High-temperature-resistant high-strength plastic micro-nano inoculant reinforced die steel and preparation method

Abstract

The application provides a high-temperature-resistant high-strength plastic micro-nano inoculant reinforced die steel and a preparation method thereof. The preparation method of the high-temperature-resistant high-strength plastic micro-nano inoculant reinforced die steel comprises the following steps: placing Ti powder, B powder and Al powder in a mixing machine to obtain a mixture; wrapping the mixture with aluminum foil, and then performing thermal explosion reaction to obtain an alloy containing micron-size inoculants; placing C powder, Ti powder and Fe powder in a mixing machine to obtain a powder mixture, and wrapping the powder mixture with aluminum foil; heating the alloy containing the micron-size inoculants and commercial die steel to obtain a molten liquid, and then adding the aluminum foil-wrapped powder mixture into the molten liquid until complete melting; and after impurity removal, vacuum casting, forging and heat treatment, the high-temperature-resistant high-strength plastic micro-nano inoculant reinforced die steel is obtained, wherein the yield strength of the high-temperature-resistant high-strength plastic micro-nano inoculant reinforced die steel is greater than or equal to 970 MPa, the tensile strength is greater than or equal to 1033 MPa, and the fracture strain is greater than or equal to 13.1% at a temperature greater than or equal to 600 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of mold steel manufacturing technology, specifically relating to high-temperature resistant, high-strength, and plastic mold steel reinforced with micro-nano inoculants and its preparation method. Background Technology

[0002] As a key basic material in modern manufacturing, mold steel's high-temperature service performance directly affects the processing accuracy and product quality of critical processes such as precision molding and high-temperature die casting. In high-end manufacturing fields such as automobile manufacturing and aerospace, mold steel typically needs to withstand continuous thermal loads exceeding 500°C. This high-temperature environment leads to a decrease in the strength, toughness, and wear resistance of the mold, resulting in mold dimensional deformation and ultimately affecting product quality. Therefore, developing mold steel with excellent high-temperature service performance has become a core research direction for overcoming the bottleneck of mold service life. Existing technologies mainly improve the high-temperature performance of mold steel by further increasing the content of precious metal elements to introduce MC and M2C type high-temperature strengthening phases. However, adding a large amount of alloying elements not only increases the brittleness and processing difficulty of mold steel but also significantly increases its cost. In addition, existing technologies typically use quenching-deep cryogenic treatment-multi-stage tempering to improve the high-temperature performance of mold steel, but these processes will generate residual stress in the mold steel during application, leading to deformation or cracking. In summary, while existing technologies can improve the high-temperature performance of mold steel, they also increase its high-temperature brittleness, cracking, and processing difficulty, and make it difficult to simultaneously improve its strength and plasticity. This is detrimental to large-scale industrial production. Therefore, how to reduce raw material costs, simplify processes, and simultaneously improve the high-temperature performance, strength, and plasticity of mold steel while maintaining its toughness and processing properties, and achieving large-scale industrial production, is a pressing technical problem that needs to be solved. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides a high-temperature resistant, high-strength, and plastic mold steel reinforced with micro-nano inoculants, the preparation method of which includes the following steps:

[0004] (1) Ti powder, B powder and Al powder are mixed in a mass ratio of 1-3:2-6:11-17 in a mixer with a speed of 30-50 r / min for 20-60 min to obtain powder mixture 1; powder mixture 1 is wrapped in aluminum foil and subjected to a thermal explosion reaction to obtain an alloy containing micron-sized inoculant; C powder, Ti powder and Fe powder are mixed in a mass ratio of 1-2:1-2:6-8 in a mixer with a speed of 20-60 r / min for 15-45 min to obtain powder mixture 2; powder mixture 2 is packaged in aluminum foil to obtain mixture 3;

[0005] The particle size range of B powder is 60-120μm, the particle size range of Ti powder is 25-90μm, the particle size range of Al powder is 15-130μm, the particle size range of C powder is 40-150μm, and the particle size range of Fe powder is 10-80μm.

