A high-aluminum boron die steel with high zinc hot corrosion resistance for zinc alloy large plastic deformation and a preparation method thereof

Abstract

The application discloses a zinc alloy large plastic deformation zinc hot corrosion resistant high-aluminum boron die steel and a preparation method thereof, a cast ingot is obtained by adopting a sand casting method; homogenization and high-temperature austenitization treatment are conducted on the cast ingot, then hot die forging is conducted and cooling is conducted to obtain a heat-treated piece; the heat-treated piece is subjected to heat treatment by adopting a quenching plus high-temperature tempering mode to obtain a forged piece; the forged piece is subjected to finishing treatment to obtain the zinc hot corrosion resistant high-aluminum boron die steel; the zinc hot corrosion resistant high-aluminum boron die steel prepared by the application can be more suitable for severe working conditions, and provides a new idea for design and manufacture of large plastic deformation die equipment of zinc alloy and a series of non-ferrous alloys.

Description

Technical Field

[0001] This invention belongs to the field of zinc alloy large plastic deformation technology, specifically relating to a zinc hot melt resistant high-alumina boron-containing mold steel for zinc alloy large plastic deformation and its preparation method. Background Technology

[0002] With the continuous development of industrial technology, people have increasingly higher requirements for material properties. The strength and plasticity of cast zinc alloys can no longer meet the needs of various industrial applications. Large plastic deformation is a widely studied and applied method for strengthening zinc alloys. A common method of large plastic deformation processing is to mechanically constrain the zinc alloy at high temperatures using a mold, thereby inducing large plastic hot deformation. This method can significantly improve the strength and plasticity of zinc alloys and plays a crucial role in expanding the application fields of zinc alloys. Furthermore, zinc alloy die-casting molds and zinc ingot molds used in zinc ingot production need to repeatedly withstand high-temperature zinc erosion and thermal fatigue, leading to a growing demand for zinc-resistant hot-melt mold materials.

[0003] Based on the application of the mold, the mold steel used in thermoplastic deformation processing belongs to the hot extrusion mold steel category within hot work mold steels. Common hot extrusion mold steels are mainly divided into two categories: medium-heat resistant mold steels with an operating temperature of 550–600℃, typically such as 4Cr5MoSiV(H13), 4Cr5MoSiV1, and 4Cr5W2SiV; and high-heat resistant mold steels with an operating temperature of 580–650℃, typically such as 3Cr2W8V, 3Cr3Mo3W2V, and 4Cr3Mo3SiV. 4Cr5MoSiV(H13) steel is generally considered one of the best materials for making die-casting molds for aluminum, copper, zinc, and their alloys, and is also a commonly used material for zinc alloy large plastic deformation mold steels. However, this mold material is relatively expensive, especially in the hot extrusion production process of zinc alloys with strong thermal erosion, exhibiting a shorter service life, frequent fractures, and thermal spalling. On the one hand, hot-working dies are subjected to high working stress and impact loads during operation, as well as repeated heating and cooling, and metal impact and friction, resulting in extremely harsh service conditions and a high risk of die failure. On the other hand, compared to other common non-ferrous metal alloys, such as copper and aluminum alloys, zinc alloys have a lower melting point, higher viscosity, and stronger adhesion, easily forming deposits on the die surface. These deposits, under high-temperature mechanical action, form hardened, corrosive deposits, resulting in thermal erosion, significantly reducing the die's service life. In short, these factors restrict the service life of dies used for the high plasticity processing of zinc alloys, leading to high costs and hindering the large-scale application of zinc alloys. Therefore, there is an urgent need to develop a new type of die steel to solve this problem.

