Rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking and preparation method thereof

Abstract

The invention belongs to the field of external refining, and particularly relates to a rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking and a preparation method thereof. The invention provides a rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking. The whole cored wire is composed of a center core wire, core powder and a thin layer belt. The core powder comprises three parts, namely rare earth praseodymium-titanium alloy powder, ferro-silicon nitride particles and fluorite particles. And the thin-layer strip comprises three parts, namely a first-layer thin steel strip, a second-layer thin aluminum strip and an outermost-layer thin steel strip. And the thin steel strip on the outermost layer and the fluorite layer form an outer protective layer. And the rare earth layer is a middle layer and is fixed by the first thin steel strip and the second thin aluminum strip. And ferro-silicon nitride is used as an inner layer. According to the rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking and the preparation method of the rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire, the main purpose of improving the molten steel deoxidation efficiency and efficiently increasing nitrogen of molten steel in the wire feeding process is achieved.

Description

Technical Field

[0001] This application belongs to the field of secondary steelmaking, and specifically relates to a rare earth praseodymium titanium silicon nitride aluminum alloy cored wire for steelmaking and a preparation method thereof. Background Art

[0002] The wire feeding process is to feed different types of cored wires through a wire feeder during the secondary steelmaking process. After the cored wire passes through the steel slag to reach the ideal position in the molten steel and melts or vaporizes, it moves together with the argon blown from the bottom of the ladle and the molten steel to achieve refining treatments such as deoxidation, desulfurization, surface treatment of non-metallic inclusions, and alloying. As a common cored wire, calcium alloy wire, at the normal temperature of molten steel, metallic calcium will melt within 1 - 3 seconds, and there is not enough time to react with the oxygen in the molten steel, failing to meet the deoxidation requirements for refining; in the wire feeding technology, the aluminum yield is extremely high, up to 98.6%. In conventional calcium-iron cored wires and ferrosilicon nitride cored wires, the calcium grains and ferrosilicon nitride grains contained have a calcium purity usually below 90%, and it is very easy to introduce harmful elements (such as S, P, etc.) into the molten steel. Nitrogen, as one of the common elements in steel, has a beneficial effect on the properties of steel. For example, in austenitic steel, it can be used as a solid solution strengthening element, expand and stabilize the formation of austenite structure, and improve the mechanical properties and corrosion resistance of steel; or promote the precipitation of V(C, N) in the austenite region, providing heterogeneous nucleation centers for sub-micron precipitates. In duplex stainless steel, nitrogen can effectively adjust the ratio of ferrite and austenite phases, improve strength and hardness, and improve the plasticity, hot working performance, and fatigue performance of steel. The traditional nitrogen increasing method is to first add a deoxidizer to the converter molten steel for pre-deoxidation and then blow nitrogen from the bottom of the molten steel for nitrogen increasing, which is divided into two operation steps, with a cumbersome process, requiring long-time treatment, and also increasing energy consumption.

[0003] The patent "Calcium Cored Wire and Method for Treating Molten Steel with the Calcium Cored Wire" (CN103555884A) discloses a method for treating molten steel with a calcium cored wire. This calcium cored wire includes a solid calcium wire and a steel strip coating the calcium wire, and the calcium wire has a calcium content of 96%. Although this calcium cored wire is easy to produce and is not likely to introduce harmful elements into the molten steel, its production cost is relatively high; the requirements for the raw material calcium wire are extremely high; and high-purity calcium melts extremely fast in the molten steel, which is not conducive to deoxidizing the molten steel. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art in the above technical background, this application provides a rare earth praseodymium titanium silicon nitride aluminum alloy cored wire for steelmaking and a preparation method thereof, realizing improving the deoxidation efficiency of molten steel and the efficient and rapid nitrogen increasing of molten steel during the wire feeding process.

