Preparation method of ultrahigh-toughness large-length-diameter-ratio deep blind hole component

Abstract

The invention discloses a preparation method of an ultrahigh-toughness large-length-diameter-ratio deep blind hole component. The preparation method comprises the following steps: preparing an ultrahigh-toughness steel bar, preparing a large-length-diameter-ratio deep blind hole blank, carrying out toughening treatment on the obtained blank, and then carrying out precise cutting processing to obtain the ultrahigh-toughness large-length-diameter-ratio deep blind hole component. The ultrahigh-toughness large-length-diameter-ratio deep blind hole component prepared through the scheme is low in impurity content, the grain size is remarkably refined, almost no component segregation exists, the internal quality grade of the component is grade A through ultrasonic flaw detection, the impact absorbing energy of all parts of the component is not lower than 80 J, the structure uniformity and the performance consistency are high, and the advantage of being high in material utilization rate is further achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of large aspect ratio deep blind hole components, and specifically relates to a preparation method for ultra-high strength and toughness large aspect ratio deep blind hole components. Background Art

[0002] Ultra-high strength and toughness steel alloy materials are widely used in the manufacturing technologies of military and civilian equipment such as aviation, aerospace, military, and automotive industries due to their advantages of ultra-high strength (tensile strength ≥ 1500 MPa), excellent plastic toughness (elongation after fracture ≥ 6%), high anti-shear instability ability, and not being prone to deformation and failure when deforming at high temperature and high strain rate.

[0003] There are many existing manufacturing methods for large aspect ratio (aspect ratio not less than 5) deep blind hole components, mainly including integral extrusion forming, forged bar cutting machining, and radial precision forging. Integral extrusion forming directly forms the final deep blind hole forging through one-time large deformation, but it has extremely high requirements for the tonnage of the forming equipment (the forming equipment tonnage requirement for deep blind hole components with a length of 1.5 meters is more than 20,000 tons). The heating temperature of the blank before one-time forming is relatively high, resulting in rapid grain growth in the forging, uneven tissue properties, and uneven deformation leading to uneven tissue properties, poor strength and toughness matching of the component, and many folding defects; forged bar cutting machining generally obtains a steel forged bar with uniform structure by applying severe large plastic deformation to the original steel ingot, refining the grains and forging and closing the casting defects, and then obtaining the final large aspect ratio deep blind hole component by direct cutting machining. Especially for ultra-high strength and toughness steel materials containing a certain proportion of precious metal Co, the raw material consumption is serious; radial precision forging also first obtains a steel forged bar, then preforms a shallow hole in the core of the bar, and then penetrates a mandrel for radial precision forging. However, due to the deep inner hole of the deep blind hole shell, it is difficult to withdraw the core die, and flash is easily generated on the outer surface of the forging, and the coaxiality of the inner and outer holes is low, which requires high requirements for subsequent finishing. Based on the problems in the existing technology, it is necessary to develop a preparation method for ultra-high strength and toughness large aspect ratio deep blind hole components.

[0004] Research and tests show that the transition part between the head (tapered part) and the waist of the existing large aspect ratio deep blind hole component is likely to become a weak part of the component's performance, especially its ability to resist impact loads needs to be further optimized / improved. Summary of the Invention

[0005] At least aiming at the problems mentioned in the background art, the purpose of the present invention is to provide a preparation method for ultra-high strength and toughness large aspect ratio deep blind hole components.

[0006] The present invention adopts the following technical solutions.

[0007] A preparation method for ultra-high strength and toughness large aspect ratio deep blind hole components, the steps include: Step 1: Based on the part drawing of the deep blind hole component with a large length-diameter ratio, considering machining allowance and material consumption, design the forging drawing of the deep blind hole component with a large length-diameter ratio to obtain the original steel ingot structure dimensions; Step 2: Prepare ultra-high strength and toughness steel bars; Step 3: Prepare a deep blind hole blank with a large length-diameter ratio; Step 4: Perform a strengthening and toughening treatment on the obtained blank, and after completion, carry out precision cutting machining to obtain an ultra-high strength and toughness deep blind hole component with a large length-diameter ratio.

