Method for preparing bimetal hot-working die by hot isostatic pressing and application thereof

Abstract

The present application belongs to the technical field of powder metallurgy, and particularly relates to a method for preparing a bimetallic hot-working die by hot isostatic pressing and application, which comprises solid-powder combination of a die steel blank and GH4099 powder by a hot isostatic pressing process. The maximum size of the steel ingot is designed according to the stress distribution and size in the die use process, and a sawtooth structure is processed on the contact surface of the steel ingot and the GH4099 powder to increase the bonding force of the steel blank and the GH4099 powder. By controlling the cooling speed of multi-stage hot isostatic pressing, the organization densification and organization performance regulation can be completed by one step of hot isostatic pressing without subsequent heat treatment. The target die surface is subjected to shot blasting treatment to achieve the effect of strengthening the surface. By the method, a bimetallic hot-working die with high performance, low cost and short process can be prepared, and the use of low-cost steel material in the low-stress area and the use of high-temperature alloy material in the high-stress area of the die under normal use conditions are realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of powder metallurgy, and particularly relates to a method for preparing a bimetallic hot-working die by hot isostatic pressing and application. BACKGROUND

[0002] In modern industrial production, hot-working dies have become a kind of high-quality, efficient and low-consumption process equipment. As an important means of modern manufacturing, the hot-working dies play an important role in the economic operation of China and the development of various industrial departments.

[0003] For common hot-working die steels (5CrNiMo, 4Cr5MoSiV1 and 3Cr2W8V), the high-temperature performance is poor after long-term service, which leads to the occurrence of concave, folding and wear in the use of the hot-working dies, thereby greatly reducing the service life of the hot-working dies.

[0004] The maximum service temperature of GH4099 alloy is 900 DEG C, and no harmful precipitated phase appears when the alloy is kept at 700-800 DEG C for a long time. The microstructure stability of the alloy is strong at high temperature, and the alloy can still maintain good mechanical properties, and can be used for hot-working dies. However, the GH4099 alloy is usually expensive, which greatly increases the cost of manufacturing a hot-working die made of the high-temperature alloy.

[0005] Therefore, there is an urgent need for a method for preparing a bimetallic hot-working die with good high-temperature performance and low cost.

[0006] In view of this, the application is proposed. SUMMARY

[0007] The application aims to overcome the defects of the prior art, and provides a method for preparing a bimetallic hot-working die by hot isostatic pressing and application. The method controls the surface roughness and shape of a steel ingot, controls the solid-powder combination process of hot isostatic pressing of the steel ingot and a high-temperature alloy, and enhances the surface strengthening of a working surface of the hot-working die to prepare a bimetallic hot-working die with high quality and low cost. The working area of the hot-working die is made of GH4099 high-temperature alloy, and other areas are made of steel ingots. The high-temperature alloy is used in the working area of the hot-working die, and the steel ingots are used in other areas to achieve the goal of reducing the cost.

[0008] In order to achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0009] In one aspect, the application provides a method for preparing a bimetallic hot-working die by hot isostatic pressing, and the method is characterized in that the method comprises the following steps:

[0010] Step 1: GH4099 powder is prepared by using a super-high-speed plasma rotating electrode, and the GH4099 powder is pretreated to obtain GH4099 powder with a specific particle size range.

[0011] Step 2: numerical simulation is performed according to the actual working condition of the target working die to be prepared, stress values of different regions of the target working die in the use process are obtained, and the bottom ingot size of the target working die is determined according to the stress values;

[0012] Step 3: a billet is prepared by VIM+ESR+VAR (vacuum induction melting+electroslag remelting+vacuum consumable arc melting) three-process technology according to the ingot size obtained in step 2, and then the prepared billet is processed to obtain an ingot;

[0013] The end of the ingot in contact with the GH4099 powder of a specific particle size section is a sawtooth structure.

[0014] Step 4: the ingot prepared in step 3 is placed in a pre-prepared can, the ingot and the can are fixedly connected, and then the can is sealed and welded;

[0015] Step 5: the can containing the ingot is placed on a vibration platform, then the GH4099 powder pretreated in step 1 is filled into the can through the can nozzle, and then vacuum degassing and sealing and welding of the can nozzle are performed;

[0016] Step 6: the can sealed in step 5 is subjected to hot isostatic pressing to obtain a working die blank, and then the working die blank is sequentially machined and subjected to shot peening to obtain a target working die.

