A manufacturing method of 1000mpa grade high titanium steel

Abstract

The application discloses a manufacturing method of 1000MPa high-titanium steel and belongs to the field of steel smelting. The method comprises the following steps: placing semi-steel in a converter to perform converter vanadium extraction and desulfurization, and obtaining desulfurized molten steel; performing initial smelting on the desulfurized molten steel, and blowing argon gas from the bottom of the converter during the whole process of converter blowing; feeding a titanium-iron alloy core wire and performing alloying treatment on a small argon blowing platform behind the furnace; transporting the molten steel from the small platform behind the furnace to an RH furnace for refining; and hoisting the molten steel from the station to a casting machine for continuous casting and pouring to obtain 1000MPa high-titanium steel. The manufacturing method of 1000MPa high-titanium steel provided by the application can stably control the components at multiple nodes in the production process, reduce the fluctuation of the titanium content in the high-titanium steel, and improve the stability of product production.

Description

Technical Field

[0001] This invention relates to the field of steel smelting technology, and more specifically to a method for manufacturing 1000MPa grade high titanium steel. Background Technology

[0002] High-titanium steel utilizes titanium alloying to improve its properties, making it widely used in industries such as automotive, shipbuilding, bridges, pressure vessels, and construction. High-titanium steel offers numerous advantages, including high strength and toughness. Its strength and toughness surpass those of traditional steel, meaning it can withstand greater loads and stresses without easily deforming or breaking. This makes it widely applicable in fields requiring high strength and toughness. High-titanium steel is also lightweight, with a lower density than traditional steel. This reduces structural weight, energy consumption, and emissions, aligning with environmental protection requirements. Furthermore, high-titanium steel exhibits corrosion and heat resistance, allowing it to operate in harsh environments. This makes it widely used in marine engineering, chemical industries, and energy sectors. Finally, high-titanium steel offers excellent machinability, undergoing heat treatment, plastic forming, and welding to meet diverse application requirements. While its price is slightly higher than traditional steel, its longer service life and lower maintenance costs result in a lower overall cost.

[0003] Titanium significantly affects the microstructure, mechanical properties, and processing performance of steel. Titanium has a strong affinity for nitrogen, oxygen, and carbon, acting as an excellent deoxidizer and effective element for fixing nitrogen and carbon in steel. The titanium-carbon compound (TiC) exhibits extremely strong bonding and high stability, only slowly dissolving into the iron solid solution when heated above 1000℃. TiC particles inhibit grain growth and coarsening in steel. Titanium is also a strong ferrite-forming element, reducing the austenite phase region. Solid-solution titanium improves the hardenability of steel, while the presence of TiC particles reduces it. At certain titanium content levels, precipitation hardening occurs due to the dispersed precipitation of TiFe2. Titanium also significantly affects the mechanical properties of steel; when titanium exists in solid solution within ferrite, its strengthening effect is higher than aluminum, manganese, nickel, and molybdenum, but lower than beryllium, phosphorus, copper, and silicon. The effect of titanium on the mechanical properties of steel depends on its form, the Ti / C content ratio, and the heat treatment method. A titanium mass fraction between 0.03% and 0.1% can improve yield strength, but when the Ti / C content ratio exceeds 4, its strength and toughness decrease sharply. Titanium can also improve the endurance strength and creep resistance of steel. Titanium can also improve the corrosion resistance of stainless acid-resistant steel, especially its resistance to intergranular corrosion.

[0004] However, in the manufacturing process of 1000MPa grade high-strength high-titanium steel, the titanium content fluctuates greatly and is unstable, which seriously affects and destroys the quality stability of this type of steel. Summary of the Invention

[0005] The purpose of this invention is to provide a method for manufacturing 1000MPa grade high-titanium steel, so as to solve the problem of large fluctuations and instability of titanium content in high-titanium steel in the prior art.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0007] According to one aspect of the present invention, a method for manufacturing 1000MPa grade high-titanium steel is provided, the method comprising the following steps:

[0008] The semi-steel is placed in a converter for vanadium extraction and desulfurization to obtain desulfurized molten steel;

[0009] The desulfurized molten steel is subjected to primary refining. During the primary refining, argon gas is blown into the bottom of the converter throughout the entire process. The target requirements for the molten steel at the end of the converter refining are a C content of 0.05±0.01wt%, a Ti content of 0.26±0.05wt%, and a temperature of 1630~1660℃.

