Production process of 95MnNbA steel wire for ultrahigh-strength traction rope

Abstract

The invention belongs to the technical field of wire production, and particularly relates to a production process of a 95MnNbA steel wire for an ultrahigh-strength traction rope, which comprises the following steps: 1) taking a 95MnNbA steel wire rod as a raw material; 2) drawing a semi-finished product: performing circulating water cooling on a winding drum and a die box of a wire drawing machine in the drawing process, and controlling the temperature of a die to be lower than 90 DEG C; 3) heat treatment: ensuring that the wire temperature is in a range of 925-935 DEG C, and keeping the lead bath temperature in a range of 550-560 DEG C; 4) pickling the steel wire after heat treatment; (5) hot galvanizing, wherein the zinc temperature is controlled within the range of 450-460 DEG C; 11-12 passes are adopted for drawing of a wire drawing machine, the single-pass compression ratio of the first pass is controlled to be 15%-17%, the total compression ratio is controlled to be 85%-92%, the average compression ratio of all the passes is controlled to be 16%-18%, and a special wire drawing die is used as a wire drawing die of the last three passes.

Description

Technical Field

[0001] This invention belongs to the field of wire production technology, and specifically relates to a production process for 95MnNbA steel wire used in ultra-high strength traction ropes. Background Technology

[0002] As the diameter of traction wire ropes becomes increasingly thinner while their strength continues to increase, the steel wires must meet ultra-high strength requirements. This drives the continuous development of steel wire production towards ultra-high strength, while also ensuring good fatigue resistance and corrosion resistance. Currently, the 18mm 2260MPa grade galvanized traction wire ropes produced in China use extremely fine diameter steel wires, with the smallest diameter being 0.55mm. Traditional drawing methods employ wet drawing with water tank machines, resulting in low production efficiency and numerous drawing passes. Furthermore, the pre-plating followed by drawing method, with its multiple drawing passes, leads to significant zinc layer loss and lower zinc weight. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a production process for 95MnNbA steel wire for ultra-high strength traction ropes, which has good steel wire performance and minimal loss of strength, zinc weight and toughness.

[0004] To achieve the above objectives, the present invention employs the following technical solution: A manufacturing process for 95MnNbA steel wire used in ultra-high strength traction ropes, with the following specific steps: 1) The raw material is 95MnNbA steel wire rod, with the following chemical composition by mass percentage: C content 0.95%~1.0%, Si content 0.30%~0.33%, Mn content 0.79%~0.82%, and Nb content 0.02%~0.03%; 2) Semi-finished product drawing: During the drawing process, the wire drawing machine drum and die box are circulated with water cooling. The water cooling inlet temperature is less than 20℃, the die temperature is controlled below 90℃, and the wire drawing powder is sufficient to ensure adequate lubrication. 3) Heat treatment: Ensure the wire temperature is within the range of 935-945℃, the DV value is 35-45mm·m / min, the lead bath temperature is maintained within the range of 550-560℃, ensure that there is no slag at the outlet before and after the lead bath, no lead adhering to the surface of the steel wire, and that the sorbitization rate of the steel wire is greater than 95%; 4) After heat treatment, the steel wire is pickled. The concentration of hydrochloric acid during pickling is 170-200 g / L. After pickling, the hot water washing temperature is 60-70℃, and the concentration of ferrous chloride is controlled to be ≤100 g / L. 5) Hot-dip galvanizing: Before galvanizing, the surface of the steel wire is cleaned. After entering the zinc pot, the zinc temperature is controlled within the range of 450-460℃, the DV value is 80-90mm·m / min, and the zinc layer is smooth after being wiped evenly with an air knife. 6) After galvanizing, the steel wire is immersed in a low-concentration phosphating bath for micro-phosphating. The total acidity is 50-60 Pt, the free acid is 3-4 Pt, and the temperature is 50-60℃. After micro-phosphating, a thin phosphating film is formed on the surface of the galvanized steel wire, with a film weight of 2-4 g / m². 2 ; 7) Finished product drawing: The wire drawing machine uses 11 to 12 passes. The compression rate of the first pass is controlled at 15% to 17%, the total compression rate is controlled at 85% to 92%, and the average compression rate of all passes is controlled at 16% to 18%. The wire drawing dies for the last three passes use special wire drawing dies, the sizing strip length d≤0.6mm, the working cone angle is 8 to 9°, and special wire drawing powder for post-plating is used. During the drawing process, avoid the zinc layer from overheating and falling off.

