High-titanium welding wire steel, continuous casting crystallizer casting powder for high-titanium welding wire steel and preparation method and application of continuous casting crystallizer casting powder

Abstract

The invention relates to high-titanium welding wire steel, continuous casting crystallizer casting powder for the high-titanium welding wire steel and a preparation method and application of the continuous casting crystallizer casting powder. The mass of Ti in the high-titanium welding wire steel is 0.16-0.21%. The casting powder of the continuous casting crystallizer comprises the following components in percentage by mass: 19.51 to 25.4 percent of SiO2, 25.37 to 32.16 percent of CaO, 9 to 25.37 percent of BaO, 8 to 20.25 percent of TiO2, 8 to 10 percent of Al2O3, 4 to 8 percent of C, 1 to 2 percent of Li2O, 1 to 3 percent of B2O3, 1 to 5 percent of MnO and the balance of inevitable impurities. The preparation method comprises the following steps: mixing the raw materials except the carbonaceous material, and then pre-melting the mixture to obtain a mixture; carrying out water quenching, natural dehydration and drying on the mixture, and then grinding to obtain a base material; adding a carbonaceous material, a binder and water into the base material, and mixing to obtain slurry; and the slurry is subjected to spray granulation, drying and baking, and the continuous casting crystallizer casting powder is obtained. Slag film uniformity is improved, and heat transfer stability of the casting powder is guaranteed.

Description

Technical Field

[0001] The present invention relates to a high-titanium welding wire steel, a continuous casting mold powder for high-titanium welding wire steel, a preparation method and an application thereof, and belongs to the technical field of continuous casting mold powder. Background Art

[0002] High-titanium welding wire steel has excellent low spatter property during welding, and at the same time has good corrosion resistance and wear resistance, and has broad application prospects in fields such as bridges, aerospace, and chemical engineering. The titanium element content of high-titanium welding wire steel is high (Ti = 0.16 - 0.21, wt%), and the titanium element is active. During the actual continuous casting production process, it is easy to combine with nitrogen and oxygen in the molten steel to form nitride and oxide inclusions, causing nozzle blockage and destroying the mold flow field; at the same time, the high-titanium molten steel reacts with oxidizing components such as SiO 2 in the mold powder, resulting in a decrease in the SiO 2 content of the mold powder and an increase in the TiO 2 content of the mold powder, severely deteriorating the performance of the mold powder and unable to normally perform functions such as lubrication and heat transfer, resulting in quality problems such as slag entrainment, depression, and cracks in the cast slab, seriously affecting the smooth progress of continuous casting and reducing production efficiency. Therefore, when designing the mold powder for high-titanium welding wire steel, it is necessary to improve the performance stability of the mold powder after the steel-slag reaction, reduce nozzle nodulation, and keep it with good heat transfer and lubrication effects.

[0003] At high temperatures, the substances volatilized from the fluorine-containing mold powder are easy to combine with water to form HF, which has strong acidity to the secondary cooling water system for recycling, corrodes the equipment, increases the maintenance cost, and pollutes the environment; in addition, problems such as slag rings are likely to occur during the pouring of high-titanium welding wire steel, and the on-site operators directly contact the mold powder, and the volatilized fluorides cause great harm to the human body; when the fluoride content in the mold powder increases, the reaction of SiO 2 +2CaF 2 =2CaO+SiF 4 (g) occurs, and the corrosion of the nozzle also increases, reducing the production continuity and increasing the cost at the same time.

[0004] Patent application CN108127094A discloses a non-reactive mold powder for high-titanium steel, and its component mass percentages are: CaO 9 - 16%, Al 2 O 3 15 - 30%, BaO 20 - 32%, Li 2 O 5 - 12%, MgO≤2%, F 8 - 15%, TiO 2 4 - 10%, C 2 - 12%, and the rest are inevitable impurities, and keep (Na 2 O+K 2 O+SiO 2) ≤ 3%. The invention application has a low SiO content compared to traditional slag systems. At the same time, it increases the Al in the mold powder. 2 The content is low, while increasing the Al in the mold powder. 2 O 3 and TiO 2 It reduces the reaction intensity between molten steel and slag in the mold, reduces the reactivity between the mold powder and molten steel, ensures the relative stability of the composition and performance of the mold powder during the casting process, ensures the smooth progress of the continuous casting process, increases the number of consecutive casting heats and the quality of the cast billet. However, the mold powder composition of this patent application contains a relatively large amount of F. Although the fluorine in this type of mold powder can modify the structures of silicates, aluminates, etc., effectively reduce the viscosity and fracture temperature of the mold powder, and improve the lubrication effect of the mold powder, due to the volatility of fluorides, it will cause health hazards, environmental pollution, and equipment corrosion.