[0017] Further, in step 1, the pretreatment includes sequentially performing screening treatment-electromagnetic impurity removal treatment-mixing treatment on the GH4099 powder to obtain GH4099 powder of a particle size section of 53-106 μm.

[0018] Specifically, after screening, the powder of different particle sizes may be unevenly distributed, and then the screened and impurity-removed powder is poured into a mixer and rotated and mixed to obtain GH4099 powder of a particle size section of 53-106 μm.

[0019] Further, in step 2, the Deform software is used to simulate and calculate the stress values of different regions of the target working die in the use process, and when the maximum stress value of a region is less than the yield strength of the steel material at the use temperature, the region is prepared by using the steel material to obtain the ingot size.

[0020] Further, in step 3, the sawtooth structure is machined on the billet, and then the entire surface of the billet is finished to obtain the ingot; the surface roughness Ra of the ingot is less than 0.8 μm.

[0021] Further, in step 3, the sawtooth structure comprises a plurality of inverted trapezoidal teeth, in particular, the tooth width is 20-35 mm, the tooth height is 30-50 mm, and the tooth spacing is 15-20 mm.

[0022] Further, in step 5, the powder loading is performed under continuous vibration of the vibration platform, and the vibration frequency is set to 30-45 Hz and the amplitude is ±2 mm.

[0023] Further, in step 5, the vacuum degassing temperature is 400-450℃, the vacuum degree is <1.0×10 -4 Pa, and then the cladding sealing treatment is performed.

[0024] Further, in step 6, the hot isostatic pressing process is specifically as follows: the temperature is raised to 1200-1250℃ at a temperature raising speed of 0.05-0.1℃ / s, the pressure is 180-200 MPa, the temperature is kept for 3-4 h, then the temperature is lowered to 500-550℃ at a temperature lowering speed of 0.3-0.5℃ / s, the pressure is 75-85 MPa, the temperature is kept for 0.5-1 h, then the temperature is raised to 750-800℃ at a temperature raising speed of 0.05-0.1℃ / s, the pressure is 120-130 MPa, the temperature is kept for 16-20 h, then the temperature is lowered to 500-550℃ at a temperature lowering speed of 0.3-0.5℃ / s, the pressure is 75-85 MPa, the temperature is kept for 3-4 h, and finally the temperature is lowered to room temperature at a temperature lowering speed of 0.3-0.5℃ / s.

[0025] Further, in step 6, the work die blank after the machining treatment is subjected to shot blasting treatment on the use surface, in particular, the shot blasting treatment uses 304 stainless steel shot particles with a particle size of 0.15-0.2 mm, and the shot blasting pressure is 0.5-0.75 MPa.

[0026] In another aspect, the present application provides a work die prepared by the method for preparing a bimetallic hot work die by hot isostatic pressing, which is applied in the field of forging.

[0027] Compared with the prior art, the present application has the following beneficial effects:

[0028] 1) The present application provides a method for preparing a bimetallic hot work die by hot isostatic pressing, which designs the maximum size of the steel blank according to the stress distribution and size in the use process of the die, and then performs solid-powder combination of dissimilar metals by hot isostatic pressing, so that the organization is dense and the organization performance is controlled in one step, thereby ensuring that the interface of the dissimilar metals is combined well and the organization is dense; in addition, the preparation method has the advantages of short process flow and high efficiency;

[0029] Specifically, a sawtooth structure is processed on the surface of the ingot, and then GH4099 powder is added to one end of the sawtooth structure, so that the contact area between the ingot and the GH4099 powder is increased, and the bonding strength of the interface is improved; in addition, the teeth are designed as an inverted trapezoidal structure, the bottom of which is narrower than the upper part to form an inverted hook shape, which can prevent the interface from being disconnected from the structure;

[0030] Further, through the control of the cooling speed of the hot isostatic pressing, the densification of the hot isostatic pressing and the same effect of the microstructure and performance control of the heat treatment can be directly completed in the hot isostatic pressing equipment. Specifically, rapid cooling to 500-550 DEG C can achieve the effect of heat treatment air cooling, and then heating to 750-800 DEG C (i.e. the peak temperature of the gamma prime precipitation of GH4099 alloy) to promote the complete precipitation of gamma prime and improve the comprehensive mechanical properties of GH4099 alloy. Further rapid cooling to 500-550 DEG C and holding at 500-550 DEG C can eliminate the stress of the ingot and stabilize the microstructure.

