Steel wire production method, steel cord and tire

Abstract

The invention discloses a steel wire production method, a steel cord and a tire. Through alternate drawing, the drawing directions of the steel wire in the first half pass and the second half pass are completely opposite, the steel wire is subjected to sorbitizing and brass plating in cooperation with brass hot dipping, and special post-plating treatment is conducted through a water-based coating liquid containing polyoxyethylene organic salt and sodium hypophosphite. And the tensile strength, the torsion, the ductility, the area reduction and other properties of the steel wire are all improved.

Description

Technical Field

[0001] The invention belongs to the field of steel wire production, and in particular relates to a steel wire production method, a steel cord and a tire. Background Art

[0002] Existing semi-finished steel cord wires are obtained through wire rod pretreatment → rough drawing → intermediate heat treatment → intermediate drawing → heat treatment / electroplating → wet drawing. This method not only requires intermediate heat treatment, but also requires multiple drawing steps such as rough drawing, intermediate drawing and wet drawing. Even with the above cumbersome steps, the performance of the obtained steel wire still needs to be improved.

[0003] Patent CN107442596A discloses an improved steel cord production method, including wire rod pretreatment, coarse wire drawing, medium wire heat treatment, medium wire drawing, finished product heat treatment and brass plating and fine wire drawing. This method improves the rubber coating rate and adhesion of the steel cord by adopting a special pickling process.

[0004] However, the above production methods all require intermediate heat treatment and the drawing process is to continuously draw the fixed-length steel wire in one direction. This traditional drawing method increases the surface roughness of the steel wire, and the total equivalent strain and hardness of the steel wire surface cannot be improved, resulting in poor shaping of the steel wire. Summary of the invention

[0005] In view of the above problems existing in the prior art, the present invention provides a steel wire production method, a steel cord and a tire, which can improve the mechanical properties of the steel wire.

[0006] To achieve the above object, the technical solution provided by the present invention is as follows:

[0007] In a first aspect, the present application provides a steel wire production method, comprising the following steps:

[0008] Step 1: Select the raw material wire rod and pre-treat the wire rod;

[0009] Step 2, rough drawing: the pre-treated wire rod is drawn to a target diameter through different passes, wherein the drawing medium includes dry lubricating powder and sodium-based lubricating powder, and the drawing process includes at least one round of alternating drawing, in which the drawing directions of the steel wire in the first half pass and the second half pass are opposite;

[0010] Step 3, heat treatment; the heat treatment step includes: after being rinsed with hot water or electrolytic alkali, entering an open flame furnace with a controlled atmosphere, the DV value is 70-75, heating the steel wire to 950-1200°C and then treating it in a lead bath at 500-600°C, electrolytic pickling the steel wire after the lead bath treatment, and then rinsing, boron coating, and drying to obtain heat-treated steel wire;

[0011] Step 4: hot dip brass plating + post-plating treatment;

[0012] The post-plating treatment step comprises: washing the hot-dip brass-plated steel wire with water, drying it, and immersing the dried steel wire in a water-based coating liquid, wherein the water-based coating liquid comprises polyoxyethylene organic salt and sodium hypophosphite, and the rest is water;

[0013] Step 5: Wet drawing: Use the alternating drawing method to draw the steel wire in multiple passes.

[0014] Optionally, the wire rod pretreatment steps include: descaling, rinsing, electrolytic pickling, rinsing, hot water washing, boron coating, and drying.

[0015] Optionally, the DV value is 72.

[0016] Optionally, the usage ratio of the dry lubricating powder and the sodium-based lubricating powder in the drawing medium is (0.8-1.2):1.

[0017] Optionally, in step 4, the hot-dip brass plating step includes: (1) ultrasonically cleaning the heat-treated steel wire;

[0018] (2) Plating aid treatment: Soak the cleaned steel wire in 3-6% KF plating aid solution;

[0019] (3) Immersing the steel wire in a molten brass solution for sorbitization and brass plating, wherein the temperature of the molten brass solution is 980±20° C., the concentration of the brass solution is 63.5%±1.0%, and the immersion time is 30 to 60 seconds.