[0005] Patent application CN103042187A discloses a mold powder for continuous casting of steel for high-titanium alloy welding wires. The mass percentages of its composition components are: CaO 30 - 50%, SiO 2 40 - 60%, B 2 O 3 2 - 5%, Li 2 O 2 - 5%, CaC 2 2 - 10%, inevitable impurities 0 - 2%, S ≤ 0.03% and P ≤ 0.03% in the impurities. This mold powder has a stronger anti-oxidation effect. In addition, this mold powder has the advantages of low alkalinity and low melting point. Even after absorbing 5% of TiO 2 , the crystallization temperature is still relatively low, playing a role in lubrication and preventing steel oxidation, avoiding the problem of deterioration of the surface quality of the cast billet caused by mold powder crusting and fish formation in the mold. However, the SiO 2 content in this mold powder is relatively high. Therefore, it is difficult to avoid the problem of molten steel - slag reaction, which in turn leads to changes in the alkalinity and components of the mold powder, affecting the heat transfer performance of the mold powder and inevitably causing quality problems such as depressions or cracks in the cast billet.

[0006] Patent application CN114472824A discloses a continuous casting mold powder for titanium-containing steel. The mass percentages of its composition components are: SiO 2 28 - 33%, CaO 30 - 35%, MgO 2.5 - 3.5%, Al 2 O 3 5 - 8%, Na 2 O + K 2 O 9 - 12%, F 3 - 4%, C 4 - 8%, B 2 O 31 - 3%, MnO 1 - 3%. The mold powder of this invention application can not only reduce the amounts of TiC and TiN in the mold powder, but also reduce the transparency of the molten slag, increase the thickness of the solid slag film in the mold, improve the uniformity of the slag film, and ensure the stability of the lubricating performance of the mold powder through the combination of different components and reasonable control of the mass percentages of each component. During the continuous casting production of titanium-containing steel, the shell growth in the mold is uniform, the lubricating performance of the mold powder is good, the thermal stress of the casting blank is reduced, the incidence of surface cracks of the casting blank is decreased, and the quality of the casting blank is improved. However, this mold powder is still based on the traditional CaO - SiO 2 Based mold powder design. The steel - slag reaction will cause drastic changes in the composition of the mold powder, resulting in unstable initial heat flux and extremely strong crystallinity, which makes it very difficult to optimize the CaO - SiO 2 Based mold powder by adding various fluxes.

[0007] In view of the problems that during the continuous casting process of high - titanium welding wire steel, titanium in the steel is easily oxidized by the mold powder and combined with C and N to form high - melting - point TiO 2 、TiC and TiN enter the mold powder, increasing the viscosity and melting point of the mold powder, affecting the lubricating performance and heat transfer performance of the mold powder, leading to surface defects of the continuous casting billet, etc., and due to the accumulation of high - melting - point substances at the mold nozzle, it will cause blockage of the mold nozzle, seriously affecting the smooth progress of continuous casting. In addition, in view of the pollution problem of fluorides in traditional mold powders, the present invention designs a special mold powder for high - titanium steel without fluorine, which can not only meet the requirements of the continuous casting process but also comply with environmental protection standards. Summary of the Invention

[0008] To solve the above - mentioned existing problems, the present invention discloses a high - titanium welding wire steel, a continuous casting mold powder for high - titanium welding wire steel, its preparation method and application. The specific technical solutions are as follows:

[0009] A high - titanium welding wire steel, in which the elements in the high - titanium welding wire steel are in their mass percentage contents in sequence as follows: C 0.045 - 0.07%, Si 0.75 - 0.85%, Mn 1.44 - 1.54%, P ≤ 0.015%, S 0.006 - 0.017%, Cr ≤ 0.08%, Ni ≤ 0.08%, Cu ≤ 0.08%, Mo ≤ 0.03%, Ti 0.16 - 0.21%, V ≤ 0.10%, Al ≤ 0.006%, Ca ≤ 0.0012%, O ≤ 0.005%, N ≤ 0.0065%, and the rest are Fe and inevitable residual impurities.

[0010] A continuous casting mold powder for the above - mentioned high - titanium welding wire steel, including components and their mass percentage contents in sequence as follows: SiO 2 19.51 - 25.4%, CaO 25.37 - 32.16%, BaO 9 - 25.37%, TiO2 8 - 20.25%, Al 2 O 3 8 - 10%, C 4 - 8%, Li 2 O 1 - 2%, B 2 O 3 1 - 3%, MnO 1 - 5%, and the rest are inevitable impurities;

[0011] The binary basicity R is 1.25 - 1.50, where R is CaO / SiO 2 , the melting point is 1084 - 1139 °C, and the viscosity at 1300 °C is 0.33 - 0.49 Pa·s.