[0006] The thermal explosion reaction is carried out under argon protection at a pressure of 0.1-0.5 MPa and a temperature of 800-1300℃.

[0007] (2) The alloy containing micron-sized inoculant obtained in step (1) and commercial mold steel are heated at 1750-1950℃ for 0.5-1.5h according to a mass ratio of 0.01%-0.03%:1 to obtain a melt. Then, the mixture 3 obtained in step (1) is added to the melt at 0.01%-0.03% of the mass of commercial mold steel until it is completely melted. After impurity removal, vacuum casting, forging and heat treatment, high-temperature resistant, high-strength, plastic, micro-nano inoculant-reinforced mold steel is obtained.

[0008] The chemical composition of the commercial mold steel, by mass percentage, is as follows: Cr: 9.0-14.0 wt.%, C: 0.25-0.5 wt.%, Si: 0.50-1.00 wt.%, Mn: 0.25-1.50 wt.%, Mo: 0.15-3.00 wt.%, V: 0.10-1.00 wt.%, P: 0.025-0.045 wt.%, S: 0.025-0.045 wt.%, Fe: balance;

[0009] The forging process is as follows: the forging temperature is 850-1150℃, and the forging ratio is 7-10:1;

[0010] The heat treatment is as follows: after holding at 1020-1060℃ for 20-40 minutes, oil quenching is performed, followed by holding at 540-600℃ for 4-6 hours.

[0011] The high-temperature resistant, high-strength, and plastic, micro-nano inoculant-reinforced mold steel described herein has a yield strength ≥970MPa, tensile strength ≥1033MPa, and fracture strain ≥13.1% when used at ≥600℃. The high-temperature resistant, high-strength, and plastic, micro-nano inoculant-reinforced mold steel contains 0.01-0.03wt.% micron-sized and 0.01-0.03wt.% nano-sized inoculants, which are uniformly dispersed inside the mold steel.

[0012] Further, the particle size range of B powder in step (1) is 80-110 μm, the particle size range of Ti powder is 30-80 μm, the particle size range of Al powder is 30-100 μm, the particle size range of C powder is 50-130 μm, and the particle size range of Fe powder is 40-70 μm.

[0013] Further, the thermal explosion reaction described in step (1) is carried out under argon protection at a pressure of 0.2-0.3 MPa and a temperature of 900-1100℃.

[0014] Further, the chemical composition of the commercial mold steel described in step (2) is as follows by mass percentage: Cr: 9.5-11.5 wt.%, C: 0.30-0.40 wt.%, Si: 0.70-0.90 wt.%, Mn: 0.30-0.50 wt.%, Mo: 0.50-2.00 wt.%, V: 0.50-0.80 wt.%, P: 0.03-0.04 wt.%, S: 0.03-0.04 wt.%, Fe: balance. Attached Figure Description

[0015] Figure 1 This is the high-temperature tensile curve of the high-temperature resistant, high-strength, and plastic, micro-nano inoculant-reinforced mold steel 1 in Example 1 of the present invention at 600°C;

[0016] Figure 2 The high-temperature tensile curve of the high-temperature resistant, high-strength, and plastic, micro-nano inoculant-reinforced mold steel 2 in Example 2 of the present invention at 620°C;

[0017] Figure 3 This is the high-temperature tensile curve of the high-temperature resistant, high-strength, and plastic, micro-nano inoculant-reinforced mold steel 3 in Example 3 of the present invention at 630°C;

[0018] Figure 4 This is the high-temperature tensile curve of the commercial mold steel in step 2 of Examples 1-3 of the present invention at 600°C. Detailed Implementation

[0019] Example 1

[0020] The preparation method of high-temperature resistant, high-strength, and plastic mold steel reinforced with micro-nano inoculants includes the following steps:

