A vanadium-containing hot-rolled wire rod for port machinery steel wire rope, a production method thereof and a steel wire

Abstract

The present application relates to the technical field of wire rod production, and particularly relates to a vanadium-containing hot-rolled wire rod for port machinery steel wire rope, a production method thereof and a steel wire, wherein the vanadium-containing hot-rolled wire rod for port machinery steel wire rope comprises the following components in percentage by weight: C: 0.65% to 0.72%, Si: 0.17% to 0.35%, Mn: 0.40% to 0.60%, P: less than or equal to 0.020%, S: less than or equal to 0.020%, V: 0.02% to 0.04%, Cr: less than or equal to 0.10%, Ni: less than or equal to 0.05%, Cu: less than or equal to 0.05%, and the rest is Fe and inevitable impurities. The vanadium-containing hot-rolled wire rod for port machinery steel wire rope has a sorbite rate of greater than or equal to 90%, no center martensite and no grain boundary cementite, a tensile strength of greater than or equal to 1050 MPa, an elongation after fracture of greater than or equal to 15%, and a reduction of area of greater than or equal to 40%, and the wire rod can be used to prepare a steel wire with high strength and excellent torsional performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wire rod production, and particularly provides a high-performance vanadium-containing hot-rolled wire rod for port machinery steel wire rope and a production method thereof and a steel wire. BACKGROUND

[0002] With the continuous development of domestic and foreign transportation industry, the carrying capacity of port machinery steel wire rope is getting larger and larger, and the use frequency is getting higher and higher. Frequent replacement of steel wire rope will have a great impact on the operation efficiency of the port machinery. In combination with the characteristics of the port machinery hoisting equipment, such as large lifting capacity, high operation rate, and high rope replacement cost, the port machinery equipment puts forward higher requirements on the toughness, bending, torsion performance, and service life of the wire rod. At present, the material used for the wire rod is usually high-quality carbon steel hot-rolled wire rod, mainly 65# and 70#. However, when the steel wire rope made of ordinary carbon steel hot-rolled wire rod is used in port machinery equipment, the steel wire rope is prone to problems such as frequent wire breakage under the action of complex alternating stress, which cannot meet the requirement of long service life. This is because, due to the differences in temperature and cooling speed between the surface and the core of the wire rod after rolling, as well as the influence of chemical composition segregation and other factors, serious abnormal structures such as martensite and grain boundary cementite appear in the core of the wire rod, which greatly affects the performance of the wire rod.

[0003] Therefore, the prior art still needs to be improved. SUMMARY

[0004] In view of the low strength and torsion performance of the carbon steel hot-rolled wire rod, a small amount of vanadium element is added to the carbon steel, the heating system of the bloom and the cooling system of the hot-rolled wire rod are adjusted, the dispersion precipitation strengthening and solid solution strengthening effects of vanadium carbide and nitride are fully utilized, and the temperature difference between the surface and the core of the wire rod is reduced. The wire rod can be used to prepare a high-strength and torsion-resistant steel wire for port machinery.

[0005] Specifically, according to a first aspect of the present application, a vanadium-containing hot-rolled wire rod for port machinery steel wire rope is provided, which comprises the following components by weight percentage: C: 0.65% to 0.72%, Si: 0.17% to 0.35%, Mn: 0.40% to 0.60%, P≤0.020%, S≤0.020%, V: 0.02% to 0.04%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%; the rest is Fe and inevitable impurities.

[0006] According to a second aspect of the present invention, a method for producing vanadium-containing hot-rolled wire rod for port machinery wire rope is provided, comprising the following steps: a. heating a steel billet comprising the following components by weight percentage: C: 0.65%–0.72%, Si: 0.17%–0.35%, Mn: 0.40%–0.60%, P≤0.020%, S≤0.020%, V: 0.02%–0.04%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%; the remainder being Fe and unavoidable impurities; b. performing wire rolling and wire-spinning operations on the heated steel billet; c. cooling the wire-spinned wire rod; and d. coiling and packaging the cooled wire rod to obtain the vanadium-containing hot-rolled wire rod for port machinery wire rope.