[0008] As an optimized solution, the steps for preparing ultra-high strength and toughness steel bars in Step 2 include: Step 21: Prepare or obtain an ultra-high strength and toughness steel ingot and perform heat treatment; Step 22: Heat the ultra-high strength and toughness steel ingot to 1000 - 1080 °C and hold for 1.5 - 2.5 h, then perform radial precision forging deformation treatment (the billet temperature during the deformation process shall not be lower than 950 °C, otherwise return to the furnace for heating to prevent cracking during the billet deformation process) to obtain ultra-high strength and toughness steel bars.

[0009] As an optimized solution, the steps for preparing a deep blind hole blank with a large length-diameter ratio in Step 3 sequentially include: Step 31: Cut the ultra-high strength and toughness steel bars, place the obtained cut piece in a heating furnace, heat it to 1100 - 1150 °C, and hold for 2 - 3 h; Step 32: Transfer the cut piece processed in Step 31 to the extrusion forming female die. During the transfer process, the temperature drop of the cut piece shall not be greater than 50 °C, and the initial temperature of the female die is 450 - 550 °C; Step 33: Extrusion form the cut piece, control the extrusion speed at 20 - 50 mm / s to obtain a forward and backward extrusion pre-pressing type workpiece with a central punching hole and a cross-section transition part, and the inner hole length-diameter ratio of this workpiece ≤ 3; Step 34: Heat the cross-section transition part and the parts below it of the obtained forward and backward extrusion pre-pressing type workpiece, control the heating temperature at 980 - 1080 °C, and the holding time is 0.5 - 1 h. During the heating process, ensure that the temperature of the non-heated section of the workpiece does not exceed 500 °C; Step 35: Insert a mandrel into the inner hole of the forward and backward extrusion pre-pressing type workpiece, and then perform radial forging forming on the heated part to obtain a workpiece with a reduced diameter of the cylindrical section and one end formed into a truncated cone shape; Step 36: Machine the straight platform transition section of the workpiece to improve the uniformity of material flow in the next process, and then heat the cross-section transition part and the parts above it of the workpiece, the heating temperature is 1050 - 1150 °C, and the holding time is 1 - 2 h. During the heating process, ensure that the temperature of the non-heated section of the workpiece does not exceed 500 °C; Step 37: Place the workpiece in the open internal direct extrusion die station and complete the open internal direct extrusion forming on the isothermal forging equipment at an extrusion speed of 30 - 40 mm / s to obtain a deep blind hole workpiece with a length-to-diameter ratio greater than 7. Step 38: Use a punching shear to cut off the remaining metal of the deep blind hole workpiece, then put it into a heating furnace, heat it to 900 - 1000 °C and hold for 30 - 45 min. After the holding is completed, use a stretching die to perform stretching deformation on the deep blind hole workpiece at a stretching forming speed of 100 - 180 mm / s. The wall thickness change of the deep blind hole workpiece during stretching is 2 - 8%. After stretching, use mechanical or chemical methods such as shot peening and pickling to remove the glass film layer on the inner and outer surfaces of the blank.

[0010] As an optimal solution, the steps of the toughening treatment of the workpiece in Step 4 include: First, place the workpiece in a heat treatment furnace for heat preservation, set the furnace temperature to 880 - 980 °C, take out the workpiece after heat preservation for 20 - 60 min and cool it to room temperature by water cooling; during the quenching process (the process of cooling to room temperature by water cooling), if an ordinary quenching device is used to cool the component, the outer wall of the component can be cooled normally and the cooling rate is uniform. However, due to the structural characteristics of the formed workpiece in the present invention, where the inner hole has a large length-to-diameter ratio and the inner hole is relatively closed, and in addition, the average temperature of the component is above 850 °C after heating, when water is injected into the inner hole of the component, a steam film will be instantly formed on the inner surface, and at the same time, the air pressure in the hole will rise sharply, greatly reducing the cooling rate of the inner wall metal and resulting in serious non-uniformity of the component's tissue properties. Therefore, a special quenching device for deep blind hole components is designed to perform quenching heat treatment on the component; assume that the sprayed area S (m 2 ) on the specimen and the density ρ (kg·m -3 ) of water can be regarded as constants. According to the basic principles of fluid mechanics, the spraying pressure P (kPa) and the flow density q s (L·s -1 ) of the sprayed surface can be calculated, and thus Equation (1) and Equation (2) are obtained. By adjusting the nozzle flow rate Q (L·s -1 ) and the nozzle diameter d (mm), the spraying pressure P (kPa) and the flow density q s (L·s - ) of the sprayed surface can be independently adjusted; During the quenching process, ensure that the flow density at each spraying position on the outer surface is uniform, and the flow density at each spraying position on the inner surface is also uniform. At the same time, by adjusting the nozzle flow rate and the nozzle diameter, increase the spraying pressure on the inner surface of the component to ensure that the water pressure can completely break the steam film formed on the inner surface and achieve synchronous and uniform cooling of the inner and outer surfaces; After quenching, the billet is quickly placed in liquid nitrogen for cooling for 1 - 1.5 h and then warmed back to room temperature; finally, low-temperature tempering treatment is carried out, the tempering temperature is 230 - 360 °C, and the tempering time is 2 - 4 h.

