High-toughness rare-earth steel drawn wire and method for manufacturing the same

Abstract

The application relates to the technical field of steel wire drawing, and discloses a high-strength and high-toughness rare earth steel drawing wire and a preparation method thereof. The preparation method of the high-strength and high-toughness rare earth steel drawing wire comprises the following steps: heat treating, hot rolling and cooling a wire rod to obtain pretreated wire rods; drawing, quenching and tempering the pretreated wire rods to obtain high-strength and high-toughness rare earth steel drawing wires; and the drawing comprises first drawing, second drawing, first annealing treatment, third drawing, fourth drawing, second annealing treatment, fifth drawing, sixth drawing and third annealing treatment in sequence. Through the technical scheme, the problem that the steel drawing wire in the prior art is insufficient in toughness while maintaining strength is solved.

Description

Technical Field

[0001] This invention relates to the field of steel wire drawing technology, specifically to a high-strength and tough rare earth steel drawing wire and its preparation method. Background Technology

[0002] While traditional steel drawn wires are widely used in various fields such as construction, machinery, and bridges, and are suitable for various basic working conditions, there are still many problems that need to be solved.

[0003] In existing technologies, the pursuit of high strength often leads to embrittlement of the matrix structure and a decrease in the toughness of the material. This makes it impossible for the material to meet the comprehensive requirements of impact resistance, fatigue resistance and load-bearing capacity in high-end scenarios, and it is difficult to meet the needs of practical applications. Summary of the Invention

[0004] This invention proposes a high-strength and high-toughness rare earth steel drawing wire and its preparation method, which solves the problem of insufficient toughness of steel drawing wire while maintaining strength in related technologies.

[0005] The technical solution of the present invention is as follows: This invention proposes a method for preparing high-strength and high-toughness rare-earth steel drawn wire, comprising the following steps: S1. Heat-treat, hot-roll, and cool the wire rod to obtain pretreated wire rod; S2. The pretreated wire rod is drawn, quenched, and tempered to obtain high-strength and high-toughness rare earth steel drawn wire. The drawing process includes, in sequence, a first drawing, a second drawing, a first annealing treatment, a third drawing, a fourth drawing, a second annealing treatment, a fifth drawing, a sixth drawing, and a third annealing treatment; The first drawing speed is 30~45mm / s; The second drawing rate is 50~65mm / s; The third drawing speed is 150~170mm / s; The fourth drawing speed is 190~210mm / s; The fifth drawing speed is 80~90mm / s; The sixth drawing speed is 60~70mm / s.

[0006] As a further technical solution, the temperature of the first drawing is 20~30℃, and the diameter of the steel wire is changed from 10mm to 7.9mm.

[0007] As a further technical solution, the temperature of the second drawing is 20~30℃, and the diameter of the steel wire is changed from 7.9mm to 6.3mm.

[0008] As a further technical solution, the temperature of the third drawing is 20~30℃, and the diameter of the steel wire is changed from 6.3mm to 5.0mm.

[0009] As a further technical solution, the temperature of the fourth drawing is 20~30℃, and the diameter of the steel wire is changed from 5.0mm to 3.9mm.

[0010] As a further technical solution, the temperature of the fifth drawing is 20~30℃, and the diameter of the steel wire changes from 3.9mm to 3.2mm.

[0011] As a further technical solution, the temperature of the sixth drawing is 20~30℃, and the diameter of the steel wire is changed from 3.2mm to 2.5mm.

[0012] As a further technical solution, the temperature of the first annealing treatment is 800~850℃, the holding time is 3~4h, and then it is cooled to room temperature.

[0013] As a further technical solution, the temperature of the second annealing treatment is 800~850℃, the holding time is 1~2h, and then it is cooled to room temperature.

[0014] As a further technical solution, the temperature of the third annealing treatment is 800~850℃, the holding time is 2~3h, and then it is cooled to room temperature.

[0015] As a further technical solution, the heat treatment temperature is 950~1050℃, and the holding time is 15~25min.

