Drawing process of metal wire

Abstract

The application discloses a metal wire drawing process and relates to the technical field of metal wire processing. The metal wire drawing process comprises polishing, pickling, phosphating treatment and drawing treatment of the metal wire to be processed; a specific phosphating agent, ammonium polyphosphate, is used in the phosphating treatment process, a staged phosphating treatment process is used, and an activator is used to sequentially deposit a first phosphating layer with high compactness and a second phosphating layer with low compactness on the surface of the metal wire, so that the wear resistance of the surface of the metal wire is enhanced, and the adhesion of the lubricant film layer is facilitated; secondly, the metal wire passes through a lubricant with specific components in the drawing process, so that the corrosion resistance and the water-oxygen corrosion resistance of the metal wire are further enhanced, and obvious effects of preventing rust of the metal wire are achieved; in addition, the lubricant combines the wear-resistant agent with low hardness with the talc powder with soft texture, so that better lubrication is provided, and the drawing efficiency of the metal wire is improved.

Description

Technical Field

[0001] This invention relates to the field of metal wire processing technology, and in particular to a metal wire drawing process. Background Technology

[0002] In the process of drawing metal wire, the lubricant layer on the surface of the metal wire is an important factor to ensure that the metal wire can be drawn normally. With the continuous development of the technology of drawing metal wire to prepare steel wire and steel strand, the technology of phosphating surface treatment before drawing metal wire has been rapidly developed. Phosphating is a chemical reaction process in which the metal wire matrix reacts with dilute phosphoric acid or acidic phosphate to form a phosphate protective film.

[0003] Currently, phosphating processes are divided into immersion phosphating, online continuous phosphating, and electrolytic phosphating. Essentially, they involve the interaction of the metal substrate with the phosphating solution to form a crystalline phosphating film on the metal substrate surface. The phosphating film serves as a carrier for the lubricant coating to adhere to the metal wire surface, and its formation directly affects the drawing efficiency and effect of the metal wire. The film-forming effect of the phosphating process and the lubricating effect of the lubricant during the drawing process are still not ideal, leading to severe wear on the metal wire during the drawing process. Summary of the Invention

[0004] The main objective of this invention is to develop a drawing process for metal wires that significantly improves the film-forming effect of the phosphate layer on the surface of the metal wire, thereby enhancing its scratch resistance. Furthermore, it improves the lubricity of the metal wire surface, reduces the coefficient of friction between the die and the wire to be drawn, thus reducing friction and increasing drawing efficiency.

[0005] To achieve the above objectives, the present invention proposes a metal wire drawing process, which includes the following steps:

[0006] S1. Mechanically grind the metal wire to be processed to remove the surface oxide layer;

[0007] S2. Immerse the metal wire in acid solution and control the metal wire to move and rinse; then remove it and wash it with water.

[0008] S3. Immerse the metal wire processed in step S2 into a phosphating bath for phosphating treatment and let it stand.

[0009] S4. Pass the phosphated metal wire from step S3 through the lubricant, then through the wire drawing die for drawing. The wire extends out from the other end of the wire drawing die, completing one drawing operation.

[0010] S5. Repeat step S4 until the finished metal wire is drawn out, clean the surface of the finished metal wire, and complete the metal wire drawing process.

[0011] In step S3, the phosphating agent in the phosphating pool includes ammonium polyphosphate.

[0012] In one embodiment, step S3, the phosphating treatment is carried out in two stages, specifically including:

[0013] First stage phosphating treatment: Water is added to the phosphating tank, acid is added to adjust the pH to 2-3, the metal wire is immersed in the phosphating tank and left to stand for 3-5 minutes; ammonium polyphosphate and activator are added, and the phosphating reaction is carried out at 75℃-85℃ for 14-20 minutes. The metal wire is then taken out, and a first phosphating layer is formed on the surface of the metal wire.