[0020] Optionally, in step 4, the steel wire is immersed in the plating agent solution for 3-10 minutes at a temperature of 30-40°C.

[0021] Optionally, in step 4, the concentration of the plating aid solution is 5% and the immersion temperature is 35°C.

[0022] Optionally, in step 4, the temperature of the molten brass solution is 990° C., the concentration is 64%, and the immersion time is 45 seconds.

[0023] Optionally, in step 4, the water-based coating liquid comprises the following components in parts by weight: 2-5 parts of polyoxyethylene organic salt, 0.5-2 parts of sodium hypophosphite, and the rest is water.

[0024] Optionally, in step 4, the water-based coating liquid comprises 3.0 parts of potassium alkyl polyoxyethylene ether phosphate, 1.5 parts of polyoxyethylene alkylamine, 1.0 part of sodium phosphite and 94.5 parts of water.

[0025] Optionally, in step three, the pickling adopts two-stage hydrochloric acid pickling, the pickling concentration of the first stage of the hydrochloric acid tank is controlled to be 50-80 g / L, the pickling concentration of the second stage of the hydrochloric acid tank is controlled to be 140-180 g / L, and the temperature of the two acid solutions is controlled to be 70±10°C.

[0026] Optionally, in step three, the steel wire is heated to 1100°C and then treated in a lead bath at 520°C.

[0027] Optionally, in step 1, the raw material wire rod is a Φ5.5mm steel cord wire rod with a carbon content of 0.72%, a manganese content of 0.4%, a sulfur content of 0.01%, and a phosphorus content of 0.01%.

[0028] Optionally, in step 2 and step 5, the drawing is performed using a CVD diamond mold.

[0029] In a second aspect, the present application also provides a steel cord, comprising a steel wire produced by the method described in the first aspect.

[0030] In a third aspect, the present application also provides a tire comprising the steel cord described in the second aspect.

[0031] Compared with the prior art, this application has at least the following beneficial effects:

[0032] 1. The drawing process of rough drawing and wet drawing of the present invention adopts alternating drawing, which reduces the surface roughness of the steel wire and improves the organizational structure and performance of the steel wire; in the rough drawing process, a combination of dry lubricating powder and sodium-based lubricating powder is used as the drawing medium, thereby eliminating the need for an intermediate thermal heating process, improving the surface roughness of the dry-drawn wire, increasing the amount of powder on the drawing surface, and improving the lubrication effect.

[0033] 2. The plating aid can dissolve the rust layer on the surface of the steel wire, activate the surface of the steel wire, and reduce the surface tension of the brass plating solution, thereby improving the ability of the brass plating solution to wet the iron substrate and promoting the surface of the steel wire to be wetted by the plating solution; the plating aid will not cause pollution to the brass plating solution and can reduce the generation of brass slag.

[0034] 3. The uniform temperature heating of the steel wire in the molten brass ensures the uniformity of the microstructure of the steel wire after quenching, the bending range of the pearlite lamellae becomes smaller, the hard and brittle phases in the microstructure disappear, and the cold drawing properties of the steel wire are improved. In addition, intermetallic compounds are formed at the interface of the two layers, which improves the adhesion of the coating, eliminates the gradient of the copper and zinc content, avoids the formation of hard and brittle phases, and improves the plastic deformation ability of the coating.

[0035] 4. The water-based coating liquid of the present invention has good dispersibility and can be evenly coated on the surface of the steel wire; the introduction of phosphorus-containing groups and amine groups on the surface of the steel wire improves the rust prevention ability of the steel wire and further improves the lubrication effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 Schematic diagram of the process of alternating drawing and traditional unidirectional drawing, where a is traditional unidirectional drawing and b is alternating drawing;

[0038] Figure 2 This is a comparison of the surface grain size of steel wire after rough drawing by alternating drawing and traditional unidirectional drawing, where a is traditional unidirectional drawing and b is alternating drawing; DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use.

[0040] Example 1

[0041] The goal is to produce 0.35mm semi-finished steel wire.

