High-temperature-resistant and corrosion-resistant silicon-containing nano oxide dispersion strengthened steel and rapid preparation method thereof

Abstract

The invention belongs to the related field of metal material processing, and discloses high-temperature-resistant and corrosion-resistant silicon-containing nano oxide dispersion strengthened steel and a rapid preparation method thereof.The target components of the strengthened steel take Fe as the main body, and the strengthened steel further comprises 9.0%-14.0% of Cr, 1.0%-2.0% of W, 0.2%-1.0% of Mn, 1.0%-3.0% of Si, 0.4%-1.0% of Y, 0.11%-0.27% of O and smaller than or equal to 0.0016% of C; the preparation method comprises the following steps: (1) forming a plurality of pre-alloyed powder by adopting a gas atomization method; meanwhile, pre-oxidized Si powder SiOx is prepared; (2) the powder is mixed and subjected to ball milling, and a flux-cored wire is obtained through a steel belt method; and (3) the flux-cored wire is printed through an electric arc fuse wire additive manufacturing process, and the strengthened steel can be obtained. According to the preparation method, the technological process of the preparation method is improved, the actual utilization rate of the Y element is increased, a Y-Si-O nano dispersed phase with high number density is formed in a matrix, and the mechanical strength, high temperature resistance and corrosion resistance of the ODS steel are improved.

Description

Technical Field

[0001] The present invention belongs to the field related to metal material processing, and more specifically, relates to a high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel and a rapid preparation method thereof. Background Art

[0002] Oxide dispersion strengthened (ODS) steel is considered to be one of the key candidate materials for fusion reactor blanket structures because of its excellent high-temperature mechanical properties, radiation resistance, and low sensitivity to hydrogen embrittlement and helium embrittlement. The excellent high-temperature performance of ODS steel is due to the fine nano-oxide particles dispersed in the matrix. At present, ODS steel is usually prepared by powder metallurgy, which not only takes a long time and has low preparation efficiency, but also has a high preparation cost, which limits its large-scale application. Although the traditional smelting and casting method has a high preparation efficiency and can achieve large-scale production, due to the poor wettability between the oxide particles and the molten steel, coarsening and agglomeration are prone to occur during the metallurgical smelting process, resulting in the deterioration of the performance of ODS steel.

[0003] In addition, at present, the dispersion strengthening phase is generally introduced into ODS steel by directly adding nano-scale / micro-scale oxide powder, through the decomposition of oxide particles in the mechanical alloying process and precipitation in the subsequent high-temperature sintering process. However, due to the good thermal stability of oxide powder, it is difficult to dissolve in the preparation process, and the actual content in steel is far less than the added amount, which also leads to a waste of resources.

[0004] Therefore, developing a production process with fast preparation rate, low process cost, and the ability to prepare large and complex components, while effectively introducing high number density of nano-oxide particles into the matrix, is of great significance for the widespread application of ODS steel. Summary of the invention

[0005] In view of the above defects or improvement needs of the prior art, the object of the present invention is to provide a high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel and a rapid preparation method thereof, by improving the process flow of the preparation method, by separately preparing the composite pre-alloyed powder and the pre-oxidized Si powder SiO x (x<2), on the one hand, it can prevent the directly added yttrium oxide from being well dissolved in the matrix and improve the actual utilization rate of the Y element. On the other hand, it can increase the number density of the Y-Si-O nano-dispersed phase, form a high number density of Y-Si-O nano-dispersed phase in the matrix, and improve the mechanical strength and high temperature corrosion resistance of ODS steel. In addition, since the present invention is based on the arc fuse additive manufacturing process, it can be applied to the rapid preparation of fusion reactor blanket structural materials and large complex components.

[0006] To achieve the above object, according to one aspect of the present invention, a high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel is provided, characterized in that the target component of the strengthened steel is mainly composed of Fe element, and the target component also includes, by mass percentage: Cr 9.0-14.0%, W 1.0-2.0%, Mn 0.2-1.0%, Si 1.0-3.0%, Y 0.4-1.0%, O 0.11-0.27%, C ≤ 0.0016%;

[0007] The reinforced steel is prepared by a preparation method comprising the following steps:

[0008] (1) according to the target composition, each metal element except Fe, Si and O is respectively mixed with Fe to form a plurality of corresponding pre-alloyed powders by gas atomization;

[0009] The Si element and the O element are prepared according to the composition ratio of the Si element and the O element in the target component to form a pre-oxidized Si powder SiO x , x<2;

[0010] (2) Various pre-alloyed powders are mixed with the pre-oxidized Si powder SiO x The components of the target components other than Fe are mixed according to the composition ratio, and then mechanical alloying is achieved by ball milling under a protective atmosphere to obtain a uniform composite alloy powder; then, the composite alloy powder is wrapped in a steel strip, and a cored wire is obtained by drawing and reducing the diameter; wherein the steel strip is used to additionally introduce Fe elements so that the cored wire meets the target components;

[0011] (3) The flux-cored wire is printed and formed by an arc-fused wire additive manufacturing process, and the high-temperature-resistant and corrosion-resistant silicon-containing nano-oxide dispersion-strengthened steel is obtained by heat treatment.

