A 1960mpa grade steel wire rod and its preparation method and application

Abstract

The application belongs to the technical field of galvanized steel materials, and particularly relates to a 1960MPa-grade steel wire rod and a preparation method and application thereof. The steel wire rod comprises the following chemical components in percentage by mass: C 0.80-0.83%; Si 0.45-0.60%; Mn 0.45-0.55%; Ti 0.01-0.03%; V 0.01-0.03%; N 0.005-0.008%; and the balance of iron and inevitable impurities. The application adjusts the contents of C, Si, Mn and V and cooperates the overall scheme, so that the strength and surface reduction of the steel wire rod are improved while the hardenability is basically unchanged. The steel wire rod produced by the method can produce the galvanized steel wire with the strength of 1960MPa under the premise that the total compression rate is not higher than 90%. The problems that the steel wire has poor plasticity when the 82B steel wire rod is used to produce the 1960MPa-grade steel wire and the hardenability is too high when other higher-strength steel wire rods are used are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of galvanized steel materials, and particularly relates to a 1960MPa-grade wire rod for steel wire and a preparation method and application thereof. BACKGROUND

[0002] At present, the strength of steel wire for ocean engineering (marine engineering) generally reaches the 1960MPa level. The marine steel wire not only requires high strength, but also requires good plasticity and low hardenability of the steel wire. When the steel wire is used as a towing rope in seawater, it is inevitable to rub against reefs and the like. If the steel wire has high hardenability, the deformed martensite is easily generated on the surface of the steel wire, leading to failure of the steel wire.

[0003] At present, the 1960MPa-grade high-strength steel wire is mainly produced by using 82B wire rod. The components and weight percentage content of the 82B wire rod are generally as follows: C: 0.80-1.84%, Si: 0.15%-0.35%, Mn: 0.6-0.9%, Cr: 0.1-0.2%, and the rest is residual element. However, the strength of the 82B wire rod is not high, and the strength is generally 1250-1300MPa after heat treatment. The strength of the 1960MPa-grade galvanized steel wire is usually improved by increasing the compression rate of the steel wire or increasing the strength of the original wire rod. By increasing the compression rate of the steel wire, the total deformation is generally more than 92%. When the total compression rate of the 82B wire rod exceeds 90%, the plasticity of the wire rod will obviously decrease. By increasing the total compression rate during drawing, the strength of the steel wire is ensured, but the plasticity of the steel wire is poor, and the service life is low. In addition, the single wire twist of the 1960MPa-grade galvanized steel wire produced by using the 82B wire rod usually fluctuates between 3-20 times, which is unstable and cannot meet the requirement of more than 13 twists. If a higher strength wire rod is used, alloying is usually required, but conventional alloying will increase the hardenability of the wire rod.

[0004] The existing patent document discloses a 1960MPa grade galvanized steel wire for ocean engineering, the C, Si and Mn in the steel are respectively adjusted to 0.87-0.91%, 0.15-0.30% and 0.65-0.85%, the P and S in the steel are respectively reduced to below 0.015% and 0.010%, the contents of Ni, Cu and Al are respectively controlled to be less than 0.05%, 0.10% and 0.010%, the content of H is controlled to be less than 1.0ppm, the Cr and V alloy elements are respectively added to 0.15-0.25% and 0.020-0.060% to further improve the strength; the reticular cementite and martensite are avoided by optimizing the refining, continuous casting and rolling processes, the sorbitizing rate is above 90%, and the strength loss of the steel wire during hot galvanizing is greatly reduced; the production process is stable and reliable, is suitable for large-scale industrial production, the tensile strength of the galvanized steel wire is greater than 1960MPa, the torsion times are greater than 25 times, and the bending times are greater than 8 times. The document solves the problems of the strength and plasticity of the steel wire by controlling the contents of C, Si, Mn and Cr, V and the like, but the problem of high hardenability caused thereby is not solved. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to overcome the defects that the strength, plasticity and hardenability of the 1960MPa grade galvanized steel wire for ocean engineering in the prior art cannot meet the use requirements at the same time, so as to provide a 1960MPa grade steel wire rod and a preparation method and application thereof.

