly solidify and form high-silicon steel wire. The invention uses the rotating water spinning method to rapidly form the high-silicon steel wire in one step, and the diameter of the wire is 40-250 μm. The method has high requirements for the experimental conditions such as the molten pool and the cooling medium, the speed of melting the metal by induction is slow, the molten metal is easy to be oxidized, the size of the base alloy is limited, the prepared thin wire cannot be wound, and it is difficult to realize continuous preparation.

[0004] Chinese patent CN105537545A discloses "a preparation method of high silicon steel micro-wire", comprising: first, high silicon steel master alloy preparation; second, cutting the master alloy into a cylindrical rod, putting it into a crucible, vacuumizing, filling argon, melting the master alloy by induction heating, and starting the metal roller; third, feeding the master alloy melt upward through the feeding device, the melt contacts with the roller body, the rotating roller directly dips the thin layer of high silicon steel master alloy liquid from the melt, the thin layer of liquid is pulled out of the melt pool, and the thin layer of liquid is rounded into high silicon steel micro-wire under the action of surface tension, and the thin layer of liquid is rapidly solidified by heat transfer. The method needs to vacuumize the cavity of the melt pulling device to reach the set vacuum degree, which seriously limits the size of the alloy base material and the size of the melt pulling device; the speed of induction melting is slow, and the melt pool is unstable; the prepared fine wire cannot be wound, and it is difficult to realize continuous preparation.

[0005] The above patent documents all use induction heating to melt the metal, the melting speed is slow, the size of the alloy base material is limited, the prepared fine wire cannot be wound, and it is difficult to realize continuous preparation. SUMMARY

[0006] The present application aims to provide a near-net-shape preparation method of high silicon steel wire material. The near-net-shape preparation method of high silicon steel wire material of the present application can effectively overcome the defects in the prior art, has the advantages of fast melting speed, high efficiency, continuous provision of alloy base material strips, no size limitation, and continuous preparation, etc.

[0007] In order to achieve the above purpose, the present application adopts the following technical scheme: a near-net-shape preparation method of high silicon steel wire material, comprising the following steps:

[0008] S1, master material preparation: using industrial pure iron and pure silicon as raw materials, mixing, smelting, casting into ingots, and forging and blooming to obtain alloy master material slabs;

[0009] S2, cutting into strips: cutting the alloy master material slabs into strips, cleaning, and obtaining alloy strips;

[0010] S3, melting the alloy strips: adjusting the feeding speed of the alloy strips, starting the induction heating and laser, melting the alloy strips, and flowing into the melt pool crucible after the alloy is melted, and passing the protective gas into the melt pool crucible;

[0011] S4, rapid solidification of fine wire: dipping the liquid alloy in the melt pool crucible, pulling out the melt pool, and rounding the thin layer of liquid alloy into high silicon steel fine wire under the action of surface tension;

[0012] S5, winding: winding the high silicon steel fine wire to obtain high silicon steel wire material.

[0013] The near-net-shape preparation method of high silicon steel wire material of the present application starts the induction heating in step S3 first to preheat the strip, so that the alloy strip is uniformly heated and deformed small.

[0014] Preferably, the content of Fe in the prepared high-silicon steel wire material is 93-97% of the total mass of the high-silicon steel wire material, and the content of Si is 3.0-7.0% of the total mass of the high-silicon steel wire material.

[0015] More preferably, the content of Si is 3.25-6.45% of the total mass of the high-silicon steel wire material.

[0016] Preferably, the smelting conditions in step S1 are smelting at 1510-1610℃ for 45-50 minutes.

[0017] Preferably, the temperature for forging and breaking down in step S1 is 800-1200℃, and the holding time is 150-210 minutes. If the temperature for forging and breaking down is too high, the silicon steel grains are prone to grow, and oxidation is serious. If the temperature is higher than 1200℃, ferrous silicate and the like are generated, and it is difficult to remove phosphorus and clean the surface. If the temperature is too low, especially if the temperature for forging and breaking down is lower than 800℃, the material has low plasticity, and cracking is prone to occur.

[0018] Preferably, the feeding speed of the alloy strip in step S3 is 1-20 m·min -1 .