[0012] As a further preferred embodiment of the present invention, the target components of the strengthened steel specifically include, by mass percentage: Cr 9.0-14.0%, W 1.0-2.0%, Mn 0.2-1.0%, Si 1.0-3.0%, Y 0.4-1.0%, O 0.11-0.27%, C≤0.0016%, and the rest are Fe and unavoidable impurities.

[0013] According to another aspect of the present invention, the present invention provides a method for preparing the above-mentioned high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel, characterized in that it comprises the following steps:

[0014] (1) according to the target composition, each metal element except Fe, Si and O is respectively mixed with Fe to form a plurality of corresponding pre-alloyed powders by gas atomization;

[0015] The Si element and the O element are prepared according to the composition ratio of the Si element and the O element in the target component to form a pre-oxidized Si powder SiO x , x<2;

[0016] (2) Various pre-alloyed powders are mixed with the pre-oxidized Si powder SiO x The components of the target components other than Fe are mixed according to the composition ratio, and then mechanical alloying is achieved by ball milling under a protective atmosphere to obtain a uniform composite alloy powder; then, the composite alloy powder is wrapped in a steel strip, and a cored wire is obtained by drawing and reducing the diameter; wherein the steel strip is used to additionally introduce Fe elements so that the cored wire meets the target components;

[0017] (3) The flux-cored wire is printed and formed by an arc-fused wire additive manufacturing process, and the high-temperature-resistant and corrosion-resistant silicon-containing nano-oxide dispersion-strengthened steel is obtained by heat treatment.

[0018] According to another aspect of the present invention, the present invention provides a method for preparing the above-mentioned high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel, characterized in that it comprises the following steps:

[0019] (1) According to the target composition, various pre-alloyed powders such as Cr-Fe, W-Fe, Mn-Fe, and Y-Fe are formed by gas atomization;

[0020] The Si element and the O element are prepared according to the composition ratio of the Si element and the O element in the target component to form a pre-oxidized Si powder SiO x , x<2;

[0021] (2) Various pre-alloyed powders are mixed with the pre-oxidized Si powder SiO x The components of the target components other than Fe are mixed according to the composition ratio, and then mechanical alloying is achieved by ball milling under a protective atmosphere to obtain a uniform composite alloy powder; then, the composite alloy powder is wrapped in a steel strip, and a cored wire is obtained by drawing and reducing the diameter; wherein the steel strip is used to additionally introduce Fe elements so that the cored wire meets the target components;

[0022] (3) The flux-cored wire is printed and formed by an arc-fused wire additive manufacturing process, and the high-temperature-resistant and corrosion-resistant silicon-containing nano-oxide dispersion-strengthened steel is obtained by heat treatment.

[0023] As a further preferred embodiment of the present invention, in step (1), the pre-oxidized Si powder SiO x The oxygen content is 0.11-0.27wt% of the total mass of the core wire;

[0024] The pre-oxidized Si powder SiO xThe Si powder is immersed in hydrofluoric acid to remove the surface oxide layer, and then ultrasonically cleaned with acetone; then the cleaned Si powder is quickly placed in a reaction bottle into which dry oxygen is previously introduced, and dry oxygen is continuously introduced; the reaction bottle is always placed on a balance until the Si powder increases to a target oxygen content, oxygen input is stopped, and the powder is transferred to a vacuum drying oven for drying.

[0025] As a further preferred embodiment of the present invention, in step (2), the composite pre-alloyed powder and the pre-oxidized Si powder SiO x During mixing, NaF was additionally added as an arc stabilizer;

[0026] Preferably, the amount of NaF added is 0.2-0.5wt% of the total mass of the core wire;

[0027] More preferably, the composite pre-alloyed powder and the pre-oxidized Si powder SiO x During mixing, reduced iron powder is additionally added.

[0028] As a further preference of the present invention, in step (2), the ball milling is wet ball milling, and ethanol is used as a process control agent.

[0029] As a further preferred embodiment of the present invention, in step (2), the ball milling is carried out in a planetary ball mill;

[0030] Preferably, the ball milling is to first evacuate the ball mill jar and then fill it with argon as a protective gas, the ball mill speed is 350r / min, the ball milling time is 5h to 20h, the ball milling medium is stainless steel grinding balls, the diameters of the large and small balls are 10mm and 6mm respectively, and the ball-to-material mass ratio is 15:1.

[0031] As a further preferred embodiment of the present invention, in step (2), the mass of the composite alloy powder accounts for 15% to 40% of the mass of the core wire material;

[0032] Preferably, the diameter of the core wire obtained by drawing and reducing the diameter is 3 to 4 mm.

[0033] As a further preference of the present invention, in step (3), the arc fuse additive manufacturing process uses argon as the shielding gas with a gas flow rate of 20 L / min; the deposition voltage is 20 to 40 V, the deposition current is 100 to 300 A, the wire feeding speed is 3 to 8.5 m / min, and the deposition speed is 0.2 to 0.5 m / min.

[0034] Compared with the prior art, the above technical solutions conceived by the present invention can achieve the following

[0035] Beneficial effects:

[0036] 1. The present invention uses arc fuse additive manufacturing to rapidly prepare silicon-containing ODS steel. On the one hand, the characteristics of arc fuse additive manufacturing are utilized to achieve high preparation rate and low process cost preparation of ODS steel, and large and complex components can be prepared rapidly. On the other hand, a dispersed high-density Y-Si-O nano-oxide dispersed phase is formed in the matrix to improve the strength and high temperature and corrosion resistance of ODS steel.