[0016] As a further technical solution, the hot rolling temperature is 900~1000℃.

[0017] As a further technical solution, the diameter of the pre-treated wire rod is 10mm.

[0018] As a further technical solution, the quenching temperature is 850~950℃, and the holding time is 1~2min.

[0019] As a further technical solution, the tempering temperature is 500~600℃, the holding time is 0.5~1h, and it is naturally cooled to room temperature.

[0020] As a further technical solution, the method for preparing the wire rod includes the following steps: A1. Melt raw materials other than RE to obtain molten steel, add RE to the molten steel and melt again to obtain rare earth steel molten steel; A2. The rare earth steel liquid is continuously cast and slowly cooled to obtain a billet; A3. The billet is heated, rolled, filaments are produced, and coiled to obtain wire rod.

[0021] As a further technical solution, the billet is composed of the following components by mass percentage: C 0.82%~0.90%, Si 0.25%~0.30%, Mn 0.85%~0.95%, Cr 0.13%~0.25%, P ≤0.008%, S ≤0.010%, N ≤0.018%, Zr 0.02%~0.05%, RE 0.015%~0.035%, with the balance being Fe and other unavoidable impurities.

[0022] As a further technical solution, the RE is Y and (La+Ce) with a mass ratio of 2:1.

[0023] In the composition of the steel billet of the present invention, Y can reduce the oxygen and sulfur content in the steel, creating conditions for La and Ce to better improve the morphology of inclusions. At the same time, the improved inclusion morphology of La and Ce further enhances the effect of Y in removing impurities.

[0024] As a further technical solution, the mass ratio of La to Ce is 1:2.

[0025] As a further technical solution, the billet is composed of the following components by mass percentage: C 0.82%~0.90%, Si 0.25%~0.30%, Mn 0.85%~0.95%, Cr 0.13%~0.25%, P ≤0.008%, S ≤0.010%, N ≤0.018%, Zr 0.02%~0.05%, RE 0.015%~0.035%, with the balance being Fe and other unavoidable impurities, wherein 0.05%≤Zr+RE≤0.06%.

[0026] In this invention, the range of the mass percentages of Zr and RE is further defined. At this point, Zr plays a role in refining the grains, forming a large number of grain boundaries, which provides more adsorption sites for various elements in RE. This is beneficial for RE to better remove impurities and improve the distribution of inclusions. At the same time, RE purifies the molten steel, reducing the interference of impurities on the grain refining effect of Zr. The two promote each other, making the steel grains finer and more uniform, and the inclusions more dispersed, thereby significantly improving the tensile strength of the steel wire.

[0027] As a further technical solution, the casting temperature of the continuous casting is 1450~1550℃.

[0028] As a further technical solution, the descaling pressure is 20~25MPa.

[0029] As a further technical solution, the slow cooling time is 45~50h.

[0030] As a further technical solution, the billet is a square billet with dimensions of 160mm × 160mm.

[0031] As a further technical solution, the heating temperature is 1100~1200℃ and the time is 60~90min.

[0032] As a further technical solution, the rolling temperature is 840~1030℃.

[0033] As a further technical solution, the temperature of the spinning process is 810~840℃.

[0034] As a further technical solution, the filament is cooled to room temperature at a cooling rate of 15~20℃ / s after spinning.

[0035] This invention also proposes a high-strength and high-toughness rare earth steel drawing wire, which is prepared by the aforementioned method.

[0036] The working principle and beneficial effects of this invention are as follows: In this invention, limiting the drawing rate of different drawing cycles improves the toughness of rare earth steel wire while maintaining its strength. At the first drawing rate, the wire rod has sufficient time for plastic deformation, avoiding the generation of internal defects. The second drawing further increases the drawing rate, forming a finer dislocation array. After annealing to relieve stress, a third drawing is performed. At this drawing rate, the grains are further refined, forming a larger grain boundary area, which hinders crack propagation. The fourth drawing further enhances the grain refinement effect, making the steel's crystal structure more regular, resulting in more effective stress transfer and reduced stress concentration. After the second annealing to relieve stress, the fifth and sixth drawing cycles appropriately reduce the drawing rate, further adjusting the internal stress of the steel and further improving its toughness. Detailed Implementation

[0037] 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 some embodiments of the present invention, and not all 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.