[0019] Preferably, the speed of pulling out of the molten pool in step S4 is 15-900 m·min -1 . In order to maintain the stability and high consistency of the molten pool, the wire production per minute and the alloy strip feeding amount are kept consistent.

[0020] Preferably, the speed of winding the high-silicon steel fine wire in step S5 is 15-900 m·min -1 .

[0021] Preferably, the temperature of the liquid alloy in the molten pool crucible in step S3 is maintained at 1500-1600℃, which is 25-55℃ higher than the liquidus temperature (overheating degree).

[0022] Preferably, after the laser is started in step S3, argon gas is introduced for protection, and the flow rate of the argon gas is 12-30 L·min -1 . The present application introduces argon gas for protection during the laser induction composite melting process, which can effectively avoid the oxidation of the liquid metal.

[0023] Preferably, the protective gas in step S3 is CO gas, and the flow rate of the CO gas is 12-30 L·min -1 . The present application introduces CO gas near the molten pool, which can effectively prevent the oxidation of the alloy material and reduce the oxidized surface of the wire. If hydrogen gas is selected as the protective gas, H2O generated by reduction will further adhere to the surface of the wire, causing oxidation.

[0024] Preferably, nitrogen is introduced in the process of winding the high silicon steel filament in step S5, and the flow rate of the nitrogen is 12-30 L·min -1 The present application introduces nitrogen in the process of winding the high silicon steel filament, which can avoid further oxidation, cool the filament, inhibit the generation of brittle ordered structure of high silicon steel, and is beneficial to the continuous preparation of high silicon steel filament. In addition, nitrogen cooling has lower cost and good safety.

[0025] Preferably, the thickness of the alloy strip in step S2 is 0.1-3 mm, and the width is 1-20 mm.

[0026] Preferably, the cleaning in step S2 is first pickling, then sanding, and finally cleaning with alcohol.

[0027] Preferably, the solution used for pickling is hydrochloric acid, the concentration of the hydrochloric acid solution is 3-5%, and the temperature of the pickling is 60-80℃.

[0028] Preferably, the conditions of the induction heating in step S3 are to raise the temperature to 700-1000℃.

[0029] Preferably, the power of the induction heating and the power of the laser are set according to the feeding amount of the alloy strip per minute.

[0030] More preferably, the calculation formula of the induction heating power is Pg=500×(1+G / 1000), and the calculation formula of the laser power is Pj=400×(1+G / 800), wherein G is the feeding amount of the alloy strip per minute.

[0031] The calculation formula of the feeding amount of the alloy strip per minute (G) is G=ρ×δ×L×V, and the unit is g, wherein ρ=7.865-0.065×Si%, the unit is g·cm -3 , δ is the thickness of the alloy strip, L is the width of the alloy strip, and V is the feeding speed of the alloy strip.

[0032] Compared with the prior art, the present application has the following beneficial effects:

[0033] (1) the existing melt drawing technology is completed in a vacuum chamber, space is limited, a metal bar with a length of about 100 mm is used, and only inductive melting or resistance melting metal can be used, and the size is limited. The present application adopts laser and induction heating composite melting of metal base material, multi-gas protection technology, molten pool stable control and winding and the like, can realize melting, forming and winding under the protection of gas, thereby realizing continuous melt feeding, continuous preparation, and the metal melt is not limited in size and does not need to be equipped with a vacuum device in the preparation process, effectively solving the problems of size limitation of alloy base material and the like in the prior art.

[0034] (2) the present application adopts laser and induction heating composite melting of metal base material, the supply of metal raw material is flexible and continuous, the melting speed is fast, the efficiency is high, and it is also convenient for subsequent continuous and efficient operation of forming and winding, effectively solving the problems of low efficiency and slow speed of inductive heating melting of metal.

[0035] (3) the near-net-shape preparation method of high-silicon steel wire material in the present application adopts argon, CO and nitrogen protection respectively in the whole preparation process from alloy melting, solidification forming to cooling, to prevent oxidation. Especially, CO protection gas is added in the process of preparing the wire material, which can not only prevent oxidation, but also reduce the oxidized surface of the wire material; nitrogen protection is used at the winding position, which not only ensures the cooling effect, but also has lower cost, and can further cool down to reduce the ordered phase. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is an equipment structure schematic diagram of the near-net-shape preparation method of high-silicon steel wire material.