[0005] To achieve the above object, the present application provides a rare earth praseodymium titanium silicon nitride aluminum alloy cored wire for steelmaking. The entire cored wire consists of a central core wire, core powder, and a thin layer strip. The core powder includes three parts: namely, rare earth praseodymium titanium alloy powder, ferrosilicon nitride particles, and fluorite particles. The thin layer strip includes three parts: the first thin steel strip, the second thin aluminum strip, and the outermost thin steel strip. The outermost thin steel strip and the fluorite layer form an outer protective layer. The rare earth layer is the intermediate layer and is fixed by the first thin steel strip and the second thin aluminum strip. The ferrosilicon nitride layer is the inner layer and is surrounded by the first thin steel strip and the central core wire.

[0006] Further, the central core wire is a steel rod formed by winding multiple steel wires around each other. The material used is steel, with a diameter of 0.1 - 1 mm, the number of steel wires being greater than or equal to 2, and the multiple steel wires being wound in a spiral shape.

[0007] Further, the materials used for the first thin steel strip and the outermost thin steel strip are steel. The thickness of the first thin steel strip is 0.5 - 1 mm, and the thickness of the outermost thin steel strip is less than 0.8 mm; the material used for the second thin aluminum strip is aluminum, with an aluminum content greater than 95%, and the thickness of the second thin aluminum strip is 0.3 - 2 mm. The cross-sectional closing method is snap connection or welding.

[0008] Further, the material used for the ferrosilicon nitride layer is ferrosilicon nitride alloy particles, with a particle size between 0.2 - 0.5 mm and a thickness of 0.8 - 2 mm. The elements in the ferrosilicon nitride alloy particles are by weight percentage: Si content is 42 - 52%, N content is greater than or equal to 15%, and the balance is iron and inevitable other impurity elements.

[0009] Further, the rare earth layer is mainly rare earth praseodymium titanium alloy powder, with an alloy layer thickness of 0.2 - 2 mm. The elements in the rare earth praseodymium titanium alloy powder are by weight percentage: praseodymium content is greater than or equal to 85%, titanium content is 1 - 6%, silicon content is 1 - 6%, calcium content is 0.1 - 2%, and the balance is iron, manganese, and inevitable other impurity elements.

[0010] Further, the fluorite layer is mainly fluorite particles with a particle size less than 0.6 mm, with a thickness of 0.4 - 1.2 mm, and is fixed by the second thin aluminum strip and the outermost thin steel strip.

[0011] Preferably, the fluorite layer is mainly fluorite particles with a particle size less than 1 μm and a thickness of 0.4 - 0.8 mm.

[0012] A preparation method for a rare earth praseodymium titanium silicon nitride aluminum alloy cored wire for steelmaking includes the following steps:

[0013] S1. Steel wire stranding: At least two steel wires are arranged side by side and straightened, and then with one steel wire as the central axis, one ends of the remaining multiple steel wires are rotated around the central axis in the same direction, so that each steel wire is coiled in a spiral shape together to obtain a steel rod;

[0014] S2. Inner layer cored wire laying: On the cored wire machine, the first layer of thin steel strip is opened, flattened and stretched forward. During the stretching process, the steel rod is laid on the first layer of thin steel strip along the stretching direction of the first layer of thin steel strip, and then from the rear, using its feeding system according to the ratio requirements, silicon nitride iron particles are evenly spread on the steel rod and the first layer of thin steel strip;

[0015] S3. Inner layer cored wire curling production: At the front end of the stretching direction of the first layer of thin steel strip with the steel rod and silicon nitride iron particles laid, the two outer edges of the first layer of thin steel strip are gradually curled upward and gradually closed, and the closed edges are connected in the form of welding or snap-fastening to obtain the inner layer cored wire;

[0016] S4. Middle layer cored wire laying: On the cored wire machine, the second layer of thin aluminum strip is unrolled, flattened and stretched forward. While stretching, the inner layer cored wire is laid on the second layer of thin aluminum strip along the stretching direction of the first layer of thin steel strip, and then from above, using the feeding system according to the ratio requirements, rare earth praseodymium titanium alloy powder is evenly spread on the inner layer cored wire and the second layer of thin aluminum strip;

[0017] S5. Middle layer cored wire curling production: At the front end of the stretching direction of the second layer of thin aluminum strip with the inner layer cored wire and rare earth praseodymium titanium alloy powder laid, the two outer edges of the second layer of thin aluminum strip are gradually curled upward and gradually closed, and the closed edges are connected in the form of welding or snap-fastening to obtain the middle layer cored wire;