[0011] As a preferred solution, the total length of the deep blind hole component is 785 mm, the outer diameter is 152 mm, the total length of the inner hole is 600 mm, the length of the straight section is 530 mm, and the inner diameter is 91 mm. More preferably, during the radial precision forging deformation treatment, 4 - 6 hammers evenly distributed in the circumferential direction of the forward and backward extrusion pre-pressing workpiece are used to quickly and synchronously forge the workpiece, and the forging times of the hammers are 240 - 480 times / min.

[0012] Beneficial effects: The ultra-high strength and toughness deep blind hole component prepared by the solution of the present invention has low impurity content, significantly refined grain size, almost no composition segregation, the internal quality grade detected by ultrasonic flaw detection is A level, the S content (mass fraction) does not exceed 0.03%, samples are evenly taken along the axial and radial directions of the component, the average grain size is 8 - 15 μm, the impact absorption work of each part of the component is not less than 80 J, the tensile strength of the component is 2000 - 2100 MPa, the elongation after fracture is 10 - 15%, the material has high tissue uniformity and performance consistency, and also has the advantage of high material utilization rate. Description of the Drawings

[0013] Figure 1 It is a schematic diagram of the heating area (R1) of the forward and backward extrusion pre-pressing workpiece in Example 1; Figure 2 It is a schematic diagram of heating the cross-section transition part and the part above it (R2) of the workpiece in Example 1; Figure 3 It is a schematic diagram of the starting and ending positions of the stretching deformation of the deep blind hole billet in Example 1, S represents the stretching starting position, and P represents the stretching ending position; Figure 4 It is a process diagram of the strengthening and toughening treatment of the deep blind hole billet in Example 1; Figure 5 It is a forming process diagram of the deep blind hole billet in Example 1; Figure 6 It is a schematic diagram of the detection positions of the ultra-high strength and toughness deep blind hole component with a large length-diameter ratio in Example 1, A represents the tail, B represents the waist, C represents the transition part between the head (tapered part) and the waist, and D represents the head; Figure 7 It is a schematic diagram of the quenching cooling system of the deep blind hole billet in the example. Detailed Embodiments

[0014] The technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention. Embodiment 1