[0005] The ultra-high strength traction rope uses 95MnNbA steel wire with a diameter of 0.5-0.8mm and a tensile strength of 2160-2260MPa.

[0006] Compared with existing technologies, the beneficial effects of this invention are: 1. This invention utilizes high-quality 95MnNbA steel wire rod to produce ultra-high strength traction rope wire. The characteristics of the wire rod ensure that the strength and hardness of the wire after drawing meet the requirements of traction rope wire. The niobium element in the wire rod can refine the austenite and pearlite grains. The finer the grains and the more grain boundaries, the higher the strength and toughness of the wire are simultaneously improved, while also improving plasticity and drawing performance.

[0007] 2. Control the die temperature below 90℃. Controlling the temperature of the drawing die can stabilize the microstructure during the drawing process and ensure uniform grain elongation.

[0008] 3. After galvanizing, micro-phosphating is performed using a low-concentration phosphating solution for a short time, which is beneficial for smooth drawing. During the drawing process, more wire drawing powder can be carried into the drawing die from the surface of the steel wire, resulting in better lubrication.

[0009] 4. The production process adopts the process of drawing finished steel wire after galvanization. The dry drawing method is used. By controlling the compression rate of the first pass and the partial compression rate, the strength and toughness loss of the steel wire after drawing is minimized. The subsequent three drawing dies control the length of the sizing zone and the working cone angle to ensure smooth drawing, reduce coating loss, reduce drawing heat generation, improve production efficiency, and meet the high strength and corrosion resistance requirements of this type of steel wire. Detailed Implementation

[0010] It should be noted that, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein in the specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. The reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0011] A manufacturing process for 95MnNbA steel wire used in ultra-high strength traction ropes, with the following specific steps: 1) The raw material is 95MnNbA steel wire rod, with the following chemical composition by mass percentage: C content 0.95%~1.0%, Si content 0.30%~0.33%, Mn content 0.79%~0.82%, and Nb content 0.02%~0.03%; 2) Semi-finished product drawing: During the drawing process, the wire drawing machine drum and die box are circulated and cooled by water. The water inlet temperature is less than 20℃, and the die temperature is controlled below 90℃. Controlling the temperature of the drawing die can stabilize the structure during the drawing process, ensure uniform grain elongation, ensure sufficient wire drawing powder, and ensure sufficient lubrication and smooth drawing. 3) Heat treatment: Nb in the steel wire forms NbC and NbN, pinning grain boundaries and making recrystallization more difficult to initiate. Therefore, the wire temperature is increased to ensure it is within the range of 935-945℃, with a DV value of 35-45 mm·m / min. The lead bath temperature is maintained within the range of 550-560℃ to ensure no slag formation at the outlet before and after the lead bath, no lead adhering to the steel wire surface, and a sorbitization rate of greater than 95% in the steel wire. 4) After heat treatment, the steel wire is pickled. The concentration of hydrochloric acid during pickling is 170-200 g / L. After pickling, the hot water washing temperature is 60-70℃, and the concentration of ferrous chloride is controlled to be ≤100 g / L. 5) Hot-dip galvanizing: Before galvanizing, the surface of the steel wire is cleaned. After entering the zinc pot, the zinc temperature is controlled within the range of 450-460℃, the DV value is 80-90mm·m / min, and the zinc layer is smooth after being wiped evenly with an air knife. 6) After galvanizing, the steel wire is immersed in a low-concentration phosphating bath for micro-phosphating. The total acidity is 50-60 Pt, the free acid is 3-4 Pt, and the temperature is 50-60℃. After micro-phosphating, a thin phosphating film is formed on the surface of the galvanized steel wire, with a film weight of 2-4 g / m². 2After galvanizing, micro-phosphating is performed using a low-concentration phosphating solution for a short time, which is beneficial for smooth drawing. It allows more drawing powder to be carried into the drawing die on the surface of the steel wire during the drawing process, thus providing better lubrication.

