Powder spraying refining process for rare earth oxide dispersion strengthened alloy production

Abstract

The present invention discloses a powder injection refining process for the production of rare earth oxide dispersion strengthened alloys, belonging to the technical field of alloy smelting. During tapping from the converter, 4.5 - 8.5 kg / t of ferrosilicon aluminum is used for strong deoxidation; after tapping is completed, 0.2 - 0.4 kg / t of rare earth aluminum alloy is added to the slag surface of the ladle for slag surface deoxidation; the molten steel is transported to the powder injection station, the temperature of the molten steel is adjusted to 1570 - 1610 °C, and the rare earth blowing powder agent is sprayed into the molten steel at a high speed using an inert carrier gas. The working pressure of the carrier gas for powder injection in the ladle is 3.0 - 4.0 bar, the carrier gas flow rate is 40 - 60 m<supgt;3< / supgt> / h, the powder injection speed in the ladle is 10 - 50 kg / min, and the dosage of the blowing powder agent is 1.0 - 50.0 kg / t. After adopting this powder injection refining process, the content of dissolved oxygen in the steel can be increased to more than 100 ppm, and the dissolved content of RE elements can be increased to more than 300 ppm to form an alloy strengthened by nano-rare earth oxide dispersion.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy smelting, and in particular relates to a powder spraying refining process for producing rare earth oxide dispersion strengthened alloys, so as to achieve stable and accurate control of the content of dissolved oxygen and rare earth elements in the alloys. Background Art

[0002] Rare earth oxide dispersion strengthening can significantly improve the strength, high temperature resistance and service life of metal and alloy materials. It is a technical direction that has developed very rapidly in the past decade. The main feature of its microstructure is that nanoscale rare earth oxides (1 nm~100 nm) are uniformly dispersed in the metal and alloy matrix, which pins defects such as dislocations and grain boundaries and improves material properties. The difficulty in its preparation lies in how to evenly disperse nano rare earth oxides in the alloy matrix. The traditional process uses mechanical alloying non-equilibrium technology to prepare rare earth oxide dispersion strengthened alloys. Metal element powder or alloy powder is mechanically alloyed with rare earth oxide (commonly used Y2O3) in a high-energy ball mill, and then formed by hot isostatic pressing or hot extrusion. This process has a small preparation scale, high cost and poor repeatability, and cannot meet the needs of large-scale low-cost industrial production. If ODS alloys can be prepared on a large scale by smelting, it is expected to promote the engineering application of such materials. For example, in Patent 1 (Application No. US201113989230:A), industrial pickling waste liquid is mixed with yttrium chloride and spray roasted, and ODS alloy is prepared on a large scale and at low cost by surface oxidation of metal powder and subsequent hot forming. Patent 2 (Application No. CN201711113150.3) uses vacuum induction / magnetic stirring process to make steel, and quickly casts the molten steel with sufficient oxygen activity into a mold with rare earth element Y added in advance to match [O] in the molten steel, and combines rare earth element Y with [O] in the molten steel to obtain ODS steel with dispersed distribution of rare earth oxides. In Patent 3 (Application No. CN201911387729.8), supersaturated oxide dispersion alloy powder is used as precursor powder to induce rapid nucleation, and nano-oxide dispersion-strengthened steel is prepared by short-process thin strip continuous casting technology, and the problem of uneven oxide distribution and coarseness caused by long-term stirring of alloy powder in the smelting furnace is avoided by rapid solidification. However, while the above-mentioned technical process achieves large-scale preparation of ODS alloys, it leads to problems such as excessive oxide size, uneven distribution and limited profile size. It cannot achieve the oxide dispersion size and number density of traditional mechanical alloying processes, and has not yet effectively solved the demand for large-scale and low-cost industrial production of ODS alloys.

[0003] The difficulty of the relevant technology is that if oxides are introduced into the alloy melt, due to the obvious density difference between the oxides and the alloy melt, the oxides float up in the alloy melt and aggregate and grow, resulting in uneven distribution of the oxides and excessively large sizes; if the short-process thin-strip continuous casting technology with precursor powder induced nucleation is used, the thickness of the thin-strip continuous casting billet is very small because of the need for rapid cooling to avoid oxide agglomeration and growth problems, making it difficult to directly produce large-sized profiles such as medium and thick plates. The diffusion mechanism of oxides is the key to achieving technological breakthroughs. The latest research shows that the necessary conditions for the precipitation of rare earth oxides in alloys are supersaturated solid solution oxygen, high concentration of vacancies, and solid solution of elements such as Y and Ti.