[0042] Step 1: Use high-strength steel cord wire rod with carbon content of 0.72%, manganese content of 0.4%, sulfur content of 0.01%, phosphorus content of 0.01%, and steel cord wire rod Φ5.5mm; wire rod pretreatment: mechanically descaling and rinsing the surface of the steel cord wire rod, and then alternately electrolytic pickling, rinsing, hot water washing, then boron coating, drying, and then collecting on a Φ1250mm large I-shaped wheel, with a wire collection speed of 2.5m / s;

[0043] Step 2, rough wire drawing: The surface treated steel cord wire rod is pulled to a multi-head linear wire drawing machine by a large I-wheel pay-off frame, and drawn to 2.10 mm through 11 passes, of which the first five passes are forward drawing and the last six passes are reverse drawing. The drawing medium is a 1:1 mixed medium of dry lubricating powder and traditional sodium-based lubricating powder, wherein the dry lubricating powder refers to calcium-based lubricating powder;

[0044] Step 3: Heat treatment: After being rinsed with hot water or electrolytic alkali, the steel wire enters an open flame furnace with a controlled atmosphere. The DV value is 72. The steel wire is heated to 1100°C and then treated in a lead bath at 520°C. The steel wire treated in the lead bath is directly electrolytically pickled. The pickling adopts a two-stage hydrochloric acid pickling. The pickling concentration of the first stage of the hydrochloric acid tank is controlled to be 60g / L, and the second stage of the hydrochloric acid tank is controlled to be 160g / L. The temperature of the two acid solutions is controlled to be 70°C, and then rinsed, boron coated, and dried;

[0045] Step 4: Hot dip brass plating + post-plating treatment:

[0046] (1) Ultrasonic cleaning: clean the lubricant or borax remaining on the surface of the steel wire after dry drawing to ensure the cleanliness of the steel wire surface;

[0047] (2) Plating treatment: Soak the steel wire in 5% KF plating agent solution for 4 minutes at a temperature of 37°C;

[0048] (3) Brass plating: Immerse the steel wire in a molten brass plating solution for sorbitization and brass plating. The temperature of the molten brass solution is 995°C, the concentration of the brass solution is 64.2%, and the immersion time is 35 seconds.

[0049] (4) Post-plating treatment: The plated steel wire is washed with cold water and blown dry with cold air. The blown-dried steel wire is immersed in a water-based coating liquid. 3.0 parts of alkyl polyoxyethylene ether potassium phosphate, 1.5 parts of polyoxyethylene alkylamine, 1.0 part of sodium phosphite and pure water are mixed into 100 parts of a water-based coating liquid. The pH value is adjusted to 7.7 with KOH and the coating liquid is heated to 65°C.

[0050] Step 5: The qualified 2.10mm steel wire is wet-drawn through 25 dies to be drawn into 0.35mm steel wire at a speed of 15m / s, wherein the first 12 passes are forward drawing and the last 13 passes are reverse drawing.

[0051] The properties of the steel wire obtained in Example 1 and the steel wire obtained by conventional process were tested, and the results are shown in Table 1.

[0052] Table 1 Performance comparison of the steel wire obtained in Example 1 and the conventional process steel wire

[0053] Technology Diameter of single wire (mm) Tensile strength (Mpa) Twist (times) Elongation (%) Area reduction rate (%) Surface ZnO value (mg / ㎡) Conventional process 0.35 3400 ≥55 (with stratification) 10.0 45 32.9 (1 day) / 58.3 (60 days) Technical process of the present invention 0.35 3500 ≥60 (no stratification) 9.0 38 23.5 (1 day) / 49.3 (60 days)

[0054] Through the above experimental data, it is found that the mechanical properties of the semi-finished steel wire obtained by the process of the present invention and the conventional process are improved after water-drawing to Φ0.35mm, the tensile strength of the single wire, and the torsion performance are improved, and the single wire is not layered, and the elongation and surface shrinkage are improved. The drawing in the present invention adopts a CVD diamond mold. Compared with the traditional mold, the CVD diamond has the advantages of good thermal stability and long service life.