[0006] To this end, the present application provides the following technical scheme:

[0007] The present application provides a 1960MPa grade steel wire rod, which comprises the following mass percentage of chemical components: C 0.80-0.83%; Si 0.45-0.60%; Mn 0.45-0.55%; Ti 0.01-0.03%; V 0.01-0.03%; N 0.005-0.008%; and the balance is iron and inevitable impurities.

[0008] In some optional embodiments, the mass percentage requirements of some impurities include: S≤0.005%, P≤0.012%, Cu≤0.07%, Ni≤0.07%, O≤0.0015%.

[0009] In some optional embodiments, the diameter of the steel wire rod is 7-9mm, the tensile strength Rm is≥1320MPa, and the reduction of area Z is≥42%.

[0010] The present application also provides a preparation method of the above-mentioned 1960MPa grade steel wire rod, which comprises the following steps: converter or electric furnace smelting→ external refining→ square billet continuous casting→ high-speed wire rolling→ Stelmor cooling.

[0011] In some alternative embodiments, the converter or electric furnace smelting process controls the tapping temperature to be 1580-1610 DEG C, controls C: 0.10-0.45% and P≤100ppm in mass percentage; a deoxidizer is added when tapping to 1 / 4-1 / 3, and tapping is avoided to avoid slagging;

[0012] And / or, the secondary refining process is designed according to the chemical composition to perform alloying treatment, the refining temperature is 1522-1532 DEG C, and the slag is controlled during the refining process, so that the binary basicity of the slag is 2.7-2.9;

[0013] And / or, the bloom continuous casting process starts casting with a superheat of ≤30 DEG C, controls the casting speed to be 2.6-2.8 m / min, and controls the specific water amount to be 1.8-2.0 L / kg; alternatively, the superheat is 10-30 DEG C;

[0014] And / or, the high-speed wire rolling process controls the soaking segment temperature before hot rolling to be 1180-1200 DEG C, the air-fuel ratio of the soaking segment is less than 0.60, the rolling-in temperature is 1035-1065 DEG C, the finishing rolling temperature is 950-980 DEG C, and the wire drawing temperature is 840-860 DEG C;

[0015] And / or, the Stelmor cooling process controls the cooling speed before pearlite phase transformation to be more than 16 K / s, and alternatively, the cooling speed is 16-25 K / s.

[0016] The application further provides a 1960MPa-grade steel wire prepared from the above-described wire rod or the wire rod prepared by the above-described method.

[0017] In the application, the preparation method of the 1960MPa-grade steel wire is conventional in the field, and in some alternative embodiments, the preparation process of the 1960MPa-grade steel wire comprises lead bath or salt bath heat treatment, multi-pass drawing, and galvanizing, and alternatively, further comprises some steps such as pickling, phosphating, degreasing, and alkaline cleaning, and further comprises a step of twisting into a rope after hot galvanizing.

[0018] In some alternative embodiments, the diameter of the steel wire is 2.5-3.5 mm, the tensile strength reaches more than 1960MPa, the torsion frequency reaches more than 18 times, the critical cooling speed of martensite is more than 20 K / s, and the steel wire is not prone to failure caused by phase transformation martensite on the surface of the steel wire when used as a towing rope in seawater.

[0019] The application further provides an application of the above-described 1960MPa-grade steel wire in marine engineering.

[0020] The following specifically describes the role and principle of each element:

[0021] C is the most basic strengthening element in steel, and the strength of the wire rod increases by about 10 MPa for every 0.01% increase in C content, but excessive C promotes the precipitation of pro-eutectoid cementite at the center of segregation, and in severe cases, forms a network of cementite, reducing the plasticity of the wire rod and causing wire drawing breakage. Meanwhile, an increase in carbon content significantly increases the hardenability of the steel. In the present application, the C content is limited to a range of 0.80-0.83%.