[0031] 2) The method for preparing a bimetallic hot working die by hot isostatic pressing provided by the application can strengthen the surface of the working die through shot blasting treatment on the used surface of the finished bimetallic working die blank. BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings incorporated into the specification and forming a part of the specification, together with the specification, serve to explain the principles of the application.

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows, and obviously, other drawings can also be obtained by those skilled in the art without creative labor.

[0034] Figure 1 The process preparation flowchart of the bimetallic hot working die of the application;

[0035] Figure 2 The sawtooth structure schematic diagram of the contact surface of the ingot and the powder of the application;

[0036] Figure 3 The temperature and pressure curve schematic diagram in the hot isostatic pressing process of the application;

[0037] Figure 4 The stress nephogram and the schematic diagram of the ingot position corresponding to the temperature of example 1;

[0038] Figure 5 The structure schematic diagram of the U-shaped working die prepared in example 1;

[0039] Figure 6 Stress contour map corresponding to the temperature of Example 2 and the schematic diagram of the ingot position;

[0040] Figure 7 Schematic diagram of the structure of the V-die prepared for Example 2;

[0041] Figure 8 Stress contour map corresponding to the temperature of Example 3 and the schematic diagram of the ingot position;

[0042] Figure 9 Schematic diagram of the structure of the flat-die prepared for Example 3;

[0043] Figure 10 Microstructure diagram of the GH4099 alloy of the die and the ingot interface of Example 1;

[0044] Figure 11 Metallographic microstructure diagram of the GH4099 alloy of the die of Example 1;

[0045] Figure 12 Scanning electron microscope picture of the precipitated phase γ' of the GH4099 alloy of the die of Example 1;

[0046] Figure 13 Metallographic microstructure of the die GH4099 alloy prepared by the prior art (hot isostatic pressing + heat treatment);

[0047] Figure 14 Scanning electron microscope picture of the precipitated phase γ' of the die GH4099 alloy prepared by the prior art (hot isostatic pressing + heat treatment);

[0048] Figure 15 Microstructure diagram of the GH4099 alloy of the die and the ingot interface of Example 2;

[0049] Figure 16 Metallographic microstructure diagram of the GH4099 alloy of the die of Example 2;

[0050] Figure 17 Scanning electron microscope picture of the precipitated phase γ' of the GH4099 alloy of the die of Example 2;

[0051] Figure 18 Microstructure diagram of the GH4099 alloy of the die and the ingot interface of Example 3;

[0052] Figure 19 Metallographic microstructure diagram of the GH4099 alloy of the die of Example 3;

[0053] Figure 20 Scanning electron microscope picture of the precipitated phase γ' of the GH4099 alloy of the die of Example 3. DETAILED DESCRIPTION

[0054] The exemplary embodiments will be described in detail below with reference to the drawings. The embodiments described in the following exemplary embodiments do not represent all the embodiments consistent with the present application. Rather, they are merely examples consistent with some aspects of the present application as detailed in the appended claims.

[0055] In one aspect, referring to Figure 1 The present application provides a method for preparing a bimetallic hot working die by using hot isostatic pressing, comprising the following steps:

[0056] Step 1: using ultra-high speed plasma rotating electrode to prepare GH4099 powder, and pretreating the GH4099 powder to obtain GH4099 powder of a specific particle size range;

[0057] The pretreatment comprises sequentially performing screening treatment, electrostatic magnetic impurity removal treatment and mixing treatment on the GH4099 powder to obtain GH4099 powder of a particle size range of 53-106 μm.

[0058] Step 2: designing a can according to the structure and size of the target working die to be prepared, the can being formed by welding an upper cover, a side plate and a bottom plate by argon arc welding (i.e. obtaining a pre-prepared can);

[0059] Step 3: performing numerical simulation according to the actual working condition of the target working die to be prepared to obtain stress values of different regions of the target working die during use, and determining the size of the bottom ingot of the target working die according to the stress values;

[0060] Specifically, the stress values of different regions of the target working die during use are simulated and calculated using Deform software, and when the maximum stress value of a region is less than the yield strength of the steel material at the use temperature, the region is prepared with a steel ingot, i.e. the size of the region is the size of the steel ingot.