[0007] In an embodiment of the present invention, in step a, the steel billet is a square billet, the temperature of the soaking zone during heating is 1150~1220℃, and the heating time satisfies the following formula:

[0008] t=(0.7~1.2)H

[0009] Where H is the billet thickness in mm and t is the heating time in min.

[0010] In an embodiment of the present invention, step b, the wire rod rolling includes rough rolling, intermediate rolling, pre-finish rolling and finish rolling of the heated steel billet, and the wire rod wire drawing temperature is 870-890°C and the wire drawing speed is 30-35 m / s.

[0011] In an embodiment of the present invention, step c includes: cooling the coil after spinning using a Stellmore cooling line, and by matching the speed of the fan and the roller conveyor, cooling the coil to 560-600°C at a cooling rate of ≥15°C / s after rolling, and then reducing the cooling rate to 2-5°C / s.

[0012] In an embodiment of the present invention, step c further includes: performing segmented controlled cooling of the coiled wire after spinning on a Steyrmo air-cooling line, wherein the cooling rate of the coil is controlled by controlling the opening value of the fan and the speed of the air-cooling roller conveyor on the Steyrmo air-cooling line.

[0013] In an embodiment of the present invention, the speed of the inlet roller conveyor of the Steyrmore air-cooling line is 0.65 to 0.72 m / s, and the speed of the roller conveyor corresponding to the subsequent air-cooling line is gradually increased, with the speed of the last roller conveyor being 0.80 to 0.92 m / s; the first part of the fans in the Steyrmore air-cooling line is 100% open with an air volume of 200,000 m3 / h, the second part of the fans in the Steyrmore air-cooling line is 70% to 90% open, the third part of the fans in the Steyrmore air-cooling line is closed, and all the insulation covers are open.

[0014] In an embodiment of the present invention, the operating value of the air-cooled line 1 to 4# fans of the Stellmore air-cooled line is 100%, the air volume is 200,000 m3 / h, the operating value of the air-cooled line 5 to 11# fans is 70% to 90%, the air-cooled line 12 to 14# fans are closed, and the insulation cover is fully open.

[0015] In an embodiment of the present invention, the vanadium-containing hot-rolled wire rod for the port machinery wire rope in step d has a sorbite content ≥90%, no core martensite, grain boundary cementite ≤0.5 grade, tensile strength ≥1050MPa, elongation after fracture ≥15%, and reduction of area ≥40%.

[0016] According to a third aspect of the present invention, a steel wire is provided, which is made from the aforementioned port machinery wire rope using vanadium-containing hot-rolled wire rod, the steel wire having a diameter of 0.95mm to φ1.25mm, a twisting time of ≥40 times, a bending time of ≥25 times, and a tensile strength of ≥1920MPa.

[0017] The vanadium-containing hot-rolled wire rod for port machinery wire ropes described in this invention and its production method can produce steel wires with high toughness, good bending and torsional properties, and a long service life. The product quality fully meets the relevant technical requirements and user requirements, and has good prospects for promotion and application. Attached Figure Description

[0018] Figure 1 The diagram shows a process flow chart of a method for producing vanadium-containing hot-rolled wire rod for port machinery wire ropes provided by the present invention. Detailed Implementation

[0019] It should be understood that the embodiments of the invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the invention. Accordingly, all such modifications should be included within the scope of the invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the invention.

[0020] According to a first aspect of the present invention, a vanadium-containing hot-rolled wire rod for port machinery wire rope is provided, comprising the following components by weight percentage: C: 0.65%–0.72%, Si: 0.17%–0.35%, Mn: 0.40%–0.60%, P≤0.020%, S≤0.020%, V: 0.02%–0.04%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%; the remainder being Fe and unavoidable impurities.