[0010] Titanium-iron alloy core wires are used for feeding and alloying treatment on the small argon blowing platform after the furnace.

[0011] Molten steel is transported from the small platform behind the furnace to the RH furnace for refining. The target composition of the RH refining furnace must meet the following requirements: C content 0.08±0.02wt%, Si content 0.08±0.02wt%, Mn content 1.85±0.15wt%, P content below 0.015wt%, S content below 0.005wt%, V content 0.10±0.02wt%, Ti content 0.16±0.05wt%, Mo content 0.18±0.04wt%, Al content 0.035±0.010wt%, and N content below 0.0045wt%.

[0012] Molten steel is hoisted from the station to a casting machine for continuous casting to obtain 1000MPa grade high-titanium steel. The high-titanium steel comprises the following components: C content of 0.06-0.16wt%, Si content of 0.05-0.15wt%, Mn content of 1.50-2.5wt%, P content below 0.020wt%, S content below 0.010wt%, V content of 0.05-0.20wt%, Ti content of 0.080-0.30wt%, Mo content of 0.10-0.30wt%, Al content of 0.010-0.085wt%, and N content below 0.0050wt%.

[0013] According to one embodiment of the present invention, wherein:

[0014] The molten steel fed into the converter for vanadium extraction must meet the following requirements: C ≥ 4.00 wt%, P ≤ 0.100 wt%, Ti content 0.10~0.35 wt%, and temperature ≥ 1250℃;

[0015] The "semi-steel" obtained after vanadium extraction must meet the following requirements: temperature 1350±30℃, Ti content 0.080~0.30wt%;

[0016] The desulfurizing agent is a mixture of calcium oxide and silicon-magnesium alloy, with a mass ratio of 1.5 to 2.5:1.

[0017] According to one embodiment of the present invention, wherein:

[0018] The carbon content of the semi-steel fed into the furnace during the initial refining process is 3.25 ± 0.30 wt%.

[0019] The following operation is adopted for tapping steel from the converter: a sliding plate is used to block slag, and the slag thickness is ≤100mm.

[0020] According to one embodiment of the present invention, the titanium-iron alloy core wire contains 30 wt% titanium, and the wire feeding speed is controlled at 40-70 m / min.

[0021] According to one embodiment of the present invention, the composition of the molten steel leaving the station after alloying treatment by the argon blowing platform meets the following requirements: 0.09±0.02wt%, Si content is 0.08±0.02wt%, Mn content is 1.86±0.15wt%, P content is below 0.015wt%, S content is below 0.006wt%, V content is 0.10±0.02wt%, Ti content is 0.20±0.05wt%, Mo content is 0.18±0.04wt%, Al content is 0.035±0.010wt%, and N content is below 0.005wt%.

[0022] According to one embodiment of the present invention, the RH furnace refining and degassing cycle time is ≥15 minutes, and the processing time with a vacuum degree ≤300Pa is ≥10 minutes.

[0023] According to one embodiment of the present invention, the RH furnace off-site temperature requirements are as follows: if the casting cycle is >37 min, the off-site temperature is controlled at 1572±5℃; if the casting cycle is ≤37 min, the off-site temperature is controlled at 1567±5℃.

[0024] According to one embodiment of the present invention, the soft blowing time for refining in the RH furnace is not less than 8 minutes.

[0025] According to one embodiment of the present invention, the tundish temperature during continuous casting is required to be 1530–1545°C.

[0026] According to one embodiment of the present invention, the mold flux is a peritectic steel mold flux.

[0027] By adopting the above technical solutions, the manufacturing method of 1000MPa grade high-titanium steel provided by the present invention, compared with the prior art, reduces the fluctuation of titanium content in high-titanium steel and improves the stability of product production by stabilizing the composition of multiple nodes in the production process. Attached Figure Description

[0028] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0029] Figure 1 A flowchart illustrating a method for manufacturing 1000MPa grade high-titanium steel according to an embodiment of the present invention is shown. Detailed Implementation

[0030] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0031] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as in the embodiments of this application.