[0038] Example 1 The method for preparing wire rod includes the following steps: The raw materials other than RE are smelted to obtain molten steel. RE is added to the molten steel and smelted again to obtain rare earth steel. The rare earth steel molten steel was then continuously cast at a casting temperature of 1450℃ with a casting speed of 1.1 m / min. After slow cooling for 45 hours, a billet with dimensions of 160 mm × 160 mm was obtained. The billet was heated to 1100℃ and held for 90 minutes. Then, it underwent rough rolling (initial rolling temperature of 1030℃ and final rolling temperature of 980℃), finish rolling (initial rolling temperature of 950℃ and final rolling temperature of 860℃), and diameter reduction (initial rolling temperature of 850℃ and final rolling temperature of 840℃). After rolling, the wire was drawn at 840℃ and finally cooled to room temperature at a cooling rate of 15℃ / s. The wire was then coiled to obtain wire rod. The billet is composed of the following components by mass percentage: C 0.82%, Si 0.25%, Mn 0.85%, Cr 0.13%, P 0.006%, S 0.006%, N 0.016%, Zr 0.02%, RE 0.015%, with the balance being Fe and other unavoidable impurities; RE is Y and (La+Ce) in a mass ratio of 2:1; the mass ratio of La and Ce is 1:2. A method for preparing high-strength and high-toughness rare-earth steel drawn wire includes the following steps: The clean wire rod obtained by pickling with 10% hydrochloric acid and shot blasting is heat-treated at 950℃ for 25 minutes, and then hot-rolled at 900℃ in 6 passes of rough rolling, 6 passes of intermediate rolling, 2 to 6 passes of pre-finish rolling, 6 passes of finish rolling, and 2 to 4 passes of diameter reduction. It is then naturally cooled to room temperature to obtain the pre-treated wire rod. The pretreated wire rod underwent a first drawing process, with the drawing rate controlled at 30 mm / s and the temperature at 20℃, changing the wire diameter from 10 mm to 7.9 mm. A second drawing process was performed, with the drawing rate controlled at 50 mm / s and the temperature at 20℃, changing the wire diameter from 7.9 mm to 6.3 mm. Then, a first annealing treatment was carried out at 800℃ for 4 hours, followed by natural cooling to room temperature. A third drawing process was performed, with the drawing rate controlled at 150 mm / s and the temperature at 20℃, changing the wire diameter from 6.3 mm to 5.0 mm. A fourth drawing process was performed, with the drawing rate controlled at 190 mm / s and the temperature at 20℃, changing the wire diameter... The wire diameter was changed from 5.0 mm to 3.9 mm; then a second annealing treatment was performed at 800℃ for 2 hours, followed by natural cooling to room temperature; a fifth drawing was performed at a drawing rate of 80 mm / s and a temperature of 20℃, changing the wire diameter from 3.9 mm to 3.2 mm; then a sixth drawing was performed at a drawing rate of 60 mm / s and a temperature of 20℃, changing the wire diameter from 3.2 mm to 2.5 mm; finally, a third annealing treatment was performed at 800℃ for 3 hours, followed by natural cooling to room temperature; then quenched at 850℃ for 2 minutes, followed by tempering at 500℃ for 1 hour, to obtain high-strength and tough rare earth steel drawn wire.