[0021] (1) Ti powder, B powder and Al powder are mixed in a mass ratio of 1:2:7 in a mixer at a speed of 40 r / min for 40 min to obtain powder mixture 1; powder mixture 1 is wrapped in aluminum foil and subjected to a thermal explosion reaction to obtain alloy 1 containing micron-sized inoculant; C powder, Ti powder and Fe powder are mixed in a mass ratio of 3:3:14 in a mixer at a speed of 60 r / min for 20 min to obtain powder mixture 2; powder mixture 2 is packaged in aluminum foil to obtain mixture 3;

[0022] The particle size range of B powder is 60-120μm, the particle size range of Ti powder is 25-90μm, the particle size range of Al powder is 15-130μm, the particle size range of C powder is 40-150μm, and the particle size range of Fe powder is 10-80μm.

[0023] The thermal explosion reaction is carried out under argon protection at a pressure of 0.3 MPa and a temperature of 900°C.

[0024] (2) Alloy 1 containing micron-sized inoculant obtained in step (1) is heated with commercial mold steel at 1850℃ for 1 hour at a mass ratio of 0.01%:1 to obtain a melt. Then, mixture 3 obtained in step (1) is added to the melt at 0.01% of the mass of commercial mold steel until it is completely melted. After impurity removal, vacuum casting, forging and heat treatment, high-temperature resistant, high-strength, plastic, micro-nano inoculant-reinforced mold steel 1 is obtained.

[0025] The chemical composition of the commercial mold steel, by mass percentage, is: Cr: 9.95 wt.%, C: 0.32 wt.%, Si: 0.82 wt.%, Mn: 0.31 wt.%, Mo: 1.88 wt.%, V: 0.72 wt.%, P: 0.03 wt.%, S: 0.03 wt.%, Fe: balance.

[0026] The forging process is as follows: the forging temperature is 1000℃ and the forging ratio is 9:1.

[0027] The heat treatment is as follows: after holding at 1040℃ for 30 minutes, oil quenching is performed, followed by holding at 580℃ for 5 hours.

[0028] The high-temperature resistant, high-strength, and plastic, micro / nano-inotropic reinforced mold steel 1 contains 0.01 wt.% micron-sized and 0.01 wt.% nano-sized inoculants, which are uniformly dispersed inside the mold steel.

[0029] The high-temperature resistant, high-strength, and plastic mold steel 1 reinforced with micro-nano inoculants prepared in this embodiment has the following high-temperature tensile curve at 600℃: Figure 1 As shown: its yield strength is 970 MPa, tensile strength is 1033 MPa, and fracture strain is 16.4%. The high-temperature tensile curve of the commercial mold steel in step (2) at 600℃ is shown below. Figure 4 As shown, its yield strength, tensile strength, and fracture strain are 861 MPa, 965 MPa, and 11.1%, respectively. Compared with commercial mold steel, the high-temperature resistant, high-strength, and ductile mold steel 1 reinforced with micro-nano inoculants prepared in this embodiment shows an increase in yield strength, tensile strength, and fracture strain of 12.6%, 7.1%, and 47.1%, respectively. In addition, the high-temperature resistant, high-strength, and ductile mold steel 1 reinforced with micro-nano inoculants obtained by this invention simultaneously improves strength and ductility at high temperatures, while avoiding problems such as brittleness, cracking, and increased processing difficulty, making it suitable for industrial production.

[0030] Example 2

[0031] The preparation method of high-temperature resistant, high-strength, and plastic mold steel 2, reinforced with micro-nano inoculants, includes the following steps:

[0032] (1) Ti powder, B powder and Al powder are mixed in a mass ratio of 1:2:17 in a mixer at a speed of 30 r / min for 60 min to obtain powder mixture 1; powder mixture 1 is wrapped in aluminum foil and subjected to a thermal explosion reaction to obtain alloy 2 containing micron-sized inoculant; C powder, Ti powder and Fe powder are mixed in a mass ratio of 1:1:8 in a mixer at a speed of 40 r / min for 35 min to obtain powder mixture 2; powder mixture 2 is packaged in aluminum foil to obtain mixture 3;

[0033] The particle size range of B powder is 60-120μm, the particle size range of Ti powder is 25-90μm, the particle size range of Al powder is 15-130μm, the particle size range of C powder is 40-150μm, and the particle size range of Fe powder is 10-80μm.