[0004] Powder spraying metallurgy is a technology that uses compressed argon, nitrogen and other gases to spray metallurgical reactants (calcium-silicon, calcium oxide, magnesium, carbon and other powders) into molten steel during the steelmaking process. It can make the refining reactions such as dephosphorization, desulfurization and deoxidation of molten steel proceed quickly and fully, accelerate the floating removal rate of inclusions, effectively improve the quality of molten steel, shorten the smelting time, improve productivity, reduce energy consumption, and improve the quality of steel. During the powder spraying metallurgy process, when the carrier gas is sprayed into the molten steel at a high speed, it will separate into many small bubbles, which accelerates the movement of the molten steel. The powder spraying agent reacts quickly with the molten steel, which can promote the efficient dispersion of trace alloy elements and significantly increase the vacancy concentration in the solidified structure. If supersaturated solid dissolved oxygen and solid dissolved RE, Ti and other elements are introduced into the alloy through powder spraying metallurgy, it is possible to solve the problem that supersaturated O and supersaturated RE elements are difficult to add to the alloy melt, meet the necessary conditions for the formation of nano-oxides, and achieve the dispersed distribution of nano-oxides. However, traditional powder spraying metallurgy mainly achieves the effects of dephosphorization, desulfurization and deoxidation by spraying composite oxides such as calcium oxide and reducing agents such as magnesium, aluminum and carbon into the molten steel. For example, in Patent 4 (application number CN202210678030.2), the phosphorus content in semi-steel is significantly reduced by spraying calcium ferrite powder (CaO and FeO) and limestone powder. In Patent 5 (application number CN201110147607.9), the sulfur content in steel is reduced from 50~80ppm to below 12ppm by spraying CaO-SiO2-MgO-CaF2 desulfurization powder. Patent 6 (application number CN201910077604.9) reduces the free oxygen content in steel by spraying graphite carbon powder. Powder spraying metallurgy is a key technology for controlling the content of oxygen and trace alloy elements in alloys, and is a core confidential technology in the production of high-quality steel.

[0005] Patent 7 (application publication number CN119175364A) discloses a powder blowing agent for preparing nano-oxide dispersion-strengthened steel by powder metallurgy. This technology can introduce solid-dissolved rare earth and solid-dissolved oxygen into smelted steel, thereby realizing the solid phase precipitation of nano-oxide in steel. However, due to the different alloying elements and residual oxygen content in the molten steel during the smelting process of different types of steel, it is difficult to predict the degree of reaction between the alloying elements and RE and O in the powder blowing agent, which can easily cause the burning of micro-alloying elements and form oxides with poor stability. The RE and O contents are difficult to control stably, and the quality control of steel is difficult. Therefore, the powder blowing agent disclosed in this technology needs to be systematically optimized for matching each type of steel, and the development cost is high and the cycle is long. At the same time, RE elements are usually added to the alloy melt in the form of rare earth pure metal or rare earth intermediate alloy. Because the chemical properties of RE elements are very active, they are easy to react with oxygen, sulfur, nitrogen, etc. Therefore, the loss of rare earth elements in the high-temperature smelting process is relatively large, mainly including: (1) the loss caused by the reaction of rare earth elements with the atmosphere; (2) the loss caused by the reaction of rare earth elements with the crucible during vacuum induction melting; (3) the loss caused by the reaction of rare earth elements with oxide slag during electroslag remelting, which leads to large fluctuations in the rare earth content in the alloy and ultimately causes unstable performance of the alloy.

[0006] Therefore, it is extremely difficult to simultaneously obtain stable oxygen content and rare earth element content control in the alloy melt, which can easily cause alloy composition deviation, especially when RE and O are contained in the powder blowing agent, the alloy composition changes dramatically, and systematic process optimization is required for each alloy system, resulting in a long production process optimization cycle and high cost. By designing the content of oxidizing and strongly reducing alloying elements in the alloy melt during powder spraying metallurgy, the development of RE and O content stabilization control technology that is generally applicable to various alloy systems is of great significance to shortening the R&D cycle of ODS alloys and reducing development costs. Summary of the invention

[0007] The purpose of the present invention is to provide a powder spray refining process for the production of rare earth oxide dispersion strengthened alloys. By systematically controlling factors such as deoxidizer composition, dosage, powder blowing agent composition, blowing speed, powder spraying amount, temperature and Al, RE and O element contents in molten steel, stable and accurate control of RE and O contents in the alloy melt is achieved, forming a powder spray smelting process for rare earth oxide dispersion strengthened alloys, which can stably increase the solid solution oxygen content in the alloy melt to more than 100 ppm and the solid solution content of rare earth elements to more than 300 ppm, so as to form a rare earth oxide dispersion strengthened alloy.

[0008] The innovation of the present invention lies in overcoming the shortcomings of the existing rare earth oxide dispersion strengthened alloy preparation technology and the limitations of the existing powder spraying metallurgy process design. Through the systematic and innovative design of the ladle powder spraying process and the composition of the deoxidizer and the powder blowing agent, the oxidizing property of the alloy melt and the content of strongly reducing alloy elements in the powder spraying metallurgy process are regulated, thereby obtaining stable solid dissolved oxygen and solid dissolved rare earth element content in the alloy melt to achieve nano rare earth oxide dispersion strengthening in the alloy, making it generally applicable to different alloy systems, thereby significantly reducing the research and development cycle of powder spraying metallurgy to prepare ODS alloys and reducing research and development costs.