[0004] Specifically, die steels used for the large plastic deformation processing of zinc alloys face the following harsh working conditions. First, because zinc alloys with a hexagonal structure are difficult to deform with large plasticity, the die steel needs to operate under high loads, requiring good strength and wear resistance. Simultaneously, the large plastic deformation of zinc alloys often occurs at high temperatures, requiring the die steel to possess not only a certain degree of oxidation resistance but also resistance to zinc erosion and high-temperature creep strength. The main reason for the susceptibility of die steel to thermal erosion is that zinc alloys easily adhere to iron-based alloys, leading to severe erosion. During hot extrusion of zinc alloys, the die surface comes into close contact with the high-temperature zinc alloy, inducing thermal erosion, which in turn causes embrittlement, cracking, and erosion pits or scale on the die surface. Furthermore, die steels used for high-temperature extrusion of zinc alloys operate in environments containing corrosive media, stress conditions, and repeated high-temperature thermal fatigue, easily inducing severe thermal fatigue failure. Stress corrosion and thermal spalling are frequent occurrences, and the die is prone to premature failure. In conclusion, the harsh service environment of die steels used for the large plastic deformation of zinc alloys places stringent requirements on the composition design and processing methods of the die steel. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a high-alumina boron-containing die steel for zinc alloy large plastic deformation that is resistant to zinc hot melting corrosion and its preparation method, thereby solving the technical problems of severe zinc hot melting corrosion and fatigue failure of zinc alloy large plastic deformation dies, short service life, easy peeling and cracking of zinc alloy extrusion dies, high cost, and short service life of high temperature wear corrosion resistance.

[0006] The present invention adopts the following technical solution:

[0007] A method for preparing a high-alumina boron-containing die steel resistant to zinc hot melt corrosion for large plastic deformation of zinc alloys includes the following steps:

[0008] S1. Ingots are obtained by sand casting.

[0009] S2. The ingot obtained in step S1 is homogenized and subjected to high-temperature austenitization treatment, then hot forging and cooling are performed to obtain a heat-treated part.

[0010] S3. The heat-treated part obtained in step S2 is heat-treated by quenching and high-temperature tempering to obtain a forging.

[0011] S4. Perform precision machining on the forgings obtained in step S3 to obtain high-alumina boron-containing mold steel resistant to zinc hot melt corrosion.

[0012] Preferably, in step S1, the melting temperature is 1550–1600°C and the casting temperature is 1440–1480°C.

[0013] More preferably, the ingot has a cylindrical structure.

[0014] Preferably, in step S2, the temperature range for hot forging is 980–1100°C, the forging ratio is 6–8, and the strain rate is 0.01–4 s. -1 .

[0015] More preferably, the homogenization treatment temperature is 1020–1080°C, and the holding time is 3–5 hours.

[0016] More preferably, the cooling method is air cooling.

[0017] Preferably, in step S3, the quenching temperature is 1040-1080℃ and the holding time is 1.5-2h, and the tempering temperature is 480-530℃ and the holding time is 2.5-4.0h.

[0018] More preferably, the quenching medium is oil, and the furnace is cooled to room temperature using a furnace cooling method.

[0019] Preferably, in step S4, the zinc-resistant hot-melt erosion high-alumina boron-containing mold steel has a frustum-shaped structure with a taper of 9–11°.

[0020] Another technical solution of the present invention is a high-alumina boron-containing mold steel for zinc alloy large plastic deformation resistant to zinc hot melting, comprising, by weight percentage: C: 0.15%~0.25%, B: 1.4%~1.8%, W: 1.4%~1.6%, V: 1.1%~1.3%, Mo: 1.55%~1.75%, Cr: 5.0%~5.5%, Ti: 0.6%~0.8%, Si: 0.4%~1.3%, Al: 2.4%~5.8%, with the balance being Fe.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] A method for preparing high-alumina boron-containing mold steel resistant to zinc hot melting for large plastic deformation of zinc alloys involves obtaining an ingot through sand casting, followed by forging to obtain mold steel with excellent strength and toughness. The strength, toughness, stress corrosion resistance, and high-temperature wear resistance of the mold steel are improved through alloying of elements B, W, Mo, V, Cr, Ti, Si, and Al, as well as subsequent heat treatment.