[0034] The thermal explosion reaction is carried out under argon protection at a pressure of 0.2 MPa and a temperature of 1000 °C.

[0035] (2) The alloy 2 containing micron-sized inoculant obtained in step (1) and commercial mold steel are heated at 1750℃ for 1.5h at a mass ratio of 0.02%:1 to obtain a melt. Then, the mixture 3 obtained in step (1) is added to the melt at 0.02% of the mass of commercial mold steel until it is completely melted. After impurity removal, vacuum casting, forging and heat treatment, high temperature resistant, high strength, plasticity, micro-nano inoculant reinforced mold steel 2 is obtained.

[0036] The chemical composition of the commercial mold steel, by mass percentage, is: Cr: 9.95 wt.%, C: 0.32 wt.%, Si: 0.82 wt.%, Mn: 0.31 wt.%, Mo: 1.88 wt.%, V: 0.72 wt.%, P: 0.03 wt.%, S: 0.03 wt.%, Fe: balance.

[0037] The forging process is as follows: the forging temperature is 850℃ and the forging ratio is 10:1.

[0038] The heat treatment is as follows: after holding at 1020℃ for 40 minutes, oil quenching is performed, followed by holding at 540℃ for 6 hours.

[0039] The high-temperature resistant, high-strength, and plastic, micro / nano-inotropic reinforced mold steel 2 contains 0.02 wt.% micron-sized and 0.02 wt.% nano-sized inoculants, which are uniformly dispersed inside the mold steel.

[0040] The high-temperature resistant, high-strength, and plastic mold steel 2 reinforced with micro-nano inoculants prepared in this embodiment has the following high-temperature tensile curve at 620℃: Figure 2 As shown, its yield strength is 971 MPa, tensile strength is 1053 MPa, and fracture strain is 15.5%. Compared with commercial mold steel used at 600℃, the high-temperature resistant, high-strength, and ductile mold steel 2 prepared in this embodiment shows an increase in yield strength, tensile strength, and fracture strain of 12.6%, 9.1%, and 39.6%, respectively. In addition, the high-temperature resistant, high-strength, and ductile mold steel 2 obtained by this invention simultaneously improves strength and ductility at higher temperatures, while avoiding problems such as brittleness, cracking, and increased processing difficulty, making it suitable for industrial production.

[0041] Example 3

[0042] The preparation method of high-temperature resistant, high-strength, and plastic mold steel 3, reinforced with micro-nano inoculants, includes the following steps:

[0043] (1) Ti powder, B powder and Al powder are mixed in a mass ratio of 3:6:11 in a mixer at a speed of 50 r / min for 20 min to obtain powder mixture 1; powder mixture 1 is wrapped in aluminum foil and subjected to a thermal explosion reaction to obtain alloy 3 containing micron-sized inoculant; C powder, Ti powder and Fe powder are mixed in a mass ratio of 1:1:3 in a mixer at a speed of 30 r / min for 45 min to obtain powder mixture 2; powder mixture 2 is packaged in aluminum foil to obtain mixture 3;

[0044] The particle size range of B powder is 60-120μm, the particle size range of Ti powder is 25-90μm, the particle size range of Al powder is 15-130μm, the particle size range of C powder is 40-150μm, and the particle size range of Fe powder is 10-80μm.

[0045] The thermal explosion reaction is carried out under argon protection at a pressure of 0.1 MPa and a temperature of 1100°C.