[0021] According to a second aspect of the present invention, a method for producing vanadium-containing hot-rolled wire rod for port machinery wire ropes is provided, such as... Figure 1 As shown, it includes the following steps:

[0022] a. A steel billet comprising the following weight percentages is heated: C: 0.65%–0.72%, Si: 0.17%–0.35%, Mn: 0.40%–0.60%, P≤0.020%, S≤0.020%, V: 0.02%–0.04%, Cr≤0.10%, Ni≤0.05%, Cu≤0.05%; the remainder being Fe and unavoidable impurities;

[0023] b. Perform wire rod rolling and wire rod wire cutting operations on the heated steel billet;

[0024] c. Cooling the coiled wire after spinning; and

[0025] d. After cooling, the wire rod is coiled and packaged to obtain the vanadium-containing hot-rolled wire rod for port machinery wire rope.

[0026] In an embodiment of the present invention, in step a, the steel billet is a square billet, the wire rod is produced using square billets, the soaking temperature during heating is 1150~1220℃, and the heating time satisfies the following formula:

[0027] t=(0.7~1.2)H

[0028] Where H is the billet thickness in mm and t is the heating time in min.

[0029] In an embodiment of the present invention, step b, the wire rod rolling includes rough rolling, intermediate rolling, pre-finishing rolling, and finish rolling of the heated steel billet. Specifically, after heating, the billet is descaled by high-pressure water, rolled by a 30-stand high-speed wire rod mill, and then wired by a wire rod mill to obtain high-performance vanadium-containing hot-rolled wire rod for port machinery wire ropes. After finish rolling, the inlet water flow rate of the water tank is ≥50 m³ / h, the outlet water pressure is ≥3.5 bar, the wire rod temperature is 870~890℃, and the wire rod speed is 30~35 m / s.

[0030] In an embodiment of the present invention, step c includes: cooling the wire rod after coiling using a Stellmore cooling line, and by matching the speed of the fan and the roller conveyor, cooling the wire rod to 560-600°C at a cooling rate of ≥15°C / s after rolling to avoid the precipitation of preeutectoid ferrite, and then reducing the cooling rate to 2-5°C / s to allow it to fully and uniformly transform into a sorbite + a small amount of pearlite structure.

[0031] In an embodiment of the present invention, step c further includes: performing segmented controlled cooling of the coiled wire after coiling on a Steyrmo air-cooling line, wherein the cooling rate of the coil is controlled by controlling the operating value of the fans and the speed of the air-cooling roller conveyor on the Steyrmo air-cooling line. The air-cooling line includes roller conveyors and fans. After hot rolling and coiling, the coil travels on the roller conveyor, and there are fans below the roller conveyor. By turning on different roller conveyor speeds and fan air volumes, different cooling rates are achieved to obtain products that meet performance requirements. There are usually no fans below the inlet roller conveyor of the air-cooling line (hereinafter referred to as the first section roller conveyor), while there are usually two fans below the other sections of the roller conveyor.

[0032] In an embodiment of the present invention, the speed of the inlet roller conveyor of the Steyrmore air-cooling line is 0.65 to 0.72 m / s, and the speed of the roller conveyor corresponding to the subsequent air-cooling line is gradually increased, with the speed of the last roller conveyor being 0.80 to 0.92 m / s; the first part of the fans in the Steyrmore air-cooling line is 100% open with an air volume of 200,000 m3 / h, the second part of the fans in the Steyrmore air-cooling line is 70% to 90% open, the third part of the fans in the Steyrmore air-cooling line is closed, and all the insulation covers are open.

[0033] In an embodiment of the present invention, after spinning, the wire rod undergoes segmented controlled cooling on a Stellmore air-cooling line. The air-cooling line has 14 fans, numbered 1# to 14#. The cooling rate of the wire rod is controlled by adjusting the fan operating values ​​and the speed of the air-cooling roller conveyor. The specific controlled cooling process is as follows:

[0034] 1) Speed ​​control requirements for air-cooled roller conveyors: The speed of the first section of the roller conveyor is 0.65 to 0.72 m / s, increasing gradually, with the speed of the last section being 0.80 to 0.92 m / s;

[0035] 2) Fan operation requirements: Fans 1 to 4# are 100% open with an air volume of 200,000 m3 / h; Fans 5 to 11# are 70% to 90% open; Fans 12 to 14# are closed; and all insulation covers are open.