[0022] Si is a ferrite strengthening element that can increase the strength of ferrite through solid solution strengthening, and is also an important deoxidizer that helps to reduce the oxygen content in the steel and reduce inclusions. In addition, the enrichment of Si at the ferrite / cementite interface helps to prevent the decomposition of cementite during hot galvanizing and stabilization treatment, improving the thermal stability during processing. The appropriate addition of Si has little effect on the hardenability of the wire rod and does not substantially change the start and end temperatures of the martensite. In the present application, the Si content is selected in a range of 0.45-0.60%.

[0023] Mn is mainly used in steel to increase the strength of the steel, while increasing the stability of austenite and reducing the phase transition temperature. Meanwhile, Mn can change the composition of sulfides and reduce the harmful effects of S, but if the Mn content is too high, it will increase the hardenability of the wire rod and affect the drawing deformation of the steel wire. Therefore, in the present application, the Mn content is controlled in a range of 0.40-0.50%.

[0024] Ti easily combines with N in steel to form carbon nitride. By controlling the nitrogen content in the steel and the continuous casting process, the size of the precipitated TiN can be controlled. Dispersed fine TiN can play a role in refining the austenite grain size.

[0025] V is a strong carbide-forming element, and V easily forms VC particles on the austenite grain boundaries at the initial stage of phase transition, thereby reducing the content of C elements on the grain boundaries and effectively inhibiting the formation of network cementite. In addition, V precipitates between the ferrite in the pearlite during the phase transition, which has a precipitation strengthening effect on the wire rod and is beneficial to improving the strength of the wire rod. Excessive V content can increase the hardenability of the wire rod and reduce the critical cooling rate of the wire rod. In the present application, the V content is controlled in a range of 0.01-0.03%.

[0026] Impurity elements can deteriorate the toughness and plasticity of the steel, and should be controlled as much as possible under the conditions of process route and cost. In the present application, the requirements for some impurity elements are as follows: S≤0.005%, P≤0.012%, Cu≤0.07%, Ni≤0.07%, O≤0.0015%.

[0027] The technical solution of the present application has the following advantages:

[0028] The 1960MPa-grade steel wire rod provided by the application comprises the following chemical components in mass percentage: C 0.80-0.83%; Si 0.45-0.60%; Mn 0.45-0.55%; Ti 0.01-0.03%; V 0.01-0.03%; N 0.0005-0.0008%; and the balance is iron and inevitable impurities. The strength and surface reduction of the rod are improved while the hardenability is basically unchanged by adjusting the content of C, Si, Mn, V and other elements and the cooperation between the overall scheme. The galvanized steel wire with a strength of 1960MPa can be produced under the premise that the total compression rate is not higher than 90% by the method. The problems of poor plasticity of the steel wire when the 82B rod is used to produce the 1960MPa-grade steel wire and the problem of too high hardenability when other higher strength rods are used are solved. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

[0030] Figure 1 It is a preparation process flow chart of the 1960MPa-grade steel wire rod of the embodiment of the present application. EMBODIMENT

[0031] The following embodiments are provided in order to better further understand the present application, and do not limit the best embodiments, and do not constitute a limitation on the content and protection scope of the present application. Any person under the inspiration of the present application or the combination of the present application with other prior art features can obtain any product same or similar to the present application, which falls within the protection scope of the present application.

[0032] The specific experimental steps or conditions not mentioned in the embodiments can be carried out according to the conventional experimental steps described in the literature in the art or the operation or conditions. The reagents or instruments not mentioned by the manufacturer are conventional reagent products that can be obtained by market purchase.

[0033] Embodiment 1

[0034] The present embodiment provides a 1960MPa-grade steel wire rod, the chemical component design and the preparation process (the flow chart is shown in Figure 1 The present embodiment provides a 1960MPa-grade steel wire rod, the chemical component design and the preparation process (the flow chart is shown in

[0035] The chemical composition design scheme of the wire rod is in mass percentage: C 0.80%; Si 0.45%; Mn 0.45%; Ti 0.02%; V 0.01%; N 0.005%; and the balance of iron and impurities; wherein the mass percentage of part of the impurities is: S 0.004%, P 0.01%, Cu 0.06%, Ni 0.06%, O 0.001%.