[0061] For example, the yield strength of the steel material at the forging use temperature is 200 MPa, and in the simulation, the region with a stress < 200 MPa is prepared with a steel ingot.

[0062] Step 4: preparing a steel billet according to the size of the steel ingot obtained in step 3 by using the traditional VIM+ESR+VAR three-process technology, and then processing the prepared steel billet to obtain a steel ingot;

[0063] The end of the steel ingot in contact with the GH4099 powder of a particle size range of 53-106 μm is a sawtooth structure; specifically, the sawtooth structure is machined on the steel billet, and then the entire surface of the steel billet is finished by a grinding machine to obtain a steel ingot, the surface roughness Ra of the steel ingot being < 0.8 μm.

[0064] More specifically, the sawtooth structure comprises a plurality of inverted trapezoidal teeth, specifically, the tooth width is 20-35 mm, the tooth height is 30-50 mm, and the tooth spacing is 15-20 mm, as shown in Figure 2 .

[0065] Step 5: Place the steel ingot prepared in step 4 on the bottom plate of the designed package, fix them by argon arc welding, then weld the side plate and the upper cover by argon arc welding to realize the sealing of the package (the upper cover is provided with a powder adding package nozzle, which is a common knowledge in the industry);

[0066] Step 6: Place the package containing the steel ingot on the vibration platform, then fill the GH4099 powder prepared in step 1 into the package through the package nozzle, and then perform vacuum degassing and sealing treatment on the package nozzle;

[0067] wherein the powder filling is performed under continuous vibration of the vibration platform, the vibration frequency is set to 30-45 Hz, and the amplitude is ±2 mm; the vacuum degassing temperature is 400-450℃, the vacuum degree is <1.0×10 -4 Pa, and the package sealing treatment is then performed.

[0068] Step 7: Perform hot isostatic pressing treatment on the sealed package of step 6 to obtain a work die blank, then sequentially machine and shot blast the work die blank to obtain a target work die;

[0069] wherein the hot isostatic pressing treatment process is as follows: heat to 1200-1250℃ at a heating rate of 0.05-0.1℃ / s, pressure 180-200 MPa, hold for 3-4 h, then cool to 500-550℃ at a cooling rate of 0.3-0.5℃ / s, pressure 75-85 MPa, hold for 0.5-1 h, then heat to 750-800℃ at a heating rate of 0.05-0.1℃ / s, pressure 120-130 MPa, hold for 16-20 h, then cool to 500-550℃ at a cooling rate of 0.3-0.5℃ / s, pressure 75-85 MPa, hold for 3-4 h, and finally cool to room temperature at a cooling rate of 0.3-0.5℃ / s, as shown in Figure 3 .

[0070] After hot isostatic pressing treatment, the excess material is removed by machining, and the use surface is shot blasted for strengthening.

[0071] Specifically, the shot blasting treatment uses 304 stainless steel shot with a particle size of 0.15-0.2 mm, and the shot blasting pressure is 0.5-0.75 MPa.

[0072] It should be noted that the order of steps 1, 2, and 3 above is not limited and can be performed simultaneously.

[0073] In another aspect, the present application provides a work die prepared by the method for preparing a bimetallic hot work die by adopting hot isostatic pressing, which is applied in the field of forging, such as a die for free forging, die forging, isothermal forging and the like.

[0074] The method of the present application is for preparing a die for forging. In order to further verify the efficacy of the present application, the inventors have conducted the following specific tests:

[0075] Example 1

[0076] In this example, a U-shaped work die for 8000-ton titanium alloy free forging is prepared, and the detailed preparation process is as follows:

[0077] Step 1: GH4099 powder is prepared by using ultra-high speed plasma rotating electrode, and the GH4099 powder is sequentially subjected to screening treatment, electrostatic magnetic impurity removal treatment and mixing treatment to obtain GH4099 powder with a particle size of 53-106 μm;

[0078] Step 2: The sleeve part is welded by using argon arc welding according to the structure and size of the U-shaped work die to be prepared;

[0079] Step 3: Numerical simulation is performed according to the actual working conditions (temperature, press pressure, reduction rate and reduction amount during production) of the U-shaped work die to be prepared, to obtain the stress values of different regions of the U-shaped work die during use, and the size of the bottom ingot of the U-shaped work die is determined according to the stress values;