[0037] 2. The composite pre-alloyed powder prepared by the gas atomization method of the present invention is pre-oxidized Si powder SiO x (x<2) Quantitatively control the oxygen content introduced into the ODS steel, realize the separate introduction of rare earth elements and oxygen elements into the ODS steel, avoid the problem of directly added oxide particles being difficult to dissolve, and improve the utilization rate of raw materials.

[0038] Different from the conventional method of directly adding rare earth oxide powder, the present invention prepares the composite pre-alloyed powder and the pre-oxidized Si powder SiO separately. x , that is, the composite alloy powder prepared by gas atomization method and the pre-oxidized Si powder SiO x , and at the same time quantitatively control the oxygen content in the matrix to achieve the separate introduction of rare earth elements and oxygen elements in ODS steel, which can not only improve the raw material utilization rate, but also form dispersed high-density nano-oxide particles through the recombination of Si with rare earth element atoms and oxygen atoms in the matrix, thereby significantly improving the high-temperature strength and high-temperature corrosion resistance.

[0039] 3. The composite pre-alloyed powder prepared by the gas atomization method of the present invention is simultaneously pre-oxidized Si powder SiO x Quantitatively control the oxygen content introduced into ODS steel to achieve the separate introduction of rare earth elements and oxygen elements into ODS steel, and avoid directly adding too much rare earth oxide powder, which will cause the oxide particles in ODS steel to be unevenly distributed and easily agglomerated to form large particles, thereby deteriorating the performance of ODS steel and seriously affecting its welding performance.

[0040] 4. The present invention is to combine the composite pre-alloyed powder with the pre-oxidized Si powder SiO x The components of the target reinforced steel are mixed and ball milled according to the proportions. By means of ball milling, a mechanical alloying method, 1-3% Si is dissolved in the iron matrix to form a Si-Fe solid solution, thereby increasing the lattice constant of the matrix. After heat treatment, Y and O supersaturated in the matrix are dispersed and precipitated with the participation of Si, and Y-Si-O complex oxide nanoparticles are generated in the iron-silicon alloy matrix as a strengthening phase. The dispersed high-number-density nano-oxide particles (taking the product of Example 1 as an example, the number density is about 5.89×10 23 m -3, with an average grain size of 3.7 nm) can effectively pin dislocations, hinder grain growth and grain boundary migration, thereby improving the strength of ODS steel (compared with the product of comparative example 1, the hardness of the alloy is increased from 405 HV to 689 HV in Example 1 below). The ODS steel matrix prepared by the present invention is a martensitic structure. Taking the product of Example 1 below as an example, the average grain size is 2.31 μm and the geometric necessary density is 1.49×10 14 m -2 .

[0041] 5. The present invention, by adding Si element, can not only promote the formation of continuous and dense SiO2 oxide layer during oxidation of ODS steel, hindering the further inward diffusion of O, but also reduce the critical Cr content for forming a continuous Cr2O3 oxide film, promote the outward diffusion of Cr, and facilitate the formation of a protective Cr2O3 oxide film. Taking Example 1 as an example, the oxidation rate of the ODS steel obtained in Example 1 when oxidized in an air environment at 800°C for 200h is 0.36×10 -3 mg cm -2 ·h -1 , which is much better than most commercial steels currently available (taking commercial T91 steel and SIMP steel as examples, it has been reported in the prior art that the oxidation weight gain rates of T91 steel and SIMP steel oxidized in an air environment at 800°C for 200h are approximately 0.175 mg·cm -2 ·h -1 and 3.25×10 -3 mg cm -2 ·h -1 ).

[0042] In summary, the present invention can realize the batch production of ODS steel with high raw material utilization rate, high preparation rate and low process cost, and can realize the rapid forming of large-sized complex parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 The present invention provides a schematic flow chart of a method for rapidly preparing high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel.

[0044] Figure 2 It is the BSE diagram and Y element distribution diagram of the high temperature and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel prepared in Comparative Example 1 and Example 1 of the present invention; wherein, Figure 2 (a) corresponds to the product of Example 1, Figure 2 (b) corresponds to the product of Example 1.

[0045] Figure 3 This is a grain boundary diagram of the high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel prepared in Example 1 of the present invention.

[0046] Figure 4 TEM image of the high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel prepared in Example 1 of the present invention, wherein: Figure 4 (a) is the microstructure of heat-treated ODS steel. Figure 4 (b) is a bright field TEM image. Figure 4 (c) is a high-resolution image of oxide particles.

[0047] Figure 5 The cross-sectional morphology SEM and element line scan results of the oxide layer of the high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel prepared in Example 1 of the present invention; wherein, Figure 5 (a) corresponds to the cross-sectional morphology SEM, Figure 5 (b) in the figure corresponds to the element line scan result.