[0014] Second stage phosphating treatment: Adjust the pH of the liquid in the phosphating tank to 3.3-4.6, immerse the metal wire in the phosphating tank again, add ammonium polyphosphate, and carry out the phosphating reaction again at 55℃-60℃ for 25min-35min. Take out the metal wire, and a second phosphating layer is formed on the surface of the metal wire.

[0015] In one embodiment, in step S3, before the phosphating reaction in the first stage of phosphating treatment, the concentration of ammonium polyphosphate is 10 g / L to 16 g / L, and the concentration of the activator is 0.4 g / L to 0.8 g / L.

[0016] In one embodiment, in step S3, during the second stage of phosphating treatment, before the phosphating reaction, the concentration of ammonium polyphosphate is 5 g / L to 10 g / L.

[0017] In one embodiment, in step S3, the activator is selected from at least one of sodium nitrite, sodium nitrate, hydrogen peroxide, manganese nitrate, sodium fluorosilicate, and zinc chloride.

[0018] In one embodiment, in step S4, the lubricant comprises the following raw materials in parts by weight:

[0019] Zinc stearate: 10-25 parts; imidazole and / or pyridinyl modified siloxane: 2-4 parts; abrasion resistant agent: 20-35 parts; talc: 10-30 parts; silane coupling agent: 0.8-1.5 parts; pentafluorophenyl acrylate: 2-3 parts; epoxy resin: 30-50 parts.

[0020] In one embodiment, the wear-resistant agent in the lubricant is selected from at least one of calcium carbonate, silica, barium sulfate, calcium titanate, and aluminum hydroxide; and the particle size of the wear-resistant agent is 10 μm to 100 μm.

[0021] In one embodiment, the preparation process of the lubricant includes the following steps:

[0022] The wear-resistant agent, talc, silane coupling agent and imidazole and / or pyridinyl modified siloxane are mixed according to the formula and stirred at 60℃~70℃ for 0.5h~1h. Then the remaining raw materials are added and mixed evenly to obtain the lubricant.

[0023] In one embodiment, in step S4, when the metal wire passes through the lubricant, the dwell time of the metal wire is 0.5 min to 3 min, and the temperature of the lubricant is 80°C to 95°C.

[0024] In one embodiment, in steps S4 and S5, the deformation of the metal wire during the drawing process is 8% to 15%.

[0025] In one embodiment, the drawing temperature of the metal wire during the drawing process is 120°C to 200°C.

[0026] In one embodiment, the metal wire is made of one of iron, aluminum, iron-based alloys, and aluminum-based alloys.

[0027] The technical solution of this invention designs a drawing process for metal wires. During the phosphating process, a specific phosphating agent, ammonium polyphosphate, is used, along with a staged phosphating process. An activator is added to sequentially deposit a highly dense first phosphating layer and a less dense second phosphating layer on the surface of the metal wire, effectively enhancing the wear resistance of the metal wire. Secondly, during the drawing process, the metal wire is passed through a lubricant of a specific composition. This causes the intermediate short-chain polyphosphates attached to the second phosphating layer to decompose into phosphates, which then react with metal ions at high temperatures to form phosphate crystals, further enhancing the wear resistance of the metal wire. The lubricant adsorbed on the surface of the metal wire has strong resistance to water and oxygen corrosion, significantly preventing rusting. Furthermore, the lubricant combines a low-hardness, wear-resistant agent with soft talc powder, providing better lubrication, improving the drawing efficiency of the metal wire, and preventing wire breakage. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0030] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0031] In the process of drawing metal wire, the lubricant layer on the surface of the metal wire is an important factor to ensure that the metal wire can be drawn normally. With the continuous development of the technology of drawing metal wire to prepare steel wire and steel strand, the technology of phosphating surface treatment before drawing metal wire has been rapidly developed. Phosphating is a chemical reaction process in which the metal wire matrix reacts with dilute phosphoric acid or acidic phosphate to form a phosphate protective film.