[0036] 3) By matching the speed of the fan and roller conveyor in the Stellmore air-cooling line after rolling, the temperature is first cooled to 560-600℃ at a cooling rate of ≥15℃ / s to avoid the precipitation of proeutectoid ferrite as much as possible, promote the precipitation of V, and increase the nucleation driving force, thereby obtaining a higher sorbite ratio, as well as fine pearlite clusters and lamellar spacing; then the cooling rate is reduced to 2-5℃ / s to allow it to fully and uniformly transform into a sorbite + a small amount of pearlite structure.

[0037] In an embodiment of the present invention, the vanadium-containing hot-rolled wire rod used for the port machinery wire rope in step d has a sorbite content ≥90%, no core martensite, grain boundary cementite ≤0.5 grade, tensile strength ≥1050MPa, elongation after fracture ≥15%, and reduction of area ≥40%. The steel wire made from this wire rod exhibits significantly improved torsional properties, increased average number of bends, and increased Rm by more than 10MPa.

[0038] According to a third aspect of the present invention, a steel wire is provided, which is made of vanadium-containing hot-rolled wire rod from the port machinery wire rope described in the foregoing embodiments, having a diameter of 0.95mm to φ1.25mm, a twisting time of ≥40 times, a bending time of ≥25 times, and a tensile strength of ≥1920Mpa.

[0039] The present invention will be described in detail below with reference to the embodiments. It should be noted that the embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above-described invention.

[0040] Example 1

[0041] A metal products company obtained the following by using the method described in this invention: The production process for high-performance port machinery wire ropes with vanadium-containing hot-rolled wire rods is as follows: billet is heated in a walking beam furnace → rolled by a high-speed wire rod mill → wire is spun out by a wire spinner → cooled by a Steyrmo air-cooling line → coiled by a coiler → packaged.

[0042] Specifically, a 200mm × 200mm square billet with the following composition is first heated in a walking beam furnace: C: 0.70%, Si: 0.26%, Mn: 0.56%, P: 0.011%, S: 0.009%, V: 0.02%, Cr: 0.02%, Ni: 0.03%, Cu: 0.04%, with the remainder being Fe and unavoidable impurities. The billet is then subjected to a soaking in a heating zone at 1185℃ for 209 minutes. After descaling with high-pressure water, it is rolled into a 30-stand high-speed wire rod mill. The standard-sized round wire is spun into wire by a wire spinning machine, with an actual spinning temperature of 885℃.

[0043] After spinning, the wire rod undergoes controlled cooling on the Steyrmore air-cooled line. The control parameters of the Steyrmore air-cooled line are as follows:

[0044] 1) Speed ​​control requirements for air-cooled roller conveyor: The speed of the first section of the roller conveyor is 0.7 m / s, increasing gradually to 0.86 m / s for the last section;

[0045] 2) Fan operation requirements: Fans 1-4# are 100% open, fans 5-8# are 90% open, fans 9-11# are 80% open, and fans 12-14# are closed; all insulation covers are open.

[0046] 3) By matching the speed of the fan and roller conveyor of the Stellmore air-cooling line after rolling, the outlet temperature of fan #4 is 580℃, and the actual cooling rate is 17℃ / s.

[0047] The above methods were used to obtain... High-performance port machinery wire ropes made from vanadium-containing hot-rolled wire rods have a pearlitic microstructure, with 90% sorbite, and a martensitic microstructure lacking grain boundaries; the tensile strength is 1055 MPa, the reduction of area is 47%, and the elongation after fracture is 19%; products made from this wire rod... The steel wire has a strength of 1920 MPa, a torsion count of 42, and an average bending count of 29.

[0048] Example 2

[0049] A metal products company obtained the following by using the method described in this invention: The production process for high-performance port machinery wire ropes with vanadium-containing hot-rolled wire rods is as follows: billet is heated in a walking beam furnace → rolled on a high-speed wire rod mill → wire is spun on a wire rod mill → cooled on a Steyrmo air-cooling line → coiled by a coiler → packaged.