[0015] Combined with Figures 1 to 5 As shown, a preparation method for a super-high strength and toughness deep blind hole component with a large length-diameter ratio is as follows: Step 1: Based on the part drawing of the deep blind hole component with a large length-diameter ratio (the total length is 785 mm, the outer diameter is Φ152 mm, the total length of the inner hole is 600 mm, the length of the straight section is 530 mm, and the inner diameter is Φ91 mm), considering the near-net extrusion forming process method and machining allowance, design the forging drawing of the deep blind hole component with a large length-diameter ratio. Among them, the total length of the forging is 910 mm, the outer diameter is Φ172 mm, the total length of the inner hole is 553 mm, the length of the straight section is 493 mm, and the inner diameter is Φ71 mm; According to the principle of constant volume during the forming process and considering the material consumption caused by surface oxidation during the hot forming process, reverse-calculate the volume of the original super-high strength and toughness steel bar (the main chemical components (mass fraction) / % of this super-high strength and toughness steel bar: C content 0.2%, Cr content 2%, Ni content 9%, Co content 8%, Mo content 1%, Nb content ≤0.02%, W content ≤0.5%, Al content ≤0.07%), and obtain the required size of the super-high strength and toughness steel bar as Φ250 mm × 370 mm, and initially obtain the mass of the original steel ingot as 145 kg; Step 2: Prepare the super-high strength and toughness steel bar: According to the required mass of the input original steel ingot, use the multi-dimensional shear flow casting process to prepare the super-high strength and toughness steel ingot. By detecting the chemical composition of the steel ingot, it is obtained that: S content (mass fraction) 0.001%, S content (mass fraction) 0.008%. Then, heat the steel ingot to 980 °C, keep it warm for 2 h, and then perform radial precision forging deformation treatment (use 6 hammers evenly distributed in the circumferential direction of the super-high strength and toughness steel ingot to quickly and synchronously forge the ingot, the forging frequency of the hammer is 300 times / min. At the same time, the ingot rotates at a low speed and moves axially (rotation speed 30 r / min, axial feed speed 15 mm / s) to realize the reduction of the cross-sectional area of the ingot and the increase of the length along the axis, and finally obtain a super-high strength and toughness steel bar blank (bar diameter Φ255 mm) with fine and uniform structure, high strength level and good plasticity and toughness; In this step, macro and micro defects such as shrinkage cavities and porosity inside the steel ingot are eliminated by cumulative severe plastic deformation, carbides are broken, the deformation amount of the material is increased, and the grains are refined to improve the tissue performance; Step 3: Prepare the deep blind hole blank with a large length-diameter ratio. Specifically: First, cut the large-sized ultra-high-strength and tough steel bars. Using processes such as turning and wire cutting, process the steel bar blank with an original diameter of Φ255mm into individual blanks with a size of Φ250mm×370mm. Turn the outer surface to remove surface defects of the steel billet. Subsequently, heat the blank in a heating furnace to the deformation temperature of 1130±5°C and hold for 2.5h. After that, use a moving tooling to quickly transfer it to the extrusion forming female die. During the transfer process, the temperature drop of the blank is not more than 50°C, and the initial temperature of the female die is 500°C; Next, perform hot extrusion preforming of the blank on an isothermal forging device. Control the extrusion speed at 40mm / s to obtain a forward and backward extrusion pre-pressed type workpiece with a central punching hole and a cross-section transition part. The length-diameter ratio of the inner hole of the workpiece is ≤3; After the pre-pressing process is completed, heat a local position of the workpiece (the cross-section transition part and the small cross-section part below it, that is, the area shown as R1) (as Figure 1 shown). The heating temperature is 1000°C, and the holding time is 0.5h. During the heating process, ensure that the temperature of the non-heating section of the workpiece (that is, the forward and backward extrusion pre-pressed type workpiece) does not exceed 500°C; After the holding is completed, insert the mandrel into the inner hole of the workpiece (that is, the forward and backward extrusion pre-pressed type workpiece), and then perform radial forging forming on the heating section to obtain the workpiece. Among them, the workpiece performs circumferential rotation and axial feeding movement (rotation speed 25 revolutions / min, axial feeding speed 12mm / s), and the hammer head only performs rapid forging movement in one direction. Finally, form the outer surface of the workpiece from the original cylindrical shape into a geometric shape combined with a cylindrical section with a reduced diameter and a truncated cone. Through rapid forging forming, the deformation amount of the material at the closed end of the workpiece can be effectively increased; After the forming is completed, perform cutting processing on the straight platform transition section of the workpiece to improve the uniformity of material flow in the next process. Then, heat the cross-section transition part and the large cross-section part above it (that is, the area shown as