[0009] The present invention proposes a new technical solution for a powder refining process for rare earth oxide dispersion strengthening alloy production. By applying the process solution to alloy production, a stable supersaturated solid solution oxygen content and solid solution rare earth element content can be simultaneously obtained in the alloy solidification structure, so that the solid solution rare earth element and solid solution oxygen are combined to form nano rare earth oxide particles during solidification and subsequent thermomechanical treatment. Through the pinning effect of the rare earth oxide particles on dislocations and grain boundaries, the rare earth element and oxygen combination can improve the high temperature performance of the alloy, and the oxygen in the alloy is converted from a harmful element to a beneficial element that plays a positive role. The technical solution provided by the present invention can greatly reduce the number of coarse oxides in high-oxygen content alloys to the same level as the number of coarse oxides in ultra-low oxygen content alloys, and additionally produce a large number of rare earth oxides with a size less than 10nm, which have an additional pinning effect on dislocations, phase interfaces and grain boundaries, and improve the high temperature strength, creep life and oxidation resistance of the alloy. The ladle powder spraying refining process disclosed in the present invention can be used in the fields of preparing steel and high-temperature alloys for aircraft engines and gas turbine components, nuclear reactor radiation-resistant alloys, high-speed train rails and wheel materials, non-magnetic high-strength steel plates for ships, and high-strength and toughness steel plates for automobiles.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

[0011] A powder spraying refining process for producing rare earth oxide dispersion strengthened alloys comprises the following steps:

[0012] 1) The converter steel is strongly deoxidized by using an iron-silicon-aluminum deoxidizer of 4.5-8.5 kg / t, wherein the iron-silicon-aluminum deoxidizer comprises the following elements in percentage by mass: Fe: 40-55%, Si: 35-45%, Al: 3-15%, and the mass ratio of Si and Al elements meets the requirement of Si / Al≥3:1;

[0013] 2) After steel tapping, add 0.2-0.4 kg / t of rare earth aluminum alloy to the slag surface of the ladle for slag surface deoxidation, wherein the rare earth aluminum alloy includes the following elements in percentage by mass: Al: 95-98%, RE: 2-5%;

[0014] 3) The molten steel is transported to the powder spraying station, and the temperature of the molten steel is adjusted to 1570~1610℃. The rare earth powder blowing agent is sprayed into the molten steel at high speed using an inert carrier gas. The working pressure of the carrier gas for ladle powder spraying is 3.0-4.0bar, and the carrier gas flow rate is 40-60m 3 / h, ladle powder spraying speed 10-50kg / min, blowing agent dosage 1.0~50.0kg / t; the blowing agent includes the following elements in percentage by mass: Fe: 50.0~99.0%, RE: 0.7~15.0%, O: 0.3~10.0%, and the mass ratio of RE and O elements meets RE / O (1.5:1)~(5:1); RE and O in the blowing agent are dissolved into the matrix in the form of atoms;

[0015] The RE is a rare earth.

[0016] The above kg / t refers to kg / ton of molten steel. The O element in the blowing agent does not exist in the blowing agent in the form of oxides, but exists in the blowing agent in the form of atoms. The preparation method of the above blowing agent is as follows: adopt a smelting process to melt Fe and RE raw materials into an alloy according to the component ratio, and obtain atomized alloy powder through an atomization powder making process; mix the atomized alloy powder with rare earth oxides, and control the mass ratio of RE, Si, and O elements by the relative addition amount of atomized alloy powder and rare earth oxide, so that RE / O is (1.5:1)~(5:1); place the mixed raw material powder into a mechanical alloying sealed tank, and perform mechanical alloying under the protection of an inert atmosphere; grade and screen the mechanically alloyed powder, select powder with a particle size of 1 to 500µm, and obtain the blowing agent.

[0017] After deoxidation in step 1) and step 2), it can be ensured that after the ladle arrives at the station, FeO+MnO in the top slag is ≤2.0wt%, and the oxygen content in the molten steel is ≤20ppm, the Al content is 0.010~0.030wt% and the RE content is 0.001~0.020wt%.

[0018] Further, the powder blowing agent also contains at least one of Cr, Ni, W, V, Mn, Si, Ti, Zr, and Ca, and the mass proportions of the above elements are as follows: Cr: 0~15.0%, Ni: 0~15.0%, W: 0~5.0%, V: 0~5%, Mn: 0~15.0%, Si: 0~15.0%, Ti: 0~10.0%, Zr: 0~5.0%, Ca: 0~5.0%, and the mass proportion of the elements conforms to (RE+Cr+Ni+W+V+Mn+Si+Ti+Zr+Ca) / O is (1.5:1)~(19:1). The preparation method of the powder blowing agent refers to CN119175364A. According to the alloy composition in the molten steel, adding elements other than Fe, RE and O to the powder blowing agent can reduce the severity of the rare earth oxide synthesis reaction after heat treatment on the one hand, and make the density of the powder blowing agent more consistent with that of the alloy liquid on the other hand.

