Preparation method of green short-process hot work die steel

Abstract

The invention belongs to the technical field of ferrous metallurgy and material modification, and particularly relates to a preparation method of green short-process hot work die steel, which comprises the following steps: obtaining scrap steel, adding alloy, and smelting to obtain molten steel; the molten steel is refined through fluoride-free rare earth refining slag, and refined molten steel is obtained; adding a nanoparticle modifier into the refined molten steel to obtain modified molten steel; and the modified molten steel is subjected to continuous casting or die casting, and the hot work die steel is obtained. According to the method, the fluorine-free rare earth slag refining and nano particle modification combined technology is adopted, fluorine-containing refining slag and traditional electroslag remelting are effectively replaced, power consumption and carbon emission in the smelting process are reduced, the technical development requirements of current green manufacturing and dual-carbon targets are met, and green short-process manufacturing of the hot work die steel is achieved; and the prepared hot work die steel has higher cleanliness, a more uniform organization structure and more excellent thermal fatigue performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of steel metallurgy and material modification, and specifically relates to a preparation method of a green short-process hot-working die steel. BACKGROUND

[0002] Hot-working die steel refers to alloy tool steel suitable for manufacturing molds for hot deformation of metals, such as hot forging dies, hot extrusion dies, die-casting dies, hot upsetting dies and the like. At present, the steel with a relatively large market share is H13 steel introduced from abroad, which is generally called 4Cr5MoSiV1 steel in China and belongs to a chromium-molybdenum type steel mainly containing alloy elements such as Cr, Mo and V, and has relatively high toughness, wear resistance, hot cracking resistance, thermal stability and hardenability. At present, the traditional preparation process of H13 steel mainly includes steps such as electric arc furnace smelting (EAF), secondary refining (LF / VD) and electroslag remelting (ESR). Among them, the secondary refining and electroslag remelting processes are widely used for further purifying the molten steel, removing inclusions and improving the uniformity of the structure. However, this multi-process process has the following significant problems: (1) complex process, high energy consumption and serious environmental pollution: the high-temperature volatilization of CaF2 in the refining slag produces fluorine-containing gas, which is harmful to the health of the operating personnel, and the fluorine-containing slag is difficult to be harmlessly treated, polluting the soil and groundwater; the ESR process not only has large power consumption and a long production cycle, but also produces a large amount of CO2 emission in the smelting link, which does not meet the current development direction of energy saving and emission reduction and green manufacturing in the steel industry; (2) limited inclusion control capability: the traditional floating-type inclusion control method mainly relies on the electroslag flotation in the ESR process, and it is difficult to effectively control the morphology of inclusions, especially the control capability of <10 μm small inclusions, which affects the high-temperature service life of the die steel; (3) single strengthening mechanism and limited thermal fatigue life: the traditional strengthening method of H13 steel mainly relies on the precipitation of carbides in the heat treatment process, and lacks a more efficient dispersion strengthening mechanism, which makes it difficult to meet the performance requirements of complex molds in the multiple heating-cooling cycle process.

[0003] Therefore, the industry has begun to explore a green short-process technical path, trying to replace the traditional electroslag remelting process by optimizing the refining process, introducing new purification technologies and strengthening means, to realize the green transformation and high-performance breakthrough of the die steel preparation process. In recent years, nano-particle modification technology has been gradually applied to the steel metallurgy process, which uses rare earth oxides, carbides and other nano-particles to induce the modification and spheroidization of inclusions, and at the same time provides nucleation sites for the second phase, forming fine and dispersed strengthening phases, so as to balance the cleanliness of the molten steel and the strengthening effect of the structure without relying on ESR. SUMMARY

[0004] The application provides a preparation method of green short-process hot work die steel, which integrates deep refining and nanoparticle modification technology, can simplify the process, reduce energy consumption, improve the inclusion control level and organizational strengthening ability, has significant theoretical value and engineering application prospect, realizes the green manufacturing and high-performance integrated control of hot work die steel, and is suitable for short-process production of hot work die steels such as H13.

[0005] The preparation method of green short-process hot work die steel provided by the application comprises the following steps: S1, obtaining scrap steel, adding alloy, melting to obtain molten steel; S2, refining the molten steel by using fluorine-free rare earth refining slag to obtain refined molten steel; S3, adding a nanoparticle modifier to the refined molten steel to obtain modified molten steel; S4, continuously casting or die casting the modified molten steel to obtain hot work die steel.