[0080] Specifically, the stress values of different regions of the U-shaped work die during use are simulated and calculated by using Deform software. When the maximum stress value of a certain region is less than the yield strength at the service temperature of the steel material, the steel ingot is prepared by using the steel material in the region, i.e. the size of the region is the size of the steel ingot, as shown in Figure 4

[0081] Step 4: 5CrNiMo is poured according to the ingot size simulated in step 3 by using the traditional VIM+ESR+VAR triple process to obtain 5CrNiMo billets, and then the obtained 5CrNiMo billets are processed to obtain 5CrNiMo ingots;

[0082] Specifically, the sawtooth structure is machined on the 5CrNiMo billet, and then the entire surface of the 5CrNiMo billet is finished by a grinding machine to obtain the 5CrNiMo ingot, and the surface roughness Ra of the 5CrNiMo ingot is 0.8 μm.

[0083] ​More specifically, the sawtooth structure comprises a plurality of inverted trapezoidal teeth, specifically, the tooth width is 20mm, the tooth height is 35mm, and the tooth spacing is 15mm.

[0084] Step 5: The 5CrNiMo steel ingot prepared in step 4 is placed in a sheath, the 5CrNiMo steel ingot and the sheath are fixed by argon arc welding, and then a cover is welded on the sheath, and all the processes here are the same as the above-mentioned manner.

[0085] Step 6: The sheath containing the 5CrNiMo steel ingot is placed on a vibration platform, and then the GH4099 powder pretreated in step 1 is filled into the sheath through the sheath nozzle, and then vacuum degassing and sealing welding treatment are performed on the sheath nozzle.

[0086] The powder filling is performed under continuous vibration of the vibration platform, the vibration frequency is set to 30-45Hz, and the amplitude is ±2mm; the vacuum degassing temperature is 450℃, the vacuum degree is 1.0×10 -4 Pa, and then the sheath sealing welding treatment is performed.

[0087] Step 7: The sheath sealed in step 6 is subjected to hot isostatic pressing treatment to obtain a work die blank, and then the work die blank is sequentially subjected to machining and shot peening treatment to obtain a U-shaped work die, as shown in Figure 5 .

[0088] The process of the hot isostatic pressing treatment is specifically as follows: the temperature is raised to 1200℃ at a temperature raising speed of 0.05℃ / s, the pressure is 190MPa, the temperature is kept and the pressure is kept for 4h, then the temperature is lowered to 550℃ at a temperature lowering speed of 0.5℃ / s, the pressure is 75MPa, the temperature is kept and the pressure is kept for 0.5h, then the temperature is raised to 800℃ at a temperature raising speed of 0.05℃ / s, the pressure is 120MPa, the temperature is kept and the pressure is kept for 16h, then the temperature is lowered to 500℃ at a temperature lowering speed of 0.3℃ / s, the pressure is 75MPa, the temperature is kept and the pressure is kept for 4h, and finally the temperature is lowered to room temperature at a temperature lowering speed of 0.5℃ / s.

[0089] After the hot isostatic pressing treatment, the machining removes the excess amount, and the shot peening is performed on the use surface.

[0090] Specifically, the shot peening uses 304 stainless steel shot particles with a particle size of 0.15-0.2mm, and the shot peening pressure is 0.5MPa.

[0091] Figure 10 The figure of the microstructure of the interface between the U-shaped work die GH4099 alloy and the steel ingot shows that the dense microstructure interface between the GH4099 alloy and the steel ingot can be obtained by the present application.

[0092] In order to prove the technical effect of the present application, the present application compares example 1 with the prior art (hot isostatic pressing + heat treatment), as shown in Figures 11-14In addition, the performance of the mold was tested according to GB / T228.2-2015 for high-temperature tensile test, GB / T228.1-2021 for room-temperature tensile test, and GB / T229-2020 for impact performance test, and the test results are shown in Tables 1 and 2.

[0093] Table 1 Mechanical property data of U-shaped tooling mold GH4099 alloy

[0094]

[0095] Table 2 Mechanical property data of U-shaped tooling mold GH4099 alloy prepared by prior art

[0096]

[0097] As shown in Tables 1 and 2, the prior art and the present application have similar microstructure precipitated phase size and consistent mechanical properties.

[0098] As can be seen from the comparison, the present application achieves the same effect of microstructure regulation as heat treatment by controlling the cooling speed of hot isostatic pressing, without subsequent heat treatment process.