[0019] For example, the inert carrier gas is argon or nitrogen.

[0020] For example, the RE element is one of yttrium, lanthanum, cerium, gadolinium, erbium, neodymium, praseodymium, terbium, samarium, dysprosium or scandium, or a combination of multiple elements thereof.

[0021] The above-mentioned deoxidizer, powder blowing agent and process parameters specially designed for the above-mentioned powder spray refining process have precise composition ratios that can make the oxidizing and strongly reducing alloying element contents of the alloy melt within an appropriate range, obtain balanced coexistence of solid-dissolved oxygen and alloying elements, and make stable contents of rare earth elements RE and oxygen O evenly distributed in the melt in the form of solid solution, which is crucial to improving metallurgical efficiency and product quality. When the Si / Al ratio in the Fe-Si-Al deoxidizer is too low, that is, lower than 3:1, too much Al residue may be generated in the alloy melt. These Al residues combine with RE and O in the powder blowing agent to form RE-Al-O ternary oxides, which have poor thermal stability and large size, and will reduce the comprehensive performance of the final material; when the oxidizability of the top slag (FeO+MnO) at the ladle station is greater than 2.0% or the oxygen content in the molten steel is greater than 20ppm, the RE in the powder blowing agent is ablated in large quantities, resulting in a decrease in the RE content in the solidified structure, and it is impossible to achieve stable RE content control; when the RE / O ratio of the mass ratio of RE and O elements in the powder blowing agent is too low, the supersaturated solid solution oxygen is easily converted into free oxygen, causing the alloy melt to boil and cause alloy defects. On the contrary, if the ratio is too high, that is, higher than 5:1, it will lead to excessive solid solution RE in the alloy. During the cooling process of the alloy, these RE will precipitate along the grain boundaries, reduce the grain boundary strength, and reduce the material performance. When the blowing agent contains elements such as Cr, Ni, W, V, Mn, Si, Ti, Zr, and Ca, these elements exert an influence similar to that of RE.

[0022] The present invention has the following beneficial effects:

[0023] 1. The powder spray refining process provided by the present invention adopts a technical concept different from that of traditional powder spray metallurgy in which the oxygen content is reduced to avoid the generation of impurities such as oxides. A high oxygen content powder spray metallurgy process is systematically designed. In actual production, a stable content of rare earth elements and oxygen can be evenly distributed in the alloy melt in the form of a solid solution, and rare earth oxides are formed in the subsequent solidification and processing process, producing a dispersion strengthening effect, and converting the oxygen in the alloy from a harmful element to a beneficial element that plays a positive role.

[0024] 2. The powder spray refining process provided by the present invention creatively realizes the simultaneous stable and precise control of supersaturated solid-solution rare earth elements and solid-solution oxygen elements. Through the overall innovative design of the process scheme, the difficult problem of accurate control of rare earth content and stable control of solid-solution oxygen and solid-solution rare earth content in traditional rare-earth-containing alloys is solved, thereby solving the problem that the powder blowing agent in the existing ODS alloy powder spray smelting technology is difficult to apply to different alloy systems.

[0025] 3. The powder spraying refining process for rare earth oxide dispersion strengthening alloy production provided by the present invention can, through the powder spraying process and the deoxidizer and powder blowing agent composition design, make the prepared alloy have better mechanical properties and organizational stability at high temperature without significantly changing the existing production equipment, and have excellent corrosion resistance in oxidizing atmosphere and high-temperature steam environment, and can meet the performance requirements of special application environments such as steel and high-temperature alloys for aircraft engines and gas turbine components, nuclear reactor radiation-resistant alloys, high-speed train rails and wheel materials, non-magnetic high-strength steel plates for ships, and high-strength and tough steel plates for automobiles. The ladle powder spraying refining process has general applicability to existing mainstream alloy production processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a powder spray refining process flow chart for the production of rare earth oxide dispersion strengthened alloys. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention application are described in detail below in combination with the embodiments and drawings. The embodiments are only part of the embodiments of the present invention, not all of them. In the following description, the specific features, structures, or characteristics of one or more embodiments can be combined in any suitable form, and other embodiments obtained by combining without creative work are all within the scope of protection of the present invention.

[0028] Unless otherwise specified, the proportions of the components in the following embodiments of the present invention are all in mass percentage.

[0029] like Figure 1As shown, a powder spraying refining process for producing rare earth oxide dispersion strengthened alloys comprises the following steps:

[0030] 1) The converter steel is deoxidized with 4.5~8.5kg / t of FeSiAl deoxidizer.

[0031] 2) After steel tapping, add 0.2~0.4kg / t of rare earth aluminum alloy to the slag surface of the ladle for deoxidation.