[0039] Example 2 The method for preparing wire rod includes the following steps: The raw materials other than RE are smelted to obtain molten steel. RE is added to the molten steel and smelted again to obtain rare earth steel. The rare earth steel molten steel was then continuously cast at a casting temperature of 1550℃ with a casting speed of 1.1 m / min. After slow cooling for 50 hours, a billet with dimensions of 160 mm × 160 mm was obtained. The billet was heated to 1200℃ and held for 60 minutes. Then, it underwent rough rolling (initial rolling temperature of 1030℃, final rolling temperature of 980℃), finish rolling (initial rolling temperature of 950℃, final rolling temperature of 860℃), and diameter reduction (initial rolling temperature of 850℃, final rolling temperature of 840℃). After rolling, the wire was drawn at 810℃ and finally cooled to room temperature at a cooling rate of 20℃ / s. The wire was then coiled to obtain wire rod. The billet is composed of the following components by mass percentage: C 0.90%, Si 0.30%, Mn 0.95%, Cr 0.25%, P 0.008%, S 0.010%, N 0.018%, Zr 0.05%, RE 0.035%, with the balance being Fe and other unavoidable impurities; RE is Y and (La+Ce) in a mass ratio of 2:1; the mass ratio of La and Ce is 1:2. A method for preparing high-strength and high-toughness rare-earth steel drawn wire includes the following steps: The clean wire rod obtained by pickling with 10% hydrochloric acid and shot blasting is heat-treated at 1050℃ for 15 minutes, and then hot-rolled at 1000℃ in 6 passes of rough rolling, 6 passes of intermediate rolling, 2 to 6 passes of pre-finish rolling, 6 passes of finish rolling, and 2 to 4 passes of diameter reduction. It is then naturally cooled to room temperature to obtain the pre-treated wire rod. The pretreated wire rod underwent a first drawing process, with the drawing rate controlled at 45 mm / s and the temperature at 30℃, changing the wire diameter from 10 mm to 7.9 mm. A second drawing process was then performed, with the drawing rate controlled at 65 mm / s and the temperature at 30℃, changing the wire diameter from 7.9 mm to 6.3 mm. Next, a first annealing treatment was carried out at 850℃ for 3 hours, followed by natural cooling to room temperature. A third drawing process was performed, with the drawing rate controlled at 170 mm / s and the temperature at 30℃, changing the wire diameter from 6.3 mm to 5.0 mm. A fourth drawing process was performed, with the drawing rate controlled at 210 mm / s and the temperature at 30℃, changing the wire diameter... The diameter of the wire was changed from 5.0 mm to 3.9 mm; then it underwent a second annealing treatment at 850℃ for 1 hour, and was naturally cooled to room temperature; a fifth drawing was performed at a drawing rate of 90 mm / s and a temperature of 30℃, changing the wire diameter from 3.9 mm to 3.2 mm; then a sixth drawing was performed at a drawing rate of 70 mm / s and a temperature of 30℃, changing the wire diameter from 3.2 mm to 2.5 mm; finally, a third annealing treatment was performed at 850℃ for 2 hours, and then it was naturally cooled to room temperature; after that, it was quenched at 950℃ for 1 minute, and then tempered at 600℃ for 0.5 hours to obtain high-strength and tough rare earth steel drawn wire.