[0055] Figure 1 FIG. 1 is a schematic diagram of the process of the alternating drawing and the conventional unidirectional drawing of this embodiment. The surface grain size of the steel wire after rough drawing by the alternating drawing and the conventional unidirectional drawing is tested. The results are as follows: Figure 2 It can be seen that compared with the traditional wire drawing method, alternating wire drawing can effectively suppress the compression ratio of the grains on the surface of the steel wire, thereby improving the performance of the steel wire.

[0056] Example 2

[0057] The goal is to produce 0.20mm semi-finished steel wire.

[0058] Step 1: Use high-strength steel cord wire rods with a carbon content of 0.72%, a manganese content of 0.4%, a sulfur content of 0.01%, and a phosphorus content of 0.01%. The steel cord wire rods are Φ5.5mm; wire rod pretreatment: the qualified steel cord wire rods are subjected to mechanical surface descaling and rinsing, and then alternately electrolytic pickling, rinsing, and hot water washing in sequence, and then boron coating, drying, and then collected on a Φ1000mm large I-shaped wheel, with a take-up speed of 2.0m / s;

[0059] Step 2, rough wire drawing: The surface treated steel cord wire rod is pulled to a multi-head linear wire drawing machine by a large I-wheel pay-off frame, and drawn to 2.81 mm through 11 passes, of which the first five passes are forward drawing and the last six passes are reverse drawing. The drawing medium is a 0.8:1 mixed medium of dry lubricating powder and traditional sodium-based lubricating powder;

[0060] After 8 passes, the diameter of the steel sheet is pulled from 2.81mm to 1.15mm. The first four passes are forward pulling, and the last four passes are reverse pulling. The pulling medium is a 0.8:1 mixed medium of dry lubricating powder and traditional sodium-based lubricating powder, where the dry lubricating powder refers to calcium-based lubricating powder.

[0061] Step 3: Heat treatment: After being rinsed with hot water or electrolytic alkali, the steel wire enters an open flame furnace with a controlled atmosphere. The DV value is 72. The steel wire is heated to 1100°C and then treated in a lead bath at 520°C. The steel wire treated in the lead bath is directly electrolytically pickled. The pickling adopts a two-stage hydrochloric acid pickling. The pickling concentration of the first stage of the hydrochloric acid tank is controlled to be 60g / L, and the second stage of the hydrochloric acid tank is controlled to be 160g / L. The temperature of the two acid solutions is controlled to be 70°C, and then rinsed, boron coated, and dried;

[0062] Step 4: Hot dip brass plating + post-plating treatment:

[0063] (1) Ultrasonic cleaning: clean the lubricant or borax remaining on the surface of the steel wire after dry drawing to ensure the cleanliness of the steel wire surface;

[0064] (2) Plating treatment: Soak the steel wire in 4.5% KF plating agent solution for 4 minutes at a temperature of 35°C;

[0065] (3) Brass plating: Immerse the steel wire in a molten brass plating solution for sorbitization and brass plating. The temperature of the molten brass solution is 990°C, the concentration of the brass solution is 64.7%, and the immersion time is 45 seconds.

[0066] (4) Post-plating treatment: The plated steel wire is washed with cold water and blown dry with cold air. The blown-dried steel wire is immersed in a water-based coating liquid. 3.0 parts of alkyl polyoxyethylene ether potassium phosphate, 1.5 parts of polyoxyethylene alkylamine, 1.0 part of sodium phosphite and pure water are mixed into 100 parts of a water-based coating liquid. The pH value is adjusted to 7.7 with KOH and the coating liquid is heated to 65°C.

[0067] Step 5: The qualified 1.15mm steel wire is wet-drawn through 26 dies to be drawn into 0.20mm steel wire at a speed of 13m / s, wherein the first 13 passes are forward drawing and the last 13 passes are reverse drawing.

[0068] The properties of the steel wire obtained in Example 2 and the steel wire obtained by conventional process were tested, and the results are shown in Table 2.