[0032] Currently, phosphating processes are divided into immersion phosphating, online continuous phosphating, and electrolytic phosphating. Essentially, they involve the interaction of the metal substrate with the phosphating solution to form a crystalline phosphating film on the metal substrate surface. The phosphating film serves as a carrier for the lubricant coating to adhere to the metal wire surface, and its formation directly affects the drawing efficiency and effect of the metal wire. The film-forming effect of the phosphating process and the lubricating effect of the lubricant during the drawing process are still not ideal, leading to severe wear on the metal wire during the drawing process.

[0033] To address the aforementioned technical issues, a metal wire drawing process was developed. This process significantly improves the film-forming effect of the phosphate layer on the metal wire surface, enhancing its scratch resistance. Furthermore, it improves the lubricity of the metal wire surface, reduces the coefficient of friction between the die and the wire to be drawn, thereby reducing friction and increasing drawing efficiency.

[0034] This invention proposes a drawing process for metal wires, characterized in that the drawing process for metal wires includes the following steps:

[0035] S1. Mechanically grind the metal wire to be processed to remove the surface oxide layer;

[0036] S2. Immerse the metal wire in acid solution and control the metal wire to move and rinse; then remove it and wash it with water.

[0037] S3. Immerse the metal wire processed in step S2 into a phosphating bath for phosphating treatment and let it stand.

[0038] S4. Pass the phosphated metal wire from step S3 through the lubricant, then through the wire drawing die for drawing. The wire extends out from the other end of the wire drawing die, completing one drawing operation.

[0039] S5. Repeat step S4 until the finished metal wire is drawn out, clean the surface of the finished metal wire, and complete the metal wire drawing process.

[0040] In step S3, the phosphating agent in the phosphating pool includes ammonium polyphosphate.

[0041] It should be noted that conventional phosphating processes use orthophosphates as phosphating agents, which form a phosphating layer by directly depositing phosphate crystals with metal ions. However, the ammonium polyphosphate used in this application is a condensed polyphosphate, which under normal circumstances only has the ability to chelate metal ions. Its chelating effect is not conducive to forming the desired dense phosphating layer. This application, taking advantage of the aforementioned characteristics of ammonium polyphosphate, designs a two-stage phosphating process. In the first stage of phosphating, a more acidic environment is used to rapidly increase the concentration of metal ions in the phosphating solution, and also promotes the hydrolysis of ammonium polyphosphate to obtain a large amount of phosphate. Furthermore, under the action of a strong oxidizing activator, a highly dense first phosphating layer is rapidly deposited on the surface of the metal wire. In the second stage of phosphating, the acidity of the phosphating solution decreases, and ammonium polyphosphate cannot be completely hydrolyzed in a short time, mainly existing in the form of intermediate short-chain polyphosphate. Furthermore, the concentration of metal ions in the phosphating solution is low due to consumption in the first stage of phosphating. Therefore, the density of the second phosphating layer deposited in the second stage of phosphating is relatively lower. At the same time, there are still many short polyphosphate chains on the surface of the second phosphating layer. Under the action of the active groups in the short polyphosphate chains, the polar groups in the lubricant are easily adsorbed onto the surface of the second phosphating layer. In addition, under the steric hindrance of the short polyphosphate chains, the second phosphating layer has good adhesion to the lubricant, thereby providing better lubrication and improving the drawing efficiency of the metal wire and preventing the metal wire from breaking.

[0042] In one embodiment, step S3, the phosphating treatment is carried out in two stages, specifically including:

[0043] First stage phosphating treatment: Water is added to the phosphating tank, acid is added to adjust the pH to 2-3, the metal wire is immersed in the phosphating tank and left to stand for 3-5 minutes; ammonium polyphosphate and activator are added, and the phosphating reaction is carried out at 75℃-85℃ for 14-20 minutes. The metal wire is then taken out, and a first phosphating layer is formed on the surface of the metal wire.