[0036] The preparation method of the 1960MPa-grade steel wire rod comprises the following steps: converter smelting, LF refining, bloom continuous casting, high-speed wire rod rolling, and Stelmor cooling, and each step of the preparation method will be introduced as follows:

[0037] (1) Converter smelting

[0038] The molten iron is moved into the converter and scrap steel is added for smelting, oxygen blowing is performed, the tapping temperature is 1580℃, the end point C content is 0.15%, and the P content is 0.01%; the deoxidizer is added when the tapping is 1 / 3, and the tapping is avoided to be slagged.

[0039] (2) LF refining

[0040] The molten steel of the converter smelting is moved into the LF furnace for refining, heating to 1525℃, and alloying treatment according to the chemical composition design scheme, and the slag is controlled during the refining process, so that the binary basicity of the slag is 2.7-2.9 (during the steelmaking process, some parameters are actually controlled in a range, and accurate control cannot be achieved, and the same applies below).

[0041] (3) Bloom continuous casting

[0042] The molten steel obtained in the vacuum smelting is continuously cast into a continuous casting billet with a cross-sectional size of 140mm*140mm, the casting is started with an overheating degree of 20℃, a constant pulling speed of 2.8m / min is maintained, the gas mist cooling is used in the secondary cooling zone, and the specific water quantity is controlled to be 1.80L / kg.

[0043] (4) High-speed wire rod rolling

[0044] The billet obtained by the continuous casting is hot-rolled into a wire rod with a diameter of 7mm through the high-speed wire rod rolling process; the soaking section temperature before hot rolling is 1180-1200℃ and the air-fuel ratio of the soaking section is 0.55-0.60, the opening rolling temperature is 1035-1060℃, the finish rolling temperature is 900-920℃, and the wire drawing temperature is 840-860℃.

[0045] (5) Stelmor cooling

[0046] The wire rod prepared in the high-speed wire rod rolling process is cooled on a Stelmor cooling line, the cooling speed before pearlite phase transformation (approximately corresponding to a temperature of 630°C or above) is controlled to be 16K / s or above, and then the wire rod is coiled.

[0047] Example 2

[0048] The present example provides a 1960MPa grade wire rod for steel wire, the chemical composition design and preparation process are as follows:

[0049] The chemical composition design scheme of the wire rod is as follows in terms of mass percentage: C 0.83%; Si 0.60%; Mn 0.55%; Ti 0.03%; V 0.03%; N 0.008%; and the balance of iron and impurities; wherein the mass percentage requirements of part of the impurities include: S 0.003%, P 0.01%, Cu 0.05%, Ni 0.05%, O 0.0012%.

[0050] The preparation method of the 1960MPa grade wire rod for steel wire includes the following processes: converter smelting, secondary refining, bloom continuous casting, high-speed wire rod rolling, and Stelmor cooling, and each process of the preparation method will be introduced below.

[0051] (1) Converter smelting

[0052] The molten iron is moved into the converter and scrap steel is added for smelting, oxygen blowing is performed, the tapping temperature is controlled to be 1610°C, the end point C content is 0.40%, and the P content is 0.01%; deoxidizing agent is added when tapping to 1 / 3, and tapping is avoided to avoid slagging.

[0053] (2) LF refining

[0054] The molten steel of the converter smelting is moved into the LF furnace for refining, heated to 1532°C, and alloyed according to the chemical composition design scheme, and in the refining process, the slag is controlled to have a binary basicity of 2.7-2.9.

[0055] (3) Bloom continuous casting

[0056] The molten steel obtained in the vacuum smelting is continuously cast into a continuous casting billet with a cross-sectional size of 140mmx140mm, and in the continuous casting process, the pouring is started with a superheat of 30°C, a constant pulling speed of 2.8m / min is maintained, the gas mist cooling is used in the secondary cooling zone, and the specific water amount is controlled to be 2.0L / kg.