[0032] 3) The molten steel is transported to the powder spraying station, the temperature of the molten steel is adjusted at 1570~1610℃, and the rare earth powder blowing agent is sprayed into the molten steel at high speed using an inert carrier gas.

[0033] The iron-silicon-aluminum deoxidizer includes the following elements in mass percentage: Fe: 40-55%, Si: 35-45%, Al: 3-15%, and the mass ratio of Si and Al elements meets Si / Al≥3:1. The rare earth aluminum alloy includes the following elements in mass percentage: Al: 95-98%, RE: 2-5%. The ladle powder spraying conveying carrier gas working pressure is 3.0-4.0 bar, and the carrier gas flow rate is 40-60m 3 / h, ladle powder spraying speed 10-50kg / min, blowing agent dosage 1.0~50.0kg / t. The blowing agent includes the following elements in mass percentage: Fe: 50.0~99.0%, RE: 0.7~15.0%, O: 0.3~10.0%, and the mass ratio of RE and O elements meets RE / O (1.5:1)~(5:1); RE and O in the blowing agent are dissolved into the matrix in the form of atoms.

[0034] Embodiment 1:

[0035] Alloy type: Fe-25Mn-3Al-3Si TWIP steel

[0036] Use Figure 1 The powder spray refining process shown in the figure is used to prepare TWIP steel, and includes the following steps:

[0037] 1) The converter output is 150 tons. The converter uses 5.5kg / t of strong deoxidation with an iron-silicon-aluminum deoxidizer. The composition of the iron-silicon-aluminum deoxidizer is: Fe 40%, Si 45%, Al 15%;

[0038] 2) After steel tapping, add 0.3kg / t of rare earth aluminum alloy to the slag surface of the ladle for deoxidation. The composition of the rare earth aluminum alloy is: Al 97%, Y 3%;

[0039] After the ladle arrives at the station, the top slag oxidizability (FeO+MnO) = 0.8%, and the oxygen content in the molten steel is ≤20ppm, Al% is 0.013%, and Y% is 0.009%;

[0040] 3) When the molten steel reaches the powder spraying station, the temperature of the molten steel is adjusted to 1590℃, and the high oxygen content rare earth powder blowing agent is sprayed into the molten steel at high speed using an inert carrier gas. The working pressure of the carrier gas for ladle powder spraying is 3.5 bar, and the carrier gas flow rate is 45 m 3 / h, ladle powder spraying speed is 25 kg / min, the amount of blowing agent is 10.0 kg / t, and the components of the blowing agent are: Fe 90.0%, Si 6.0%, Y 2.5%, O1.5%.

[0041] After powder spray refining, continuous casting treatment was carried out to obtain solidified oxygen-containing rare earth-containing TWIP steel. The oxygen content was determined by GB / T 11261-2006 "Determination of oxygen content of steel-Pulse heating inert gas melting-infrared absorption method" and the Y content was determined by GB / T 223.49-1994 "Chemical analysis method for steel and alloys-Extraction separation-Azochlorophosphonium mA spectrophotometric method for determination of total rare earth content". The solidified TWIP steel had a solid dissolved oxygen content of 159 ppm and a solid dissolved Y content of 320 ppm. The three-dimensional atom probe (Atom Probe Tomograph) measured that after heat treatment, the ODS TWIP steel produced an average size of 3.2nm and a number density of 1.17×10 24 m -3 of rare earth oxides.

[0042] The high temperature tensile mechanical property test method of GB / T228.2-2015 and the creep property test method of GB / T 2039-2012 were used to test rod samples. The results showed that the yield strength of the ODS TWIP steel after heat treatment was 527MPa, the tensile strength was 623MPa, and the elongation at break was 47% at 500℃; the creep life was 3270 hours at 500℃ / 300MPa.

[0043] Embodiment 2:

[0044] The preparation method is the same as that of Example 1, except that the components of the blowing agent used are: Fe 50.0%, Si 10.0%, Y 15.0%, O 10.0%, Mn 15%, and the amount of the blowing agent is 1.0 kg / t.

[0045] After powder spray refining, continuous casting treatment was carried out to obtain solidified oxygen-containing rare earth-containing TWIP steel. The oxygen content was determined by GB / T 11261-2006 "Determination of oxygen content of steel-Pulse heating inert gas melting-infrared absorption method" and the Y content was determined by GB / T 223.49-1994 "Chemical analysis method for steel and alloys-Extraction separation-Azochlorophosphonium mA spectrophotometric method for determination of total rare earth content". The solidified TWIP steel had a solid dissolved oxygen content of 113 ppm and a solid dissolved Y content of 310 ppm. The three-dimensional atom probe (Atom Probe Tomograph) measured that after heat treatment, the ODS TWIP steel produced an average size of 2.2nm and a number density of 1.07×10 24 m -3 of rare earth oxides.