[0018] S6. Outer layer cored wire laying: On the cored wire machine, the outermost layer of thin steel strip is unrolled, flattened and stretched forward. While stretching, the middle layer cored wire is laid on the outermost layer of thin steel strip along the direction of the outermost layer of thin steel strip, and then from above, using the feeding system according to the ratio requirements, fluorite particles are evenly spread on the middle layer cored wire and the outermost layer of thin steel strip;

[0019] S7. Outer layer cored wire curling production: At the front end of the stretching direction of the outermost layer of thin steel strip with the outer layer cored wire and fluorite particles laid, the two outer edges of the outermost layer of thin steel strip are gradually curled upward and gradually closed, and the closed edges are connected in the form of welding or snap-fastening to obtain the rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking.

[0020] In summary, the present application has the following beneficial effects:

[0021] The rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire prepared by the present application has an outer layer including the outermost layer of thin steel strip and fluorite. The outermost layer of thin steel strip reacts with the steel slag, and fluorite reacts with CaO and SiO in the steel slag 2React with other components to generate low-melting-point compounds, which can reduce the melting point of steel slag, improve the fluidity of steel slag. The fluorite used has a particle size less than 1 μm, greatly improving the reaction efficiency, reducing the fluorite consumption, and lowering the cost.

[0022] The main material of the rare earth layer is rare earth praseodymium-titanium alloy powder. When fed into the molten steel, it reacts synergistically with the thin aluminum layer. The thin aluminum layer first reacts with the molten steel to remove the oxygen in it. The deoxidation product of aluminum has a low density and is easy to float up to form a slag layer. However, some alumina inclusions cannot be completely discharged and will remain in the molten steel, causing pollution to the molten steel and leading to the problem of nozzle coking. After the aluminum layer reacts, the rare earth layer reacts with the molten steel. The rare earth element praseodymium, as a strong reducing agent, can also react with the oxygen in the molten steel, and can improve the morphology of alumina inclusions, improve the fluidity of the molten steel, achieve deep deoxidation treatment of the molten steel, and improve the deoxidation efficiency of the molten steel.

[0023] The ferrosilicon nitride layer, its main material is ferrosilicon nitride alloy particles. After being mixed with the molten steel, silicon nitride decomposes at the high temperature of the molten steel to release nitrogen into the molten steel, which can improve the strength and hardness of the steel. And the nitrogen increment effect of the molten steel is closely related to the oxygen in the molten steel. The oxygen in the molten steel will compete with nitrogen for adsorption sites. Oxygen occupies some of the positions that can adsorb nitrogen, thus hindering the adsorption of nitrogen at these positions. The higher the concentration of oxygen in the molten steel, the more positions it occupies, the lower the nitrogen increment effect, and the slower the nitrogen increment speed; after deoxidation, a low-viscosity synthetic slag can also be formed on the surface of the molten steel, reducing nitrogen overflow and nitrogen loss. The cored wire of this application reacts with the molten steel in a hierarchical manner. The deoxidizer first contacts the molten steel and reacts with the oxygen in it to reduce the oxygen content in the molten steel. Then silicon nitride reacts with the molten steel to achieve efficient and rapid nitrogen increment of the molten steel by the ferrosilicon nitride layer, realizing efficient deoxidation and nitrogen increment of the molten steel during the wire feeding process. This rare earth praseodymium-titanium-silicon-nitrogen-aluminum alloy cored wire strengthens the strength of the entire cored wire through the outermost thin steel strip, the second-layer thin aluminum strip, the first-layer thin steel strip, and the central core rod. Brief Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of this application, the drawings required for describing the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0025] Figure 1 is a cross-sectional view of the rare earth praseodymium-titanium-silicon-nitrogen-aluminum alloy cored wire;

[0026] In the figure: 1, central core wire; 2, ferrosilicon nitride particles; 3, first-layer thin steel strip; 4, rare earth layer; 5, second-layer thin aluminum strip; 6, fluorite particles; 7, outermost thin steel strip;

[0027] Figure 2It is a cross-sectional view of the central core wire inside the rare earth praseodymium titanium silicon nitride aluminum alloy cored wire. Detailed implementation manners

[0028] Next, in combination with the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0029] The purity of the thin aluminum strip used in the specific implementation manner of the present application is 99.99%.