[0046] (2) The alloy 3 containing micron-sized inoculant obtained in step (1) and commercial mold steel are heated at 1950℃ for 0.5h at a mass ratio of 0.03%:1 to obtain a melt. The mixture 3 obtained in step (1) is then added to the melt at 0.03% of the mass of commercial mold steel until it is completely melted. After impurity removal, vacuum casting, forging and heat treatment, high-temperature resistant, high-strength, plastic, micro-nano inoculant-reinforced mold steel 3 is obtained.

[0047] The chemical composition of the commercial mold steel, by mass percentage, is: Cr: 9.95 wt.%, C: 0.32 wt.%, Si: 0.82 wt.%, Mn: 0.31 wt.%, Mo: 1.88 wt.%, V: 0.72 wt.%, P: 0.03 wt.%, S: 0.03 wt.%, Fe: balance.

[0048] The forging process is as follows: the forging temperature is 1150℃ and the forging ratio is 7:1.

[0049] The heat treatment is as follows: after holding at 1060℃ for 20 minutes, oil quenching is performed, followed by holding at 600℃ for 4 hours.

[0050] The high-temperature resistant, high-strength, and plastic, micro / nano-inotropic reinforced mold steel 3 contains 0.03 wt.% micron-sized and 0.03 wt.% nano-sized inoculants, which are uniformly dispersed inside the mold steel.

[0051] The high-temperature resistant, high-strength, and plastic mold steel 3 reinforced with micro-nano inoculants prepared in this embodiment has the following high-temperature tensile curve at 630℃: Figure 3 As shown, its yield strength is 1061 MPa, tensile strength is 1157 MPa, and fracture strain is 13.1%. Compared with commercial mold steel used at 600℃, the high-temperature resistant, high-strength, and ductile mold steel 3 prepared in this embodiment shows an increase in yield strength, tensile strength, and fracture strain of 23.2%, 19.8%, and 18%, respectively. In addition, the high-temperature resistant, high-strength, and ductile mold steel 3 obtained by this invention simultaneously improves strength and ductility at higher temperatures, while avoiding problems such as brittleness, cracking, and increased processing difficulty, making it suitable for industrial production.

[0052] In summary, compared with commercially available mold steel, the mold steel obtained by this invention, at the same or higher operating temperatures, improves strength and plasticity while avoiding problems such as brittleness, cracking, and increased processing difficulty, making it suitable for industrial production. Furthermore, compared with existing technologies, this invention controls the inoculant content to ≤0.06wt%, saving costs and simplifying the process, simultaneously improving the strength and plasticity of the mold steel and avoiding problems such as brittleness, cracking, and increased processing difficulty, making it suitable for industrial production. The components, proportions, and process parameters used in Examples 1-3 of this invention are all different. The mold steel obtained in Example 3 has the best strength, while the mold steel obtained in Example 1 has the best plasticity. However, the particle content, proportions, and process parameters in Examples 1 and 3 are different, indicating that the superior performance of the mold steel obtained by this invention is not determined by a single component, proportion, or process parameter, but is achieved through the interaction of components, component proportions, and the synergistic regulation of processes and process parameters. Furthermore, compared to commercially available mold steel, the mold steel obtained in all embodiments of this invention exhibits superior performance at the same or higher operating temperatures. This simultaneously improves the strength and plasticity of the mold steel while avoiding problems such as brittleness, cracking, and increased processing difficulty. Therefore, compared to existing technologies, this invention achieves significantly enhanced technical effects. Only within the scope of the claims of this invention can the simultaneous improvement of high-temperature strength and plasticity of mold steel, along with the avoidance of brittleness, cracking, and increased processing difficulty, be achieved. In addition, the micron- and nano-sized inoculants obtained in this invention are uniformly dispersed in the mold steel matrix without agglomeration. The inoculant content is controlled at ≤0.06wt%, resulting in lower raw material costs and a simplified process. Therefore, this invention simplifies the process, reduces production costs, and simultaneously improves the high-temperature strength and plasticity of mold steel, making it suitable for industrial production.