[0012] Furthermore, the components are in the following mass percentage contents in sequence: SiO 2 18 - 24%, CaO 22 - 32%, BaO 10.72 - 18%, TiO 2 8.12 - 18%, Al 2 O 3 7 - 9%, C 4 - 8%, Li 2 O 1.2 - 1.8%, B 2 O 3 1.5 - 2.8%, MnO 1.4 - 4.8%, and the rest are inevitable impurities.

[0013] A preparation method of a continuous casting mold powder for high - titanium welding wire steel, comprising the following steps:

[0014] S1: Weigh the raw materials except the carbonaceous material according to the formula ratio described in claim 2, mix them to obtain a mixture, and then perform pre - melting treatment on the mixture to obtain the pre - melted mixture;

[0015] S2: Quench the pre - melted mixture with water, dehydrate it naturally and then dry it, and then grind it to obtain a base material, with the particle size requirement being 0.25 - 0.35 mm;

[0016] S3: Add carbonaceous material, binder, and water to the base material and mix them to obtain a slurry;

[0017] S4: Perform spray granulation, drying, and baking on the slurry to obtain the continuous casting mold powder.

[0018] Furthermore, in step S1, the pre - melting temperature is 1450 - 1600 °C, and the heat - preservation time is 1 - 2 h.

[0019] Furthermore, in step S2, the natural dehydration time is 10 - 24 h, the drying time is 3 - 4 h, and the drying temperature is 100 - 200 °C.

[0020] Further, in the step S3, the binder is selected from one or any combination of plant starch, dextrin, carboxymethyl cellulose, and clay; the addition amount of the binder is 2-3% of the mass of the base material.

[0021] Further, in the step S3, the mass ratio of the base material to water is 1:(2.5-3.0).

[0022] Further, in the step S4, the drying temperature is 500-570 °C, the drying time is 5-20 s, the baking temperature is 100-200 °C, and the baking time is 3-4 h.

[0023] Further, the particle size of the continuous casting mold powder is ≥100 mesh.

[0024] Application of a continuous casting mold powder for high-titanium welding wire steel in continuous casting.

[0025] The implementation principle of the present invention is:

[0026] In the continuous casting process of high-titanium welding wire steel, titanium in the steel is easily oxidized by the mold powder and combined with C and N to form high-melting-point TiO 2 , TiC, and TiN enter the mold powder, increasing the viscosity and melting point of the mold powder, affecting the lubrication performance and heat transfer performance of the mold powder, resulting in surface defects of the continuous casting billet, etc. Moreover, due to the accumulation of high-melting-point substances at the nozzle of the mold, the nozzle of the mold will be blocked, seriously affecting the smooth progress of continuous casting. In addition, aiming at the pollution problem of fluorides in traditional mold powders, the present invention designs a fluoride-free special mold powder for high-titanium steel, which can not only meet the requirements of continuous casting processes but also meet environmental protection standards.

[0027] The key point of the present invention is to use TiO 2 to replace SiO 2 to reduce the steel-slag reaction of the mold powder, reduce the fluctuation of the mold powder alkalinity, and maintain the stability of the mold powder performance; using BaO to replace CaO can control the formation of perovskite and reduce the risk of sticking breakout; MnO reacts with TiC / TiN to reduce the negative effect of TiC / TiN; B 2 O 3 , Li 2 O as a flux can depolymerize the complex large network structure and effectively reduce the viscosity of the mold powder; the super carbon black and graphite mixed carbonaceous materials in the present invention can ensure that the mold powder forms a relatively wide melting temperature range and a stable three-layer structure, and ensure the thickness of the liquid slag layer, improving the lubrication effect.

[0028] The beneficial effects of the present invention are:

[0029] By combining different components and reasonably controlling the mass percentages of each component, the present invention can not only effectively absorb the amounts of TiC and TiN in molten steel, but also reduce the transparency of the slag, control the thickness of the solid slag film at the meniscus of the mold, improve the uniformity of the slag film, and ensure the stability of heat transfer of the mold powder. During the continuous casting production process of high-titanium welding wire steel, the shell growth in the mold is uniform, the lubrication performance of the mold powder is good, the thermal stress of the casting blank is reduced, and the incidence rates of slag entrainment, transverse depression, cracks, etc. on the surface of the casting blank are decreased, thus improving the quality of the casting blank. Specific Embodiments

[0030] The present invention will be further illustrated below in conjunction with specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and not to limit the scope of the present invention.