[0046] The high temperature tensile mechanical property test method of GB / T228.2-2015 and the creep property test method of GB / T 2039-2012 were used to test rod samples. The results showed that the yield strength of the ODS TWIP steel after heat treatment was 439MPa, the tensile strength was 556MPa, and the elongation at break was 49% at 500℃; the creep life was 2257 hours at 500℃ / 300MPa.

[0047] Embodiment 3:

[0048] The preparation method is the same as that of Example 1, except that the components of the blowing agent used are: Fe 99.0%, Y 0.7%, O 0.3%, and the amount of the blowing agent is 50 kg / t.

[0049] After powder spray refining, continuous casting treatment was carried out to obtain solidified oxygen-containing rare earth-containing TWIP steel. The oxygen content was determined by GB / T 11261-2006 "Determination of oxygen content of steel-Pulse heating inert gas melting-infrared absorption method" and the Y content was determined by GB / T 223.49-1994 "Chemical analysis method for steel and alloys-Extraction separation-Azochlorophosphonium mA spectrophotometric method for determination of total rare earth content". The solidified TWIP steel had a solid dissolved oxygen content of 139 ppm and a solid dissolved Y content of 320 ppm. The three-dimensional atom probe (Atom Probe Tomograph) measured that after heat treatment, the ODS TWIP steel produced an average size of 2.7nm and a number density of 1.09×10 24 m -3 of rare earth oxides.

[0050] The high temperature tensile mechanical property test method of GB / T228.2-2015 and the creep property test method of GB / T 2039-2012 were used to test rod samples. The results showed that the yield strength of the ODS TWIP steel after heat treatment was 467MPa, the tensile strength was 583MPa, and the elongation at break was 46% at 500℃; the creep life was 2720 hours at 500℃ / 300MPa.

[0051] Embodiment 4:

[0052] The preparation method is the same as that of Example 1, except that the components of the blowing agent used are: Fe 98.2%, Y 1.5%, O 0.3%, and the amount of the blowing agent is 45 kg / t.

[0053] After powder spray refining, continuous casting treatment was carried out to obtain solidified oxygen-containing rare earth-containing TWIP steel. The oxygen content was determined by GB / T 11261-2006 "Determination of oxygen content of steel-Pulse heating inert gas melting-infrared absorption method" and the Y content was determined by GB / T 223.49-1994 "Chemical analysis method for steel and alloys-Extraction separation-Azochlorophosphonium mA spectrophotometric method for determination of total rare earth content". The solidified TWIP steel had a solid dissolved oxygen content of 135 ppm and a solid dissolved Y content of 523 ppm. The three-dimensional atom probe (Atom Probe Tomograph) measured that after heat treatment, the ODS TWIP steel produced an average size of 3.5nm and a number density of 1.12×10 24 m -3 of rare earth oxides.

[0054] The high temperature tensile mechanical property test method of GB / T228.2-2015 and the creep property test method of GB / T 2039-2012 were used to test rod samples. The results showed that the yield strength of the ODS TWIP steel after heat treatment was 494MPa, the tensile strength was 607MPa, and the elongation at break was 42% at 500℃; the creep life was 3130 hours at 500℃ / 300MPa.

[0055] Embodiment 5:

[0056] Alloy type: X80 steel

[0057] Use Figure 1 The powder spray refining process shown in the figure prepares X80 steel, including the following steps:

[0058] 1) The output of the converter is 100 tons. The converter uses 4.5kg / t of strong deoxidation agent, and the composition of the deoxidizer is: Fe 52%, Si 45%, Al 3%.

[0059] 2) After steel tapping, add 0.2kg / t of rare earth aluminum alloy to the slag surface of the ladle for slag surface deoxidation. The composition of the rare earth aluminum alloy is: Al 95%, Ce 5%;

[0060] After the ladle arrives at the station, the top slag oxidizability (FeO+MnO) = 1.0%, and the oxygen content in the molten steel is ≤20ppm, Al% is 0.009%, and Ce% is 0.007%;

[0061] 3) When the molten steel reaches the powder spraying station, the temperature of the molten steel is adjusted to 1610℃, and the high oxygen content rare earth powder blowing agent is sprayed into the molten steel at high speed using an inert carrier gas. The ladle powder spraying carrier gas working pressure is 4.0 bar and the flow rate is 60 m 3 / h, ladle powder spraying speed is 50kg / min, the amount of blowing agent is 30.0 kg / t, and the percentages of each component of the blowing agent for ladle powder spraying in the total mass are: Fe85.0%, Cr 7.0%, Si 3.5%, Ce 3.0%, and O 1.5%.