[0057] (4) High-speed wire rod rolling

[0058] The billet obtained by continuous casting is hot-rolled into a wire rod with a diameter of 9 mm through a high-speed wire rolling process; the soaking section temperature before hot rolling is 1180-1200 °C and the air-fuel ratio of the soaking section is 0.55-0.60, the starting rolling temperature is 1045-1065 °C, the finishing rolling temperature is 900-920 °C, and the wire laying temperature is 840-860 °C.

[0059] (5) Stelmor cooling

[0060] The wire rod prepared in the high-speed wire rolling process is cooled on a Stelmor cooling line, the cooling speed before pearlite phase transformation (approximately corresponding to a temperature of 630 °C or above) is controlled to be 16 K / s or above, and then the wire rod is coiled.

[0061] Example 3

[0062] The present embodiment provides a wire rod for a 1960 MPa steel wire, the chemical composition design and the preparation process of which are as follows:

[0063] The chemical composition design scheme of the wire rod, in terms of mass percentage, is: C 0.82%; Si 0.52%; Mn 0.50%; Ti 0.02%; V 0.02%; N 0.006%; and the balance of iron and impurities; wherein the mass percentage requirements of some impurities include: S 0.003%, P 0.01%, Cu 0.04%, Ni 0.05%, O 0.0008%.

[0064] The preparation method of the 1960 MPa wire rod for steel wire includes the following processes: converter smelting, secondary refining, bloom continuous casting, high-speed wire rolling, and Stelmor cooling, which will be introduced respectively.

[0065] (1) Converter smelting

[0066] The molten iron is moved into the converter and scrap steel is added for smelting, oxygen blowing is performed, the tapping temperature is controlled to be 1590 °C, the end point C content is 0.30%, and the P content is 0.008%; the deoxidizer is added when the tapping is 1 / 3, and the tapping is avoided to be slagged.

[0067] (2) LF refining

[0068] The molten steel of the converter smelting is moved into the LF furnace for refining, heated to 1527 °C, and alloyed according to the chemical composition design scheme, and the slag is controlled during the refining process, so that the binary basicity of the slag is 2.7-2.9.

[0069] (3) Bloom continuous casting

[0070] The molten steel obtained in the vacuum melting is continuously cast into a continuously cast billet with a cross-sectional dimension of 140 mm x 140 mm. In the continuous casting process, the casting is started at a superheat of 25°C, a constant casting speed of 2.8 m / min is maintained, and the specific water quantity is controlled to be 1.9 L / kg by using gas mist cooling in the secondary cooling zone.

[0071] (4) High-speed wire rolling

[0072] The billet obtained by the continuous casting is hot-rolled into a wire rod with a diameter of 8 mm by a high-speed wire rolling process. The soaking segment temperature before the hot rolling is 1180-1200°C, the soaking segment air-fuel ratio is 0.55-0.60, the starting rolling temperature is 1040-1060°C, the finishing rolling temperature is 900-920°C, and the wire laying temperature is 840-860°C.

[0073] (5) Stelmor cooling

[0074] The wire rod prepared in the high-speed wire rolling process is cooled on a Stelmor cooling line. The cooling speed before the pearlite phase transformation (corresponding to a temperature of 630°C or higher) is controlled to be 16 K / s or higher, and then the wire rod is coiled.

[0075] Example 4

[0076] This example provides a 1960 MPa grade steel wire, the preparation method and specific operation parameters of which are as follows:

[0077] The 7 mm wire rod prepared in Example 1 is first subjected to lead bath heat treatment. The heating temperatures of the three temperature zones of the heating furnace before the lead bath heat treatment are 910°C-940°C-930°C, the wire speed is 4.5 m / min, and the lead temperature is 540°C. After the heat treatment, the wire rod is drawn to 2.9 mm through 9 passes, and then is subjected to hot galvanizing at a temperature of 450°C. After the hot galvanizing, the strength and torsion of the steel wire are detected, and the critical cooling speed of the steel wire is measured by using a thermal simulation testing machine. The relevant detection results are shown in Table 1.