[0030] Embodiment 1

[0031] A preparation method of a rare earth praseodymium titanium silicon nitride aluminum alloy cored wire for steelmaking includes the following steps:

[0032] S1. Steel wire stranding: At least 7 steel wires with a diameter of 0.05 mm are arranged side by side and straightened, and then with one steel wire as the central axis, one ends of the remaining 6 steel wires are rotated around the central axis in the same direction, so that each steel wire is spirally wound together to obtain steel rod 1;

[0033] S2. Inner layer cored wire material laying: On the cored wire machine, the first layer of thin steel strip 3 with a thickness of 1 mm is opened, flattened, and stretched forward. During the stretching process, steel rod 1 is laid on the first layer of thin steel strip 3 along the stretching direction of the first layer of thin steel strip 3, and then using its feeding system from the rear, silicon nitride iron particles 2 are evenly spread on steel rod 1 and the first layer of thin steel strip 3 according to the ratio of 50% Si content, 40% N content, the balance being iron and inevitable other impurity elements, with a particle size of 0.5 mm and a thickness of 1.5 mm;

[0034] S3. Inner layer cored wire curling production: At the front end along the stretching direction of the steel rod 1 and the first layer of thin steel strip 3 on which silicon nitride iron particles 2 are spread, the two outer edges of the first layer of thin steel strip 3 are gradually curled upward and gradually closed, and the closed edges are connected in a snap-fastener form to obtain the inner layer cored wire;

[0035] S4. Middle layer cored wire material laying: On the cored wire machine, the second layer of thin aluminum strip 5 with a thickness of 2 mm is unrolled, flattened, and stretched forward. While stretching, the inner layer cored wire is laid on the second layer of thin aluminum strip 5 along the stretching direction of the first layer of thin steel strip 3, and then using the feeding system from above, rare earth praseodymium titanium alloy powder 4 is evenly spread on the inner layer cored wire and the second layer of thin aluminum strip 5 according to the ratio of 90% praseodymium content, 4% titanium content, 4% silicon content, 1% calcium content, the balance being iron, manganese and inevitable other impurity elements, with an alloy layer thickness of 1 mm;

[0036] S5. Intermediate layer cored wire curling production: For the laid inner layer cored wire and the second thin aluminum strip 5 of rare earth praseodymium titanium alloy powder 4 at the front end along the stretching direction, gradually curl the two outer edges of the second thin aluminum strip 5 upward and gradually close them. The closed edges are connected in a snap-fastening form to obtain the intermediate layer cored wire;

[0037] S6. Outer layer cored wire laying: On the cored wire machine, unwind, flatten, and stretch forward the outermost thin steel strip 7 with a thickness of 0.8 mm. While stretching, lay the intermediate layer cored wire along the direction of the outermost thin steel strip 7 on the outermost thin steel strip 7. Then, from above, use the feeding system to evenly spread fluorite particles 6 with a particle size of 0.5 μm and a thickness of 0.8 mm on the intermediate layer cored wire and the outermost thin steel strip 7 according to the ratio requirements;

[0038] S7. Outer layer cored wire curling production: For the laid outer layer cored wire and the outermost thin steel strip 7 of fluorite particles 6 at the front end along the stretching direction, gradually curl the two outer edges of the outermost thin steel strip 7 upward and gradually close them. The closed edges are connected in a snap-fastening form to obtain the rare earth praseodymium titanium silicon nitride aluminum alloy cored wire for steelmaking.