[0033] This invention provides a method for manufacturing 1000MPa grade high-titanium steel. For example... Figure 1 As shown, the method generally includes the following steps:

[0034] Step 1: Place the semi-steel in a converter for vanadium extraction and desulfurization to obtain desulfurized molten steel;

[0035] Step 2: Perform preliminary refining on the desulfurized molten steel. During the preliminary refining, argon gas is blown into the bottom of the converter throughout the entire process. The target requirements for the molten steel at the end of the converter refining are: C content of 0.05±0.01wt%, Ti content of 0.26±0.05wt%, and temperature of 1630~1660℃.

[0036] Step 3: Use titanium-iron alloy core wire for feeding and alloying treatment at the small argon blowing platform after the furnace;

[0037] Step 4: Transfer the molten steel from the small platform behind the furnace to the RH furnace for refining. The target composition of the RH refining furnace must meet the following requirements: C content 0.08±0.02wt%, Si content 0.08±0.02wt%, Mn content 1.85±0.15wt%, P content below 0.015wt%, S content below 0.005wt%, V content 0.10±0.02wt%, Ti content 0.16±0.05wt%, Mo content 0.18±0.04wt%, Al content 0.035±0.010wt%, and N content below 0.0045wt%.

[0038] Step 5: The molten steel is hoisted from the station to the casting machine for continuous casting to obtain 1000MPa grade high-titanium steel. The high-titanium steel includes the following components: C content of 0.06-0.16wt%, Si content of 0.05-0.15wt%, Mn content of 1.50-2.5wt%, P content below 0.020wt%, S content below 0.010wt%, V content of 0.05-0.20wt%, Ti content of 0.080-0.30wt%, Mo content of 0.10-0.30wt%, Al content of 0.010-0.085wt%, and N content below 0.0050wt%.

[0039] In some embodiments, the molten steel fed into the converter for vanadium extraction must meet the following requirements: C ≥ 4.00 wt%, P ≤ 0.100 wt%, Ti content 0.10–0.35 wt%, and temperature ≥ 1250°C. The molten steel fed into the converter for vanadium extraction can be molten steel refined in a blast furnace from vanadium-titanium magnetite, which may contain approximately 4.5 wt% C, 0.15 wt% Si, 0.19 wt% Mn, 0.27 wt% V, 0.12 wt% Ti, other alloying elements, and Fe. After vanadium extraction in the converter, most of the vanadium enters the vanadium slag in the form of oxides, which are used to produce other products. The resulting molten steel is called "semi-steel."

[0040] In some embodiments, the "semi-steel" obtained after vanadium extraction must meet the following requirements: temperature of 1350±30℃ and Ti content of 0.080~0.30wt%.

[0041] In some embodiments, the desulfurizing agent is a mixture of calcium oxide and magnesium silicon alloy, with a mass ratio of 1.5 to 2.5:1. The sulfur content in steel directly affects its performance; excessive sulfur content leads to poor hot workability and causes "hot brittleness." Furthermore, it significantly reduces weldability, causing high-temperature cracking. The plasticity of steel also deteriorates significantly with increasing sulfur content. In pure iron or silicon steel sheets, high sulfur content increases hysteresis loss. In this invention, injection desulfurization is preferred, using a mixture of calcium oxide and magnesium silicon alloy as the desulfurizing agent. When the titanium content is high, titanium reacts with the calcium oxide desulfurizing agent, resulting in a lower desulfurization rate and a lower titanium content in the molten steel. Using a magnesium silicon alloy can increase the desulfurization rate and reduce the final sulfur content. In some embodiments, the sulfur content after desulfurization is below 0.002 wt%.

[0042] In some embodiments, the carbon content of the initial "semi-steel" fed into the furnace is 3.25 ± 0.30 wt%. Argon is blown into the bottom of the converter throughout the entire refining process; a full-process argon blowing mode is not selected. The target temperature for converter refining is 1630–1660 °C, and further, 1640 °C.

[0043] In some embodiments, the converter tapping process involves the following operations: slag baffles are used, with a slag thickness ≤100mm and a clearance of 300–800mm. The slag washing operation during tapping includes adding 1000±100kg of active lime. The amount of ladle top slag modifier added is 150±15kg.

[0044] In some embodiments, the argon blowing time of the ladle on the refining platform after the converter is ≥3 min, the titanium content of the ferrotitanium alloy core wire is 30 wt%, and the wire feeding speed is controlled at 40–70 m / min. Due to the low specific gravity of ferrotitanium, unstable titanium absorption often occurs during titanium addition treatment. Therefore, a wire feeding method is used to add ferrotitanium. By controlling the wire feeding speed, the ferrotitanium alloy core wire quickly penetrates the slag layer and enters the depths of the molten steel, melting at the bottom of the ladle. This increases the contact time and area between the ferrotitanium and the molten steel, stabilizing the titanium absorption rate.