[0040] Example 3 The method for preparing wire rod includes the following steps: The raw materials other than RE are smelted to obtain molten steel. RE is added to the molten steel and smelted again to obtain rare earth steel. The rare earth steel molten steel was then continuously cast at a casting temperature of 1500℃ with a casting speed of 1.1 m / min. After slow cooling for 48 hours, a billet with dimensions of 160 mm × 160 mm was obtained. The billet was heated to 1150℃ and held for 75 minutes. Then, it underwent rough rolling (initial rolling temperature of 1030℃, final rolling temperature of 980℃), finish rolling (initial rolling temperature of 950℃, final rolling temperature of 860℃), and diameter reduction (initial rolling temperature of 850℃, final rolling temperature of 840℃). After rolling, the wire was drawn at 830℃ and finally cooled to room temperature at a cooling rate of 15℃ / s. The wire was then coiled to obtain wire rod. The billet is composed of the following components by mass percentage: C 0.85%, Si 0.28%, Mn 0.90%, Cr 0.20%, P 0.005%, S 0.008%, N 0.015%, Zr 0.045%, RE 0.03%, with the balance being Fe and other unavoidable impurities; RE is Y and (La+Ce) in a mass ratio of 2:1; the mass ratio of La and Ce is 1:2. A method for preparing high-strength and high-toughness rare-earth steel drawn wire includes the following steps: The clean wire rod obtained by pickling with 10% hydrochloric acid and shot blasting is heat-treated at 1000℃ for 20 minutes, and then hot-rolled at 950℃ in 6 passes of rough rolling, 6 passes of intermediate rolling, 2 to 6 passes of pre-finish rolling, 6 passes of finish rolling, and 2 to 4 passes of diameter reduction. It is then naturally cooled to room temperature to obtain the pre-treated wire rod. The pretreated wire rod underwent a first drawing process, with the drawing rate controlled at 40 mm / s and the temperature at 30℃, changing the wire diameter from 10 mm to 7.9 mm. A second drawing process was performed, with the drawing rate controlled at 55 mm / s and the temperature at 30℃, changing the wire diameter from 7.9 mm to 6.3 mm. Then, a first annealing treatment was carried out at 830℃ for 3.5 hours, followed by natural cooling to room temperature. A third drawing process was performed, with the drawing rate controlled at 160 mm / s and the temperature at 30℃, changing the wire diameter from 6.3 mm to 5.0 mm. A fourth drawing process was performed, with the drawing rate controlled at 200 mm / s and the temperature at 30℃, changing the wire diameter from 5 mm to 6.3 mm. The wire diameter was changed from 0.0 mm to 3.9 mm; then it underwent a second annealing treatment at 830℃ for 1.5 hours, and was naturally cooled to room temperature; a fifth drawing was performed at a drawing rate of 85 mm / s and a temperature of 30℃, changing the wire diameter from 3.9 mm to 3.2 mm; a sixth drawing was performed at a drawing rate of 65 mm / s and a temperature of 30℃, changing the wire diameter from 3.2 mm to 2.5 mm; finally, a third annealing treatment was performed at 830℃ for 2.5 hours, and then it was naturally cooled to room temperature; after that, it was quenched at 900℃ for 1.5 minutes, and then tempered at 550℃ for 45 minutes to obtain high-strength and tough rare earth steel drawn wire.

[0041] Example 4 The difference between this embodiment and Embodiment 3 lies only in that the billet is composed of the following components by mass percentage: C 0.85%, Si 0.28%, Mn 0.90%, Cr 0.20%, P 0.005%, S 0.008%, N 0.015%, Zr 0.035%, RE 0.025%, with the balance being Fe and other unavoidable impurities; RE is Y and (La+Ce) in a mass ratio of 2:1; and the mass ratio of La and Ce is 1:2.

[0042] Example 5 The difference between this embodiment and Embodiment 3 lies only in that the billet is composed of the following components by mass percentage: C 0.85%, Si 0.28%, Mn 0.90%, Cr 0.20%, P 0.005%, S 0.008%, N 0.015%, Zr 0.03%, RE 0.02%, with the balance being Fe and other unavoidable impurities; RE is Y and (La+Ce) in a mass ratio of 2:1; and the mass ratio of La and Ce is 1:2.

[0043] Example 6 The difference between this embodiment and Embodiment 3 lies only in that the billet is composed of the following components by mass percentage: C 0.85%, Si 0.28%, Mn 0.90%, Cr 0.20%, P 0.005%, S 0.008%, N 0.015%, Zr 0.02%, RE 0.015%, with the balance being Fe and other unavoidable impurities; RE is Y and (La+Ce) in a mass ratio of 2:1; and the mass ratio of La and Ce is 1:2.