[0023] Furthermore, the pouring temperature range enables the molten metal to have good filling ability, which is conducive to obtaining ingots with complete shape and clear outline.

[0024] Furthermore, after homogenization treatment at 1020–1080℃ for 3–6 hours, the ingot is hot-forged at 980–1100℃ with a forging ratio of 6–8 and a strain rate range of 0.01–4 s. -1The cooling method after hot forging is air cooling. This operation significantly breaks down and refines the originally fishbone-like boride reinforcing phase in the matrix. Therefore, the toughness of the high-alumina boron-containing die steel resistant to zinc hot erosion is improved.

[0025] Furthermore, a homogenization heat treatment is performed at a temperature of 1020–1080℃ for 3–5 hours before forging. This operation makes the ingot composition more uniform, eliminates dendritic segregation, and obtains a microstructure of high-temperature austenitic matrix and boride strengthening phase, thereby improving the thermoplastic deformation capacity during forging and facilitating the smooth progress of the forging process.

[0026] Furthermore, a quenching treatment is performed using oil at a heating temperature of 1040–1080℃ and a holding time of 1.5–2 hours. Following quenching, a high-temperature tempering treatment is performed at 480–530℃ and a holding time of 2.5–4.0 hours. The tempered forgings are then furnace cooled to room temperature. The quenching process transforms the microstructure of the die steel into martensite and ferrite. The martensitic matrix possesses excellent strength and hardness, while the broken borides are further isolated and agglomerated. The tempering process effectively reduces the residual stress generated during quenching and achieves precipitate strengthening, thereby improving the strength, toughness, and high-temperature wear resistance of the die.

[0027] A high-alumina boron-containing mold steel for zinc alloy large plastic deformation, resistant to zinc hot melting, is provided. The addition of boron element improves the hardenability of the mold and creates boride phases with excellent strength and hardness in the microstructure; the addition of Al element enhances the mold's oxidation resistance and zinc melting resistance; the addition of Si element slows down the high-temperature oxidation process of the mold and enhances its oxidation resistance; the addition of Cr element enhances the mold's resistance to zinc melting and oxidation.

[0028] In summary, the prepared zinc-resistant high-alumina boron-containing mold steel is better suited to harsh working conditions, providing a new approach for the design and manufacturing of large plastic deformation molds for zinc alloys and other non-ferrous alloys.

[0029] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0030] Figure 1 SEM image of the zinc-resistant hot-melting high-alumina boron-containing mold steel prepared in Example 1 of this invention;

[0031] Figure 2 This is a flowchart of the preparation process of the present invention;

[0032] Figure 3 Photograph of a cone-shaped liner made of high-alumina boron-containing mold steel resistant to zinc hot melt corrosion;

[0033] Figure 4Macroscopic photographs of H13 mold steel mold liners and high-alumina boron-containing mold steel resistant to zinc hot erosion after 20 service cycles. Detailed Implementation

[0034] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined to form new technical solutions.

[0036] Unless otherwise specified, all the technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0037] In this invention, unless otherwise specified, percentage (%) or parts refer to weight percentage or parts relative to the composition.

[0038] Unless otherwise specified, the components or preferred components involved in this invention can be combined with each other to form new technical solutions.

[0039] In this invention, unless otherwise specified, the numerical range "a~b" represents an abbreviation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "6~22" means that all real numbers between "6~22" have been listed in this document, and "6~22" is simply an abbreviation of these numerical combinations.

[0040] The "scope" disclosed in this invention can be in the form of a lower limit and an upper limit, and can be one or more lower limits and one or more upper limits, respectively.

[0041] In this invention, the term "and / or" as used herein refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes such combinations.

[0042] In this invention, unless otherwise stated, the various reactions or operation steps may be performed sequentially or in a particular order. Preferably, the reaction methods described herein are performed sequentially.

[0043] Unless otherwise stated, the technical and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be used in this invention.