[0006] In the above technical scheme, the fluorine-free rare earth refining slag and the nanoparticle modifier cooperate to realize deep deoxidation and desulfurization, modification and refinement and organizational strengthening of inclusions in the molten steel; in step S2, deep deoxidation and desulfurization is performed by using a fluorine-free rare earth slag system to improve the cleanliness of the molten steel; in step S3, the nanoparticle modifier is added to induce modification and refinement of inclusions, effectively modifying hard inclusions such as Al2O3 into rare earth inclusions, simultaneously obtaining a second phase for dispersion strengthening, effectively pinning dislocations and grain boundaries, reducing the size and sharpness of inclusions, and improving the service stability of the steel.

[0007] As a preferred scheme of the preparation method of green short-process hot work die steel provided by the application, in step S1, melting is performed by using an electric arc furnace; in step S2, the fluorine-free rare earth refining slag and the molten steel are subjected to first refining by using an LF furnace, and then subjected to second refining by using a VD vacuum furnace; The temperature of the electric arc furnace melting is 1600-1650 DEG C, the temperature of the first refining is 1580-1620 DEG C, and the temperature of the second refining is 1540-1580 DEG C.

[0008] As a preferred scheme of the preparation method of green short-process hot work die steel provided by the application, in step S3, the nanoparticle modifier is added by using a cored wire feeding method or a bottom argon blowing method; The nanoparticle modifier has a modified core-shell structure obtained by a chemical precipitation method, so as to be effectively added, inert gas protection is provided during the addition, and stirring is performed after the addition to uniformly disperse the nanoparticle modifier into the molten steel.

[0009] As a preferred scheme of the preparation method of green short-process hot work die steel provided by the application, in step S4, the modified molten steel is continuously cast or die cast under an inert atmosphere or under the coverage of a protective slag. The secondary oxidation can be avoided, and a compact casting blank can be formed.

[0010] As a preferred scheme of the preparation method of the green short process hot work die steel, the fluorine-free rare earth refining slag comprises CaO, Al2O3, MgO, SiO2 and CeO2. With the increase of the CeO2 addition amount, the number of non-bridge oxygen increases and the polymerization degree of the melt decreases, the viscosity increases, the melting point and the fluidity are affected; the low basicity slag generates round inclusions, the medium and high basicity slag generates square or irregular inclusions, and the inclusions are more easily captured; the inclusions are mainly Al2O3-SiO2-MnO-(MgO-CaO), with the increase of the CeO2 content, the proportion of liquid inclusions first increases and then decreases, the inclusions in the low basicity slag are rich in SiO2 and increase with the increase of the CeO2 addition amount; the inclusions in the medium and high basicity slag are rich in Al2O3 and decrease with the increase of the CeO2 addition amount; at the same time, with the increase of the CeO2, the elastic modulus of the inclusions decreases, and the inclusions are more easily broken to form smaller inclusions; in addition, the CeO2 in the slag can be reduced to Ce and partially enter the molten steel to realize rare earth modification.

[0011] As a preferred scheme of the preparation method of the green short process hot work die steel, the basicity of the fluorine-free rare earth refining slag is 3-7, the calcium-aluminum ratio is 2.1-4.0, and the addition amount of CeO2 is 5wt%-20wt% of the fluorine-free rare earth refining slag; under the same basicity, the higher the CeO2 content, the greater the sulfur capacity of the refining slag, under the same CeO2 content, with the increase of the basicity, the [O] content in the molten steel decreases, and the deoxidation effect is enhanced; under the fixed basicity and calcium-aluminum ratio, with the increase of the CeO2 content, the activities of CaO, MgO and Ce2O3 increase, and the activities of SiO2 and Al2O3 decrease, which is beneficial to the removal of SiO2 and Al2O3 in the molten steel.

[0012] As a preferred scheme of the preparation method of the green short process hot work die steel, the particle size of the nano-particle modifier is 30-500nm, and the addition amount of the nano-particle modifier is 0.01wt%-0.1wt% of the refining molten steel.

[0013] As a preferred scheme of the preparation method of the green short process hot work die steel, the nano-particle modifier comprises at least one of rare earth oxide nano-particles, carbide nano-particles and boride nano-particles.