[0069] Table 2 Performance comparison of the steel wire obtained in Example 2 and the conventional steel wire

[0070] Technology Diameter of single wire (mm) Tensile strength (Mpa) Twist (times) Elongation (%) Area reduction rate (%) Surface ZnO value (mg / ㎡) Conventional process 0.20 3000 ≥50 (with stratification) 9.8 43 31.8 (1 day) / 56.3 (60 days) Technical process of the present invention 0.20 3100 ≥55 (no stratification) 8.8 39 24.6 (1 day) / 54.8 (60 days)

[0071] Through the above experimental data, it is found that the mechanical properties of the semi-finished steel wire obtained by the process of the present invention and the conventional process after water tank drawing to Φ0.20mm, the tensile strength of the single wire, and the torsional performance are all improved, and the single wire is not layered, and the elongation and surface shrinkage are improved.

[0072] Through experiments, it was found that using a combination of dry lubricating powder and sodium-based lubricating powder as a drawing medium during the rough drawing process improved the surface roughness of the dry drawn wire, increased the amount of powder on the drawing surface, and improved the lubrication effect compared to using an equal amount of the same lubricating medium alone.

[0073] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A method for producing a steel wire, characterized in that: The steps include: Step 1: Select the raw material wire rod and pre-treat the wire rod; Step 2, rough drawing: the pre-treated wire rod is drawn to a target diameter through different passes, wherein the drawing medium includes dry lubricating powder and sodium-based lubricating powder, and the drawing process includes at least one round of alternating drawing, in which the drawing directions of the steel wire in the first half pass and the second half pass are opposite; Step 3, heat treatment; the heat treatment step includes: after being rinsed with hot water or electrolytic alkali, entering an open flame furnace with a controlled atmosphere, the DV value is 70-75, heating the steel wire to 950-1200°C and then treating it in a lead bath at 500-600°C, electrolytic pickling the steel wire after the lead bath treatment, and then rinsing, boron coating, and drying to obtain heat-treated steel wire; Step 4: hot dip brass plating + post-plating treatment; The post-plating treatment step comprises: washing the hot-dip brass-plated steel wire with water, drying it, and immersing the dried steel wire in a water-based coating liquid, wherein the water-based coating liquid comprises polyoxyethylene organic salt and sodium hypophosphite, and the rest is water; Step 5: Wet drawing: Use the alternating drawing method to draw the steel wire in multiple passes.

2. A steel wire production method according to claim 1, characterized in that: The dosage ratio of dry lubricating powder and sodium-based lubricating powder in the drawing medium is (0.8-1.2):

1.

3. A steel wire production method according to claim 1, characterized in that: In step 4, the hot-dip brass plating step includes: (1) ultrasonically cleaning the heat-treated steel wire; (2) Plating aid treatment: Soak the cleaned steel wire in 3-6% KF plating aid solution; (3) Immersing the steel wire in a molten brass solution for sorbitization and brass plating, wherein the temperature of the molten brass solution is 980±20° C., the concentration of the brass solution is 63.5%±1.0%, and the immersion time is 30 to 60 seconds.

4. A steel wire production method according to claim 1, characterized in that: In step 4, the water-based coating liquid includes the following components in parts by weight: 2-5 parts of polyoxyethylene organic salt, 0.5-2 parts of sodium hypophosphite, and the rest is water.

5. A steel wire production method according to claim 1, characterized in that: In step three, the pickling adopts two-stage hydrochloric acid pickling, the pickling concentration of the first stage of the hydrochloric acid tank is controlled to be 50-80g / L, the pickling concentration of the second stage of the hydrochloric acid tank is controlled to be 140-180g / L, and the temperature of the two acid solutions is controlled to be 70±10°C.

6. A steel wire production method according to claim 4, characterized in that: In step three, the steel wire is heated to 1100°C and then treated in a lead bath at 520°C.

7. A steel wire production method according to claim 1, characterized in that: In the step 1, the raw material wire rod is a Φ5.5 mm steel cord wire rod with a carbon content of 0.72%, a manganese content of 0.4%, a sulfur content of 0.01%, and a phosphorus content of 0.01%.

8. A steel wire production method according to claim 1, characterized in that: In step 2 and step 5, the drawing is performed using a CVD diamond mold.

9. A steel cord, characterized in that: The invention comprises a steel wire produced by the method according to any one of claims 1 to 8.

10. A tire, characterized in that: Comprising the steel cord as claimed in claim 9.

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