A composite inoculated cored wire and its preparation method

Abstract

This invention provides a composite inoculated cored wire, belonging to the technical field of cored wire. The composite inoculated cored wire comprises the following raw materials by mass fraction: 50-60% low-barium silicon and 40-50% formulated powder. The formulated powder composition is: 6-6.5% Mg, 1.5-3% Ca, 2-2.5% RE, 44-46% Si, with the balance being iron. The preparation method involves mixing and melting magnesium ingots, calcium silicon, rare earth silicon, and ferrosilicon in a certain proportion to obtain alloy blocks; then crushing the obtained blocks into formulated powder with a particle size of 0.2-2 mm; similarly crushing the low-barium silicon raw material into powder with a particle size of 0.2-2 mm; mixing the low-barium silicon alloy powder (50-60%) and formulated powder (40-50%) evenly; and finally winding the powder into the composite inoculated cored wire using steel strip. The use of composite inoculated cored wire provided by this invention can improve the residual Mg value and the graphite grade of the casting. It can not only reduce the amount of spheroidized cored wire used, but also improve the mechanical properties of the casting and enhance its roundness and uniformity.

Description

Technical Field

[0001] This invention relates to the field of cored wire technology, and more specifically, to a composite inoculated cored wire. Background Art

[0002] Cored wire is made by wrapping alloy powder around a strip of steel. During use, the cored wire is added to molten iron using a wire feeder to complete the iron treatment. Depending on the alloy powder used, it can be classified as: silicon-calcium cored wire, silicon-manganese-calcium cored wire, silicon-calcium-barium cored wire, barium-aluminum cored wire, aluminum-calcium cored wire, calcium-iron cored wire, pure calcium cored wire, etc. Cored wire is used for deoxidation treatment of molten iron to improve the steel's strength, toughness, and electromagnetic orientation properties; this method is called inoculation treatment.

[0003] In the existing process, the absorption rate of Mg (15-30%), the main component of spheroidized cored wire, in molten iron fluctuates slightly, resulting in a low and unstable residual magnesium value in the final casting, and the graphite grade cannot meet customer requirements. Summary of the Invention

[0004] Embodiments of the present invention provide a composite inoculated cored wire, which aims to solve the problems mentioned in the background art.

[0005] This invention provides a composite inoculated cored wire comprising the following raw materials by mass fraction: 50-60% low-barium silicon, 40-50% formulated powder, wherein the formulated powder comprises: 6-6.5% Mg, 1.5-3% Ca, 2-2.5% RE, 44-46% Si, and the balance being iron.

[0006] In this embodiment, the use of composite inoculated cored wire provided by the present invention can make the residual Mg value more stable, and improve the absorption rate of Mg and the graphite grade of the casting. It can not only reduce the amount of spheroidized cored wire used, but also improve the mechanical properties of the casting and enhance its roundness and uniformity.

[0007] In one embodiment of the present invention, the raw material ratio of the composite inoculated cored wire is: 50% low barium silicon and 50% powder.

[0008] In this embodiment, a raw material ratio of 50% low-barium silicon and 50% powder is used, which can meet the needs of most customers.

[0009] This invention also provides a method for preparing the above-mentioned composite inoculated cored wire, comprising the following steps:

[0010] S1. A certain proportion of magnesium ingots, calcium silicon, rare earth silicon and ferrosilicon are mixed and smelted to obtain a block of material with the following composition: Mg 6-6.5%, Ca 1.5-3%, RE 2-2.5%, Si 44-46%, and the balance being iron.

[0011] S2. Crush the block material obtained in S1 into a powder with a particle size of 0.2-2mm;

[0012] S3. The low-barium silicon raw material is also crushed into low-barium silicon alloy powder with a particle size of 0.2-2mm;

[0013] S4. Mix the low-barium silicon alloy powder (50-60%) with the powder (40-50%) until homogeneous.

[0014] S5. The powder mixed in step S4 is then wrapped with steel strip to form the composite inoculated cored wire.

[0015] The composite inoculated cored wire prepared using the raw material ratio and preparation method of this invention produces the following beneficial effects in actual use:

[0016] 1. It can effectively increase the upper limit of residual Mg and improve the Mg absorption rate in composite inoculated cored wire, thereby appropriately reducing the amount of spheroidized cored wire used and reducing costs;

[0017] 2. To make the residual Mg value of castings more stable, improve the graphite grade of castings, and improve the mechanical properties of products in terms of roundness and uniformity;

[0018] 3. When molten iron reacts with composite inoculated cored wire, a small amount of elements such as Mg, RE, and Ca can act as a preparatory element to make the spheroidizing process more gentle and controllable. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The composite inoculated cored wire and its preparation method provided by this invention will produce slightly different residual Mg values ​​in the castings under different raw material ratios. The following is a comparative analysis of several typical and specific embodiments selected from multiple experiments.