[0044] This invention provides a high-alumina boron-containing die steel resistant to zinc hot-melt corrosion for zinc alloys undergoing large plastic deformation, and its preparation method. By modifying the composition, forging, and heat treatment, the morphology and structure of the borides are improved, resulting in work hardening and precipitation strengthening effects. This yields a high-alumina boron-containing die steel with high-temperature toughness, excellent resistance to stress corrosion, and good thermal fatigue performance. This die steel possesses excellent mechanical properties and can serve as a superior alternative to H13 hot-work die steel.

[0045] Please see Figure 2 This invention discloses a method for preparing high-alumina boron-containing mold steel resistant to zinc hot melt corrosion for large plastic deformation of zinc alloys, comprising the following steps:

[0046] S1. Obtain cylindrical ingots by sand casting;

[0047] The alloy is smelted in a high-frequency induction furnace at a melting temperature of 1550–1600℃ and a casting temperature of 1440–1480℃. Cylindrical ingots are obtained by sand casting.

[0048] S2, Hot forging;

[0049] After annealing, the ingot is hot-forged, and the cooling method after hot forging is air cooling.

[0050] The homogenization treatment temperature before hot forging is 1020–1080℃, the homogenization holding time is 3–5 h, the hot die forging temperature range is 980–1100℃, the forging ratio is 6–8, and the strain rate range is 0.01–4 s. -1 The cooling method is air cooling.

[0051] S3. The heat treatment method of quenching followed by high-temperature tempering is adopted.

[0052] The quenching temperature is 1040–1080℃, the holding time is 1.5–2h, and the quenching medium is oil. The tempering temperature is 480–530℃, the holding time is 2.5–4.0h, and the heat-treated parts are cooled to room temperature by furnace cooling after tempering.

[0053] S4. Perform precision machining on the forging to obtain a frustum-shaped mold liner.

[0054] The heat-treated forgings are precision machined to obtain a frustum-shaped inner liner with a taper of 9–11°.

[0055] This invention discloses a high-alumina boron-containing die steel for zinc alloys subjected to large plastic deformation and resistant to zinc hot melting, comprising, by weight percentage: C: 0.15%–0.25%, B: 1.4%–1.8%, W: 1.4%–1.6%, V: 1.1%–1.3%, Mo: 1.55%–1.75%, Cr: 5.0%–5.5%, Ti: 0.6%–0.8%, Si: 0.4%–1.3%, Al: 2.4%–5.8%, with the balance being Fe.

[0056] The zinc alloy high-alumina boron-containing mold steel for large plastic deformation prepared by the method of this invention is low in cost, has a dense structure, and exhibits highly dispersed secondary precipitates after tempering. The alloy has a reduced density, high intragranular dislocation density, high strength and good toughness, high temperature wear resistance, and achieves lightweight manufacturing.

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0058] Example 1

[0059] This embodiment provides a high-alumina boron-containing mold steel resistant to zinc hot melt corrosion for large plastic deformation of zinc alloys and its preparation method, including the following steps:

[0060] (1) The raw materials with the composition of C: 0.15%, B: 1.4%, W: 1.4%, V: 1.1%, Mo: 1.55%, Cr: 5.0%, Ti: 0.6%, Si: 0.4%, Al: 2.4%, and the balance being Fe were melted to 1550℃, and cylindrical ingots were obtained by sand casting. The pouring temperature was 1440℃, and the castings were cooled to room temperature by air cooling.

[0061] (2) After homogenization treatment at 1020℃ for 3 hours, the ingot is hot-forged at 980℃ with a forging ratio of 6 and a strain rate of 0.01s. -1 The cooling method after hot forging is air cooling.

[0062] (3) The quenching treatment is carried out with a heating temperature of 1040℃, a holding time of 1.5 hours and an oil medium. After quenching, the forging is subjected to a high-temperature tempering treatment with a heating temperature of 480℃ and a holding time of 2.5 hours. The tempered forging is cooled to room temperature with the furnace.