[0099] Specifically, the prior art scheme is to perform heat treatment after conventional hot isostatic pressing, wherein the hot isostatic pressing system is to heat to 1200℃ at a heating rate of 0.05℃ / s, with a pressure of 150MPa, holding for 4h, and cooling in the furnace. The heat treatment system is solid solution treatment at 1100℃ / 4h / AC + aging treatment at 700-800℃ / 20h / AC.

[0100] Example 2

[0101] In this embodiment, a 12000-ton high-temperature alloy free forging V-shaped tooling mold is prepared, and the detailed preparation process is as follows:

[0102] Step 1: GH4099 powder is prepared using ultra-high speed plasma rotating electrode, and the GH4099 powder is sequentially subjected to screening treatment, electrostatic magnetic impurity removal treatment and mixing treatment to obtain GH4099 powder with a particle size of 53-106μm;

[0103] Step 2: The sleeve is designed according to the structure and size of the V-shaped tooling mold to be prepared, and the sleeve components are welded using argon arc welding;

[0104] Step 3: Numerical simulation is performed according to the actual working conditions (temperature, press pressure, reduction rate and reduction amount in the production process) of the V-shaped tooling mold to be prepared, to obtain the stress values of different regions of the V-shaped tooling mold in use, and the bottom ingot size of the V-shaped tooling mold is determined according to the stress values;

[0105] Specifically, the stress values of different regions of the V-shaped tool in use are simulated and calculated by using the Deform software. When the maximum stress value of a region is less than the yield strength of the steel material at the use temperature, the region is made of the steel ingot, i.e., the size of the region is the size of the steel ingot, as shown in Figure 6 .

[0106] Step 4: Pouring 4Cr5MoSiV1 according to the size of the steel ingot simulated in step 3 by a traditional VIM+ESR+VAR triple process to obtain a 4Cr5MoSiV1 billet, and then processing the obtained 4Cr5MoSiV1 billet to obtain a 4Cr5MoSiV1 ingot;

[0107] Specifically, the sawtooth structure is machined on the 4Cr5MoSiV1 billet, and then the entire surface of the 4Cr5MoSiV1 billet is finished by a grinding machine to obtain the 4Cr5MoSiV1 ingot, and the surface roughness Ra of the 4Cr5MoSiV1 ingot is 0.63 μm.

[0108] More specifically, the sawtooth structure includes a plurality of inverted trapezoidal teeth, specifically, the tooth width is 35 mm, the tooth height is 50 mm, and the tooth spacing is 15 mm.

[0109] Step 5: Placing the 4Cr5MoSiV1 ingot obtained in step 4 in a pre-prepared can, and sealing the 4Cr5MoSiV1 ingot and the can by argon arc welding, and then welding the cover on the can, wherein all the processes are the same as the above method;

[0110] Step 6: Placing the can containing the 4Cr5MoSiV1 ingot on a vibration platform, and then filling the GH4099 powder pre-processed in step 1 into the can, and then performing vacuum degassing and can sealing treatment;

[0111] Wherein, the powder is filled under continuous vibration of the vibration platform, the vibration frequency is set to 30-45 Hz, and the amplitude is ±2 mm; the vacuum degassing temperature is 450°C, the vacuum degree is 5.0×10 -5 Pa, and then the can sealing treatment is performed.

[0112] Step 7: Hot isostatic pressing the can sealed in step 6 to obtain a tool blank, and then sequentially machining and shot blasting the tool blank to obtain a V-shaped tool, as shown in Figure 7 , and the microstructure diagram is as shown in Figures 15-17 .

[0113] The hot isostatic pressing process is specifically as follows: heating to 1250 DEG C at a heating rate of 0.05 DEG C / s, pressure 200 MPa, holding for 4 h, then cooling to 520 DEG C at a cooling rate of 0.5 DEG C / s, pressure 85 MPa, holding for 0.5 h, then heating to 750 DEG C at a heating rate of 0.05 DEG C / s, pressure 130 MPa, holding for 20 h, then cooling to 500 DEG C at a cooling rate of 0.4 DEG C / s, pressure 85 MPa, holding for 4 h, and finally cooling to room temperature at a cooling rate of 0.5 DEG C / s.

[0114] After the hot isostatic pressing treatment, the excess amount is removed by machining, and shot peening is performed on the use surface.