[0045] In some embodiments, the composition of the molten steel leaving the station after alloying treatment on the argon-blown small platform meets the following requirements: 0.09±0.02wt%, Si content is 0.08±0.02wt%, Mn content is 1.86±0.15wt%, P content is below 0.015wt%, S content is below 0.006wt%, V content is 0.10±0.02wt%, Ti content is 0.20±0.05wt%, Mo content is 0.18±0.04wt%, Al content is 0.035±0.010wt%, and N content is below 0.005wt%.

[0046] In some embodiments, the RH furnace refining degassing cycle time is ≥15 minutes, the vacuum degree is ≤300 Pa, and the treatment time is ≥10 min. The molten steel is washed in a vacuum chamber before production, and the number of smooth argon small tube passages in the vacuum chamber is more than 8.

[0047] In some embodiments, the RH furnace off-site temperature requirement is: pouring cycle > 37 min, off-site temperature control is 1572±5℃, pouring cycle ≤37 min, off-site temperature control is 1567±5℃.

[0048] In some embodiments, the RH furnace refining soft blowing time is not less than 8 minutes, and the soft blowing effect is preferably slightly fluctuating liquid surface. Blowing large argon is strictly prohibited to prevent secondary oxidation caused by molten steel turbulence and exposure.

[0049] In some embodiments, the tundish temperature during continuous casting is required to be 1530-1545℃.

[0050] In some embodiments, the crystallizer protective slag is a peritectic steel protective slag.

[0051] The technical solutions of the present application will be further illustrated by specific embodiments. Unless otherwise specified, the raw materials, equipment, consumables, etc. used in the following examples can be obtained by conventional commercial means.

[0052] Example 1

[0053] The vanadium-containing molten steel is placed in a converter for vanadium extraction by converter, and the molten steel in the converter has a C content of about 4.00wt%, a P content of about 0.100wt%, a Ti content of about 0.10wt% and a temperature of 1250℃. After the vanadium extraction, the obtained "semi-molten steel" has a C content of 3.30wt% and a temperature of 1320℃. Desulfurization is performed by spraying, and the desulfurizing agent is a mixture of calcium oxide and silicon-magnesium alloy, and the mass ratio of the two is 1.5:1. After the desulfurization, the S content is about 0.0018wt%. The desulfurized molten steel is subjected to primary refining, and the end-point temperature is controlled at 1630℃. The carbon content of the "semi-molten steel" in the primary refining is 2.95wt%. Argon is blown at the bottom of the converter throughout the whole process of converter blowing, and the mode of blowing argon throughout the whole process is not selected. At the end of the converter blowing, the C content of the molten steel is 0.04wt%, the Ti content is 0.21wt%, and the temperature is 1630℃. The converter tapping is performed by using the following operation: the slide plate is used to block the slag, and the thickness of the slag is not more than 100mm. After the primary refining is completed, the titanium-iron alloy core wire is fed and alloyed at the small platform behind the furnace after the tapping by blowing argon. The titanium-iron alloy core wire contains 30wt% of titanium, and the feeding speed is controlled at 40m / min. The composition of the molten steel at the small platform behind the furnace after the tapping is as follows: the C content is 0.07wt%, the Si content is 0.06wt%, the Mn content is 1.71wt%, the P content is less than 0.015wt%, the S content is less than 0.005wt%, the V content is 0.08wt%, the Ti content is 0.15wt%, the Mo content is 0.14wt%, the Al content is 0.025wt%, and the N content is less than 0.0045wt%. Silicon-manganese, metallic manganese, molybdenum-iron, vanadium-iron and aluminum-iron are recommended to be added for alloying treatment during the tapping. The molten steel is transported from the small platform behind the furnace to the RH furnace for refining. The temperature of the molten steel at the RH station is controlled at 1607℃. Before the production, the molten steel is washed in the vacuum chamber (furnace washing). The argon tube (smooth) is inserted into the vacuum chamber, and the number of the argon tube is greater than or equal to 8, and the insertion depth of the argon tube is 530mm. The degassing cycle time is not less than 15 minutes, and the treatment time of the vacuum degree of less than or equal to 300Pa (3mbar) is 10min. Soft blowing is adopted, and the soft blowing time is 8min. The soft blowing effect is appropriate with slight fluctuation of the liquid surface, and large argon blowing is strictly prohibited to prevent secondary oxidation caused by the molten steel being exposed due to the violent boiling. The silicon-iron, manganese-iron, aluminum particles and sponge titanium are added for silicon, manganese, aluminum and titanium alloying before the RH molten steel treatment. The requirements for the temperature at the RH refining station are as follows: the pouring cycle is greater than 37min, the temperature at the station is controlled at 1572±5℃, the pouring cycle is less than or equal to 37min, and the temperature at the station is controlled at 1567±5℃. The target composition at the RH refining station is as follows: the C content is 0.06wt%, the Si content is 0.06wt%, the Mn content is 1.7wt%, the P content is less than 0.015wt%, the S content is lessThe tundish temperature requirement during continuous casting is 1530°C, and the crystallizer protecting slag is a peritectic steel protecting slag.