[0050] Specifically, a 160mm × 160mm square billet with the following chemical composition is first heated in a walking beam furnace: C: 0.69%, Si: 0.25%, Mn: 0.55%, P: 0.012%, S: 0.010%, V: 0.03%, Cr: 0.02%, Ni: 0.03%, Cu: 0.05%, with the remainder being Fe and unavoidable impurities. The billet is then subjected to a soaking in a 1150℃ heating zone for 130 minutes. After descaling with high-pressure water, it is rolled into a 30-stand high-speed wire rod mill. The standard-sized round wire is spun into wire by a wire spinning machine, with an actual spinning temperature of 870℃.

[0051] After spinning, the wire rod undergoes controlled cooling on the Steyrmo air-cooled line, with a rated airflow of 2 × 10⁻⁶ fans. 5 m 3 The control parameters for the Stellmore air-cooled line are as follows: / h

[0052] 1) Speed ​​control requirements for air-cooled roller conveyor: The speed of the first section of the roller conveyor is 0.66 m / s, increasing gradually to 0.80 m / s for the last section;

[0053] 2) Fan operation requirements: Fans 1-4# are 100% open, fans 5-8# are 80% open, fans 9-11# are 70% open, fans 12-14# are closed, and all insulation covers are open.

[0054] 3) By matching the speed of the fan and roller conveyor of the Stellmore air-cooling line after rolling, the outlet temperature of fan #4 is 560℃, and the actual cooling rate is 15℃ / s.

[0055] The above methods were used to obtain... High-performance port machinery wire ropes made from vanadium-containing hot-rolled wire rods have a pearlitic microstructure, with 95% sorbite and no grain boundary cementite or martensite; tensile strength is 1050 MPa, reduction of area is 42%, and elongation after fracture is 16%; products made from this wire rod... The steel wire has a strength of 1925 MPa, a torsion cycle of 40 times, and a bending cycle of 27 times.

[0056] Example 3

[0057] A metal products company obtained the following by using the method described in this invention: The production process for high-performance port machinery wire ropes with vanadium-containing hot-rolled wire rods is as follows: billet is heated in a walking beam furnace → rolled on a high-speed wire rod mill → wire is spun on a wire rod mill → cooled on a Steyrmo air-cooling line → coiled by a coiler → packaged.

[0058] Specifically, a 200mm × 200mm square billet with the following chemical composition is first heated in a walking beam furnace: C: 0.72%, Si: 0.32%, Mn: 0.52%, P: 0.011%, S: 0.009%, V: 0.04%, Cr: 0.05%, Ni: 0.05%, Cu: 0.05%, with the remainder being Fe and unavoidable impurities. The billet is then subjected to a soaking in a 1220℃ heating zone for 240 minutes. After descaling with high-pressure water, it is rolled into a 30-stand high-speed wire rod mill. The standard-sized round wire is spun into wire by a wire spinning machine, with an actual spinning temperature of 890℃.

[0059] After spinning, the wire rod undergoes controlled cooling on the Steyrmore air-cooled line. The control parameters of the Steyrmore air-cooled line are as follows:

[0060] 1) Speed ​​control requirements for air-cooled roller conveyor: The speed of the first section of the roller conveyor is 0.72m / s, increasing gradually to 0.92m / s for the last section;

[0061] 2) Fan operation requirements: Fans 1-4# are 100% open, fans 5-8# are 90% open, fans 9-11# are 70% open, and fans 12-14# are closed; all insulation covers are open.

[0062] 3) By matching the speed of the fan and roller conveyor of the Stellmore air-cooling line after rolling, the outlet temperature of fan #4 is 600℃ and the actual cooling rate is 18℃ / s.