[0031] The continuous casting mold powder for high-titanium welding wire steel provided by the present invention comprises, by mass percentage: SiO 2 19.51 - 25.4%, CaO 25.37 - 32.16%, BaO 9 - 25.37%, TiO 2 8.12 - 20.25%, Al 2 O 3 8 - 10%, C 4 - 8%, Li 2 O 1 - 2%, B 2 O 3 1 - 3%, MnO 1 - 5%, and the balance being inevitable impurities.

[0032] For the high-titanium welding wire steel targeted by the present invention, the mass percentages of each element are in sequence: C 0.045 - 0.07%, Si 0.75 - 0.85%, Mn 1.44 - 1.54%, P ≤ 0.015%, S 0.006 - 0.017%, Cr ≤ 0.08%, Ni ≤ 0.08%, Cu ≤ 0.08%, Mo ≤ 0.03%, Ti 0.16 - 0.21%, V ≤ 0.10%, Al ≤ 0.006%, Ca ≤ 0.0012%, O ≤ 0.005%, N ≤ 0.0065%, and the balance being Fe and inevitable residual impurities.

[0033] Specific examples, comparative examples and examples are given below to verify the specific use effects of the present invention.

[0034] Example 1

[0035] This example provides a continuous casting mold powder for high-titanium welding wire steel. The components, by mass percentage, are: SiO 2 20%, CaO 30%, BaO 10%, TiO 2 10%, Al 2 O 3 8%, C 8%, Li2 O 2%, B 2 O 3 3%, MnO 4%, and the rest are inevitable impurities.

[0036] The binary basicity CaO / SiO of the mold powder described above 2 is 1.5, the melting point is 1084 °C, and the viscosity at 1300 °C is 0.33 Pa·s.

[0037] The preparation method of the mold powder includes the following steps:

[0038] S1: Weigh silicon dioxide, calcium carbonate, barium carbonate, titanium dioxide, aluminum oxide, lithium carbonate, boron trioxide, and manganese monoxide according to the component content of the mold powder in this embodiment, then put them into a mixer and mix well to obtain a mixed material. Then add the mixed material into a melting furnace for pre-melting. The pre-melting temperature is 1450 °C, and the holding time is 1.0 h to obtain the pre-melted mixed material;

[0039] S2: Quench the pre-melted mixed material with water, dehydrate it naturally, and then dry and grind it to obtain a base material with a particle size requirement of 0.25 - 0.35 mm;

[0040] S3: Add graphite and a plant starch binder (the addition amount of the plant starch binder is 2% of the mass of the base material), and water (the mass ratio of the base material to water is 1:2.5) to the base material, and mix evenly to obtain a slurry;

[0041] S4: Spray the slurry through a high-pressure spray gun and perform spray granulation in a spray granulation tower. After granulation, perform drying, baking, and screening to obtain the continuous casting mold powder; the drying temperature is 500 °C, the drying time is 20 s, the baking temperature is 100 °C, the baking time is 3 h, and the particle size of the continuous casting mold powder is 100 mesh.

[0042] Example 2

[0043] This example provides a continuous casting mold powder for high-titanium welding wire steel, and the components are by mass percentage: SiO 2 22%, CaO 32%, BaO 9%, TiO 2 11%, Al 2 O 3 9%, C 4%, Li 2 O 2%, B 2 O 3 2%, MnO 4%, and the rest are inevitable impurities.

[0044] The binary basicity CaO / SiO of the mold powder described above 2is 1.45, the melting point is 1139 °C, and the viscosity at 1300 °C is 0.42 Pa·s.

[0045] The preparation method of the mold powder includes the following steps:

[0046] S1: Weigh silicon dioxide, calcium carbonate, barium carbonate, titanium dioxide, alumina, lithium carbonate, boric anhydride, and manganese monoxide according to the component content of the mold powder in this embodiment, put them into a mixer and mix well to obtain a mixed material, and then add the mixed material into a melting furnace for pre-melting. The pre-melting temperature is 1500 °C, and the heat preservation time is 1.5 h to obtain the pre-melted mixed material;

[0047] S2: Quench the pre-melted mixed material with water, naturally dehydrate and dry it, and then grind it to obtain a base material with a particle size requirement of 0.25 - 0.35 mm;

[0048] S3: Add graphite and dextrin binder (the addition amount of the dextrin binder is 2.5% of the mass of the base material), and water (the mass ratio of the base material to water is 1:2.7) to the base material, and mix evenly to obtain a slurry;

[0049] S4: Spray the slurry through a high-pressure spray gun, and perform spray granulation in a spray granulation tower. After granulation, perform drying, baking, and screening to obtain the continuous casting mold powder; the drying temperature is 530 °C, the drying time is 15 s, the baking temperature is 150 °C, the baking time is 3.5 h, and the particle size of the continuous casting mold powder is 120 mesh.