R2) of the workpiece (as Figure 2 ) again. The heating temperature is 1100°C, and the holding time is 1.5h. During the heating process, ensure that the temperature of the non-heating section of the workpiece does not exceed 500°C; Next, place the workpiece in the open internal forward extrusion die station, and complete the open internal forward extrusion forming on the isothermal forging equipment to obtain a deep blind hole workpiece with a length-diameter ratio greater than 7. The extrusion speed is 30 mm / s, and there is a metal thickness of 90 mm left on the large cross-section at one end of the deep blind hole workpiece after forward extrusion. During the open internal forward extrusion forming process, since the core rod has a relatively large length-diameter ratio and the stress environment is harsh, at the position where the outer surface of the core rod contacts the severely deformed section of the metal, it is subjected to shear stress and normal stress for a long time, and the temperature rises rapidly, which easily leads to an increase in the deflection and bending deformation of the core rod after temperature rise. Therefore, a cooling water circular hole channel is designed inside the core rod to reduce the temperature inside and on the outer surface of the core rod. To ensure the strength requirements during the use of the core rod, the diameter of the cooling water circular hole channel is not less than 1 / 10 of the core rod diameter and does not exceed 1 / 3 of the core rod diameter. In this example, the designed cooling water circular hole channel is Φ15 mm; After the open internal forward extrusion forming is completed, use a punching shear to cut off the tail metal of the large cross-section at one end of the deep blind hole workpiece, put the deep blind hole workpiece with the tail cut off into a heating furnace, heat it to 950 °C and hold it for 30 min. After that, use a stretching die to perform a single-pass stretching deformation on the local part of the deep blind hole workpiece (as Figure 3 shown), the stretching deformation speed is 150 mm / s, and the wall thickness change of the deep blind hole workpiece is 5%, that is, the outer diameter of the component is reduced by 2.6 mm on one side. The functions are: one is to further increase the length-diameter ratio of the inner hole of the workpiece, and the second is to correct the dimensions and geometric tolerances of the extruded workpiece to ensure key dimensions such as coaxiality and straightness; in addition, during the forming process, a layer of special hot forming lubricants such as glass lubricant and oil-based graphite is evenly covered on the contact surface between the workpiece and the die to reduce the friction between the workpiece and the die, reduce the equipment load and extend the service life of the die; after stretching, use mechanical or chemical methods such as shot peening and pickling to remove the glass film layer on the inner and outer surfaces of the blank; Step 4, perform a strengthening and toughening treatment on the obtained workpiece, and perform precision cutting after the strengthening and toughening treatment to obtain an ultra-high strength and toughness deep blind hole component with a large length-diameter ratio; specifically: As Figure 4 shown, first place the workpiece in a heat treatment furnace for heat preservation, set the furnace temperature to 900 ± 5 °C, take out the workpiece after heat preservation for 40 ± 5 min and water-cool it to room temperature; during the quenching process (the process of water-cooling to room temperature), use a special quenching device for deep blind hole components (as Figure 7 shown) to perform quenching treatment on the component. Assume that the sprayed area S (m 2 ) on the specimen and the density ρ (kg·m -3 ) of water can be regarded as constants. According to the basic principles of fluid mechanics, the spraying pressure P (kPa) and the flow density q s (L·s -1 ) of the sprayed surface can be calculated, thus obtaining Equation (1) and Equation (2). By adjusting the nozzle flow rate Q (L·s -1) and the nozzle diameter d (mm), the water spray pressure P (kPa) and the flow density q of the sprayed surface can be independently adjusted s (L·s -1 ); During the quenching process, ensure that the flow density at each spraying position on the outer surface is uniform, and the flow density at each spraying position on the inner surface is also uniform. At the same time, by adjusting the nozzle flow rate and nozzle diameter, increase the water spray pressure on the inner surface of the component to ensure that the water pressure can completely break the steam film formed on the inner surface, and achieve synchronous and uniform cooling of the inner and outer surfaces; for the cooling system 1 for cooling the inner wall of the component, the nozzle flow rate Q = 0.42 L·s -1 , and the nozzle diameter is 4 mm; for the cooling system 2 for cooling the inner wall of the component, the nozzle flow rate Q = 0.5 L·s -1 , and the nozzle diameter is 6 mm; After quenching, quickly place the billet in liquid nitrogen for cooling for 1 h and then warm it back to room temperature; finally, perform low-temperature tempering treatment, the tempering temperature is 250 ± 5 °C, and the tempering time is 2.5 h; Then, referring to the part structure drawing of the ultra-high strength and toughness deep blind hole component with a large length-diameter ratio, perform precision cutting on the workpiece (billet) to obtain Figure 6 the ultra-high strength and toughness deep blind hole component as shown.