[0048] Figure 6 The optical microscopic observation image of the silicon-containing nano-oxide dispersion-strengthened steel prepared in Comparative Example 2 of the present invention and the high-resolution image of the oxide particles therein; wherein, Figure 6 (a) in the figure corresponds to the image observed by light microscope. Figure 6 (b) corresponds to the high-resolution image of oxide particles. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] In the following comparative examples and embodiments, after the ODS steel is obtained, the ODS steel is further subjected to conventional heat treatment to obtain the final sample. The heat treatment used in the following comparative examples and embodiments is air cooling heat treatment (1050°C, 1 hour). Of course, heat treatments with other temperatures and holding times, as well as cooling methods, may also be used.

[0051] Example 1

[0052] A rapid preparation method for high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel comprises the following steps:

[0053] Step 1: Prepare Cr-Fe, W-Fe, Mn-Fe, and Y-Fe pre-alloyed powders respectively by gas atomization. Similar to the conventional gas atomization method, this embodiment uses argon as the atomizing gas, the gas pressure is 6 MPa, the gas flow rate is 300 L / min, and the collected powder particle size range is 5 to 20 μm.

[0054] Step 2, preparing pre-oxidized Si powder, the specific preparation steps are: soaking 75g Si powder with a particle size of 5-20μm in hydrofluoric acid to remove the surface oxide layer, and then ultrasonic cleaning with acetone; then quickly putting the cleaned Si powder into a reaction bottle that has been pre-flowed with dry high-purity oxygen for 10 minutes, and continuously flowing dry oxygen; the reaction bottle is always placed on a balance until the Si powder increases to 83.25g (that is, the oxygen content is 8.25g, and the oxygen content is 0.11wt.% of the total mass of the designed core wire), stopping the oxygen input, and transferring to a vacuum drying oven for drying.

[0055] Step 3: weigh the prepared pre-alloyed powders of each element, 964.3g Cr-Fe alloy powder (70% Cr; that is, the mass percentage of Cr in the Cr-Fe alloy powder is 70%; the following expressions are similar), 160.7g W-Fe alloy powder (70% W), 80g Mn-Fe alloy powder (75% Mn), 500g Y-Fe alloy powder (6% Y), 86.75g reduced iron powder and 83.25g pre-oxidized Si powder, and add 18.8g NaF as an arc stabilizer.

[0056] All powders were mechanically alloyed in a planetary ball mill. The ball mill was first evacuated and then filled with high-purity argon as a protective gas to reduce the oxidation of the alloy powder during the ball milling process. The ball mill speed was 350r / min, the ball milling time was 10h, and the ball milling medium was stainless steel balls. The diameters of the large and small balls were 10mm and 6mm respectively, and the ball-to-material ratio was 15:1. During the mechanical alloying process, ethanol was used as a process control agent. After ball milling, the powder was dried at 80°C in vacuum for 10h and packaged in a vacuum sealed bag for storage.

[0057] Step 4: Put the composite alloy powder into a steel strip and draw and reduce it to prepare a cored wire with a diameter of 4 mm. The filling rate is 25% (mass percentage; the same below), and the target composition of the cored wire is (by mass content) Fe-9Cr-1.5W-0.8Mn-1Si-0.4Y-0.11O (in this expression, except for Fe, the Arabic numerals before each element represent the target mass percentage of the element in the cored wire; taking Cr as an example, the mass percentage of Cr in the cored wire is 9%; the remainder is Fe and unavoidable impurities; the same below). Of course, if the cored wire is not used immediately, it can be stored in a vacuum dry environment to avoid oxidation.

[0058] Step 5: Prepare the above-mentioned flux-cored wire into ODS steel using arc fuse additive manufacturing technology. In the arc fuse additive manufacturing process, high-purity argon is used as the shielding gas with a gas flow rate of 20L / min; the deposition voltage is 25.8V, the deposition current is 170A, the wire feeding speed is 5.5m / min, and the deposition speed is 0.36m / min.

[0059] EPMA was used to perform elemental analysis on the prepared samples, and the results were as follows: Figure 2 As shown in (b), the actual Y content in the sample matrix is ​​about 0.31wt.%, and the actual introduction rate of rare earth elements is greatly improved compared with Comparative Example 1. EBSD is used to characterize the grain boundaries of the sample and measure and calculate its geometric dislocation density. The results are as follows: Figure 3 As shown in Figure 2, the matrix of the sample is found to be martensite, with an average grain size of 2.31 μm and a geometric necessary density of 1.49×10 14 m -2 TEM was further used to characterize and analyze the matrix of the sample and the nano-oxide particles therein, such as Figure 4 As shown in the figure, dispersed high-density nano-Y2SiO5 oxide particles (number density of about 5.89×10 23 m -3 , with an average particle size of 3.7 nm). Figure 4 As can be seen from (b) in the figure, the precipitated nano-oxide particles can inhibit the movement and annihilation of dislocations, hinder grain growth and grain boundary migration, and thus maintain the high dislocation density of the matrix. The hardness was tested using a Vickers hardness tester, and it was found that the hardness of the prepared sample was increased to 689HV compared with that of Comparative Example 1. The sample was subjected to an oxidation test at 800°C for 200 hours in a muffle furnace, and its oxidation cross section was observed. Figure 5 As shown in the figure, it was found that the sample formed a three-layer structure of Cr with a total thickness of about 2.19 μm. 1.5 Mn 1.5 O4 / Cr2O3 / SiO2 oxide layer. Adding Si element can not only promote the formation of continuous and dense SiO2 oxide layer during oxidation of ODS steel, hindering the further diffusion of O, but also reduce the critical Cr content for the formation of continuous Cr2O3 oxide film, promote the outward diffusion of Cr, and facilitate the formation of protective Cr2O3 oxide film. The oxidation rate of ODS steel oxidized in air environment at 800℃ for 200h is 0.36×10 -3 mg cm -2 ·h -1 , which is much better than most commercial steels currently available (taking commercial T91 steel and SIMP steel as examples, it has been reported in the prior art that the oxidation weight gain rates of T91 steel and SIMP steel oxidized in an air environment at 800°C for 200h are approximately 0.175 mg·cm-2 ·h -1 and 3.25×10 -3 mg cm -2 ·h -1 ).