[0050] Example 3

[0051] This example provides a continuous casting mold powder for high-titanium welding wire steel, and its components are by mass percentage: SiO 2 24%, CaO 30%, BaO 12%, TiO 2 8%, Al 2 O 3 10%, C 4%, Li 2 O 1%, B 2 O 3 1%, MnO 5%, and the rest are inevitable impurities.

[0052] Among them, the binary basicity CaO / SiO of the mold powder 2 is 1.25, the melting point is 1129 °C, and the viscosity at 1300 °C is 0.49 Pa·s.

[0053] The preparation method of the mold powder includes the following steps:

[0054] S1: Weigh silicon dioxide, calcium carbonate, barium carbonate, titanium dioxide, aluminum oxide, lithium carbonate, boron trioxide, and manganese monoxide according to the above formula ratio, put them into a mixer and mix well to obtain a mixed material. Then add the mixed material into a melting furnace for pre-melting. The pre-melting temperature is 1500 °C and the heat preservation time is 2.0 h to obtain the pre-melted mixed material.

[0055] S2: Subject the pre-melted mixed material to water quenching, natural dehydration, and drying, and then grind it to obtain a base material with a particle size requirement of 0.25 - 0.35 mm.

[0056] S3: Add graphite, carboxymethyl cellulose binder (the addition amount of carboxymethyl cellulose binder is 3% of the mass of the base material), and water (the mass ratio of the base material to water is 1:3) to the base material, and mix evenly to obtain a slurry.

[0057] S4: Spray the slurry through a high-pressure spray gun, perform spray granulation in a spray granulation tower, and after granulation, perform drying, baking, and screening to obtain the continuous casting mold powder; the drying temperature is 570 °C, the drying time is 5 s, the baking temperature is 200 °C, the baking time is 4 h, and the particle size of the continuous casting mold powder is 150 mesh.

[0058] The above embodiments do not limit the present invention in any way. Any technical solutions obtained by using equivalent replacements or equivalent transformations fall within the protection scope of the present invention.

[0059] Comparative Example 1

[0060] This comparative example provides a continuous casting mold powder for high-titanium welding wire steel. The composition is by mass percentage: SiO 2 26%, CaO 21%, BaO 12%, TiO 2 10%, Al 2 O 3 8%, C 8%, Li 2 O 2%, B 2 O 3 3%, MnO 5%, and the rest are inevitable impurities.

[0061] Among them, the binary basicity CaO / SiO of the powder 2 is 0.81, the melting point is 1090 °C, and the viscosity at 1300 °C is 0.39 Pa·s.

[0062] The preparation method of the powder includes the following steps:

[0063] S1: Weigh silicon dioxide, calcium carbonate, barium carbonate, titanium dioxide, aluminum oxide, lithium carbonate, boron trioxide, and manganese monoxide according to the above formula ratio, put them into a mixer for full mixing to obtain a mixed material, and then add the mixed material into a melting furnace for pre-melting. The pre-melting temperature is 1450 °C and the heat preservation time is 1.0 h to obtain the pre-melted mixed material;

[0064] S2: Quench the pre-melted mixed material with water, dehydrate it naturally, and then dry and grind it to obtain a base material with a particle size requirement of 0.25 - 0.35 mm;

[0065] S3: Add graphite and a plant starch binder (the addition amount of the plant starch binder is 2% of the mass of the base material) and water (the mass ratio of the base material to water is 1:2.5) to the base material, mix evenly to obtain a slurry;

[0066] S4: Spray the slurry through a high-pressure spray gun, perform spray granulation in a spray granulation tower, and after granulation, perform drying, baking, and screening to obtain the continuous casting mold powder; the drying temperature is 500 °C, the drying time is 20 s, the baking temperature is 100 °C, the baking time is 3 h, and the particle size of the continuous casting mold powder is 100 mesh.

[0067] Comparative Example 2

[0068] This comparative example provides a continuous casting mold powder for high-titanium welding wire steel, and its components are by mass percentage: SiO 2 18%, CaO 24%, BaO 20%, TiO 2 8%, Al 2 O 3 10%, C 8%, Li 2 O 2%, B 2 O 3 1%, MnO 4%, and the rest are inevitable impurities.