[0014] As a preferred scheme of the preparation method of the green short-process hot work die steel, the rare earth oxide nanoparticles include CeO2, La2O3 or Y2O3; the carbide nanoparticles include TiC or VC; the boride nanoparticles include TiB2; in addition, in some embodiments of the present application, other metal oxide nanoparticles such as TiO2 are used, and better implementation effects can also be obtained.

[0015] As a preferred scheme of the preparation method of the green short-process hot work die steel, the size of the inclusions in the green short-process hot work die steel is less than 1 μm.

[0016] The present application provides a preparation method of a green short-process hot work die steel, which has the following beneficial effects: the combination of fluorine-free rare earth slag refining and nanoparticle modification technology effectively replaces fluorine-containing refining slag and traditional electroslag remelting, reduces the power consumption and carbon emissions of the smelting process, meets the technical development needs of current green manufacturing and the "double carbon" target, and realizes green short-process manufacturing of hot work die steel; the prepared hot work die steel has higher cleanliness, more uniform microstructure and more excellent thermal fatigue performance. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only represent some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor on the basis of the drawings shown.

[0018] Figure 1 SEM-EDS diagrams of the hot work die steels prepared for Example 1, Comparative Example 1 and Comparative Example 2; Figure 2 Inclusion size distribution statistics of the green short-process hot work die steel prepared for Example 1.

[0019] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the drawings. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments will be described clearly and completely below. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] The technical solutions proposed in the present application include the following steps: S1, obtaining scrap steel, adding alloy, smelting, obtaining molten steel; Specifically, scrap steel meeting the chemical composition of H13 steel is selected, and alloy elements such as Cr, Mo and V are added in proportion according to the target composition, and then smelting is carried out at 1600-1650°C by an electric arc furnace to obtain molten steel. S2, refining the molten steel by using fluoride-free rare earth refining slag to obtain refined molten steel. Specifically, the fluoride-free rare earth refining slag and the molten steel are subjected to first refining by an LF furnace, and then subjected to second refining by a VD vacuum furnace to obtain refined molten steel. The first refining temperature is 1580-1620°C, the second refining temperature is 1540-1580°C, the fluoride-free rare earth refining slag comprises CaO, Al2O3, MgO, SiO2 and CeO2, the basicity is 3-7, the calcium-aluminum ratio is 2.1-4.0, and the addition amount of CeO2 is 5wt%-20wt% of the fluoride-free rare earth refining slag. Specifically, the basicity of the refining slag can be any one of 3, 4, 5, 6, 7 or a range between any two of them, the calcium-aluminum ratio can be any one of 2.1, 2.5, 3, 3.5, 4.0 or a range between any two of them, and the addition amount of CeO2 can be any one of 5wt%, 10wt%, 15wt%, 20wt% of the fluoride-free rare earth refining slag or a range between any two of them.

[0022] S3, adding a nano-particle modifier to the refined molten steel to obtain modified molten steel. Specifically, the nano-particle modifier with a particle size of 30-500nm is added to the refined molten steel by cored wire feeding or bottom argon blowing under the protection of inert gas, the addition amount of the nano-particle modifier is 0.01wt%-0.1wt% of the refined molten steel, and after the addition, ultrasonic stirring device, mechanical stirring device and electromagnetic stirring device are used for stirring to uniformly disperse the nano-particle modifier into the molten steel. The nano-particle includes at least one of rare earth oxide nano-particle (such as CeO2, La2O3 or Y2O3), carbide nano-particle (such as TiC or VC), boride nano-particle (such as TiB2) or other metal oxide nano-particle (such as TiO2). Specifically, the addition amount of the nano-particle modifier can be any one of 0.01wt%, 0.03wt%, 0.05wt%, 0.07wt%, 0.09wt%, 0.1wt% of the refined molten steel or a range between any two of them.

[0023] S4, continuously casting or mold casting the modified molten steel to obtain hot work die steel.

[0024] Specifically, the modified molten steel is continuously cast or mold cast under an inert atmosphere or under the covering of a protective slag.

[0025] The technical solutions of the present application are further described below in combination with specific embodiments.