[0060] Example 2

[0061] A rapid preparation method for high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel comprises the following steps:

[0062] Step 1: Prepare Cr-Fe, W-Fe, Mn-Fe, and Y-Fe pre-alloyed powders respectively by gas atomization method, use argon as atomizing gas, the gas pressure is 6 MPa, the gas flow rate is 300 L / min, and the collected powder particle size range is 5 to 20 μm.

[0063] Step 2, preparing pre-oxidized Si powder, the specific preparation steps are: soaking 150g Si powder with a particle size of 5 to 20μm in hydrofluoric acid to remove the surface oxide layer, and then ultrasonically cleaning with acetone; then quickly putting the cleaned Si powder into a reaction bottle that has been pre-flowed with dry high-purity oxygen for 10 minutes, and continuously flowing dry oxygen; the reaction bottle is always placed on a balance until the Si powder increases to 159.75g (that is, the oxygen content is 9.75g, and the oxygen content is 0.13wt.% of the total mass of the designed core wire), stopping the oxygen input, and transferring to a vacuum drying oven for drying.

[0064] Step three, weigh the prepared pre-alloyed powders of each element, 1285.7g Cr-Fe alloy powder (70% Cr), 214.3g W-Fe alloy powder (70% W), 20g Mn-Fe alloy powder (75% Mn), 625g Y-Fe alloy powder (6% Y), 95.25g reduced iron powder and 159.75g pre-oxidized Si powder, and add 24g NaF as an arc stabilizer.

[0065] All powders were mechanically alloyed in a planetary ball mill. The ball mill was first evacuated and then filled with high-purity argon as a protective gas to reduce the oxidation of the alloy powder during the ball milling process. The ball mill speed was 350r / min, the ball milling time was 10h, and the ball milling medium was stainless steel balls. The diameters of the large and small balls were 10mm and 6mm respectively, and the ball-to-material ratio was 15:1. During the mechanical alloying process, ethanol was used as a process control agent. After ball milling, the powder was dried at 80°C in vacuum for 10h and packaged in a vacuum sealed bag for storage.

[0066] Step 4: Put the composite alloy powder into a steel strip and prepare a cored wire with a diameter of 4 mm by drawing and reducing. The filling rate is 32%, and the target composition of the cored wire is (by mass content) Fe-12Cr-2W-0.2Mn-1.5Si-0.5Y-0.13O.

[0067] Step 5: Prepare the above-mentioned flux-cored wire into ODS steel using arc fuse additive manufacturing technology. In the arc fuse additive manufacturing process, high-purity argon is used as the shielding gas with a gas flow rate of 20L / min; the deposition voltage is 25.8V, the deposition current is 170A, the wire feeding speed is 5.5m / min, and the deposition speed is 0.36m / min.

[0068] Example 3

[0069] A rapid preparation method for high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel comprises the following steps:

[0070] Step 1: Prepare Cr-Fe, W-Fe, Mn-Fe, and Y-Fe pre-alloyed powders respectively by gas atomization method. Argon is used as atomizing gas, the gas pressure is 6 MPa, the gas flow rate is 300 L / min, and the collected powder particle size range is 5 to 20 μm.

[0071] Step 2, preparing pre-oxidized Si powder, the specific preparation steps are: soaking 150g Si powder with a particle size of 5 to 20μm in hydrofluoric acid to remove the surface oxide layer, and then ultrasonically cleaning with acetone; then quickly putting the cleaned Si powder into a reaction bottle that has been pre-flowed with dry high-purity oxygen for 10 minutes, and continuously flowing dry oxygen; the reaction bottle is always placed on a balance until the Si powder increases to 159.75g (that is, the oxygen content is 9.75g, and the oxygen content is 0.13wt.% of the total mass of the designed core wire), stopping the oxygen input, and transferring to a vacuum drying oven for drying.

[0072] Step three, weigh the prepared pre-alloyed powders of each element, 1500g Cr-Fe alloy powder (70% Cr), 214.3g W-Fe alloy powder (70% W), 20g Mn-Fe alloy powder (75% Mn), 625g Y-Fe alloy powder (6% Y), 105.95g reduced iron powder and 159.75g pre-oxidized Si powder, and add 25g NaF as an arc stabilizer.