[0044] Second stage phosphating treatment: Adjust the pH of the liquid in the phosphating tank to 3.3-4.6, immerse the metal wire in the phosphating tank again, add ammonium polyphosphate, and carry out the phosphating reaction again at 55℃-60℃ for 25min-35min. Take out the metal wire, and a second phosphating layer is formed on the surface of the metal wire.

[0045] It should be noted that the phosphating treatment in this application is carried out in two stages. In the first stage of phosphating treatment, the pH is 2 to 3. In a more acidic environment, after the metal wire is immersed in the phosphating solution, the concentration of metal ions increases rapidly, the hydrolysis reaction of ammonium polyphosphate is violent, and a large amount of phosphate is obtained. In addition, under the action of a strong oxidizing activator, a first phosphating layer with high density is rapidly deposited on the surface of the metal wire.

[0046] It should also be noted that during the second stage of phosphating, the pH value of the phosphating solution changes to 3.3–4.6, and the ammonium polyphosphate cannot be completely hydrolyzed in a short time, mainly existing in the form of intermediate short-chain polyphosphate. Furthermore, due to the consumption of metal ions in the first stage of phosphating, the concentration of metal ions in the phosphating solution is greatly reduced. Therefore, the precipitation reaction between metal ions and phosphates is relatively slow during the second stage of phosphating, resulting in a relatively lower density of the deposited second phosphating layer. At the same time, there are still many short chains of polyphosphate on the surface of the second phosphating layer.

[0047] In one embodiment, in step S3, during the first stage of phosphating treatment, before the phosphating reaction, the concentration of ammonium polyphosphate is 10 g / L to 16 g / L, and the concentration of the activator is 0.4 g / L to 0.8 g / L.

[0048] In one embodiment, in step S3, during the second stage of phosphating treatment, before the phosphating reaction, the concentration of ammonium polyphosphate is 5 g / L to 10 g / L.

[0049] It should be noted that during the first stage of phosphating, by controlling the concentration of ammonium polyphosphate in the phosphating solution to be higher and the reaction temperature to be higher, and by using a strong oxidizing activator, the activation efficiency was improved, and the rapid formation of the first phosphating layer on the surface of the metal wire was accelerated, thus giving the first phosphating layer a better film-forming effect. The second phosphating layer, based on homogeneity, has a better deposition effect on the surface of the first phosphating layer. At the same time, the second phosphating layer has lower density and more short polyphosphate chains on the surface, which is beneficial to improving the adhesion of the lubricant coating during metal wire drawing, thereby improving the drawing efficiency.

[0050] In one embodiment, in step S3, the activator is selected from at least one of sodium nitrite, sodium nitrate, hydrogen peroxide, manganese nitrate, sodium fluorosilicate, and zinc chloride.

[0051] It should be noted that the activator used in this application is a strong oxidizing activator. On the one hand, it can oxidize metal ions to a higher valence state. On the other hand, under acidic conditions, the strong oxidizing activator can also promote the scission of ammonium polyphosphate chains to obtain phosphate ions, which is conducive to accelerating the rapid formation of the first phosphate film on the surface of the metal wire and forming a more dense first phosphate layer.

[0052] In one embodiment, in step S4, the lubricant comprises the following raw materials in parts by weight: zinc stearate: 10 to 25 parts; imidazole and / or pyridinyl modified siloxane: 2 to 4 parts; wear-resistant agent: 20 to 35 parts; talc: 10 to 30 parts; silane coupling agent: 0.8 to 1.5 parts; pentafluorophenyl acrylate: 2 to 3 parts; epoxy resin: 30 to 50 parts.

[0053] It should be noted that the imidazole and / or pyridinyl modified siloxanes in the lubricant of this application have multiple active sites, which can both complex with metal ions and adsorb onto the surface of the second phosphate layer or the wear-resistant agent through the active sites. This application also adds zinc stearate to the lubricant. During the drawing process, the intermediate short-chain polyphosphate attached to the second phosphate layer of the metal wire with adsorbed lubricant decomposes into phosphate at high temperature. The phosphate and zinc ions in zinc stearate form crystals at high temperature, so that new phosphate layers are continuously re-solidified on the surface of the metal wire during the drawing process, which has a good lubrication effect and plays a role in rust prevention and lubrication.