[0062] After powder spray refining, continuous casting treatment was carried out to obtain solidified oxygen-containing rare earth X80 steel. The oxygen content was determined by GB / T 11261-2006 "Determination of oxygen content of steel-Pulse heating inert gas melting-infrared absorption method" and the Ce content was determined by GB / T 223.49-1994 "Chemical analysis method for steel and alloys-Extraction separation-Azochlorophosphonium mA spectrophotometric determination of total rare earth content". The solidified X80 steel had a solid dissolved oxygen content of 166 ppm and a solid dissolved Ce content of 359 ppm. The three-dimensional atom probe (Atom Probe Tomograph) measured that after heat treatment, the ODS X80 steel produced an average size of 4.7nm and a number density of 1.03×10 24 m -3 of rare earth oxides.

[0063] The GB / T228.2-2015 high temperature tensile mechanical property test method and the GB / T 2039-2012 creep property test method were used to test the rod-shaped samples. The results showed that the yield strength of the ODS X80 steel after heat treatment at 500°C was 327MPa, the tensile strength was 447MPa, and the elongation at break was 22%; the creep life at 500°C / 220MPa was 1500 hours. A rectangular sample of 2mm×8mm×10mm was used and punched for oxidation resistance test in high temperature air environment, and the oxidation increment per unit area at 1000°C / 100min was <5mg / cm 2 , which is significantly better than the existing commercial X80 steel (the oxidation increment per unit area at 1000℃ / 100min is about 15~20mg / cm 2 ).

[0064] Embodiment 6:

[0065] Alloy type: T92 heat-resistant steel

[0066] Use Figure 1 The powder spraying refining process shown in the figure is used to prepare T92 heat-resistant steel, comprising the following steps:

[0067] 1) The output of the converter is 150 tons. The converter uses 8.5kg / t of strong deoxidation of FeSiAl. The composition of the FeSiAl deoxidizer is: Fe 55%, Si 35%, Al 10%;

[0068] 2) After steel tapping, add 0.4kg / t of rare earth aluminum alloy to the slag surface of the ladle for deoxidation. The composition of the rare earth aluminum alloy is: Al 98%, Er 2%;

[0069] After the ladle arrives at the station, the top slag oxidizability (FeO+MnO) = 0.8%, and the oxygen content in the molten steel is ≤15ppm, Al% is 0.011%, and Er% is 0.006%;

[0070] 3) When the molten steel reaches the powder spraying station, the temperature of the molten steel is adjusted to 1570℃, and the high oxygen content rare earth powder blowing agent is sprayed into the molten steel at high speed using an inert carrier gas. The ladle powder spraying carrier gas working pressure is 3.0 bar and the flow rate is 40 m 3 / h, ladle powder spraying speed is 10kg / min, the amount of blowing agent is 18.0 kg / t, and the percentages of each component of the blowing agent for ladle powder spraying in the total mass are: Fe80.0%, Cr 10.0%, W 2.5%, Ti 2.0%, Si 1.5%, Er 3.0%, and O 1.0%.

[0071] After powder spray refining, continuous casting treatment was carried out to obtain solidified oxygen-containing rare earth-containing T92 steel. The oxygen content was determined by GB / T 11261-2006 "Determination of oxygen content of steel-Pulse heating inert gas melting-infrared absorption method" and the Er content was determined by GB / T 223.49-1994 "Chemical analysis method for steel and alloys-Extraction separation-Azochlorophosphonium mA spectrophotometric determination of total rare earth content". The solidified T92 steel had a solid dissolved oxygen content of 182 ppm and a solid dissolved Er content of 379 ppm. The three-dimensional atom probe (Atom Probe Tomograph) measured that after heat treatment, the ODS T92 steel produced an average size of 3.5nm and a number density of 1.46×10 24 m -3 of rare earth oxides.

[0072] The high temperature tensile mechanical property test method of GB / T228.2-2015 and the creep property test method of GB / T 2039-2012 were used to test rod samples. The results showed that after heat treatment, the yield strength of the ODS T92 steel at 650°C was 358MPa, the tensile strength was 372MPa, and the elongation at break was 18%; the creep life at 700°C / 120MPa was 3200 hours.

[0073] Embodiment 7:

[0074] Alloy type: 316L stainless steel

[0075] This embodiment focuses on demonstrating the effect when the powder blowing agent contains Cr, Ni, W, V, Mn, Si, Ti, Zr, and Ca elements.

[0076] Use Figure 1 The powder spray refining process shown in the figure prepares 316L stainless steel, including the following steps:

[0077] 1) The converter output is 150 tons. The converter uses 6.0kg / t of strong deoxidation of FeSiAl. The composition of the FeSiAl deoxidizer is: Fe 55%, Si 35%, Al 10%;

[0078] 2) After steel tapping, add 0.3kg / t of rare earth aluminum alloy to the slag surface of the ladle for deoxidation. The composition of the rare earth aluminum alloy is: Al 98%, Er 2%;

[0079] After the ladle arrives at the station, the top slag oxidizability (FeO+MnO) = 0.8%, and the oxygen content in the molten steel is ≤20ppm, Al% is 0.011%, and Er% is 0.004%;