[0021] Example 1

[0022] Magnesium ingots, calcium silicon, rare earth silicon, and ferrosilicon are mixed and smelted in a certain proportion to produce a block material with the following composition: Mg 6%, Ca 1.5%, RE 2%, Si 44%, and the balance being iron.

[0023] The above-mentioned lumps are then crushed into powder with a particle size of 0.2mm.

[0024] Similarly, the low-barium silicon raw material was crushed into low-barium silicon alloy powder with a particle size of 0.2mm.

[0025] Mix the low-barium silicon alloy powder (50%) with the powder in a uniform ratio of 50%.

[0026] Finally, the mixed powder is wrapped with steel strip to produce composite inoculated cored wire A1.

[0027] Example 2

[0028] Magnesium ingots, calcium silicon, rare earth silicon, and ferrosilicon are mixed and smelted in a certain proportion to produce a block of material with the following composition: Mg 6.2%, Ca 2.2%, RE 2.3%, Si 45%, and the balance being iron.

[0029] The above-mentioned lumps are then crushed into powder with a particle size of 1mm.

[0030] Similarly, the low-barium silicon raw material was crushed into low-barium silicon alloy powder with a particle size of 1mm.

[0031] Mix the low-barium silicon alloy powder (55%) with the powder (45%) in a uniform ratio.

[0032] Finally, the mixed powder is wrapped with steel strip to produce composite inoculated cored wire A2.

[0033] Example 3

[0034] Magnesium ingots, calcium silicon, rare earth silicon, and ferrosilicon are mixed and smelted in a certain proportion to produce a block of material with the following composition: Mg 6.5%, Ca 3%, RE 2.5%, Si 46%, and the balance being iron.

[0035] The above-mentioned block material is then crushed into a powder with a particle size of 2mm.

[0036] Similarly, the low-barium silicon raw material was crushed into low-barium silicon alloy powder with a particle size of 2mm.

[0037] Mix 60% low-barium silicon alloy powder with 40% powder in a uniform ratio.

[0038] Finally, the mixed powder is wrapped with steel strip to produce composite inoculated cored wire A3.

[0039] Example 4

[0040] The composite inoculated cored wire products A1, A2, and A3 obtained in Examples 1, 2, and 3 were respectively applied to the treatment of molten iron. The resulting castings were subjected to spectral analysis to determine the residual Mg value and graphite grade, and compared with castings obtained after conventional inoculated wire treatment. The following experimental data were obtained:

[0041]

[0042] The data above shows that the composite inoculated cored wire prepared using the raw material ratio and preparation method of this invention can effectively increase the upper limit of residual Mg in actual use, resulting in a 0.003%-0.005% increase in the final residual Mg value. This improves the Mg absorption rate in the composite inoculated cored wire, thereby appropriately reducing the amount of spheroidized cored wire used and lowering costs.

[0043] Furthermore, it can improve the graphite grade of castings. Generally, after treatment with conventional inoculation wire, the graphite grade of castings is grade 4. However, after treatment with the composite inoculation cored wire provided by this invention, the graphite grade of castings can reach grade 4.5. This improves the mechanical properties of the product in terms of roundness and uniformity, and can better meet customer needs.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite inoculated cored wire, characterized in that, The raw materials include the following mass fractions: 50-60% low-barium silicon, 40-50% formulated powder, wherein the composition of the formulated powder is: 6-6.5% Mg, 1.5-3% Ca, 2-2.5% RE, 44-46% Si, and the balance is iron; Its preparation method includes the following steps: S1. A certain proportion of magnesium ingots, calcium silicon, rare earth silicon and ferrosilicon are mixed and smelted to obtain a block of material with the following composition: Mg 6-6.5%, Ca 1.5-3%, RE 2-2.5%, Si 44-46%, and the balance being iron. S2. Crush the block material obtained in S1 into a powder with a particle size of 0.2-2mm; S3. The low-barium silicon raw material is also crushed into low-barium silicon alloy powder with a particle size of 0.2-2mm; S4. Mix the low-barium silicon alloy powder (50-60%) with the powder (40-50%) until homogeneous. S5. The powder mixed in step S4 is then wrapped with steel strip to form the composite inoculated cored wire.

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