[0054] It should also be noted that by adding pentafluorophenyl acrylate to the lubricant, the polar groups in the pentafluorophenyl acrylate are directly anchored to the surface of the metal wire as the lubricant flows during the drawing process. The unadsorbed pentafluorophenyl groups, due to their steric hindrance and stable chemical properties, are beneficial to resisting external water and oxygen corrosion, thus having a significant effect on preventing the metal wire from rusting.

[0055] In one embodiment, the wear-resistant agent in the lubricant is selected from at least one of calcium carbonate, silica, barium sulfate, calcium titanate, and aluminum hydroxide; and the particle size of the wear-resistant agent is 10 μm to 100 μm.

[0056] It should be noted that the wear-resistant agents in this application are all micron-sized powders with a low hardness between 2 and 3.5, and the particle size is controlled between 10 μm and 100 μm to prevent damage to the surface of the metal wire during the drawing process. It should also be noted that the combination of wear-resistant agents with low hardness and talc powder with a soft texture can provide better lubrication and buffering, reduce the impact of internal stress on the metal wire, thereby improving the drawing efficiency of the metal wire and preventing the metal wire from breaking.

[0057] In one embodiment, the preparation process of the lubricant includes the following steps:

[0058] The wear-resistant agent, talc, silane coupling agent and imidazole and / or pyridinyl modified siloxane are mixed according to the formula and stirred at 60℃~70℃ for 0.5h~1h. Then the remaining raw materials are added and mixed evenly to obtain the lubricant.

[0059] In one embodiment, in step S4, when the metal wire passes through the lubricant, the dwell time of the metal wire is 0.5 min to 3 min, and the temperature of the lubricant is 80°C to 95°C.

[0060] In one embodiment, the drawing temperature of the metal wire during the drawing process is 120°C to 200°C.

[0061] In one embodiment, the metal wire is made of one of iron, aluminum, iron-based alloys, and aluminum-based alloys.

[0062] It should be noted that the phosphating process in this application is mainly designed for metal wires with iron or aluminum as the main material. In this case, the effect of the activator is more significant, and the phosphating effect and subsequent lubrication effect are better.

[0063] The present invention will be further illustrated below through specific embodiments:

[0064] All raw materials used in the embodiments of this invention are commercially available, and this invention does not impose any restrictions on the source of raw materials.

[0065] Ammonium polyphosphate: purchased from Budenheim, Germany, degree of polymerization 100-500, product number [item number missing]. 3140;

[0066] Talc powder: purchased from Guangxi Longsheng Huamei Talc Development Co., Ltd., with a particle size of approximately 10 micrometers.

[0067] The wire used in this embodiment of the invention is 77MnA steel with a diameter of approximately 24mm.

[0068] Example 1

[0069] The metal wire drawing process in Example 1 includes the following steps:

[0070] S1. Mechanically grind the metal wire to be processed until there is no visible oxide layer on the surface;

[0071] S2. Immerse the polished metal wire in 10wt% hydrochloric acid and control the metal wire to move and rinse for 20 minutes at 40℃; remove and rinse twice with clean water.

[0072] S3. First stage phosphating treatment: Add water and hydrochloric acid to the phosphating tank to adjust the pH to about 2.2. Immerse the metal wire in the phosphating tank and let it stand for 3 minutes. Add ammonium polyphosphate and hydrogen peroxide. The concentration of ammonium polyphosphate is about 14.5 g / L and the concentration of hydrogen peroxide is about 0.5 g / L. Phosphating reaction is carried out at 75°C for 18 minutes. Take out the metal wire. The first phosphating layer is formed on the surface of the metal wire.