[0063] The above methods were used to obtain... High-performance port machinery wire ropes made from vanadium-containing hot-rolled wire rods have a pearlitic microstructure, with 90% sorbite, and are free of grain boundary cementite and martensite. They possess a tensile strength of 1060 MPa, a reduction of area of ​​51%, and an elongation at break of 19%. Products made from this wire rod... The steel wire has a strength of 1945 MPa, a torsion cycle of 43 times, and a bending cycle of 30 times.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications or equivalent substitutions made to the present invention without departing from the spirit and scope thereof should be covered within the protection scope of the claims of the present invention.

Claims

1. A method for producing vanadium-containing hot-rolled wire rod for port machinery wire rope, characterized in that, Includes the following steps: a. A steel billet comprising the following weight percentages is heated: C: 0.65%–0.72%, Si: 0.17%–0.35%, Mn: 0.40%–0.60%, P≤0.020%, S≤0.020%, V: 0.02%–0.04%, 0.02≤Cr≤0.10%, 0.03≤Ni≤0.05%, 0.04≤Cu≤0.05%; the remainder being Fe and unavoidable impurities. The steel billet is a square billet, and the soaking temperature during heating is 1150–1220℃. The heating time satisfies the following formula: t = (0.7–1.2 min / mm)H, where H is the thickness of the square billet in mm; t is the heating time in min. b. Perform wire rod rolling and wire rod wire stripping operations on the heated steel billet; c. The Stellmore cooling line is used to cool the coiled wire after spinning. The speed of the inlet roller conveyor of the Stellmore air-cooling line is 0.65~0.72m / s, and the speed of the roller conveyor in subsequent sections increases gradually, with the speed of the last section reaching 0.80~0.92m / s. The first section of fans in the Stellmore air-cooling line is operated at 100% capacity with an air volume of 200,000 m³ / s. 3 / h, the second section of fans in the Steyrmore air-cooled line operates at 70%–90% capacity, the third section of fans in the Steyrmore air-cooled line is off, and all insulation covers are open; and d. The cooled wire rod is coiled and packaged to obtain the vanadium-containing hot-rolled wire rod for port machinery wire rope. Step c includes: matching the speed of the fan and the roller conveyor so that the wire rod is cooled to 560-600°C at a cooling rate of ≥15°C / s after rolling, and then the cooling rate is reduced to 2-5°C / s.

2. The production method of vanadium-containing hot-rolled wire rod for port machinery wire rope according to claim 1, characterized in that, In step b, the wire rod rolling includes rough rolling, intermediate rolling, pre-finish rolling and finish rolling of the heated steel billet, and the wire rod wire drawing temperature is 870-890℃ and the wire drawing speed is 30-35m / s.

3. The production method of vanadium-containing hot-rolled wire rod for port machinery wire rope according to claim 1, characterized in that, Step c further includes: performing segmented controlled cooling of the coiled wire after spinning on the Steyrmo air-cooling line, wherein the cooling rate of the coil is controlled by controlling the opening value of the fan and the speed of the air-cooling roller conveyor on the Steyrmo air-cooling line.

4. The method for producing vanadium-containing hot-rolled wire rod for port machinery wire rope according to claim 1, characterized in that, The operating rate of fans 1-4 of the Stellmore air-cooled line is 100%, with an air volume of 200,000 m3 / h. The operating rate of fans 5-11 is 70%-90%. Fans 12-14 of the air-cooled line are turned off, and all insulation covers are opened.

5. The method for producing vanadium-containing hot-rolled wire rod for port machinery wire rope according to claim 1, characterized in that, The vanadium-containing hot-rolled wire rods used for port machinery wire ropes in step d have a sorbite content of ≥90%, no core martensite, grain boundary cementite grade ≤0.5, tensile strength ≥1050MPa, elongation after fracture ≥15%, and reduction of area ≥40%.

6. A vanadium-containing hot-rolled wire rod for port machinery wire rope, produced by a method according to any one of claims 1-5.

7. A steel wire, characterized in that, The port machinery wire rope as described in claim 6 is made of vanadium-containing hot-rolled wire rod, with a diameter of φ0.95mm~φ1.25mm, a torsion count ≥40 times, a bending count ≥25 times, and a tensile strength ≥1920Mpa.

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