[0044] Example 7 The difference between this embodiment and Embodiment 1 lies only in the method for preparing high-strength and high-toughness rare-earth steel drawn wire, which includes the following steps: The clean wire rod obtained by pickling with 10% hydrochloric acid and shot blasting is heat-treated at 950℃ for 25 minutes, and then hot-rolled at 900℃ in 6 passes of rough rolling, 6 passes of intermediate rolling, 2 to 6 passes of pre-finish rolling, 6 passes of finish rolling, and 2 to 4 passes of diameter reduction. It is then naturally cooled to room temperature to obtain the pre-treated wire rod. The pretreated wire rod underwent a first drawing process, with the drawing rate controlled at 45 mm / s and the temperature at 20℃, changing the wire diameter from 10 mm to 7.9 mm. A second drawing process was then performed, with the drawing rate controlled at 65 mm / s and the temperature at 20℃, changing the wire diameter from 7.9 mm to 6.3 mm. Next, a first annealing treatment was carried out at 800℃ for 4 hours, followed by natural cooling to room temperature. A third drawing process was performed, with the drawing rate controlled at 170 mm / s and the temperature at 20℃, changing the wire diameter from 6.3 mm to 5.0 mm. A fourth drawing process was performed, with the drawing rate controlled at 210 mm / s and the temperature at 20℃, changing the wire diameter... The wire diameter was changed from 5.0 mm to 3.9 mm; then a second annealing treatment was performed at 800℃ for 2 hours, followed by natural cooling to room temperature; a fifth drawing was performed at a drawing rate of 90 mm / s and a temperature of 20℃, changing the wire diameter from 3.9 mm to 3.2 mm; then a sixth drawing was performed at a drawing rate of 70 mm / s and a temperature of 20℃, changing the wire diameter from 3.2 mm to 2.5 mm; finally, a third annealing treatment was performed at 800℃ for 3 hours, followed by natural cooling to room temperature; then quenched at 850℃ for 2 minutes, followed by tempering at 500℃ for 1 hour, to obtain high-strength and tough rare earth steel drawn wire.

[0045] Comparative Example 1 The only difference between this comparative example and Example 1 is the method for preparing high-strength and high-toughness rare-earth steel drawn wire, which includes the following steps: The clean wire rod obtained by pickling with 10% hydrochloric acid and shot blasting is heat-treated at 950℃ for 25 minutes, and then hot-rolled at 900℃ in 6 passes of rough rolling, 6 passes of intermediate rolling, 2 to 6 passes of pre-finish rolling, 6 passes of finish rolling, and 2 to 4 passes of diameter reduction. It is then naturally cooled to room temperature to obtain the pre-treated wire rod. The pretreated wire rod underwent a first drawing process, with the drawing rate controlled at 50 mm / s and the temperature at 20℃, changing the wire diameter from 10 mm to 7.9 mm. A second drawing process was then performed, with the drawing rate controlled at 75 mm / s and the temperature at 20℃, changing the wire diameter from 7.9 mm to 6.3 mm. Next, a first annealing treatment was carried out at 800℃ for 4 hours, followed by natural cooling to room temperature. A third drawing process was performed, with the drawing rate controlled at 180 mm / s and the temperature at 20℃, changing the wire diameter from 6.3 mm to 5.0 mm. A fourth drawing process was performed, with the drawing rate controlled at 220 mm / s and the temperature at 20℃, changing the wire diameter... The wire diameter was changed from 5.0 mm to 3.9 mm; then a second annealing treatment was performed at 800℃ for 2 hours, followed by natural cooling to room temperature; a fifth drawing was performed at a drawing rate of 95 mm / s and a temperature of 20℃, changing the wire diameter from 3.9 mm to 3.2 mm; then a sixth drawing was performed at a drawing rate of 75 mm / s and a temperature of 20℃, changing the wire diameter from 3.2 mm to 2.5 mm; finally, a third annealing treatment was performed at 800℃ for 3 hours, followed by natural cooling to room temperature; then quenched at 850℃ for 2 minutes, followed by tempering at 500℃ for 1 hour, to obtain high-strength and tough rare earth steel drawn wire.