[0073] All powders were mechanically alloyed in a planetary ball mill. The ball mill was first evacuated and then filled with high-purity argon as a protective gas to reduce the oxidation of the alloy powder during the ball milling process. The ball mill speed was 350r / min, the ball milling time was 10h, and the ball milling medium was stainless steel balls. The diameters of the large and small balls were 10mm and 6mm respectively, and the ball-to-material ratio was 15:1. During the mechanical alloying process, ethanol was used as a process control agent. After ball milling, the powder was dried at 80°C in vacuum for 10h and packaged in a vacuum sealed bag for storage.

[0074] Step 4: Put the composite alloy powder into a steel strip and prepare a cored wire with a diameter of 4 mm by drawing and reducing. The filling rate is 35%, and the target composition of the cored wire is (by mass content) Fe-14Cr-2W-0.2Mn-1.5Si-0.5Y-0.13O.

[0075] Step 5: Prepare the above-mentioned flux-cored wire into ODS steel using arc fuse additive manufacturing technology. In the arc fuse additive manufacturing process, high-purity argon is used as the shielding gas with a gas flow rate of 20L / min; the deposition voltage is 25.8V, the deposition current is 170A, the wire feeding speed is 5.5m / min, and the deposition speed is 0.36m / min.

[0076] Example 4

[0077] A rapid preparation method for high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel comprises the following steps:

[0078] Step 1: Prepare Cr-Fe, W-Fe, Mn-Fe, and Y-Fe pre-alloyed powders respectively by gas atomization method. Argon is used as atomizing gas, the gas pressure is 6 MPa, the gas flow rate is 300 L / min, and the collected powder particle size range is 5 to 20 μm.

[0079] Step 2, preparing pre-oxidized Si powder, the specific preparation steps are: soaking 300g Si powder with a particle size of 5 to 20μm in hydrofluoric acid to remove the surface oxide layer, and then ultrasonically cleaning with acetone; then quickly putting the cleaned Si powder into a reaction bottle that has been pre-flowed with dry high-purity oxygen for 10 minutes, and continuously flowing dry oxygen; the reaction bottle is always placed on a balance until the Si powder increases to 320.25g (that is, the oxygen content is 20.25g, and the content of oxygen element is 0.27wt.% of the total mass of the designed core wire), stopping the oxygen input, and transferring to a vacuum drying oven for drying.

[0080] Step three, weigh the prepared pre-alloyed powders of each element, 964.3g Cr-Fe alloy powder (70% Cr), 107.1g W-Fe alloy powder (70% W), 100g Mn-Fe alloy powder (75% Mn), 1250g Y-Fe alloy powder (6% Y), 108.35g reduced iron powder and 320.25g pre-oxidized Si powder, and add 28.5g NaF as an arc stabilizer.

[0081] All powders were mechanically alloyed in a planetary ball mill. The ball mill was first evacuated and then filled with high-purity argon as a protective gas to reduce the oxidation of the alloy powder during the ball milling process. The ball mill speed was 350r / min, the ball milling time was 10h, and the ball milling medium was stainless steel balls. The diameters of the large and small balls were 10mm and 6mm respectively, and the ball-to-material ratio was 15:1. During the mechanical alloying process, ethanol was used as a process control agent. After ball milling, the powder was dried at 80°C in vacuum for 10h and packaged in a vacuum sealed bag for storage.

[0082] Step 4: Put the composite alloy powder into a steel strip and prepare a cored wire with a diameter of 4 mm by drawing and reducing. The filling rate is 38%, and the target composition of the cored wire is (by mass content) Fe-9Cr-1W-1Mn-3Si-1Y-0.27O.

[0083] Step 5: Prepare the above-mentioned flux-cored wire into ODS steel using arc fuse additive manufacturing technology. In the arc fuse additive manufacturing process, high-purity argon is used as the shielding gas with a gas flow rate of 20L / min; the deposition voltage is 25.8V, the deposition current is 170A, the wire feeding speed is 5.5m / min, and the deposition speed is 0.36m / min.

[0084] Comparative Example 1

[0085] This comparative example adopts the conventional method of directly adding rare earth oxide powder, which specifically includes the following steps:

[0086] Step 1: Prepare Cr-Fe, W-Fe, Mn-Fe, and Si-Fe pre-alloyed powders of all elements except element Y by gas atomization method, use argon as atomizing gas, the gas pressure is 6 MPa, the gas flow rate is 300 L / min, and the collected powder particle size range is 5 to 20 μm.

[0087] Step 2: Weigh the prepared pre-alloyed powders of each element, 964.3g Cr-Fe alloy powder (70% Cr), 160.7g W-Fe alloy powder (70% W), 80g Mn-Fe alloy powder (75% Mn), 100g Si-Fe (75% Si), 180g reduced iron powder and 15g nano Y2O3 powder, and add 15g NaF as an arc stabilizer.

[0088] All powders were mechanically alloyed in a planetary ball mill. The ball mill was first evacuated and then filled with high-purity argon as a protective gas to reduce the oxidation of the alloy powder during the ball milling process. The ball mill speed was 350r / min, the ball milling time was 10h, and the ball milling medium was stainless steel grinding balls. The diameters of the large and small balls were 10mm and 6mm respectively, and the ball-to-material ratio was 15:1. During the mechanical alloying process, ethanol was used as a process control agent. After ball milling, the composite alloy powder was dried at 80°C in vacuum for 10h and packaged in a vacuum sealed bag for storage.