[0115] Specifically, the shot peening uses 304 stainless steel shot particles with a particle size of 0.15-0.2 mm, and the shot peening pressure is 0.7 MPa.

[0116] Example 3

[0117] In this embodiment, a certain 12000-ton high-temperature alloy free forging flat anvil tool is prepared, and the detailed preparation process is as follows:

[0118] Step 1: using ultra-high speed plasma rotating electrode to prepare GH4099 powder, and sequentially performing screening treatment, electrostatic magnetic impurity removal treatment and mixing treatment on the GH4099 powder to obtain GH4099 powder with a particle size of 53-106 μm;

[0119] Step 2: designing a package according to the structure and size of the flat anvil tool to be prepared, and using argon arc welding to weld the package components;

[0120] Step 3: performing numerical simulation according to the actual working conditions (temperature, press pressure, press rate and press amount in the production process) of the flat anvil tool to be prepared, obtaining stress values of different regions of the flat anvil tool in the use process, and determining the size of the bottom ingot of the flat anvil tool according to the stress values;

[0121] Specifically, the stress values of different regions of the flat anvil tool in the use process are simulated and calculated using Deform software, when the maximum stress value of a region is less than the yield strength at the service temperature of the steel material, the region is prepared by using the steel material, i.e. the region size is the ingot size, as shown in Figure 8

[0122] Step 4: pouring 5CrMnMo according to the ingot size simulated in step 3 through the traditional VIM+ESR+VAR triple process to obtain 5CrMnMo billets, and then processing the obtained 5CrMnMo billets to obtain 5CrMnMo ingots;

[0123] ​The end of the 5CrMnMo steel ingot in contact with the GH4099 powder with a particle size of 53-106 μm is in a sawtooth structure; specifically, the sawtooth structure is machined on the 5CrMnMo steel blank, and then the entire surface of the 5CrMnMo steel blank is finished by a grinding machine to obtain the 5CrMnMo steel ingot, wherein the surface roughness Ra of the 5CrMnMo steel ingot is 0.63 μm.

[0124] More specifically, the sawtooth structure comprises a plurality of inverted trapezoidal teeth, specifically, the tooth width is 30 mm, the tooth height is 30 mm, and the tooth spacing is 20 mm.

[0125] Step 5: The 5CrMnMo steel ingot prepared in step 4 is placed in a pre-prepared can, the 5CrMnMo steel ingot and the can are fixed by argon arc welding, and then the cover of the can is welded, wherein all the processes are the same as the above method;

[0126] Step 6: The can containing the 5CrMnMo steel ingot is placed on a vibrating platform, and then the GH4099 powder pretreated in step 1 is filled into the can through the can nozzle, followed by vacuum degassing and sealing of the can nozzle;

[0127] The powder filling is carried out under continuous vibration of the vibrating platform, the vibration frequency is set to 30-45 Hz, and the amplitude is ±2 mm; the vacuum degassing temperature is 420℃, the vacuum degree is 7.5×10 -5 Pa, and the can sealing treatment is then carried out.

[0128] Step 7: The can sealed in step 6 is subjected to hot isostatic pressing treatment to obtain a work die blank, and then the work die blank is sequentially subjected to machining and shot peening treatment to obtain a flat anvil work die, as shown in Figure 9 , and the microstructure diagram is as shown in Figures 18-20 .

[0129] The process of the hot isostatic pressing treatment is as follows: the temperature is raised to 1230℃ at a rate of 0.1℃ / s, the pressure is 180 MPa, the temperature is kept for 4 h, then the temperature is lowered to 500℃ at a rate of 0.4℃ / s, the pressure is 80 MPa, the temperature is kept for 1.0 h, then the temperature is raised to 800℃ at a rate of 0.1℃ / s, the pressure is 125 MPa, the temperature is kept for 18 h, then the temperature is lowered to 550℃ at a rate of 0.3℃ / s, the pressure is 80 MPa, the temperature is kept for 3 h, and finally the temperature is lowered to room temperature at a rate of 0.3℃ / s.

[0130] After the hot isostatic pressing treatment, the excess amount is removed by machining, and shot peening is carried out on the use surface.

[0131] Specifically, the shot peening uses 304 stainless steel shot particles with a particle size of 0.15-0.2 mm, and the shot peening pressure is 0.7 MPa.

[0132] The foregoing is considered as illustrative only of the principles of the application. Numerous modifications and changes will readily occur to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the spirit or scope of the application.