[0037] Among them: 1, base material strip, 2, guide groove, 3, base material strip induction heating coil, 4, molten pool crucible induction heating coil, 5, molten pool crucible, 6, laser light source, 7, metal cooling copper roller, 8, alloy fine wire, 9, winding equipment. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with 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 scope of protection of the present application.

[0039] In the examples and comparative examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents and the like used are commercially available unless otherwise specified.

[0040] Example 1

[0041] A near-net shape preparation method of high silicon steel wire (Si content is 6.45%), comprising the following steps:

[0042] S1, mother material preparation: industrial pure iron, pure silicon as raw material, according to certain component ratio, vacuum induction smelting for 45 minutes at 1510℃, casting into ingot, forging into billet, forging temperature is 1060℃, holding time is 150 minutes;

[0043] S2, cutting into narrow strip: cutting the alloy mother material billet into narrow strip, first surface pickling, then sanding, finally alcohol cleaning, the thickness of the narrow strip alloy is 1mm, the width is 10mm; wherein the pickling solution is 3-5% hydrochloric acid solution;

[0044] S3, induction heating and laser composite melting alloy narrow strip: put the high silicon steel narrow strip into the guide groove, adjust the feeding speed of the narrow strip, first start induction heating, when the temperature reaches 700-1000℃, then start the laser, and use argon protection, use induction heating and laser to composite melt the alloy narrow strip, after the alloy is melted, flow into the molten pool, CO gas is introduced near the molten pool, the bottom of the molten pool crucible is provided with an induction coil, to ensure that the molten pool temperature is 1520℃, which is higher than the liquidus temperature (overheating degree) 35℃;

[0045] Wherein, the flow rate of argon is 12-30L·min -1 , the CO flow rate is 12-30L·min -1 ; the feeding speed V of the alloy narrow strip is 10m·min -1 , and the feeding amount G per minute is calculated according to the feeding speed, which is g, wherein ρ=7.865-0.065×Si%, unit is g·cm -3 ; the induction heating power needs to be compensated according to the feeding amount per minute, Pg=500×(1+G / 1000), and the laser power needs to be compensated according to the feeding amount per minute of the alloy narrow strip, Pj=400×(1+G / 800), wherein Pg is the induction power, unit is W; Pj is the laser power, unit is W;

[0046] S4, rapid solidification thin wire: start the metal cooling roller, the melt in the molten pool contacts with the metal cooling roller, the rotating roller dips the liquid alloy from the molten pool, the liquid thin layer is pulled out of the molten pool, the liquid thin layer is rounded into high silicon steel thin wire under the action of surface tension, and rapidly solidifies; the rotating speed of the cooling roller is 450m·min -1 , in order to maintain the stability and height consistency of the molten pool, the wire production per minute is consistent with the alloy feeding amount;

[0047] S5, winding: a winding shaft is arranged behind the cooling roller to wind the fine wire, nitrogen protection is arranged at the winding shaft, the winding speed is synchronous with the cooling roller speed, and the winding speed is 450 m / min -1 , the nitrogen flow is 12-30 L / min -1 .

[0048] Examples 2-6 and Comparative Examples 1-6

[0049] The preparation method refers to Example 1, and specific operation parameters are shown in Table 1.

[0050] Table 1: Operation parameters of examples and comparative examples

[0051]

[0052]

[0053] It can be known from the data in Table 1 that the method of melting the metal base material by combining laser and induction heating in the examples of the application effectively improves the melting speed, and high-efficiency continuous preparation of high-silicon steel wire material is realized by controlling the parameters such as forging breakdown temperature, superheat, and winding speed.