[0039] Example 2

[0040] A preparation method of a rare earth praseodymium titanium silicon nitride aluminum alloy cored wire for steelmaking includes the following steps:

[0041] S1. Steel wire stranding: Arrange at least 7 steel wires with a diameter of 0.05 mm side by side and straighten them. Then, with one steel wire as the central axis, rotate one end of the remaining 6 steel wires in the same direction around the central axis so that each steel wire is coiled in a spiral shape together to obtain the steel rod 1;

[0042] S2. Inner layer cored wire laying: On the cored wire machine, open, flatten, and stretch forward the first thin steel strip 3 with a thickness of 1 mm. During the stretching process, lay the steel rod 1 along the stretching direction of the first thin steel strip 3 on the first thin steel strip 3. Then, from the rear, use its feeding system to evenly spread ferrosilicon nitride particles 2 with a Si content of 50%, an N content of 40%, the balance being iron and inevitable other impurity elements, a particle size of 0.5 mm, and a thickness of 1.5 mm on the steel rod 1 and the first thin steel strip 3;

[0043] S3. Inner layer cored wire curling production: For the laid steel rod 1 and the first thin steel strip 3 of ferrosilicon nitride particles 2 at the front end along the stretching direction, gradually curl the two outer edges of the first thin steel strip 3 upward and gradually close them. The closed edges are connected in a snap-fastening form to obtain the inner layer cored wire;

[0044] S4. Intermediate layer cored wire laying: On the cored wire machine, unwind, flatten, and stretch forward the 2-mm-thick second-layer thin aluminum strip 5. While stretching, lay the inner-layer cored wire along the stretching direction of the first-layer thin steel strip 3 on the second-layer thin aluminum strip 5. Then, from above, use the feeding system to evenly sprinkle rare earth praseodymium-titanium alloy powder 4 onto the inner-layer cored wire and the second-layer thin aluminum strip 5 according to the ratio of 90% praseodymium content, 4% titanium content, 4% silicon content, 1% calcium content, with the balance being iron, manganese, and other inevitable impurity elements, and the alloy layer thickness being 2 mm.

[0045] S5. Intermediate layer cored wire coiling production: At the front end along the stretching direction of the laid inner-layer cored wire and the second-layer thin aluminum strip 5 with rare earth praseodymium-titanium alloy powder 4, gradually curl the two outer edges of the second-layer thin aluminum strip 5 upward and gradually close them. The closed edges are connected in a snap-fastener form to obtain the intermediate layer cored wire.

[0046] S6. Outer layer cored wire laying: On the cored wire machine, unwind, flatten, and stretch forward the 0.8-mm-thick outermost-layer thin steel strip 7. While stretching, lay the intermediate layer cored wire along the direction of the outermost-layer thin steel strip 7 on the outermost-layer thin steel strip 7. Then, from above, use the feeding system to evenly sprinkle fluorite particles 6 with a particle size of 0.5 μm and a thickness of 0.8 mm onto the intermediate layer cored wire and the outermost-layer thin steel strip 7 according to the ratio requirements.

[0047] S7. Outer layer cored wire coiling production: At the front end along the stretching direction of the laid outer layer cored wire and the outermost-layer thin steel strip 7 with fluorite particles 6, gradually curl the two outer edges of the outermost-layer thin steel strip 7 upward and gradually close them. The closed edges are connected in a snap-fastener form to obtain the rare earth praseodymium-titanium-silicon-nitrogen-aluminum alloy cored wire for steelmaking.

[0048] Example 3

[0049] A preparation method of a rare earth praseodymium-titanium-silicon-nitrogen-aluminum alloy cored wire for steelmaking includes the following steps:

[0050] S1. Steel wire stranding: Place at least 7 steel wires with a diameter of 0.05 mm side by side and straighten them. Then, with one steel wire as the central axis, rotate one end of the remaining 6 steel wires in the same direction around the central axis so that each steel wire is spirally coiled together to obtain a steel rod 1.

[0051] S2. Inner layer cored wire laying: On the cored wire machine, open, flatten, and stretch forward the 1-mm-thick first-layer thin steel strip 3. During the stretching process, lay the steel rod 1 along the stretching direction of the first-layer thin steel strip 3 on the first-layer thin steel strip 3. Then, from the rear, use its feeding system to evenly sprinkle ferrosilicon nitride particles 2 with a particle size of 0.5 mm, a thickness of 1.5 mm, a Si content of 50%, an N content of 40%, and the balance being iron and other inevitable impurity elements onto the steel rod 1 and the first-layer thin steel strip 3.