[0012] 7) Finished product drawing: The wire drawing machine uses 11 to 12 passes. The compression rate of the first pass is controlled at 15% to 17%, the total compression rate is controlled at 85% to 92%, and the average compression rate of all passes is controlled at 16% to 18%. The wire drawing dies for the last three passes use special wire drawing dies, the sizing strip length d≤0.6mm, the working cone angle is 8 to 9°, and special wire drawing powder for post-plating drawing is used. During the drawing process, avoid the zinc layer from overheating and falling off.

[0013] To make the objectives, technical solutions, and technical effects of this invention clearer, the technical solutions in the embodiments of this invention are now described clearly and completely. However, the embodiments described below are only some embodiments of this invention, not all embodiments. All other embodiments obtained by those skilled in the art in conjunction with the embodiments of this invention without creative effort are within the scope of protection of this invention. Example 1:

[0014] The process for producing galvanized steel wire with a diameter of 0.55mm and a strength of 2260MPa includes the following specific steps: 1) 95MnNbA steel wire rod is preferred as the drawing material, with a C content of 0.95% to 1.0%, a Si content of 0.30% to 0.33%, a Mn content of 0.79% to 0.82%, a Nb content of 0.02% to 0.03%, and a diameter of 6.5 mm; 2) Semi-finished product drawing: The semi-finished product diameter is 1.7mm. The wire drawing machine has good water cooling circulation. The temperature of the water-cooled wire drawing die is controlled below 90℃. Special wire drawing powder is used to ensure good lubrication. The dimensions of the intermediate wire drawing dies meet the tolerance requirements. 3) Heat treatment: The heat treatment DV value is 35 mm·m / min, ensuring the wire temperature is within the range of 930±5℃, the lead bath temperature is maintained within the range of 555±5℃, ensuring that there is no slag at the outlet before and after the lead bath, no lead adhering to the steel wire surface, and that the sorbitization rate of the steel wire is 96%~97%; 4) After heat treatment, the steel wire is pickled. The hydrochloric acid concentration is 170-200 g / L, the pickling time is 450 s, and the hot water washing temperature is 60-70℃ after pickling. The ferrous chloride concentration is ≤100 g / L, and the immersion time is determined according to the diameter of the steel wire.

[0015] 5) Hot-dip galvanizing: Ensure that the surface of the steel wire is clean before galvanizing. After entering the zinc pot, the zinc temperature is controlled within the range of 455±5℃. The hot-dip galvanizing DV value is 90mm·m / min. The surface of the zinc layer is smooth after being wiped evenly with an air knife. 6) After plating, the steel wire is immersed in a low-concentration phosphating bath for micro-phosphating. The total acidity is 50-60 Pt, the free acid is 3-4 Pt, the temperature is 50-60℃, and the phosphating time is 125s. After micro-phosphating, a thin phosphating film with a weight of 3g / m is formed on the surface of the plated steel wire. 2 ; 7) Finished product drawing: Finished product drawing process: 1.70mm→1.50mm→1.39mm→1.25mm→1.13mm→1.0mm→0.93mm→0.84mm→0.77mm→0.70mm→0.65mm→0.60mm→0.55mm. The last three drawing dies use special drawing dies, the sizing strip length d=0.5mm, the working cone angle is 8°, and special drawing powder for post-plating drawing is used to prevent the zinc layer from overheating and falling off during the drawing process.