[0089] Step 3: Put the composite alloy powder into a steel strip and draw and reduce it to prepare a cored wire with a diameter of 4 mm. The filling rate is 20%, and the target composition of the cored wire is (by mass content) Fe-9Cr-1.5W-0.8Mn-1Si-0.2Y2O3.

[0090] Step 4: Prepare the above-mentioned flux-cored wire into ODS steel using arc fuse additive manufacturing technology. In the arc fuse additive manufacturing process, high-purity argon is used as the shielding gas with a gas flow rate of 20L / min; the deposition voltage is 25.8V, the deposition current is 170A, the wire feeding speed is 5.5m / min, and the deposition speed is 0.36m / min.

[0091] EPMA was used to perform elemental analysis on the prepared samples, and the results were as follows: Figure 2 As shown in (a), the actual Y content in the sample matrix is ​​about 0.02wt.%, which is much lower than the actual addition amount. The hardness is tested by Vickers hardness tester, and it is found that the hardness of the sample directly adding nano Y2O3 powder is only 405HV.

[0092] Comparative Example 2

[0093] This comparative example adopts the conventional method of directly adding rare earth oxide powder, which specifically includes the following steps:

[0094] Step 1: Prepare Cr-Fe, W-Fe, Mn-Fe, and Si-Fe pre-alloyed powders of all elements except element Y by gas atomization method, use argon as atomizing gas, the gas pressure is 6 MPa, the gas flow rate is 300 L / min, and the collected powder particle size range is 5 to 20 μm.

[0095] Step 2: Weigh the prepared pre-alloyed powders of each element, 964.3g Cr-Fe alloy powder (70% Cr), 160.7g W-Fe alloy powder (70% W), 80g Mn-Fe alloy powder (75% Mn), 100g Si-Fe (75% Si), 120g reduced iron powder and 75g nano Y2O3 powder, and add 15g NaF as an arc stabilizer.

[0096] All powders were mechanically alloyed in a planetary ball mill. The ball mill was first evacuated and then filled with high-purity argon as a protective gas to reduce the oxidation of the alloy powder during the ball milling process. The ball mill speed was 350r / min, the ball milling time was 10h, and the ball milling medium was stainless steel grinding balls. The diameters of the large and small balls were 10mm and 6mm respectively, and the ball-to-material ratio was 15:1. During the mechanical alloying process, ethanol was used as a process control agent. After ball milling, the composite alloy powder was dried at 80°C in vacuum for 10h and packaged in a vacuum sealed bag for storage.

[0097] Step 3: Put the composite alloy powder into a steel strip and draw and reduce it to prepare a cored wire with a diameter of 4 mm. The filling rate is 20%, and the target composition of the cored wire is (by mass content) Fe-9Cr-1.5W-0.8Mn-1Si-1Y2O3.

[0098] Step 4: Prepare the above-mentioned flux-cored wire into ODS steel using arc fuse additive manufacturing technology. In the arc fuse additive manufacturing process, high-purity argon is used as the shielding gas with a gas flow rate of 20L / min; the deposition voltage is 25.8V, the deposition current is 170A, the wire feeding speed is 5.5m / min, and the deposition speed is 0.36m / min.

[0099] The obtained samples were observed using an optical microscope, and the results were as follows: Figure 6 As shown in (a) in the figure, crack defects were found in the matrix. This is because the excessive addition of Y2O3 deteriorated the welding performance of the sample and caused cracks and other defects during the solidification of the molten pool. TEM was further used to observe the oxide particles in the sample. The results are shown in Figure 6 As shown in (b), the oxide is Y2O3 particles with a particle size of about 17 nm.

[0100] The high-purity argon and high-purity oxygen used in the above embodiments have a purity of no less than 99.999%.

[0101] The above embodiments are only examples. For example, the high temperature and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel obtained based on the present invention may contain other non-impurity elements in addition to Cr, W, Mn, Si, Y, O, C, Fe elements and inevitable impurities, as long as the components, by mass percentage, are Cr 9.0-14.0%, W 1.0-2.0%, Mn 0.2-1.0%, Si 1.0-3.0%, Y0.4-1.0%, O 0.11-0.27%, C≤0.0016% and Fe is the main element.

[0102] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel, characterized in that: The target component of the strengthened steel is mainly composed of Fe element, and the target components also include, by mass percentage: Cr 9.0-14.0%, W 1.0-2.0%, Mn 0.2-1.0%, Si 1.0-3.0%, Y 0.4-1.0%, O 0.11-0.27%, C ≤ 0.0016%; The reinforced steel is prepared by a preparation method comprising the following steps: (1) according to the target composition, each metal element except Fe, Si and O is respectively mixed with Fe to form a plurality of corresponding pre-alloyed powders by gas atomization; The Si element and the O element are prepared according to the composition ratio of the Si element and the O element in the target component to form a pre-oxidized Si powder SiO x , x<2; (2) Various pre-alloyed powders are mixed with the pre-oxidized Si powder SiO x The components of the target components other than Fe are mixed in a proportion, and then mechanical alloying is achieved by ball milling under a protective atmosphere to obtain a uniform composite alloy powder; then, the composite alloy powder is wrapped in a steel strip, and a cored wire is obtained by drawing and reducing the diameter; wherein the steel strip is used to additionally introduce Fe elements so that the cored wire meets the target components; (3) The flux-cored wire is printed and formed by an arc-fused wire additive manufacturing process, and the high-temperature-resistant and corrosion-resistant silicon-containing nano-oxide dispersion-strengthened steel is obtained by heat treatment.