[0063] (4) Finishing: The forging is finished to obtain a truncated cone mold liner with a taper of 9°.

[0064] The microstructure of the heat-treated forgings was observed using scanning electron microscopy (SEM), and the results are as follows: Figure 1 In this process, the borides in the microstructure are significantly refined, appearing as fragmented and scattered particles distributed within a martensitic-ferrite mixed matrix. Some borides also exhibit spheroidization. In cast high-alumina boron-containing mold steel, the morphology of borides is a continuous network or fishbone pattern, which is detrimental to the alloy's toughness and fatigue resistance. However, after forging, the originally fishbone-shaped boride strengthening phases in the alloy are significantly broken and refined. After heat treatment, the sharp structures in the borides further agglomerate, thereby improving the toughness of the high-alumina boron-containing mold steel.

[0065] Example 2

[0066] This embodiment provides a high-alumina boron-containing mold steel resistant to zinc hot melt corrosion for large plastic deformation of zinc alloys and its preparation method, including the following steps:

[0067] (1) The composition is C: 0.25%, B: 1.8%, W: 1.6%, V: 1.3%, Mo: 1.75%, Cr:

[0068] The raw materials, consisting of 5.5% Ti, 0.8% Si, 1.3% Al, and the balance Fe, were melted to 1600℃ and a cylindrical ingot was obtained by sand casting. The pouring temperature was 1480℃, and the casting was then cooled to room temperature by air cooling.

[0069] (2) After homogenization treatment at 1080℃ for 5 hours, the ingot is hot forged at 1100℃ with a forging ratio of 8 and a strain rate of 4s. -1 The cooling method after hot forging is air cooling.

[0070] (3) The quenching treatment is carried out with a heating temperature of 1080℃, a holding time of 2 hours and an oil medium. After quenching, the high temperature tempering treatment is carried out with a heating temperature of 530℃ and a holding time of 4 hours. The tempered forging is cooled to room temperature with the furnace.

[0071] (4) Finishing: The forging is finished to obtain a frustum mold liner with a taper of 11°.

[0072] Photographs of the conical liner of the high-alumina boron-containing mold steel resistant to zinc hot melt corrosion are shown below. Figure 3 .

[0073] Example 3

[0074] This embodiment provides a high-alumina boron-containing mold steel resistant to zinc hot melt corrosion for large plastic deformation of zinc alloys and its preparation method, including the following steps:

[0075] (1) The composition is C: 0.25%, B: 1.6%, W: 1.6%, V: 1.3%, Mo: 1.75%, Cr:

[0076] The raw materials, consisting of 5.5% Ti, 0.7% Si, 1.2% Al, and the balance Fe, were melted to 1560℃. Cylindrical ingots were obtained by sand casting at 1460℃, and the castings were then cooled to room temperature by air cooling.

[0077] (2) After homogenization treatment at 1050℃ for 4 hours, the ingot is hot-forged at 1000℃ with a forging ratio of 8 and a strain rate of 0.05s. -1 The cooling method after hot forging is air cooling.

[0078] (3) The quenching treatment is carried out with a heating temperature of 1050℃, a holding time of 1.5 hours and an oil medium. After quenching, the forging is subjected to a high-temperature tempering treatment with a heating temperature of 500℃ and a holding time of 3 hours. The tempered forging is cooled to room temperature with the furnace.

[0079] (4) Finishing: The forging is finished to obtain a truncated cone mold liner with a taper of 10°.

[0080] Example 4

[0081] This embodiment provides a high-alumina boron-containing mold steel resistant to zinc hot melt corrosion for large plastic deformation of zinc alloys and its preparation method, including the following steps:

[0082] (1) The composition is C: 0.2%, B: 1.5%, W: 1.5%, V: 1.2%, Mo: 1.65%, Cr:

[0083] The raw materials, consisting of 5.2% Ti, 0.7% Si, 1.0% Al, and the balance Fe, were melted to 1560℃ and a cylindrical ingot was obtained by sand casting at 1460℃. The casting was then cooled to room temperature by air cooling.