[0016] The product has a steel wire diameter of 0.55mm, a tolerance of ±0.01, and a zinc weight of 82g / m. 2 Tensile strength 2260MPa, torsion cycles greater than 28, bending cycles greater than 15. Example 2:

[0017] The process for producing galvanized steel wire with a diameter of 0.62mm and a strength of 2160MPa involves the following steps: 1) 95MnNbA wire rod is preferred as the drawing material, with a C content of 0.95% to 1.0%, a Si content of 0.30% to 0.33%, a Mn content of 0.79% to 0.82%, a Nb content of 0.02% to 0.03%, and a diameter of 6.5 mm; 2) Semi-finished product drawing: The semi-finished product diameter is 1.8mm. The wire drawing machine has good water cooling circulation and the temperature of the water-cooled wire drawing die is controlled below 90℃. Special wire drawing powder is used to ensure good lubrication. The dimensions of the intermediate wire drawing dies meet the tolerance requirements.

[0018] 3) Heat treatment: The heat treatment DV value is 40 mm·m / min, ensuring the wire temperature is within the range of 930±5℃, the lead bath temperature is maintained within the range of 555±5℃, ensuring no slag formation at the outlet before and after the lead bath, no lead adhering to the steel wire surface, and a sorbitization rate of greater than 96.5% in the steel wire; 4) After heat treatment, the steel wire is pickled. The hydrochloric acid concentration is 170-200 g / L, the pickling time is 480 s, and the hot water washing temperature after pickling is 60-70℃. The ferrous chloride concentration is ≤100 g / L. 5) During the hot-dip galvanizing process, the surface of the steel wire is cleaned before galvanizing. The zinc pot temperature is controlled within the range of 455±5℃. The hot-dip galvanizing DV value is 90mm·m / min. The zinc layer is smooth after being wiped evenly with an air knife. 6) After plating, the steel wire is immersed in a low-concentration phosphating bath with a total acidity of 50-60 Pt, free acid of 3-4 Pt, a temperature of 50-60℃, and a phosphating time of 130 s. After micro-phosphating, a thin phosphating film with a film weight of 3 g / m is formed on the surface of the plated steel wire. 2 ; 7) Finished product drawing: Finished product drawing process: 1.8mm→1.65mm→1.49mm→1.35mm→1.22mm→1.11mm→1.01mm→0.93mm→0.85mm→0.78mm→0.72mm→0.67mm→0.62mm. The last three drawing dies use special drawing dies, the sizing strip length d=0.5mm, the working cone angle is 8°, and special drawing powder for post-plating drawing is used to prevent the zinc layer from overheating and falling off during the drawing process.

[0019] The product has a steel wire diameter of 0.62mm, a tolerance of ±0.01, and a zinc weight of 92g / m. 2 Tensile strength 2160MPa, torsion cycles greater than 26, bending cycles greater than 12. Example 3:

[0020] The process for producing galvanized steel wire with a diameter of 0.69mm and a strength of 2160MPa involves the following steps: 1) 95MnNbA wire rod is preferred as the drawing raw material, with a C content of 0.95%–1.0%, a Si content of 0.30%–0.33%, a Mn content of 0.79%–0.82%, and a Nb content of 0.02%–0.03%; and a diameter of 6.5 mm. 2) Semi-finished product drawing: The semi-finished product diameter is 1.9mm. The wire drawing machine has good water cooling circulation, and the temperature of the water-cooled drawing die is controlled below 90℃. Special wire drawing powder is used to ensure good lubrication, and the dimensions of the intermediate wire drawing dies meet the tolerance requirements. 3) Heat treatment: The heat treatment DV value is 35 mm·m / min, ensuring the wire temperature is within the range of 930±5℃, the lead bath temperature is maintained within the range of 555±5℃, ensuring that there is no slag at the outlet before and after the lead bath, no lead adhering to the steel wire surface, and the sorbitization rate of the steel wire is greater than 96%; 4) After heat treatment, the steel wire is pickled. The hydrochloric acid concentration is 170-200 g / L, the pickling time is 490 s, and the hot water washing temperature after pickling is 60-70℃. The ferrous chloride concentration is ≤100 g / L. 5) Hot-dip galvanizing: Before galvanizing, the surface of the steel wire is cleaned, the zinc pot temperature is controlled within the range of 455±5℃, the hot-dip galvanizing DV value is 85mm·m / min, and the zinc layer is smooth after being wiped evenly with an air knife. 6) After plating, the steel wire is immersed in a low-concentration phosphating bath with a total acidity of 50-60 Pt, free acid of 3-4 Pt, a temperature of 50-60℃, and a phosphating time of 135 s. This micro-phosphating process forms a thin phosphating film on the surface of the plating steel wire, with a film weight of 3 g / m². 2 .