[0054] Compared with Example 1, in Comparative Example 1, only induction heating is used to melt the metal base material, in Comparative Example 2, only laser is used to melt the metal base material, which leads to a significant extension of the melting time of the metal base material, and micro-oxidation occurs on the surface of the finally prepared high-silicon steel wire material; in Comparative Example 3, the temperature during the forging breakdown of the raw material is too low, which causes a large number of cracks in the prepared alloy strip, and obvious oxidation phenomenon occurs inside the cracks, the oxygen content in the molten pool increases, which leads to the failure of the wire material to be formed;

[0055] Compared with Example 6, in Comparative Example 4, the winding speed is higher than the rotation speed of the cooling roller, which leads to wire breakage; in Comparative Example 5, the superheat during the preparation process is too high, which leads to too low viscosity of the melt and insufficient cooling capacity of the cooling roller, resulting in the problem of wire breakage during the preparation process; in Comparative Example 6, the superheat during the preparation process is too low, which leads to too high viscosity of the melt, and the wire material has poor formability, and also has the phenomenon of wire breakage.

[0056] The above examples only exemplarily illustrate the principles and effects of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the application should be covered by the claims of the application.

Claims

1. A method for preparing near-net-shape high-silicon steel wire, characterized in that, Includes the following steps: S1. Preparation of base material: Using pure iron and pure silicon as raw materials, mix, smelt, cast, forge and open the billet to obtain alloy base material slab; S2. Cutting into narrow strips: Cut the alloy base material slab into narrow strips, clean them, and obtain alloy narrow strips; S3. Melting the alloy strip: Adjust the feed speed of the alloy strip, start induction heating and laser to melt the alloy strip, and after the alloy melts, it flows into the molten pool crucible. Then, a protective gas is introduced into the molten pool crucible. S4. Rapid solidification of fine wire: Dip the liquid alloy into the molten pool and draw it out to obtain high silicon steel fine wire; S5. Winding: Winding high-silicon steel filaments to obtain high-silicon steel wire.

2. The near-net-shape preparation method of high-silicon steel wire as described in claim 1, characterized in that, The obtained high-silicon steel wire has an Fe content of 93-97% of the total mass of the high-silicon steel wire and a Si content of 3.0-7.0% of the total mass of the high-silicon steel wire.

3. The near-net-shape preparation method of high-silicon steel wire as described in claim 1, characterized in that, It must include at least one of the following (1) to (2): (1) The smelting conditions described in step S1 are smelting at 1510-1610℃ for 45-50 minutes; (2) The forging temperature in step S1 is 800~1200℃ and the holding time is 150~210 minutes.

4. The near-net-shape preparation method of high-silicon steel wire as described in claim 1, characterized in that, It must include at least one of the following (1) to (3): (1) The feed rate of the alloy narrow strip in step S3 is 1~20 m·min -1 ; (2) The speed at which the molten pool is pulled out in step S4 is 15~900 m·min -1 ; (3) The speed at which the high-silicon steel wire is wound in step S5 is 15~900 m·min -1 .

5. The near-net-shape preparation method of high-silicon steel wire as described in claim 1, characterized in that, In step S3, the temperature of the liquid alloy in the molten pool crucible is maintained at 1500~1600℃, which is 25~55℃ higher than the liquidus temperature.

6. The near-net-shape preparation method of high-silicon steel wire as described in claim 1, characterized in that, It must include at least one of the following (1) to (3): (1) After starting the laser in step S3, argon gas needs to be introduced for protection. The flow rate of the argon gas is 12-30 L·min. -1 ; (2) The protective gas mentioned in step S3 is CO gas, and the flow rate of the CO gas is 12-30 L·min. -1 ; (3) Nitrogen gas is introduced during the winding of high silicon steel wire in step S5, and the flow rate of the nitrogen gas is 12-30 L·min. -1 .

7. The near-net-shape preparation method of high-silicon steel wire as described in claim 1, characterized in that, It must include at least one of the following (1) to (3): (1) The thickness of the alloy narrow strip in step S2 is 0.1~3mm and the width is 1~20mm; (2) The cleaning described in step S2 is to first pickle the surface of the narrow strip, then polish it with sandpaper, and finally clean it with alcohol; (3) The induction heating condition in step S3 is to raise the temperature to between 700-1000℃.

8. The near-net-shape preparation method of high-silicon steel wire as described in claim 1, characterized in that, The power of the induction heating and the power of the laser are set according to the feed rate of the alloy narrow strip per minute.

Images