[0052] S3. Inner layer cored wire curling production: At the front end of the first layer of thin steel strip 3 of the spread steel bars 1 and ferrosilicon nitride particles 2 along the stretching direction, gradually curl the two outer edges of the first layer of thin steel strip 3 upward and gradually close them. The closed edges are connected in a snap-fastener form to obtain the inner layer cored wire;

[0053] S4. Intermediate layer cored wire feeding: On the cored wire machine, unwind, flatten, and stretch forward the 2-mm second layer of thin aluminum strip 5. While stretching, lay the inner layer cored wire on the second layer of thin aluminum strip 5 along the stretching direction of the first layer of thin steel strip 3. Then, from above, use the feeding system to evenly spread rare earth praseodymium-titanium alloy powder 4 on the inner layer cored wire and the second layer of thin aluminum strip 5 according to the ratio of 90% praseodymium content, 4% titanium content, 4% silicon content, 1% calcium content, and the balance being iron, manganese, and other inevitable impurity elements, with the alloy layer thickness being 0.5 mm;

[0054] S5. Intermediate layer cored wire curling production: At the front end of the second layer of thin aluminum strip 5 of the laid inner layer cored wire and rare earth praseodymium-titanium alloy powder 4 along the stretching direction, gradually curl the two outer edges of the second layer of thin aluminum strip 5 upward and gradually close them. The closed edges are connected in a snap-fastener form to obtain the intermediate layer cored wire;

[0055] S6. Outer layer cored wire feeding: On the cored wire machine, unwind, flatten, and stretch forward the outermost 0.8-mm thin steel strip 7. While stretching, lay the intermediate layer cored wire on the outermost thin steel strip 7 along the direction of the outermost thin steel strip 7. Then, from above, use the feeding system to evenly spread fluorite particles 6 with a particle size of 0.5 μm and a thickness of 0.8 mm on the intermediate layer cored wire and the outermost thin steel strip 7 according to the ratio requirements;

[0056] S7. Outer layer cored wire curling production: At the front end of the outermost thin steel strip 7 of the laid outer layer cored wire and fluorite particles 6 along the stretching direction, gradually curl the two outer edges of the outermost thin steel strip 7 upward and gradually close them. The closed edges are connected in a snap-fastener form to obtain the rare earth praseodymium-titanium-silicon-nitrogen-aluminum alloy cored wire for steelmaking.

[0057] Comparative Example 1

[0058] The difference between this comparative example and Example 1 is that aluminum powder is used instead of rare earth praseodymium-titanium alloy powder.

[0059] Comparative Example 2

[0060] The difference between this comparative example and Example 3 is that magnesium powder is used instead of praseodymium-titanium alloy powder.

[0061] Comparative Example 3

[0062] The difference between this comparative example and Example 3 is that the rare earth praseodymium-titanium alloy powder is in the inner layer and the thin aluminum strip is used as the first layer of thin strip.

[0063] Performance test

[0064] Functional detection was carried out on the cored wires prepared in Examples 1-3 and Comparative Examples 1-3. The deoxidation efficiency T[O] and the nitrogen increasing effect (nitrogen recovery rate) were measured by an oxygen-nitrogen analyzer respectively.

[0065] Table 1

[0066] Functional Index T[O] Nitrogen Recovery Rate Example 1 0.0017％ 69％ Example 2 0.0011％ 75％ Example 3 0.0021％ 62％ Control Example 1 0.0039％ 56％ Control Example 2 0.0026％ 60％ Control Example 3 0.0025％ 58％

[0067] It can be seen from Table 1 that compared with Example 2, the rare earth layer in Examples 1 and 3 is thin and the content of the rare earth element praseodymium is low, and its deoxidation efficiency and nitrogen recovery rate are relatively low compared with Example 2, and the effects shown are not as good as those of Example 2; compared with Example 1, in Comparative Example 1, aluminum powder is used instead of rare earth praseodymium-titanium alloy powder, although the cost is reduced, its deoxidation efficiency and nitrogen recovery rate are not as good as those of Example 1; compared with Example 3, in Comparative Example 2, magnesium powder is used instead of praseodymium-titanium alloy powder, and there is a gap in its deoxidation effect and nitrogen recovery rate compared with Example 3, which is not as good as Example 3; compared with Example 3, in Comparative Example 3, the rare earth praseodymium-titanium alloy powder is in the inner layer, and the thin aluminum strip is used as the first thin layer strip, and its nitrogen recovery rate is quite different from that of Example 3, and the effect is not as good as that of Example 3.