[0054] The continuous casting product was detected to have the following composition: C content of 0.06 wt%, Si content of 0.05 wt%, Mn content of 1.50 wt%, P content of less than 0.020 wt%, S content of less than 0.010 wt%, V content of 0.05 wt%, Ti content of 0.080 wt%, Mo content of 0.10 wt%, Al content of 0.010 wt%, N content of less than 0.0050 wt%, and the balance of Fe and unavoidable impurities.

[0055] Example 2

[0056] The vanadium-containing molten steel is placed in a converter for vanadium extraction by converter, and the molten steel in the converter has a C content of about 4.05wt%, a P content of about 0.100wt%, a Ti content of about 0.20wt%, and a temperature of 1280℃. After the vanadium extraction, the obtained "semi-molten steel" has a C content of 3.20wt%, a Ti content of about 0.15wt%, and a temperature of 1350℃. Desulfurization is performed by spraying, and the desulfurizing agent is a mixture of calcium oxide and silicon-magnesium alloy, and the mass ratio of the two is 2:1. After the desulfurization, the S content is about 0.0015wt%. The desulfurized molten steel is subjected to preliminary refining, and the end-point temperature is controlled to be 1640℃. The carbon content of the "semi-molten steel" in the preliminary refining is 3.25wt%. Argon is blown at the bottom of the converter throughout the whole process of converter blowing, and the mode of blowing argon throughout the whole process is not selected. At the end of the converter blowing, the C content of the molten steel is 0.05wt%, the Ti content is 0.26wt%, and the temperature is 1640℃. The converter tapping is performed by using the following operation: the slide plate is used to block the slag, and the thickness of the slag is not more than 100mm. After the preliminary refining is completed, the titanium-iron alloy core wire is fed and alloyed at the small platform behind the furnace after the tapping. The titanium-iron alloy core wire has a titanium content of 30wt%, and the feeding speed is controlled to be 55m / min. The composition of the molten steel at the small platform behind the furnace after the tapping is as follows: the C content is 0.09wt%, the Si content is 0.08wt%, the Mn content is 1.85wt%, the P content is less than 0.015wt%, the S content is less than 0.005wt%, the V content is 0.10wt%, the Ti content is 0.20wt%, the Mo content is 0.18wt%, the Al content is 0.035wt%, and the N content is less than 0.005wt%. Silicon-manganese, metallic manganese, molybdenum-iron, vanadium-iron, and aluminum-iron are recommended to be added for alloying treatment during the tapping. The molten steel is transported from the small platform behind the furnace to the RH furnace for refining. The temperature of the molten steel at the RH inlet is controlled to be 1611℃. Before the production, the molten steel is washed in the vacuum chamber (furnace washing). The argon tube (smooth) is inserted into the vacuum chamber, and the number of the argon tube is greater than or equal to 8, and the insertion depth of the argon tube is 530mm. The degassing cycle time is not less than 15 minutes, and the treatment time of the vacuum degree of less than or equal to 300Pa (3mbar) is 12min. Soft blowing is adopted, and the soft blowing time is 9min. The soft blowing effect is appropriate with slight fluctuation of the liquid surface, and large argon blowing is strictly prohibited to prevent secondary oxidation caused by the molten steel being exposed due to the violent boiling. The silicon-iron, manganese-iron, aluminum particles, and sponge titanium are added for silicon, manganese, aluminum, and titanium alloying before the RH molten steel treatment. The requirements for the temperature at the RH outlet are as follows: the pouring cycle is greater than 37min, the temperature at the RH outlet is controlled to be 1572±5℃, the pouring cycle is less than or equal to 37min, and the temperature at the RH outlet is controlled to be 1567±5℃. The target composition at the RH outlet is as follows: the C content is 0.08wt%, the Si content is 0.08wt%, the Mn content is 1. 85wt%, the P content is less than 0.015wt%, the S content isThe tundish temperature requirement during continuous casting is 1540°C, and the crystallizer protecting slag is a peritectic steel protecting slag.