2. The high temperature and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel according to claim 1, characterized in that: The target components of the reinforced steel specifically include, by mass percentage, Cr 9.0-14.0%, W 1.0-2.0%, Mn 0.2-1.0%, Si 1.0-3.0%, Y 0.4-1.0%, O 0.11-0.27%, C≤0.0016%, and the rest are Fe and unavoidable impurities.

3. The method for preparing high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel according to claim 1 or 2, characterized in that: The following steps are involved: (1) according to the target composition, each metal element except Fe, Si and O is respectively mixed with Fe to form a plurality of corresponding pre-alloyed powders by gas atomization; The Si element and the O element are prepared according to the composition ratio of the Si element and the O element in the target component to form a pre-oxidized Si powder SiO x , x<2; (2) Various pre-alloyed powders are mixed with the pre-oxidized Si powder SiO x The components of the target components other than Fe are mixed in a proportion, and then mechanical alloying is achieved by ball milling under a protective atmosphere to obtain a uniform composite alloy powder; then, the composite alloy powder is wrapped in a steel strip, and a cored wire is obtained by drawing and reducing the diameter; wherein the steel strip is used to additionally introduce Fe elements so that the cored wire meets the target components; (3) The flux-cored wire is printed and formed by an arc-fused wire additive manufacturing process, and the high-temperature-resistant and corrosion-resistant silicon-containing nano-oxide dispersion-strengthened steel is obtained by heat treatment.

4. The method for preparing high temperature resistant and corrosion resistant silicon-containing nano-oxide dispersion strengthened steel as claimed in claim 2, characterized in that: The following steps are involved: (1) According to the target composition, various pre-alloyed powders such as Cr-Fe, W-Fe, Mn-Fe, and Y-Fe are formed by gas atomization; The Si element and the O element are prepared according to the composition ratio of the Si element and the O element in the target component to form a pre-oxidized Si powder SiO x , x<2; (2) Various pre-alloyed powders are mixed with the pre-oxidized Si powder SiO x The components of the target components other than Fe are mixed in a proportion, and then mechanical alloying is achieved by ball milling under a protective atmosphere to obtain a uniform composite alloy powder; then, the composite alloy powder is wrapped in a steel strip, and a cored wire is obtained by drawing and reducing the diameter; wherein the steel strip is used to additionally introduce Fe elements so that the cored wire meets the target components; (3) The flux-cored wire is printed and formed by an arc-fused wire additive manufacturing process, and the high-temperature-resistant and corrosion-resistant silicon-containing nano-oxide dispersion-strengthened steel is obtained by heat treatment.

5. The preparation method according to claim 3 or 4, characterized in that: In step (1), the pre-oxidized Si powder SiO x The oxygen content is 0.11-0.27wt% of the total mass of the core wire; The pre-oxidized Si powder SiO x The Si powder is immersed in hydrofluoric acid to remove the surface oxide layer, and then ultrasonically cleaned with acetone; then the cleaned Si powder is quickly placed in a reaction bottle into which dry oxygen is previously introduced, and dry oxygen is continuously introduced; the reaction bottle is always placed on a balance until the Si powder increases to a target oxygen content, oxygen input is stopped, and the powder is transferred to a vacuum drying oven for drying.

6. The preparation method according to claim 3 or 4, characterized in that: In step (2), the composite pre-alloyed powder and the pre-oxidized Si powder SiO x During mixing, NaF was additionally added as an arc stabilizer; Preferably, the amount of NaF added is 0.2-0.5wt% of the total mass of the core wire; More preferably, the composite pre-alloyed powder and the pre-oxidized Si powder SiO x During mixing, reduced iron powder is additionally added.

7. The preparation method according to claim 3 or 4, characterized in that: In step (2), the ball milling is wet ball milling, and ethanol is used as a process control agent.

8. The preparation method according to claim 3 or 4, characterized in that: In step (2), the ball milling is carried out in a planetary ball mill; Preferably, the ball milling is to first evacuate the ball mill jar and then fill it with argon as a protective gas, the ball mill speed is 350r / min, the ball milling time is 5h to 20h, the ball milling medium is stainless steel grinding balls, the diameters of the large and small balls are 10mm and 6mm respectively, and the ball-to-material mass ratio is 15:

1.

9. The preparation method according to claim 3 or 4, characterized in that: In step (2), the mass of the composite alloy powder accounts for 15% to 40% of the mass of the core wire material; Preferably, the diameter of the core wire obtained by drawing and reducing the diameter is 3 to 4 mm.

10. The preparation method according to claim 3 or 4, characterized in that: In step (3), the arc fuse additive manufacturing process uses argon as the shielding gas with a gas flow rate of 20 L / min; the deposition voltage is 20 to 40 V, the deposition current is 100 to 300 A, the wire feeding speed is 3 to 8.5 m / min, and the deposition speed is 0.2 to 0.5 m / min.

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