[0068] The above content is only an example and illustration of the concept of this application. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all belong to the protection scope of this application.

Claims

1. A rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking, characterized in that: The cored wire consists of three parts: a central core wire (1), core powder and a thin layer strip; the core powder includes three parts: rare earth praseodymium titanium alloy powder, silicon iron nitride particles and fluorite particles; the thin layer strip includes three parts: a first thin steel strip (3), a second thin aluminum strip (5) and an outermost thin steel strip (7); the outermost thin steel strip (7) and the fluorite layer (6) form an outer protective layer, the rare earth layer (4) is an intermediate layer, and the silicon iron nitride layer (2) is an inner layer.

2. The rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking according to claim 1, characterized in that: The central core wire (1) is a steel rod made of steel, composed of a plurality of steel wires, with a diameter of 0.1-1 mm, and the number of steel wires is greater than or equal to 2.

3. The rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking according to claim 1, characterized in that: The material used for the silicon nitride iron layer (2) is silicon nitride iron alloy particles, the particle size of which is 0.2-0.5 mm and the thickness of which is 0.8-2 mm; the weight percentage of the elements in the silicon nitride alloy particles is as follows: Si content is 42-52%, N content is greater than or equal to 15%, and the remainder is iron and other inevitable impurity elements.

4. The rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking according to claim 1, characterized in that: The rare earth layer (4) is mainly rare earth praseodymium titanium alloy powder, and the thickness of the alloy layer is 0.2-2 mm; the weight percentage of each element in the rare earth praseodymium titanium alloy powder is as follows: praseodymium content is greater than or equal to 85%, titanium content is 1-6%, silicon content is 1-6%, calcium content is 0.1-2%, and the remainder is iron, manganese and other inevitable impurity elements.

5. The rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking according to claim 1, characterized in that: The fluorite layer (6) mainly comprises fluorite particles with a particle size less than 0.6 mm and a thickness of 0.4-1.2 mm.

6. The rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking according to claim 5, characterized in that: The fluorite layer (6) mainly comprises fluorite particles with a particle size of less than 1 μm and a thickness of 0.4-0.8 mm.

7. The rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking according to claim 1, characterized in that: The material used for the first thin steel strip (3) and the outermost thin steel strip (7) is steel, the thickness of the first thin steel strip (3) is 0.5-1 mm, and the thickness of the outermost thin steel strip (7) is less than 0.8 mm; the material used for the second thin aluminum strip (5) is aluminum, the aluminum content is greater than 95%, and the thickness of the second thin aluminum strip (5) is 0.3-2 mm.

8. A method for preparing rare earth praseodymium titanium silicon nitrogen aluminum alloy cored wire for steelmaking as claimed in claims 1 to 7, characterized in that: The steps include: S1, winding at least two steel wires together in a spiral shape to obtain a steel rod (1); S2, laying the steel rod on the first layer of thin steel strip (3), and spreading the ferrosilicon nitride particles (2) according to the required proportion by using the feeding system; S3, closing the first layer of thin steel strip (3) of the spread steel rod (1) and ferrosilicon nitride particles (2) to obtain an inner cored wire; S4, using a feeding system to spread rare earth praseodymium titanium alloy powder (4) onto the inner core wire and the second thin aluminum strip (5) according to the required proportion; S5, closing the inner layer cored wire and the second layer thin aluminum strip (5) of rare earth praseodymium titanium alloy powder (4) to obtain an intermediate layer cored wire; S6, using a feeding system to spread fluorite particles (6) onto the middle layer of cored wire and the outermost layer of thin steel strip (7) according to the required proportion; S7, closing the spread outer core wire and the outermost thin steel strip (7) of the fluorite particles (6) to obtain a rare earth praseodymium titanium silicon nitrogen aluminum alloy core wire for steelmaking.

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