[0026] Example 1 The scrap steel meeting the chemical composition of H13 steel is selected, and alloy elements such as Cr, Mo and V are added in proportion according to the target composition, and the steel liquid is obtained by arc furnace smelting at 1600℃; the fluorine-free rare earth refining slag and the steel liquid are subjected to first refining by an LF furnace, and then are transferred into a VD vacuum furnace for second refining, so as to obtain a refined steel liquid, the temperature of the first refining is 1580℃, the temperature of the second refining is 1540℃, and the composition of the fluorine-free rare earth refining slag is: CaO 62.76%, Al2O3 15.69%, SiO2 12.55%, MgO 4%, and CeO2 5%; under the protection of inert gas, 0.05wt% CeO2 nanoparticles with a particle size of 30-500nm are added to the refined steel liquid by cored wire feeding, so as to obtain a modified steel liquid; the modified steel liquid is subjected to continuous casting under the protection of inert atmosphere, so as to obtain a hot die steel. Figure 1 In the table, g, h and i show the SEM-EDS diagram of the hot die steel prepared in Example 1; Figure 2 The inclusion size distribution statistics of the hot die steel prepared in Example 1 are shown; Table 1 shows the comparison of O and S contents before and after refining in Example 1.

[0027] Table 1 Example 2 The scrap steel meeting the chemical composition of H13 steel is selected, and alloy elements such as Cr, Mo and V are added in proportion according to the target composition, and the steel liquid is obtained by arc furnace smelting at 1650℃; the fluorine-free rare earth refining slag and the steel liquid are subjected to first refining by an LF furnace, and then are transferred into a VD vacuum furnace for second refining, so as to obtain a refined steel liquid, the temperature of the first refining is 1600℃, the temperature of the second refining is 1560℃, and the composition of the fluorine-free rare earth refining slag is: CaO 45.6%, Al2O3 15.2%, SiO2 15.2%, MgO 4%, and CeO2 20%; under the protection of inert gas, 0.1wt% TiC nanoparticles with a particle size of 30-500nm are added to the refined steel liquid by bottom argon blowing, so as to obtain a modified steel liquid; the modified steel liquid is subjected to mold casting under the covering of a protective slag, so as to obtain a green short-process hot die steel. Table 2 shows the comparison of O and S contents before and after refining in Example 2.

[0028] Table 2 Example 3 The waste steel meeting the chemical composition of H13 steel is selected, and alloy elements such as Cr, Mo and V are added in proportion according to the target composition, and the molten steel is obtained by arc furnace smelting at 1630 ℃; the fluoride-free rare earth refining slag and the molten steel are subjected to first refining by an LF furnace, and then transferred into a VD vacuum furnace for second refining, to obtain refined molten steel, the temperature of the first refining is 1620 ℃, the temperature of the second refining is 1580 ℃, and the composition of the fluoride-free rare earth refining slag is: CaO 56.87%, Al2O3 22.75%, SiO2 11.38%, MgO 4%, and CeO2 5%; under the protection of inert gas, 0.01wt% TiB2 nanoparticles with a particle size of 30-500 nm are added into the refined molten steel by stirring and dispersing, to obtain modified molten steel; the modified molten steel is subjected to continuous casting under inert atmosphere, to obtain hot die steel. Table 3 shows the comparison of O and S contents before and after refining of Example 3.

[0029] Table 3 Example 4 The waste steel meeting the chemical composition of H13 steel is selected, and alloy elements such as Cr, Mo and V are added in proportion according to the target composition, and the molten steel is obtained by arc furnace smelting at 1600 ℃; the fluoride-free rare earth refining slag and the molten steel are subjected to first refining by an LF furnace, and then transferred into a VD vacuum furnace for second refining, to obtain refined molten steel, the temperature of the first refining is 1580 ℃, the temperature of the second refining is 1540 ℃, and the composition of the fluoride-free rare earth refining slag is: CaO 62.76%, Al2O3 15.69%, SiO2 12.55%, MgO 4%, and CeO2 5%; under the protection of inert gas, 0.05wt% Y2O3 and VC nanoparticles with a particle size of 30-500 nm are added into the refined molten steel by cored wire feeding, to obtain modified molten steel; the modified molten steel is subjected to continuous casting under inert atmosphere, to obtain hot die steel. Table 4 shows the comparison of O and S contents before and after refining of Example 4.