[0069] Among them, the binary basicity CaO / SiO 2 of the mold powder is 1.33, the melting point is 1068 °C, and the viscosity at 1300 °C is 0.35 Pa·s.

[0070] The preparation method of the mold powder includes the following steps:

[0071] S1: Weigh silicon dioxide, calcium carbonate, barium carbonate, titanium dioxide, aluminum oxide, lithium carbonate, boron trioxide, and manganese monoxide according to the above formula ratio, put them into a mixer for full mixing to obtain a mixed material, and then add the mixed material into a melting furnace for pre-melting. The pre-melting temperature is 1450 °C and the heat preservation time is 1.0 h to obtain the pre-melted mixed material;

[0072] S2: Subject the premelted mixture to water quenching, natural dehydration and drying, followed by grinding to obtain a base material with a particle size requirement of 0.25 - 0.35 mm;

[0073] S3: Add graphite, a plant starch binder (the addition amount of the plant starch binder is 2% of the mass of the base material), and water (the mass ratio of the base material to water is 1:2.5) to the base material, and mix evenly to obtain a slurry;

[0074] S4: Spray the slurry through a high-pressure spray gun and perform spray granulation in a spray granulation tower. After granulation, perform drying, baking, and screening to obtain the continuous casting mold powder; the drying temperature is 500 °C, the drying time is 20 s, the baking temperature is 100 °C, the baking time is 3 h, and the particle size of the continuous casting mold powder is 100 mesh.

[0075] Comparative Example 3

[0076] This comparative example provides a continuous casting mold powder for high-titanium welding wire steel, and its components are by mass percentage: SiO 2 18%, CaO 19%, BaO 12%, TiO 2 21%, Al 2 O 3 9%, C 8%, Li 2 O 2%, B 2 O 3 3%, MnO 3%, and the rest are inevitable impurities.

[0077] Among them, the binary basicity CaO / SiO of the powder 2 is 1.06, the melting point is 1096 °C, and the viscosity at 1300 °C is 0.57 Pa·s.

[0078] The preparation method of the powder includes the following steps:

[0079] S1: Weigh silicon dioxide, calcium carbonate, barium carbonate, titanium dioxide, aluminum oxide, lithium carbonate, boron trioxide, and manganese monoxide according to the above formula ratio, put them into a mixer and mix well to obtain a mixture, and then add the mixture to a melting furnace for premelting. The premelting temperature is 1450 °C, and the holding time is 1.0 h to obtain the premelted mixture;

[0080] S2: Subject the premelted mixture to water quenching, natural dehydration and drying, followed by grinding to obtain a base material with a particle size requirement of 0.25 - 0.35 mm;

[0081] S3: Add graphite, a plant starch binder (the addition amount of the plant starch binder is 2% of the mass of the base material), and water (the mass ratio of the base material to water is 1:2.5) to the base material, and mix evenly to obtain a slurry;

[0082] S4: Spray the slurry through a high-pressure spray gun and perform spray granulation in a spray granulation tower. After granulation, perform drying, baking, and screening to obtain the continuous casting mold powder; the drying temperature is 500 °C, the drying time is 20 s, the baking temperature is 100 °C, the baking time is 3 h, and the particle size of the continuous casting mold powder is 100 mesh.

[0083] Comparative Example 4

[0084] This comparative example provides a continuous casting mold powder for high-titanium welding wire steel, and the composition is by mass percentage: SiO 2 26%, CaO 20%, BaO 11%, TiO 2 12%, Al 2 O 3 10%, C 8%, Li 2 O 2%, B 2 O 3 2%, MnO 4%, and the rest are inevitable impurities.

[0085] Among them, the binary basicity CaO / SiO of the powder 2 is 0.77, the melting point is 1031 °C, and the viscosity at 1300 °C is 0.41 Pa·s.

[0086] The preparation method of the powder includes the following steps:

[0087] S1: Weigh silicon dioxide, calcium carbonate, barium carbonate, titanium dioxide, aluminum oxide, lithium carbonate, boron trioxide, and manganese monoxide according to the above formula ratio, put them into a mixer and mix well to obtain a mixed material, and then add the mixed material into a melting furnace for pre-melting. The pre-melting temperature is 1450 °C, and the holding time is 1.0 h to obtain the pre-melted mixed material;

[0088] S2: Quench the pre-melted mixed material with water, perform natural dehydration and drying, and then grind it to obtain a base material with a particle size requirement of 0.25 - 0.35 mm;

[0089] S3: Add graphite and a plant starch binder (the addition amount of the plant starch binder is 2% of the mass of the base material) and water (the mass ratio of the base material to water is 1:2.5) to the base material, and mix evenly to obtain a slurry;

[0090] S4: Spray the slurry through a high-pressure spray gun and perform spray granulation in a spray granulation tower. After granulation, perform drying, baking, and screening to obtain the continuous casting mold powder; the drying temperature is 500 °C, the drying time is 20 s, the baking temperature is 100 °C, the baking time is 3 h, and the particle size of the continuous casting mold powder is 100 mesh.