[0046] Comparative Example 2 The only difference between this comparative example and Example 1 is the method for preparing high-strength and high-toughness rare-earth steel drawn wire, which includes the following steps: The clean wire rod obtained by pickling with 10% hydrochloric acid and shot blasting is heat-treated at 950℃ for 25 minutes, and then hot-rolled at 900℃ in 6 passes of rough rolling, 6 passes of intermediate rolling, 2 to 6 passes of pre-finish rolling, 6 passes of finish rolling, and 2 to 4 passes of diameter reduction. It is then naturally cooled to room temperature to obtain the pre-treated wire rod. The pretreated wire rod underwent a first drawing process, with the drawing rate controlled at 25 mm / s and the temperature at 20℃, changing the wire diameter from 10 mm to 7.9 mm. A second drawing process was then performed, with the drawing rate controlled at 45 mm / s and the temperature at 20℃, changing the wire diameter from 7.9 mm to 6.3 mm. Next, a first annealing treatment was carried out at 800℃ for 4 hours, followed by natural cooling to room temperature. A third drawing process was performed, with the drawing rate controlled at 140 mm / s and the temperature at 20℃, changing the wire diameter from 6.3 mm to 5.0 mm. A fourth drawing process was performed, with the drawing rate controlled at 180 mm / s and the temperature at 20℃, changing the wire diameter... The wire diameter was changed from 5.0 mm to 3.9 mm; then a second annealing treatment was performed at 800℃ for 2 hours, followed by natural cooling to room temperature; a fifth drawing was performed at a drawing rate of 75 mm / s and a temperature of 20℃, changing the wire diameter from 3.9 mm to 3.2 mm; then a sixth drawing was performed at a drawing rate of 55 mm / s and a temperature of 20℃, changing the wire diameter from 3.2 mm to 2.5 mm; finally, a third annealing treatment was performed at 800℃ for 3 hours, followed by natural cooling to room temperature; then quenched at 850℃ for 2 minutes, followed by tempering at 500℃ for 1 hour, to obtain high-strength and tough rare earth steel drawn wire.

[0047] Experimental Example The tensile strength and elongation properties of the rare earth steel drawn wires prepared in Examples 1-7 and Comparative Examples 1-2 were tested according to the methods specified in GB / T 228.1-2021 "Metallic materials, tensile testing—Part 1: Test at room temperature"; the number of torsion cycles were tested according to the methods specified in GB / T10128-2007 "Metallic materials, torsion test at room temperature". The test results are shown in Table 1. Table 1. Test results of rare earth steel drawn wires prepared in Examples 1-7 and Comparative Examples 1-2

[0048] 1. Compared with Comparative Examples 1 and 2, the elongation of the rare earth steel drawn wires prepared in Examples 1 to 7 increased to 14.87% to 15.81%, and the number of torsion cycles increased to 48 to 54, indicating that controlling the drawing rate of different drawing cycles improved the toughness of the rare earth steel drawn wires; at the same time, the tensile strength of the rare earth steel drawn wires prepared in Examples 1 to 7 remained above 1369 MPa.

[0049] 2. Compared with Examples 3 to 6, the tensile strength of the rare earth steel drawn wires prepared in Examples 4 to 5 is increased to 1460 to 1464 MPa, indicating that when the mass of Zr and RE is between 0.05% and 0.06%, the strength of rare earth steel drawn wires can be further improved.

[0050] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing high-strength and high-toughness rare-earth steel drawn wire, characterized in that, Includes the following steps: S1. Heat-treat, hot-roll, and cool the wire rod to obtain pretreated wire rod; S2. The pretreated wire rod is drawn, quenched, and tempered to obtain high-strength and high-toughness rare earth steel drawn wire. The drawing process includes, in sequence, a first drawing, a second drawing, a first annealing treatment, a third drawing, a fourth drawing, a second annealing treatment, a fifth drawing, a sixth drawing, and a third annealing treatment; The first drawing speed is 30~45mm / s; The second drawing rate is 50~65mm / s; The third drawing speed is 150~170mm / s; The fourth drawing speed is 190~210mm / s; The fifth drawing speed is 80~90mm / s; The sixth drawing speed is 60~70mm / s.