Claims

1. A high-temperature resistant, high-strength, and plastic mold steel reinforced with micro-nano inoculants, characterized in that... Its preparation method includes the following steps: (1) Ti powder, B powder and Al powder are mixed in a mass ratio of 1-3:2-6:11-17 in a mixer with a speed of 30-50 r / min for 20-60 min to obtain powder mixture 1; powder mixture 1 is wrapped in aluminum foil and subjected to a thermal explosion reaction to obtain an alloy containing micron-sized inoculant; C powder, Ti powder and Fe powder are mixed in a mass ratio of 1-2:1-2:6-8 in a mixer with a speed of 20-60 r / min for 15-45 min to obtain powder mixture 2; powder mixture 2 is packaged in aluminum foil to obtain mixture 3; The particle size range of B powder is 60-120μm, the particle size range of Ti powder is 25-90μm, the particle size range of Al powder is 15-130μm, the particle size range of C powder is 40-150μm, and the particle size range of Fe powder is 10-80μm. The thermal explosion reaction is carried out under argon protection at a pressure of 0.1-0.5 MPa and a temperature of 800-1300℃. (2) The alloy containing micron-sized inoculant obtained in step (1) and commercial mold steel are heated at 1750-1950℃ for 0.5-1.5h according to a mass ratio of 0.01%-0.03%:1 to obtain a melt. Then, the mixture 3 obtained in step (1) is added to the melt at 0.01%-0.03% of the mass of commercial mold steel until it is completely melted. After impurity removal, vacuum casting, forging and heat treatment, high-temperature resistant, high-strength, plastic, micro-nano inoculant-reinforced mold steel is obtained. The chemical composition of the commercial mold steel, by mass percentage, is as follows: Cr: 9.0-14.0 wt.%, C: 0.25-0.5 wt.%, Si: 0.50-1.00 wt.%, Mn: 0.25-1.50 wt.%, Mo: 0.15-3.00 wt.%, V: 0.10-1.00 wt.%, P: 0.025-0.045 wt.%, S: 0.025-0.045 wt.%, Fe: balance; The forging process is as follows: the forging temperature is 850-1150℃, and the forging ratio is 7-10:1; The heat treatment is as follows: after holding at 1020-1060℃ for 20-40 minutes, oil quenching is performed, followed by holding at 540-600℃ for 4-6 hours. The high-temperature resistant, high-strength, and plastic, micro-nano inoculant-reinforced mold steel described herein has a yield strength ≥970MPa, tensile strength ≥1033MPa, and fracture strain ≥13.1% when used at ≥600℃. The high-temperature resistant, high-strength, and plastic, micro-nano inoculant-reinforced mold steel contains 0.01-0.03wt.% micron-sized and 0.01-0.03wt.% nano-sized inoculants, which are uniformly dispersed inside the mold steel.

2. The high-temperature resistant, high-strength, and plastic mold steel reinforced with micro-nano inoculants according to claim 1, characterized in that, The particle size range of B powder in step (1) is 80-110μm, the particle size range of Ti powder is 30-80μm, the particle size range of Al powder is 30-100μm, the particle size range of C powder is 50-130μm, and the particle size range of Fe powder is 40-70μm.

3. The high-temperature resistant, high-strength, and plastic mold steel reinforced with micro-nano inoculants according to claim 1, characterized in that, The thermal explosion reaction described in step (1) is carried out under the protection of argon gas, with a pressure of 0.2-0.3 MPa and a temperature of 900-1100℃.

4. The high-temperature resistant, high-strength, and plastic mold steel reinforced with micro-nano inoculants according to claim 1, characterized in that, The chemical composition of the commercial mold steel described in step (2) is as follows (by mass percentage): Cr: 9.5-11.5 wt.%, C: 0.30-0.40 wt.%, Si: 0.70-0.90 wt.%, Mn: 0.30-0.50 wt.%, Mo: 0.50-2.00 wt.%, V: 0.50-0.80 wt.%, P: 0.03-0.04 wt.%, S: 0.03-0.04 wt.%, Fe: balance.

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