[0030] Table 4 Example 5 The waste steel meeting the chemical composition of H13 steel is selected, and alloy elements such as Cr, Mo and V are added in proportion according to the target composition, and the molten steel is obtained by arc furnace smelting at 1600℃; the fluoride-free rare earth refining slag and the molten steel are subjected to first refining by an LF furnace, and then subjected to second refining by a VD vacuum furnace to obtain refined molten steel, the first refining temperature is 1580℃, the second refining temperature is 1540℃, and the fluoride-free rare earth refining slag has the following composition: CaO 64.24%, Al2O3 16.06%, SiO2 10.70%, MgO 4%, and CeO2 5%; under the protection of inert gas, 0.03wt% of CeO2 nanoparticles with a particle size of 30-500nm are added to the refined molten steel by cored wire feeding to obtain modified molten steel; the modified molten steel is subjected to continuous casting under an inert atmosphere to obtain hot die steel. Table 5 shows the comparison of O and S contents before and after refining of Example 5.

[0031] Table 5 Comparative Example 1 The waste steel meeting the chemical composition of H13 steel is selected, and alloy elements such as Cr, Mo and V are added in proportion according to the target composition, and the molten steel is obtained by arc furnace smelting at 1600℃; the fluoride-free rare earth refining slag and the molten steel are subjected to first refining by an LF furnace, and then subjected to second refining by a VD vacuum furnace to obtain refined molten steel, the first refining temperature is 1580℃, the second refining temperature is 1540℃, and the fluoride-free rare earth refining slag has the following composition: CaO 64.24%, Al2O3 16.06%, SiO2 10.70%, MgO 4%, and CeO2 5%; under the protection of inert gas, 0.03wt% of CeO2 nanoparticles with a particle size of 30-500nm are added to the refined molten steel by cored wire feeding to obtain modified molten steel; the modified molten steel is subjected to continuous casting under an inert atmosphere to obtain hot die steel. Table 5 shows the comparison of O and S contents before and after refining of Example 5. Figure 1 a, b and c are SEM-EDS diagrams of the hot die steel prepared by ESR remelting of Comparative Example 1, and Table 6 shows the comparison of O and S contents before and after refining of Comparative Example 1.

[0032] Table 6 Comparative Example 1 uses a traditional fluoride-containing refining slag to prepare hot die steel, which needs to be subjected to mold casting after refining (LF / VD), and then subjected to multiple electroslag remelting (ESR) to obtain hot die steel meeting the requirements; while the technical solution of the present application only needs to be subjected to continuous casting / mold casting after refining (LF / VD) to obtain hot die steel, which greatly shortens the production process; on the other hand, electroslag remelting needs to be subjected to mold casting first, and then the ingot is welded into a consumable electrode for electroslag remelting, which cannot be continuously produced, and the energy consumption is large, and the technical solution of the present application can realize continuous production.

[0033] Comparative Example 2 The waste steel meeting the chemical composition of H13 steel is selected, and alloy elements such as Cr, Mo and V are added in proportion according to the target composition, and the molten steel is obtained by arc furnace smelting at 1600 DEG C; the fluoride-free rare earth refining slag and the molten steel are subjected to first refining by the LF furnace, and then transferred into the VD vacuum furnace for second refining, to obtain the refined molten steel, the temperature of the first refining is 1580 DEG C, the temperature of the second refining is 1540 DEG C, and the composition of the fluoride-free rare earth refining slag is: CaO 62.76%, Al2O3 15.69%, SiO2 12.55%, MgO 4%, CeO2 5%; the refined molten steel is subjected to mold casting under inert atmosphere to obtain the ingot; and then the ingot is subjected to ESR remelting to obtain the hot work die steel. Figure 1 The SEM-EDS diagrams of the hot work die steel prepared by using only the fluoride-free rare earth slag refining in Comparative Example 2 are shown in FIG. 2D, FIG. 2E and FIG. 2F, and the O and S content before and after refining of Comparative Example 2 is shown in Table 7.

[0034] Table 7 Comparative Example 2 differs from Example 1 in that no nano-particle modifier is added, and it still needs to be subjected to electroslag remelting to obtain the qualified hot work die steel, and the inclusion composition and morphology of the prepared hot work die steel are obviously different from those of Example 1.