[0078] Example 5

[0079] This example provides a 1960 MPa grade steel wire, the preparation method and specific operation parameters of which are as follows:

[0080] The 9 mm wire rod prepared in Example 2 is first subjected to lead bath heat treatment. The heating temperatures of the three temperature zones of the heating furnace before the lead bath heat treatment are 910°C-940°C-930°C, the wire speed is 4.5 m / min, and the lead temperature is 540°C. After the heat treatment, the wire rod is drawn to 3.4 mm through 8 passes, and then is subjected to hot galvanizing at a temperature of 450°C. After the hot galvanizing, the strength and torsion of the steel wire are detected, and the critical cooling speed of the steel wire is measured by using a thermal simulation testing machine. The relevant detection results are shown in Table 1.

[0081] Example 6

[0082] This example provides a 1960 MPa grade steel wire, its preparation method and specific operation parameters are as follows:

[0083] The 8 mm wire rod prepared in Example 3 is first subjected to lead bath heat treatment, the heating furnace three temperature zones before lead bath heat treatment are 910℃-940℃-930℃, the linear speed is 4.5 m / min, and the lead temperature is 540℃. The wire rod after heat treatment is drawn to 3.2 mm through 9 passes, and then hot galvanizing is carried out, the hot galvanizing temperature is 450℃. The strength and torsion of the steel wire after hot galvanizing are detected, and the critical cooling speed of the steel wire is measured by a thermal simulation testing machine, and the related test results are shown in Table 1.

[0084] Comparative Example 1

[0085] This comparative example provides a wire rod for steel wire, its preparation process is the same as Example 2, the difference is only that the chemical composition is designed as follows: C 0.75%; Si 0.65%; Mn 0.40%; Ti 0.05%; V 0.005%; N 0.010%; and the balance of iron and impurities; wherein the mass percentage content requirements of part of the impurities include: S 0.003%, P 0.01%, Cu 0.05%, Ni 0.05%, O 0.0012%.

[0086] Comparative Example 2

[0087] This comparative example provides a wire rod for steel wire, its preparation process is the same as Example 2, the difference is only that the chemical composition is designed as follows: C 0.88%; Si 0.40%; Mn 0.60%; Ti 0.005%; V 0.05%; N 0.003%; and the balance of iron and impurities; wherein the mass percentage content requirements of part of the impurities include: S 0.003%, P 0.01%, Cu 0.05%, Ni 0.05%, O 0.0012%.

[0088] Comparative Example 3

[0089] This comparative example provides a wire rod for steel wire, its preparation process is the same as Example 1, and the chemical composition is designed as follows: C 0.87%; Si 0.19%; Mn 0.72%; P 0.008%; S 0.007%; Cr 0.21%; Ni 0.03%; Cu 0.05%; V 0.03%; Alt 0.005%, H 0.5ppm, the balance is iron and inevitable impurities.

[0090] Comparative Example 4

[0091] This comparative example provides a steel wire using the wire rod of comparative example 1, and its preparation process and operating parameters are consistent with those of example 5.

[0092] Comparative Example 5

[0093] This comparative example provides a steel wire using the wire rod of comparative example 2, and its preparation process and operating parameters are consistent with those of example 5.

[0094] Comparative Example 6

[0095] This comparative example provides a steel wire using the wire rod of comparative example 3, and its preparation process and operating parameters are consistent with those of example 5.