[0084] (2) After homogenization treatment at 1060℃ for 4 hours, the ingot is hot-forged at 1100℃ with a forging ratio of 6 and a strain rate of 0.04s. -1 The cooling method after hot forging is air cooling.

[0085] (3) The quenching treatment is carried out with a heating temperature of 1050℃, a holding time of 1.5 hours and an oil medium. After quenching, the forging is subjected to a high-temperature tempering treatment with a heating temperature of 500℃ and a holding time of 4 hours. The tempered forging is cooled to room temperature with the furnace.

[0086] (4) Finishing: The forging is finished to obtain a truncated cone mold liner with a taper of 10°.

[0087] Example 5

[0088] This embodiment provides a high-alumina boron-containing mold steel resistant to zinc hot melt corrosion for large plastic deformation of zinc alloys and its preparation method, including the following steps:

[0089] (1) The composition is C: 0.2%, B: 1.5%, W: 1.5%, V: 1.2%, Mo: 1.65%, Cr:

[0090] The raw materials, consisting of 5.2% Ti, 0.7% Si, 1.0% Al, and the balance Fe, were melted to 1560℃ and a cylindrical ingot was obtained by sand casting at 1460℃. The casting was then cooled to room temperature by air cooling.

[0091] (2) After homogenization treatment at 1050℃ for 4 hours, the ingot is hot-forged at 1100℃ with a forging ratio of 8 and a strain rate of 0.1s. -1 The cooling method after hot forging is air cooling.

[0092] (3) The quenching treatment is carried out with a heating temperature of 1050℃, a holding time of 1.5 hours and an oil medium. After quenching, the forging is subjected to a high-temperature tempering treatment with a heating temperature of 500℃ and a holding time of 4 hours. The tempered forging is cooled to room temperature with the furnace.

[0093] (4) Finishing: The forging is finished to obtain a truncated cone mold liner with a taper of 10°.

[0094] Please see Figure 4 , Figure 4 As shown in (a), at the location indicated by the light-colored arrow, the surface of the mold liner is covered with zinc; at the location indicated by the dark-colored arrow, there are obvious zinc melting marks in the H13 mold steel mold liner, with cracks running perpendicular to the surface of the mold liner and penetrating the entire mold, and thermal fatigue spalling has occurred at the outer edge of the mold. This is mainly because the H13 mold liner is subjected to the combined effects of zinc adhesive corrosion and high-temperature oxidation during the large plastic deformation process of the zinc alloy, leading to embrittlement of the mold liner surface. This makes it more susceptible to stress corrosion and cracking under high stress conditions, increasing the tendency of the mold to fracture due to thermal fatigue during service. Figure 4As shown in (b), the zinc-resistant high-alumina mold steel prepared by this invention showed no obvious zinc corrosion after long-term and frequent service. This indicates that the zinc-resistant high-alumina boron-containing mold steel of this invention is unlikely to adhere to zinc alloys and has good resistance to zinc corrosion. Therefore, the mold liner manufactured by this invention is not prone to stress corrosion during service, which could eventually lead to cracking and failure of the liner.

[0095] This invention proposes an alternative alloy for H13 hot work die steel: a high-alumina boron-containing die steel resistant to zinc hot melt corrosion. The die steel proposed in this invention possesses excellent high-temperature mechanical properties, high-temperature corrosion resistance, and low manufacturing cost. This invention achieves this by simultaneously adding low-carbon and high-boron elements to form high-hardness borides. These borides, with their good high-temperature stability, high-temperature hardness, and resistance to zinc hot melt corrosion, replace carbides. Appropriate alloying elements are added to improve the hardenability, strength, toughness, and high-temperature oxidation resistance of the matrix. Through hot forging and crushing, and by controlling the morphology, size, and distribution of the hard phase of the borides, a low-carbon martensite and ferrite multiphase matrix with good toughness is obtained through heat treatment. Ultimately, this results in a high-alumina boron-containing hot work die steel with good service safety and a long service life under the high plastic deformation conditions of zinc alloys.