[0057] It is detected that the continuous casting product has the following components: C content is 0.10wt%, Si content is 0.09wt%, Mn content is 2.0wt%, P content is below 0.020wt%, S content is below 0.010wt%, V content is 0.15wt%, Ti content is 0.23wt%, Mo content is 0.20wt%, Al content is 0.055wt%, N content is below 0.0050wt%, and the balance is Fe and inevitable impurities.

[0058] Example 3

[0059] The vanadium-containing molten steel is placed in a converter for vanadium extraction by converter, and the vanadium extraction is carried out in the molten steel with about 4.10wt% of C, about 0.080wt% of P, about 0.35wt% of Ti and 1260℃ of temperature. After the vanadium extraction, the obtained "semi-steel" has about 3.35wt% of C, about 0.30wt% of Ti and 1380℃ of temperature. Desulfurization is carried out by spraying, and the desulfurizing agent is a mixture of calcium oxide and silicon-magnesium alloy with a mass ratio of 2.5:1, and the S content of the molten steel after desulfurization is about 0.0017wt%. The molten steel is subjected to preliminary refining, and the end-point temperature is controlled at 1660℃. The carbon content of the "semi-steel" after preliminary refining is 3.55wt%. The converter blowing is carried out by bottom argon blowing throughout the whole blowing process, and the full-argon blowing mode is not selected. The C content of the molten steel at the end of the converter blowing is 0.06wt%, the Ti content is 0.31wt%, and the temperature is 1660℃. The converter tapping is carried out by using the following operation: the slide plate is used to block the slag, and the thickness of the slag is not more than 100mm. After the preliminary refining is completed, the titanium-iron alloy wire is fed and alloyed in the post-converter argon blowing platform. The titanium content of the titanium-iron alloy wire is 30wt%, and the feeding speed is controlled at 70m / min. The composition of the molten steel after the post-converter platform is as follows: the C content is 0.11wt%, the Si content is 0.10wt%, the Mn content is 2.01wt%, the P content is less than 0.015wt%, the S content is less than 0.005wt%, the V content is 0.12wt%, the Ti content is 0.25wt%, the Mo content is 0.22wt%, the Al content is 0.045wt%, and the N content is less than 0.0045wt%. The silicon-manganese, metallic manganese, molybdenum-iron, vanadium-iron and aluminum-iron are recommended to be added for alloying treatment during the tapping. The molten steel is transported from the post-converter platform to the RH furnace for refining, and the temperature of the molten steel at the RH station is controlled at 1612℃. The molten steel is washed in the vacuum chamber (furnace washing) before production, the argon tube (smooth) is inserted into the vacuum chamber, the number of tubes is ≥8, and the insertion depth of the tube is 530mm. The degassing cycle time is not less than 15 minutes, the treatment time of the vacuum degree ≤300Pa (3mbar) is 10min. Soft blowing is used, the soft blowing time is 10min, and the soft blowing effect is appropriate with slight fluctuation of the liquid surface. The steel is strictly prevented from being exposed and oxidized again due to the violent blowing of argon. The silicon-iron, manganese-iron, aluminum particles and sponge titanium are added for silicon, manganese, aluminum and titanium alloying before the RH molten steel treatment. The requirements for the off-station temperature are as follows: the pouring cycle is >37min, the off-station temperature is controlled at 1572±5℃, the pouring cycle is ≤37min, and the off-station temperature is controlled at 1567±5℃. The target composition of the RH refining off-station is as follows: the C content is 0.10wt%, the Si content is 0.10wt%, the Mn content is 2.0wt%, the P content is less than 0.015wt%, the S content is less 0.005wt%, the V content is 0.12wt%, the Ti contentThe tundish temperature requirement during continuous casting is 1545℃, and the crystallizer protective slag adopts peritectic steel protective slag.