[0073] Second stage phosphating treatment: Adjust the pH of the liquid in the phosphating tank to 4.2, immerse the metal wire in the liquid in the phosphating tank again, add ammonium polyphosphate, the concentration of ammonium polyphosphate is about 8 g / L, at this time the concentration of hydrogen peroxide in the phosphating tank is about 0.04 g / L, phosphating reaction is carried out at 55℃ for 30 min, the metal wire is taken out, and a second phosphating layer is formed on the surface of the metal wire.

[0074] Complete the phosphating process;

[0075] S4. Prepare the lubricant, pass the phosphated metal wire through the lubricant, control the temperature of the lubricant to be about 88℃, the speed of the metal wire passing through the lubricant to be 4m / min, the residence time of the metal wire in the lubricant to be about 1.5min, and then perform a drawing. The wire temperature reaches about 140℃ during the drawing, and the deformation per pass during the drawing is controlled to be 9% to 12%.

[0076] S5. Repeat step S4 until the finished metal wire is drawn out (about 14 times in total). Rinse the surface of the finished metal wire with water and dry it to complete the drawing process of the metal wire.

[0077] The lubricant preparation process in step S3 of this embodiment includes the following steps:

[0078] 25 parts by weight of calcium carbonate (D50 about 30 μm), 18 parts by weight of talc (D50 about 10 μm), 1.5 parts by weight of KH-570 and 3.5 parts by weight of 2-pyridylethyltriethoxysilane were mixed and stirred at 70°C for 0.5 h. Then, 18 parts by weight of zinc stearate, 2 parts by weight of pentafluorophenyl acrylate and 45 parts by weight of bisphenol A epoxy resin were added and mixed well to obtain a lubricant.

[0079] Example 2

[0080] The metal wire drawing process in Example 2 includes the following steps:

[0081] S1. Mechanically grind the metal wire to be processed until there is no visible oxide layer on the surface;

[0082] S2. Immerse the polished metal wire in 10wt% hydrochloric acid and control the metal wire to move and rinse for 20 minutes at 40℃; remove and rinse twice with clean water.

[0083] S3. First stage phosphating treatment: Add water and hydrochloric acid to the phosphating tank to adjust the pH to about 2.8. Immerse the metal wire in the phosphating tank and let it stand for 5 minutes. Add ammonium polyphosphate and sodium nitrite. The concentration of ammonium polyphosphate is about 12 g / L and the concentration of hydrogen peroxide is about 0.4 g / L. Phosphating reaction is carried out at 75°C for 18 minutes. Take out the metal wire. The first phosphating layer is formed on the surface of the metal wire.

[0084] The second stage of phosphating treatment: Adjust the pH of the liquid in the phosphating tank to about 3.7, immerse the metal wire in the liquid in the phosphating tank again, add ammonium polyphosphate, the concentration of ammonium polyphosphate is about 5.5 g / L, at this time the concentration of sodium nitrite in the phosphating tank is about 0.07 g / L, phosphating reaction is carried out at 55℃ for 35 min, the metal wire is taken out, and a second phosphating layer is formed on the surface of the metal wire;

[0085] Complete the phosphating process;

[0086] S4. Prepare the lubricant, pass the phosphated metal wire through the lubricant, control the temperature of the lubricant to be about 88℃, the speed of the metal wire passing through the lubricant to be 4m / min, the residence time of the metal wire in the lubricant to be about 1.5min, and then perform a drawing. The wire temperature reaches about 160℃ during the drawing, and the deformation per pass during the drawing is controlled to be 12% to 14%.

[0087] S5. Repeat step S4 until the finished metal wire is drawn out (about 11 times in total). Rinse the surface of the finished metal wire with water and dry it to complete the drawing process of the metal wire.

[0088] Comparative Example 1

[0089] Comparative Example 1 is based on Example 1, except that the metal wire drawing process in Comparative Example 1 only performs the first stage of phosphating treatment during the phosphating process.