[0091] Comparative Example 5

[0092] This comparative example provides a continuous casting mold powder for high-titanium welding wire steel, and its composition is by mass percentage: SiO 2 20%, CaO 34%, BaO 8%, TiO 2 8%, Al 2 O 3 9%, C 8%, Li 2 O 1%, B 2 O 3 3%, MnO 4%, and the rest are inevitable impurities.

[0093] Among them, the binary basicity CaO / SiO of the mold powder 2 is 1.7, the melting point is 1055 °C, and the viscosity at 1300 °C is 0.32 Pa·s.

[0094] The preparation method of the mold powder includes the following steps:

[0095] S1: Weigh silicon dioxide, calcium carbonate, barium carbonate, titanium dioxide, aluminum oxide, lithium carbonate, boron trioxide, and manganese monoxide according to the above formula ratio, put them into a mixer and mix well to obtain a mixed material, and then add the mixed material into a melting furnace for pre-melting. The pre-melting temperature is 1450 °C, and the holding time is 1.0 h to obtain the pre-melted mixed material;

[0096] S2: Quench the pre-melted mixed material with water, dehydrate it naturally and then dry it, and then grind it to obtain a base material with a particle size requirement of 0.25 - 0.35 mm;

[0097] S3: Add graphite and a plant starch binder (the addition amount of the plant starch binder is 2% of the mass of the base material) and water (the mass ratio of the base material to water is 1:2.5) to the base material, and mix evenly to obtain a slurry;

[0098] S4: Spray the slurry through a high-pressure spray gun and perform spray granulation in a spray granulation tower. After granulation, dry, bake, and screen to obtain the continuous casting mold powder; the drying temperature is 500 °C, the drying time is 20 s, the baking temperature is 100 °C, the baking time is 3 h, and the particle size of the continuous casting mold powder is 100 mesh.

[0099] Test Example 1

[0100] The following production process KR→BOF→LF→RH→CC is used to produce high-titanium welding wire steel, which specifically includes the following steps:

[0101] KR process: Mechanically stir the molten iron and spray lime powder and fluorite for desulfurization;

[0102] BOF process: Pour the hot metal obtained by KR desulfurization into a converter, blow oxygen into the hot metal to raise the temperature, decarburize and dephosphorize to obtain low-carbon molten steel.

[0103] LF process: Transport the low-carbon molten steel to the refining process for deoxidation, desulfurization, alloying, and temperature raising to obtain molten steel with a composition close to the target composition.

[0104] RH process: Further, lift the molten steel to the vacuum refining process for degassing, alloying, and temperature control to obtain molten steel with the required temperature and composition.

[0105] CC process: Lift the molten steel with the required temperature and composition to the continuous casting platform for protected casting to obtain continuous casting billets.

[0106] The mass percentage content of the chemical composition of the high-titanium welding wire steel prepared above is: C 0.06%, Si 0.045 - 0.07%, Si 0.75 - 0.85%, Mn 1.44 - 1.54%, P ≤ 0.015%, S 0.006 - 0.017%, Cr ≤ 0.08%, Ni ≤ 0.08%, Cu ≤ 0.08%, Mo ≤ 0.03%, Ti 0.16 - 0.21%, V ≤ 0.10%, Al ≤ 0.006%, Ca ≤ 0.0012%, O ≤ 0.005%, N ≤ 0.0065%, and the rest is Fe and inevitable residual impurities.

[0107] Among them, during the production of high-titanium welding wire steel, the continuous casting billets are subjected to protected casting using the fluxes of Examples 1 - 3 and Comparative Examples 1 - 5 respectively. The casting section size is a small square billet of 140mm × 140mm, and the casting speed is 2.8m / min.

[0108] Statistical analysis is carried out on the surface depression incidence rate and crack incidence rate of the billets in the examples and comparative examples. The statistical method is to count the number of depressions and cracks on the surfaces of 500 continuous casting billets corresponding to each flux. The statistical results are shown in Table 1. Depression incidence rate (%) = number of billets with depressions / 500 · 100%, crack incidence rate (%) = number of billets with cracks / 500 · 100%.