[0035] The typical inclusion in different production processes is shown in Figure 1 , Figure 1 The SEM-EDS diagrams of the hot work die steel prepared in Example 1, Comparative Example 1 and Comparative Example 2 are shown in FIG. 1A, FIG. 1B and FIG. 1C; wherein Figure 1 The SEM-EDS diagrams of the hot work die steel prepared by ESR remelting in Comparative Example 1 are shown in FIG. 2A, FIG. 2B and FIG. 2C, Figure 1 The SEM-EDS diagrams of the hot work die steel prepared by using only the fluoride-free rare earth slag refining in Comparative Example 2 are shown in FIG. 2D, FIG. 2E and FIG. 2F, Figure 1 The SEM-EDS diagrams of the hot work die steel prepared by using the combination of fluoride-free rare earth slag refining and nano-particle modification in Example 1 are shown in FIG. 2G, FIG. 2H and FIG. 21.

[0036] According to the examples and comparative examples, it can be seen that the combination of fluoride-free rare earth slag refining and nano-particle modification can effectively replace the fluoride-containing refining slag and the traditional electroslag remelting; and the addition of the nano-particle modifier can effectively modify the hard inclusions such as Al2O3 into rare earth inclusions.

[0037] The application provides a preparation method of a green short-process hot work die steel, and has the following beneficial effects: the fluorine-free rare earth slag refining and nanoparticle modification combined technology effectively replaces the fluorine-containing refining slag and the traditional electroslag remelting, reduces the power consumption and carbon emission of the smelting process, meets the technical development needs of the current green manufacturing and "double carbon" target, and realizes the green short-process manufacturing of the hot work die steel; and the prepared hot work die steel has higher cleanliness, more uniform microstructure and more excellent thermal fatigue performance.

[0038] The above is only the preferred embodiment of the application, and does not limit the patent scope of the application, and any equivalent structural transformation, direct / indirect application in other related technical fields, or direct / indirect application in other related technical fields made by using the content of the application specification within the inventive concept of the application are included in the patent protection scope of the application.

Claims

1. A method for preparing a green short-process hot working die steel, characterized in that: The following steps are involved: S1. Obtain scrap steel, add alloy, and smelt to obtain molten steel; S2, refining the molten steel with fluorine-free rare earth refining slag to obtain refined molten steel; S3, adding a nanoparticle modifier to the refined molten steel to obtain a modified molten steel; S4. Continuously casting or die casting the modified molten steel to obtain the hot working die steel.

2. The method for preparing a green short-process hot working die steel according to claim 1, characterized in that: In the step S1, smelting is performed in an electric arc furnace; in the step S2, the fluorine-free rare earth refined slag and the molten steel are first refined in an LF furnace and then transferred to a VD vacuum furnace for a second refining.

3. The method for preparing a green short-process hot working die steel according to claim 1, characterized in that: In step S3, the nanoparticle modifier is added by core wire feeding or bottom argon blowing.

4. The method for preparing a green short-process hot working die steel according to claim 1, characterized in that: In the step S4, the modified molten steel is continuously cast or mold cast in an inert atmosphere or covered by protective slag.

5. The method for preparing a green short-process hot working die steel according to claim 1, characterized in that: The fluorine-free rare earth refined slag includes CaO, Al2O3, MgO, SiO2 and CeO2.

6. The method for preparing a green short-process hot working die steel according to claim 5, characterized in that: The basicity of the fluorine-free rare earth refined slag is 3-7, the calcium-aluminum ratio is 2.1-4.0, and the addition amount of CeO2 is 5wt%-20wt% of the fluorine-free rare earth refined slag.

7. The method for preparing a green short-process hot working die steel according to claim 1, characterized in that: The particle size of the nanoparticle modifier is 30-500 nm, and the amount of the nanoparticle modifier added is 0.01 wt%-0.1 wt% of the refined steel liquid.

8. The method for preparing a green short-process hot working die steel according to claim 1, characterized in that: The nanoparticle modifier includes at least one of rare earth oxide nanoparticles, carbide nanoparticles, and boride nanoparticles.

9. The method for preparing a green short-process hot working die steel according to claim 8, characterized in that: The rare earth oxide nanoparticles include CeO2, La2O3 or Y2O3; the carbide nanoparticles include TiC or VC; and the boride nanoparticles include TiB2.

10. The method for preparing a green short-process hot working die steel according to claim 1, characterized in that: The size of inclusions in the hot working die steel is less than 1 μm.

Images