[0090] The drawing process of the metal wire in Comparative Example 1 specifically includes the following steps:

[0091] S1. Mechanically grind the metal wire to be processed until there is no visible oxide layer on the surface;

[0092] S2. Immerse the polished metal wire in 10wt% hydrochloric acid and control the metal wire to move and rinse for 20 minutes at 40℃; remove and rinse twice with clean water.

[0093] S3. First stage phosphating treatment: Add water and hydrochloric acid to the phosphating tank to adjust the pH to about 2.2. Immerse the metal wire in the phosphating tank and let it stand for 3 minutes. Add ammonium polyphosphate and hydrogen peroxide. The concentration of ammonium polyphosphate is about 14.5 g / L and the concentration of hydrogen peroxide is about 0.5 g / L. Phosphating reaction is carried out at 75°C for 18 minutes. Take out the metal wire. The first phosphating layer is formed on the surface of the metal wire.

[0094] Complete the phosphating process;

[0095] S4. Prepare the lubricant, pass the phosphated metal wire through the lubricant, control the temperature of the lubricant to be about 88℃, the speed of the metal wire passing through the lubricant to be 4m / min, the residence time of the metal wire in the lubricant to be about 1.5min, and then perform a drawing. The wire temperature reaches about 140℃ during the drawing, and the deformation per pass during the drawing is controlled to be 9% to 12%.

[0096] S5. Repeat step S4 until the finished metal wire is drawn out (about 14 times in total). Rinse the surface of the finished metal wire with water and dry it to complete the drawing process of the metal wire.

[0097] Comparative Example 2

[0098] Comparative Example 2 is based on Example 1, except that in the drawing process of the metal wire in Comparative Example 2, the phosphating agent is replaced by ammonium polyphosphate in the phosphating process of step S3 with zinc dihydrogen phosphate corresponding to an equimolar amount of phosphate.

[0099] Comparative Example 3

[0100] Comparative Example 3 is based on Example 1, except that no activator is added during the phosphating process in step S3 of the drawing process of the metal wire in Comparative Example 3.

[0101] Comparative Example 4

[0102] Comparative Example 4 is based on Example 1, except that the wear-resistant agent in the lubricant of Comparative Example 4 is replaced with silica (hardness about 4 to 5), which has a higher hardness.

[0103] Performance testing

[0104] (1) The total film thickness (μm) of the phosphate layer and lubricant layer on the surface of the drawn metal wires in Examples 1-2 and Comparative Examples 1-4 was determined by microscopic measurement method in the national standard GB6462-2005 "Microscopic Measurement of Cross-sectional Thickness of Oxide Coating of Metals".

[0105] (2) The average film weight (g / m²) of different sections of the drawn metal wires in Examples 1-2 and Comparative Examples 1-4 was determined according to the national standard GB 9792-2003 "Determination of film mass per unit area of ​​conversion coating on metallic materials". 2 Each segment is 20cm long, with a 5cm gap between segments, and 5 segments are measured in each group.

[0106] (3) The adhesion strength of the lubricant film on the surface of the metal wire was determined using the MQ-800 four-ball abrasion tester in accordance with the test method of standard SY-2665-77.

[0107] (4) Corrosion resistance test: The drawn metal wires from Examples 1-2 and Comparative Examples 1-4 were immersed in a 5wt% sulfuric acid solution to test their corrosion resistance and calculate the corrosion loss (g / mm). 2 ·h).

[0108] The measurement results are shown in Table 1.

[0109] Table 1

[0110]

[0111] Analysis of the data in Table 1 shows that the lubricant layer in this invention has a better film-forming effect, and the adhesion between the lubricant layer and the phosphating layer, especially the second phosphating layer, is good. The film adhesion strength reaches more than 79 kg, and the total film thickness of the phosphating layer and the lubricant layer is close to 10 μm. The film uniformity is also better, which greatly improves the drawing efficiency of metal wire and reduces the drawing cost.