[0109] Table 1 Surface crack incidence rate and depression incidence rate of high-titanium welding wire steel billets

[0110] Incidence rate of surface cracks, % Incidence rate of surface depressions, % Example 1 0.3 0.1 Example 2 0.4 0.2 Example 3 0.5 0.3 Comparative Example 1 12.1 10.5 Comparative Example 2 2.8 2.5 Comparative Example 3 2.9 2.7 Comparative Example 4 1.0 0.8 Comparative Example 5 1.1 0.9

[0111] As can be seen from Table 1, using the flux of the present invention can improve the lubrication performance of the flux, significantly reduce the surface crack incidence rate and surface depression incidence rate of the billets.

[0112] Taking the ideal embodiments of the present invention described above as inspiration, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A high titanium welding wire steel, characterized in that: The mass percentages of the elements in the high titanium welding wire steel are as follows: 0.045~0.07%, Si 0.75~0.85%, Mn 1.44~1.54%, P≤0.015%, S 0.006~0.017%, Cr≤0.08%, Ni≤0.08%, Cu≤0.08%, Mo≤0.03%, Ti 0.16~0.21%, V≤0.10%, Al≤0.006%, Ca≤0.0012%, O≤0.005%, N≤0.0065%, the rest are Fe and unavoidable residual impurities.

2. A continuous casting mold protection slag for the high titanium welding wire steel according to claim 1, characterized in that: The components and their mass percentages are as follows: SiO2 19.51-25.4%, CaO 25.37-32.16%, BaO 9-25.37%, TiO2 8-20.25%, Al2O3 8-10%, C 4-8%, Li2O 1-2%, B2O3 1-3%, MnO 1-5%, and the rest are inevitable impurities; The binary basicity R is 1.25-1.50, R is CaO / SiO2, the melting point is 1084-1139°C, and the viscosity at 1300°C is 0.33-0.49 Pa·s.

3. The continuous casting mold protection slag for high titanium welding wire steel according to claim 2, characterized in that: The components are as follows in terms of mass percentage: SiO2 18-24%, CaO 22-32%, BaO 10.72-18%, TiO2 8.12-18%, Al2O3 7-9%, C 4-8%, Li2O 1.2-1.8%, B2O3 1.5-2.8%, MnO 1.4-4.8%, and the rest are inevitable impurities.

4. A method for preparing continuous casting mold protection slag for high titanium welding wire steel, characterized in that: The following steps are involved: S1: weighing raw materials other than the carbonaceous material according to the formula ratio of claim 2, mixing them to obtain a mixture, and then pre-melting the mixture to obtain a pre-melted mixture; S2: The pre-melted mixture is quenched with water, naturally dehydrated and dried before being ground to obtain a base material with a particle size requirement of 0.25 to 0.35 mm; S3: adding carbonaceous material, binder and water to the base material and mixing them to obtain slurry; S4: spray granulating, drying and baking the slurry to obtain the continuous casting mold protection slag.

5. The method for preparing continuous casting mold protection slag for high titanium welding wire steel according to claim 4, characterized in that: In the step S1, the pre-melting temperature is 1450-1600° C., and the holding time is 1-2 hours.

6. The method for preparing continuous casting mold protection slag for high titanium welding wire steel according to claim 4, characterized in that: In step S2, the natural dehydration time is 10 to 24 hours, the drying time is 3 to 4 hours, and the drying temperature is 100 to 200°C.

7. The method for preparing continuous casting mold protection slag for high titanium welding wire steel according to claim 4, characterized in that: In step S3, the binder is selected from one or any combination of plant starch, dextrin, carboxymethyl cellulose and clay; the amount of the binder added is 2-3% of the mass of the base material.

8. The method for preparing continuous casting mold protection slag for high titanium welding wire steel according to claim 4, characterized in that: The mass ratio of the base material to water in step S3 is 1:(2.5-3.0).

9. The method for preparing continuous casting mold protection slag for high titanium welding wire steel according to claim 4, characterized in that: In step S4, the drying temperature is 500-570° C., the drying time is 5-20 seconds, the baking temperature is 100-200° C., and the baking time is 3-4 hours.

10. The method for preparing continuous casting mold protection slag for high titanium welding wire steel according to claim 4, characterized in that: The particle size of the continuous casting crystallizer protection slag is ≥100 mesh.

11. Use of the continuous casting mold protection slag for high titanium welding wire steel according to claim 2 or 3 in continuous casting.