[0133] It is to be understood that the application is not limited to the details of the above-described embodiments and that numerous modifications and changes can be effected without departing from the scope of the application. It is intended that the scope of the application be limited only by the appended claims.

Claims

1. A method for producing a bimetallic hot working die by using hot isostatic pressing, characterized by, The method comprises the following steps: Step 1: GH4099 powder is prepared by using a super-high-speed plasma rotating electrode, and the GH4099 powder is pretreated to obtain GH4099 powder of a specific particle size range; Step 2: numerical simulation is performed according to actual working conditions of a target working die to be prepared, stress values of different regions of the target working die in use are obtained, and the size of a bottom ingot of the target working die is determined according to the stress values; Deform software is used to simulate and calculate the stress values of different regions of the target working die in use, and when the maximum stress value of a certain region is less than the yield strength of a steel material at a service temperature, the region is prepared by using the steel material to obtain the size of the ingot; Step 3: a billet is prepared by using a VIM+ESR+VAR three-process technology according to the size of the ingot obtained in step 2, and the prepared billet is processed to obtain an ingot; A sawtooth structure is machined on the billet, and then the surface of the entire billet is finished to obtain the ingot; the surface roughness Ra of the ingot is less than 0.8 μm; The end of the ingot in contact with the GH4099 powder of the specific particle size range is the sawtooth structure; Step 4: the ingot prepared in step 3 is placed in a pre-prepared can, the ingot and the can are fixedly connected, and then the can is sealed and welded; Step 5: the can containing the ingot is placed on a vibration platform, the GH4099 powder pretreated in step 1 is filled into the can through a can nozzle, and then vacuum degassing and sealing and welding treatment are performed on the can nozzle; Step 6: the can sealed in step 5 is subjected to hot isostatic pressing treatment to obtain a working die blank, and then the working die blank is sequentially subjected to machining and shot blasting treatment to obtain a target working die; The hot isostatic pressing treatment process is as follows: the temperature is raised to 1200-1250 ℃ at a temperature raising speed of 0.05-0.1 ℃ / s, the pressure is 180-200 MPa, the temperature and pressure are maintained for 3-4 h, then the temperature is lowered to 500-550 ℃ at a temperature lowering speed of 0.3-0.5 ℃ / s, the pressure is 75-85 MPa, the temperature and pressure are maintained for 0.5-1 h, then the temperature is raised to 750-800 ℃ at a temperature raising speed of 0.05-0.1 ℃ / s, the pressure is 120-130 MPa, the temperature and pressure are maintained for 16-20 h, then the temperature is lowered to 500-550 ℃ at a temperature lowering speed of 0.3-0.5 ℃ / s, the pressure is 75-85 MPa, the temperature and pressure are maintained for 3-4 h, and finally the temperature is lowered to room temperature at a temperature lowering speed of 0.3-0.5 ℃ / s; The working die blank after the machining treatment is subjected to shot blasting treatment on the use surface, specifically, 304 stainless steel shot particles with a particle size of 0.15-0.2 mm are selected for the shot blasting treatment, and the shot blasting pressure is 0.5-0.75 MPa.

2. The method of claim 1, wherein the bimetallic hot working die is prepared by using hot isostatic pressing. In step 1, the pretreatment comprises sequentially performing screening treatment, electrostatic magnetic impurity removal treatment and mixing treatment on the GH4099 powder to obtain GH4099 powder of a particle size range of 53-106 μm.

3. The method of claim 1, wherein the method further comprises the step of: In step 3, the sawtooth structure comprises a plurality of inverted trapezoidal teeth, specifically, the tooth width is 20-35 mm, the tooth height is 30-50 mm, and the tooth spacing is 15-20 mm. ​ 4. The method of manufacturing a bimetal hot work die by using hot isostatic pressing according to claim 1, wherein In step 5, the powder is filled under the continuous vibration of the vibration platform, and the vibration frequency is set to 30-45 Hz, and the amplitude is ±2 mm.

5. The method of manufacturing a bimetal hot work die by using hot isostatic pressing according to claim 1, wherein In Step 5, the vacuum degassing temperature is 400 to 450°C, and the vacuum degree is <1.0 x 10 -4 After 1,000 Pa, the sheath sealing treatment is performed.

6. A tool made by the method of any one of claims 1 to 5, for use in the field of forging.

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