[0021] 7) Finished product drawing: Finished product drawing process: 1.9mm→1.75mm→1.44mm→1.31mm→1.20mm→1.10mm→1.01mm→0.93mm→0.86mm→0.80mm→0.74mm→0.69mm; The last three drawing dies use special drawing dies, the sizing strip length d=0.6mm, the working cone angle is 9°, and special drawing powder for post-plating drawing is used to avoid the zinc layer from overheating and falling off during the drawing process.

[0022] The product has a steel wire diameter of 0.69mm, a tolerance of ±0.01, and a zinc weight of 92g / m. 2 It has a strength of 2160MPa, a torsion cycle of more than 26 times, and a bending cycle of more than 12 times.

[0023] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A manufacturing process for 95MnNbA steel wire used in ultra-high strength traction ropes, characterized in that, The specific steps are as follows: 1) The raw material is 95MnNbA steel wire rod, with the following chemical composition by mass percentage: C content 0.95%~1.0%, Si content 0.30%~0.33%, Mn content 0.79%~0.82%, and Nb content 0.02%~0.03%; 2) Semi-finished product drawing: During the drawing process, the wire drawing machine drum and die box are circulated with water cooling. The water cooling inlet temperature is less than 20℃, the die temperature is controlled below 90℃, and the wire drawing powder is sufficient to ensure adequate lubrication. 3) Heat treatment: Ensure the wire temperature is within the range of 935-945℃, the DV value is 35-45mm·m / min, the lead bath temperature is maintained within the range of 550-560℃, ensure that there is no slag at the outlet before and after the lead bath, no lead adhering to the surface of the steel wire, and that the sorbitization rate of the steel wire is greater than 95%; 4) After heat treatment, the steel wire is pickled. The concentration of hydrochloric acid during pickling is 170-200 g / L. After pickling, the hot water washing temperature is 60-70℃, and the concentration of ferrous chloride is controlled to be ≤100 g / L. 5) Hot-dip galvanizing: Before galvanizing, the surface of the steel wire is cleaned. After entering the zinc pot, the zinc temperature is controlled within the range of 450-460℃, the DV value is 80-90mm·m / min, and the zinc layer is smooth after being wiped evenly with an air knife. 6) After galvanizing, the steel wire is immersed in a low-concentration phosphating bath for micro-phosphating. The total acidity is 50-60 Pt, the free acid is 3-4 Pt, and the temperature is 50-60℃. After micro-phosphating, a thin phosphating film is formed on the surface of the galvanized steel wire, with a film weight of 2-4 g / m². 2 ; 7) Finished product drawing: The wire drawing machine uses 11 to 12 passes. The compression rate of the first pass is controlled at 15% to 17%, the total compression rate is controlled at 85% to 92%, and the average compression rate of all passes is controlled at 16% to 18%. The wire drawing dies for the last three passes use special wire drawing dies, the sizing strip length d≤0.6mm, the working cone angle is 8 to 9°, and special wire drawing powder for post-plating is used. During the drawing process, avoid the zinc layer from overheating and falling off.

2. The steel wire produced by the manufacturing process of 95MnNbA steel wire for ultra-high strength traction rope according to claim 1, characterized in that, The ultra-high strength traction rope uses 95MnNbA steel wire with a diameter of 0.5-0.8mm and a tensile strength of 2160-2260MPa.