[0096] Test Case

[0097] The wire rods provided in Examples 1-3 and Comparative Examples 1-3 of the present application and the steel wires provided in Examples 4-6 and Comparative Examples 4-6 were subjected to performance tests. The specific test methods are as follows: the tensile strength and area reduction rate of the wire rods and steel wires were tested using the relevant test methods in GB / T228.1 "Tensile test of metallic materials", and the torsional performance of the steel wire was tested using GB / T 239.1 "Unidirectional torsion test method for metallic wires". The critical cooling rate of the steel wire is measured using a thermal simulation test machine. Before the measurement, the sample is kept at 950°C for 10 minutes, and then cooled at cooling rates from small to large (the critical cooling rate can be obtained using a stepwise approximation method, such as using a larger interval cooling rate for wire winding, such as 1K / s, 5K / s, 10K / s, 15K / s, 20K / s, 25K / s, and 30K / s for testing. After finding the critical cooling rate range, the test cooling rate adjustment interval is narrowed, and the critical cooling rate is gradually approximated). Combined with metallographic testing, the cooling rate at which the sample structure is just completely martensite is determined. This cooling rate is the critical cooling rate of the sample.

[0098] The specific test results are shown in the table below:

[0099] Table 1

[0100] Rod tensile strength, MPa Rod reduction of area, % Example 1 1235 48 Example 2 1240 42 Example 3 1238 45 Comparative Example 1 1170 38 Comparative Example 2 1246 40 Comparative Example 3 1262 40

[0101] Table 2

[0102]

[0103] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A 1960MPa grade steel wire rod, characterized in that: The chemical composition includes the following mass percentages: C 0.80~0.83%; Si 0.45~0.60%; Mn 0.45~0.55%; Ti 0.01~0.03%; V 0.01~0.03%; N 0.005~0.008%; the balance is iron and unavoidable impurities; The mass percentage requirements of some impurities include: S≤0.005%, P≤0.012%, Cu≤0.07%, Ni≤0.07%, O≤0.0015%; The diameter of the wire rod is 7-9 mm, the tensile strength Rm is ≥ 1220 MPa, and the cross-sectional shrinkage Z is ≥ 42%.

2. A method for preparing the 1960 MPa grade steel wire rod according to claim 1, characterized in that: The process includes the following steps: converter or electric furnace smelting → refining outside the furnace → billet continuous casting → high-speed wire rolling → Stelmor cooling.

3. The method for preparing 1960 MPa grade steel wire according to claim 2, wherein: The converter or electric furnace smelting process controls the tapping temperature to 1580-1610° C., controls C to 0.10-0.45% and P to ≤100 ppm by mass; adds a deoxidizer when the tapping reaches 1 / 4-1 / 3, and avoids slag during tapping; And / or, the off-furnace refining process is alloying treatment according to the chemical composition design, the refining temperature is 1522-1532°C, and the slag formation is controlled during the refining process so that the binary basicity of the slag is 2.7-2.9; And / or, the billet continuous casting process starts casting at a superheat of ≤30°C, controls the casting speed to 2.6-2.8m / min, and controls the specific water content to 1.8-2.0L / kg; And / or, in the high-speed wire rolling process, the soaking zone temperature before hot rolling is controlled to be 1180-1200° C., the air-fuel ratio in the soaking zone is less than 0.60, the start rolling temperature is 1035-1065° C., the finishing rolling temperature is 900-920° C., and the spinning temperature is 840-860° C.; And / or, the cooling rate before the pearlite transformation in the Stelmor cooling process is controlled to be above 16K / s.

4. The method for preparing 1960 MPa grade steel wire according to claim 2, characterized in that: The superheat degree of the billet continuous casting process is 10-30°C; And / or, the Stelmor cooling process controls the cooling rate before the pearlite transformation to 16-25 K / s.

5. A 1960MPa grade steel wire, characterized in that: The wire rod is prepared by the wire rod described in claim 1 or the wire rod prepared by the preparation method according to any one of claims 2 to 4.

6. The 1960 MPa grade steel wire according to claim 5, characterized in that The preparation process includes: lead bath or salt bath heat treatment - drawing - galvanizing.

7. The 1960 MPa grade steel wire according to claim 5 or 6, characterized in that The diameter of the steel wire is 2.5-3.5 mm, the tensile strength reaches above 1960 MPa, the number of torsion times reaches above 18 times, and the critical cooling rate for forming martensite is above 20 K / s.

8. Use of the 1960 MPa grade steel wire according to any one of claims 5 to 7 in marine engineering.

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