2. The method for preparing high-strength and high-toughness rare-earth steel drawn wire according to claim 1, characterized in that, The temperature of the first drawing is 20~30℃, and the diameter of the steel wire changes from 10mm to 7.9mm; The temperature of the second drawing is 20~30℃, and the diameter of the steel wire changes from 7.9mm to 6.3mm; The temperature of the third drawing is 20~30℃, and the diameter of the steel wire changes from 6.3mm to 5.0mm; The temperature for the fourth drawing process is 20~30℃, and the diameter of the steel wire changes from 5.0mm to 3.9mm. The temperature for the fifth drawing process is 20~30℃, and the diameter of the steel wire changes from 3.9mm to 3.2mm; The temperature of the sixth drawing is 20~30℃, and the diameter of the steel wire changes from 3.2mm to 2.5mm.

3. The method for preparing high-strength and high-toughness rare-earth steel drawn wire according to claim 1, characterized in that, The first annealing treatment is performed at a temperature of 800~850℃, with a holding time of 3~4 hours, followed by cooling to room temperature; The second annealing process is carried out at a temperature of 800~850℃ for 1~2 hours, followed by cooling to room temperature. The third annealing process is carried out at a temperature of 800~850℃ for 2~3 hours, followed by cooling to room temperature.

4. The method for preparing high-strength and high-toughness rare-earth steel drawn wire according to claim 1, characterized in that, The heat treatment temperature is 950~1050℃, and the holding time is 15~25min; The hot rolling temperature is 900~1000℃; The diameter of the pre-treated wire rod is 10 mm; The quenching temperature is 850~950℃, and the holding time is 1~2min; The tempering temperature is 500~600℃, the holding time is 0.5~1h, and then it is cooled to room temperature.

5. The method for preparing high-strength and high-toughness rare-earth steel drawn wire according to claim 1, characterized in that, The method for preparing the wire rod includes the following steps: A1. Melt raw materials other than RE to obtain molten steel, add RE to the molten steel and melt again to obtain rare earth steel molten steel; A2. The rare earth steel liquid is continuously cast and slowly cooled to obtain a billet; A3. The billet is heated, rolled, filaments are produced, and coiled to obtain wire rod.

6. The method for preparing high-strength and high-toughness rare-earth steel drawn wire according to claim 5, characterized in that, The billet is composed of the following components by mass percentage: C 0.82%~0.90%, Si 0.25%~0.30%, Mn 0.85%~0.95%, Cr 0.13%~0.25%, P ≤0.008%, S ≤0.010%, N ≤0.018%, Zr 0.02%~0.05%, RE 0.015%~0.035%, with the balance being Fe and other unavoidable impurities.

7. The method for preparing high-strength and high-toughness rare-earth steel drawn wire according to claim 6, characterized in that, The billet is composed of the following components by mass percentage: C 0.82%~0.90%, Si 0.25%~0.30%, Mn 0.85%~0.95%, Cr 0.13%~0.25%, P ≤0.008%, S ≤0.010%, N ≤0.018%, Zr 0.02%~0.05%, RE 0.015%~0.035%, with the balance being Fe and other unavoidable impurities, wherein 0.05%≤Zr+RE≤0.06%.

8. The method for preparing high-strength and high-toughness rare-earth steel drawn wire according to claim 5, characterized in that, The casting temperature of the continuous casting is 1450~1550℃; The slow cooling time is 45-50 hours; The billet is a square billet with dimensions of 160mm × 160mm.

9. The method for preparing high-strength and high-toughness rare-earth steel drawn wire according to claim 5, characterized in that, The heating temperature is 1100~1200℃, and the time is 60~90min; The rolling temperature is 840~1030℃; The temperature at which the silk is spun is 810~840℃; After spinning, the material is cooled to room temperature at a rate of 15~20℃ / s.

10. A high-strength, high-toughness rare-earth steel drawing wire, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 9.

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