[0096] In summary, this invention provides a zinc alloy high-aluminum boron-containing die steel resistant to zinc hot melt corrosion and its preparation method. Through forging work hardening, precipitation strengthening, boride morphology improvement and zinc melt corrosion resistance mechanisms, it meets the performance requirements of zinc alloy large plastic deformation dies for long-term stable service under harsh service conditions of high temperature, high load and strong corrosion.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high-alumina boron-containing die steel resistant to zinc hot melt corrosion for large plastic deformation of zinc alloys, characterized in that, Includes the following steps: S1. Ingots are obtained by sand casting. S2. The ingot obtained in step S1 is homogenized and subjected to high-temperature austenitization treatment, then hot forging and cooling are performed to obtain a heat-treated part. The forging ratio of hot forging is 6~8. S3. The heat-treated part obtained in step S2 is heat-treated by quenching and high-temperature tempering to obtain a forging. The heating temperature for tempering is 480~530℃. S4. The forgings obtained in step S3 are precision machined to obtain high-alumina boron-containing die steel resistant to zinc hot melt corrosion, comprising, by weight percentage: C: 0.15%~0.25%, B: 1.4%~1.8%, W: 1.4%~1.6%, V: 1.1%~1.3%, Mo: 1.55%~1.75%, Cr: 5.0%~5.5%, Ti: 0.6%~0.8%, Si: 0.4%~1.3%, Al: 2.4%~5.8%, balance Fe.

2. The method for preparing zinc-resistant hot-melt-corrosion-resistant high-alumina boron-containing mold steel for large plastic deformation of zinc alloys according to claim 1, characterized in that, In step S1, the melting temperature is 1550~1600℃ and the casting temperature is 1440~1480℃.

3. The method for preparing zinc-resistant hot-melt-corrosion-resistant high-alumina boron-containing mold steel for large plastic deformation of zinc alloys according to claim 2, characterized in that, The ingot has a cylindrical structure.

4. The method for preparing zinc-resistant hot-melt-corrosion-resistant high-alumina boron-containing mold steel for large plastic deformation of zinc alloys according to claim 1, characterized in that, In step S2, the temperature range for hot forging is 980~1100℃, and the strain rate is 0.01~4s. -1 .

5. The method for preparing zinc-resistant hot-melt-corrosion-resistant high-alumina boron-containing mold steel for large plastic deformation of zinc alloys according to claim 4, characterized in that, The homogenization treatment temperature is 1020~1080℃, and the holding time is 3~5h.

6. The method for preparing zinc-resistant hot-melt-corrosion-resistant high-alumina boron-containing mold steel for large plastic deformation of zinc alloys according to claim 4, characterized in that, The cooling method is air cooling.

7. The method for preparing zinc-resistant hot-melt-corrosion-resistant high-alumina boron-containing mold steel for large plastic deformation of zinc alloys according to claim 1, characterized in that, In step S3, the heating temperature for quenching is 1040~1080℃, the holding time is 1.5~2h, and the holding time is 2.5~4.0h.

8. The method for preparing zinc-resistant hot-melt-corrosion-resistant high-alumina boron-containing mold steel for large plastic deformation of zinc alloys according to claim 7, characterized in that, The quenching medium is oil, and the furnace is used for cooling to room temperature.

9. The method for preparing zinc-resistant hot-melt-corrosion-resistant high-alumina boron-containing mold steel for large plastic deformation of zinc alloys according to claim 1, characterized in that, In step S4, the zinc-resistant hot-melt erosion high-alumina boron-containing mold steel has a frustum-shaped structure with a taper of 9~11°.

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