[0080] 3) When the molten steel reaches the powder spraying station, the temperature of the molten steel is adjusted to 1600℃, and the high oxygen content rare earth powder blowing agent is sprayed into the molten steel at high speed using an inert carrier gas. The ladle powder spraying carrier gas working pressure is 3.5 bar and the flow rate is 50 m 3 / h, ladle powder spraying speed 25kg / min, powder blowing agent dosage 25.0 kg / t, the percentage of each component of Fe, Cr, Ni, W, V, Mn, Si, Ti, Zr, Ca, Er, O in the powder blowing agent for ladle powder spraying in the total mass is as follows:

[0081]

[0082] After powder spray refining, continuous casting treatment is carried out to obtain solidified oxygen-containing rare earth 316L steel. The oxygen content is determined by GB / T 11261-2006 "Determination of oxygen content of steel-Pulse heating inert gas melting-infrared absorption method", and the Er content is determined by GB / T 223.49-1994 "Chemical analysis methods for steel and alloys-Extraction separation-Azochlorophosphonazo mA spectrophotometry for the determination of total rare earth content". The rare earth oxides in the heat-treated ODS 316L steel are determined by a three-dimensional atom probe (Atom Probe Tomograph). The values ​​in samples with different numbers are as follows:

[0083]

[0084] The GB / T228.2-2015 high temperature tensile mechanical property test method and the GB / T 2039-2012 creep property test method were used to test the rod-shaped samples. The tensile properties of the ODS 316L steel at 650℃ and the creep properties at 650℃ / 200MPa after heat treatment were tested. The values ​​of the samples with different numbers are as follows:

[0085]

[0086] It should be noted that in other embodiments of the present invention, other different schemes obtained by making specific selections within the scope of the steps, components, ratios, and process parameters recorded in the present invention can all achieve the technical effects recorded in the present invention, so the present invention will no longer list them one by one.

[0087] The above describes the embodiments of the present invention in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made according to the purpose of the invention of the present invention. Any changes, modifications, substitutions, combinations or simplifications made according to the spirit and principle of the technical solution of the present invention should be equivalent replacement methods. As long as they meet the purpose of the present invention and do not deviate from the high oxygen content rare earth hybrid nickel-based high temperature alloy technology and its preparation method principles and inventive concepts, they all belong to the protection scope of the present invention.

Claims

1. A powder spraying refining process for the production of rare earth oxide dispersion strengthened alloys, characterized in that: The following steps are involved: 1) The converter steel is strongly deoxidized by using an iron-silicon-aluminum deoxidizer of 4.5-8.5 kg / t, wherein the iron-silicon-aluminum deoxidizer comprises the following elements in percentage by mass: Fe: 40-55%, Si: 35-45%, Al: 3-15%, and the mass ratio of Si and Al elements meets the requirement of Si / Al≥3:1; 2) After steel tapping, add 0.2-0.4 kg / t of rare earth aluminum alloy to the slag surface of the ladle for slag surface deoxidation, wherein the rare earth aluminum alloy includes the following elements in percentage by mass: Al: 95-98%, RE: 2-5%; 3) The molten steel is transported to the powder spraying station, and the temperature of the molten steel is adjusted to 1570~1610℃. The rare earth powder blowing agent is sprayed into the molten steel at high speed using an inert carrier gas. The working pressure of the carrier gas for ladle powder spraying is 3.0-4.0bar, and the carrier gas flow rate is 40-60m 3 / h, ladle powder spraying speed 10-50kg / min, blowing agent dosage 1.0~50.0kg / t; the blowing agent includes the following elements in percentage by mass: Fe: 50.0~99.0%, RE: 0.7~15.0%, O: 0.3~10.0%, and the mass ratio of RE and O elements meets RE / O (1.5:1)~(5:1); RE and O in the blowing agent are dissolved into the matrix in the form of atoms; The RE is a rare earth.

2. The powder spray refining process for producing rare earth oxide dispersion strengthened alloy according to claim 1, characterized in that: The blowing powder agent further comprises at least one of the elements Cr, Ni, W, V, Mn, Si, Ti, Zr and Ca, and the mass proportions of the above elements are as follows: Cr: 0-15.0%, Ni: 0-15.0%, W: 0-5.0%, V: 0-5%, Mn: 0-15.0%, Si: 0-15.0%, Ti: 0-10.0%, Zr: 0-5.0%, Ca: 0-5.0%, and the mass proportion relationship of the elements conforms to (RE+Cr+Ni+W+V+Mn+Si+Ti+Zr+Ca) / O is (1.5:1)-(19:1).

3. The powder spray refining process for producing rare earth oxide dispersion strengthened alloy according to claim 1, characterized in that: The RE element is one of yttrium, lanthanum, cerium, gadolinium, erbium, neodymium, praseodymium, terbium, samarium, dysprosium or scandium, or a combination of multiple elements thereof.

4. The powder spray refining process for producing rare earth oxide dispersion strengthened alloy according to claim 1, characterized in that: The inert carrier gas is argon or nitrogen.

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