[0112] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A drawing process for metal wire, characterized in that, The drawing process of the metal wire includes the following steps: S1. Mechanically grind the metal wire to be processed to remove the surface oxide layer; S2. Immerse the metal wire in acid solution and control the metal wire to move and rinse; then remove it and wash it with water. S3. Immerse the metal wire processed in step S2 into a phosphating bath for phosphating treatment and let it stand. S4. Pass the phosphated metal wire from step S3 through the lubricant, then through the wire drawing die for drawing. The wire extends out from the other end of the wire drawing die, completing one drawing operation. S5. Repeat step S4 until the finished metal wire is drawn out, clean the surface of the finished metal wire, and complete the metal wire drawing process. In step S3, the phosphating agent in the phosphating pool includes ammonium polyphosphate; In step S3, the phosphating treatment is carried out in two stages, specifically including: First stage phosphating treatment: Water is added to the phosphating tank, and acid is added to adjust the pH to 2-3. The metal wire is immersed in the phosphating tank and left to stand for 3-5 minutes. Ammonium polyphosphate and an activator are added. Before the phosphating reaction, the concentration of the ammonium polyphosphate is 10 g / L-16 g / L, and the concentration of the activator is 0.4 g / L-0.8 g / L. The phosphating reaction is carried out at 75℃-85℃ for 14-20 minutes. The metal wire is then removed, and a first phosphating layer is formed on the surface of the metal wire. Second stage phosphating treatment: Adjust the pH of the liquid in the phosphating tank to 3.3~4.6, and the concentration of the ammonium polyphosphate is 5g / L~10g / L. Immerse the metal wire in the phosphating tank again, add ammonium polyphosphate, and carry out the phosphating reaction again at 55℃~60℃ for 25min~35min. Take out the metal wire, and a second phosphating layer is formed on the surface of the metal wire.

2. The metal wire drawing process as described in claim 1, characterized in that, In step S3, the activator is selected from at least one of sodium nitrite, sodium nitrate, hydrogen peroxide, manganese nitrate, sodium fluorosilicate, and zinc chloride.

3. The metal wire drawing process as described in claim 1, characterized in that, In step S4, the lubricant comprises the following raw materials in parts by weight: Zinc stearate: 10 to 25 parts; Imidazolyl and / or pyridyl modified siloxanes: 2 to 4 parts; Abrasion-resistant agent: 20-35 parts; Talc powder: 10 to 30 parts; Silane coupling agent: 0.8 parts to 1.5 parts; Pentafluorophenyl acrylate: 2 to 3 parts; Epoxy resin: 30 to 50 parts.

4. The metal wire drawing process as described in claim 3, characterized in that, In the lubricant, the wear-resistant agent is selected from at least one of calcium carbonate, silica, barium sulfate, calcium titanate, and aluminum hydroxide; Furthermore, the particle size of the wear-resistant agent is 10μm~100μm.

5. The metal wire drawing process as described in claim 4, characterized in that, The preparation process of the lubricant includes the following steps: The wear-resistant agent, talc, silane coupling agent and imidazole and / or pyridinyl modified siloxane are mixed according to the formula and stirred at 60℃~70℃ for 0.5h~1h. Then the remaining raw materials are added and mixed evenly to obtain the lubricant.

6. The metal wire drawing process as described in claim 1, characterized in that, In step S4, when the metal wire passes through the lubricant, the residence time of the metal wire is 0.5 min to 3 min. Furthermore, the temperature of the lubricant is 80℃~95℃.

7. The metal wire drawing process as described in claim 1, characterized in that, In steps S4 and S5, the deformation of the metal wire per pass during the drawing process is 8% to 15%. And / or, the drawing temperature of the metal wire during the drawing process is 120℃~200℃.

8. The metal wire drawing process as described in claim 1, characterized in that, The metal wire is made of one of the following materials: iron, aluminum, iron-based alloys, and aluminum-based alloys.

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