[0060] It is detected that the continuous casting product has the following components: the C content is 0.16wt%, the Si content is 0.15wt%, the Mn content is 2.50wt%, the P content is below 0.020wt%, the S content is below 0.010wt%, the V content is 0.2wt%, the Ti content is 0.30wt%, the Mo content is 0.30wt%, the Al content is 0.085wt%, the N content is below 0.0050wt%, and the balance is Fe and inevitable impurities.

[0061] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details of the above-described embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0062] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combinations.

[0063] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the idea of the present application, and it should also be considered as disclosed by the present application.

Claims

1. A method for manufacturing 1000MPa grade high-titanium steel, characterized in that, Includes the following steps: The semi-steel is placed in a converter for vanadium extraction and desulfurization to obtain desulfurized molten steel. The molten steel entering the converter for vanadium extraction must meet the following requirements: C≥4.00wt%, P≤0.100wt%, Ti content 0.10~0.35wt%, temperature≥1250℃. The "semi-steel" obtained after vanadium extraction must meet the following requirements: temperature 1350±30℃, Ti content 0.080~0.30wt%, and the desulfurizing agent is a mixture of calcium oxide and silicon-magnesium alloy with a mass ratio of 1.5~2.5:

1. The desulfurized molten steel is subjected to primary refining. During the primary refining, argon gas is blown into the bottom of the converter throughout the entire process. The target requirements for the molten steel at the end of the converter refining are a C content of 0.05±0.01wt%, a Ti content of 0.26±0.05wt%, and a temperature of 1630~1660℃. Titanium-iron alloy core wire was used for feeding and alloying treatment on the small argon blowing platform after the furnace. The titanium content of the titanium-iron alloy core wire was 30wt%, and the feeding speed was controlled at 40~70m / min. After alloying treatment on the small argon blowing platform, the composition of the molten steel leaving the station met the following requirements: C content was 0.09±0.02wt%, Si content was 0.08±0.02wt%, Mn content was 1.86±0.15wt%, P content was below 0.015wt%, S content was below 0.006wt%, V content was 0.10±0.02wt%, Ti content was 0.20±0.05wt%, Mo content was 0.18±0.04wt%, Al content was 0.035±0.010wt%, and N content was below 0.005wt%. Molten steel is transported from the small platform behind the furnace to the RH furnace for refining. The target composition of the RH refining furnace must meet the following requirements: C content 0.08±0.02wt%, Si content 0.08±0.02wt%, Mn content 1.85±0.15wt%, P content below 0.015wt%, S content below 0.005wt%, V content 0.10±0.02wt%, Ti content 0.16±0.05wt%, Mo content 0.18±0.04wt%, Al content 0.035±0.010wt%, and N content below 0.0045wt%. Molten steel is hoisted from the station to a casting machine for continuous casting to obtain 1000MPa grade high-titanium steel. The high-titanium steel comprises the following components: C content of 0.06~0.16wt%, Si content of 0.05~0.15wt%, Mn content of 1.50~2.5wt%, P content below 0.020wt%, S content below 0.010wt%, V content of 0.05~0.20wt%, Ti content of 0.080~0.30wt%, Mo content of 0.10~0.30wt%, Al content of 0.010~0.085wt%, and N content below 0.0050wt%.

2. The method according to claim 1, characterized in that, in: The carbon content of the semi-steel fed into the furnace during the initial refining process is 3.25 ± 0.30 wt%. The following operations are used for tapping steel from the converter: Use a sliding plate to block slag, with a slag thickness of ≤100mm.

3. The method according to claim 1, characterized in that, The RH furnace refining and degassing circulation time is ≥15 minutes, and the processing time for vacuum degree ≤300Pa is ≥10 minutes.

4. The method according to claim 3, characterized in that, RH furnace off-site temperature requirements: for pouring cycles > 37 min, the off-site temperature is controlled at 1572 ± 5 ℃; for pouring cycles ≤ 37 min, the off-site temperature is controlled at 1567 ± 5 ℃.

5. The method according to claim 4, characterized in that, The refining soft blowing time in the RH furnace shall not be less than 8 minutes.

6. The method according to claim 1, characterized in that, The required temperature for the tundish during continuous casting is 1530~1545℃.

7. The method according to claim 1, characterized in that, The protective slag for the crystallizer is made of peritectic steel.

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