[0016] Comparative example: Adopt the traditional integral extrusion forming process, and the extrusion process parameters (extrusion speed 4 mm / s).

[0017] Detect the ultra-high strength and toughness deep blind hole components in Example 1 and the comparative example. Respectively, at the head cone part D (head), waist part B, tail part A and the transition part C between the head and the waist of the component along the axial direction, and evenly select 3 specimens along the radial direction at each position ( Figure 6 as shown), detect the impact toughness, mechanical properties and other indicators of the specimens, and the results are shown in Table 1. Table 1 Detection results of the microstructure and properties of the ultra-high strength and toughness deep blind hole component with a large length-diameter ratio

[0018] Perform ultrasonic flaw detection on the ultra-high strength and toughness deep blind hole components in Example 1 and the comparative example. The results show that the internal quality grade of the components in Example 1 is all Grade A, and the internal quality grade of the components in the comparative example is Grade A (head cone part D, waist part B, tail part A) and Grade B (transition part C).

Claims

1. A preparation method for a super-high strength and toughness deep blind hole component with a large length-diameter ratio, characterized in that the steps Including: Step 1: Based on the part drawing of the deep blind hole component with a large length-diameter ratio, considering the machining allowance and material consumption, design the forging drawing of the deep blind hole component with a large length-diameter ratio to obtain the original steel ingot structure dimensions; Step 2: Prepare ultra-high strength and toughness steel bars; Step 3: Prepare a deep blind hole blank with a large length-diameter ratio; Step 4: Perform a strengthening and toughening treatment on the obtained blank, and after completion, carry out precision cutting to obtain an ultra-high strength and toughness deep blind hole component with a large length-diameter ratio.

2. The preparation method according to claim 1, wherein The steps for preparing ultra-high strength and toughness steel bars in Step 2 include: Step 21: Prepare or obtain an ultra-high strength and toughness steel ingot and perform a heat treatment; Step 22: Heat the ultra-high strength and toughness steel ingot to 1000 - 1080 °C and hold for 1.5 - 2.5 h, then perform a radial precision forging deformation treatment to obtain ultra-high strength and toughness steel bars.

3. The preparation method according to claim 1, characterized in that, The steps for preparing a deep blind hole blank with a large length-diameter ratio in Step 3 sequentially include: Step 31: Cut the ultra-high strength and toughness steel bars, place the obtained cut piece in a heating furnace, heat it to 1100 - 1150 °C and hold for 2 - 3 h; Step 32: Transfer the cut piece processed in Step 31 to an extrusion forming female die. During the transfer process, the temperature drop of the cut piece does not exceed 50 °C, and the initial temperature of the female die is 450 - 550 °C; Step 33: Extrude the cut piece, control the extrusion speed at 20 - 50 mm / s to obtain a forward and backward extrusion pre-pressed type workpiece with a central punching hole and a cross-section transition part, and the length-diameter ratio of the inner hole of this workpiece ≤ 3; Step 34: Heat the cross-section transition part and the parts below it of the obtained forward and backward extrusion pre-pressed type workpiece, control the heating temperature at 980 - 1080 °C, and the holding time at 0.5 - 1 h. During the heating process, ensure that the temperature of the non-heated section of the workpiece does not exceed 500 °C; Step 35: Insert a mandrel into the inner hole of the forward and backward extrusion pre-pressed type workpiece and then perform a radial forging forming on the heated part to obtain a workpiece with a reduced diameter of the cylindrical section and one end formed into a truncated cone shape; Step 36: Perform a cutting process on the straight platform transition section of the workpiece, then heat the cross-section transition part and the parts above it of the workpiece, the heating temperature is 1050 - 1150 °C, and the holding time is 1 - 2 h. During the heating process, ensure that the temperature of the non-heated section of the workpiece does not exceed 500 °C; Step 37: Place the workpiece on the open inner type forward extrusion die station and complete the open inner type forward extrusion forming on an isothermal forging device, the extrusion speed is 30 - 40 mm / s to obtain a deep blind hole blank with a length-diameter ratio greater than 7; Step 38: Use a punching shear to cut off the remaining metal of the deep blind hole blank, then put it into a heating furnace, heat it to 900 - 1000 °C and hold for 30 - 45 min. After the holding is completed, use a stretching die to perform a stretching deformation on the deep blind hole blank, the stretching forming speed is 100 - 180 mm / s, the wall thickness change of the deep blind hole blank during stretching is 2 - 8%. After stretching, use mechanical or chemical methods such as shot peening and pickling to remove the glass film layer on the inner and outer surfaces of the blank.

4. The preparation method according to claim 1, characterized in that, The steps for performing a strengthening and toughening treatment on the blank in Step 4 include: First, place the blank in a heat treatment furnace for heat preservation. Set the furnace temperature to 880 - 980 °C. After heat preservation for 20 - 60 min, take out the blank and cool it in water to room temperature; during the quenching process, the flow density at each spraying position on the inner surface of the workpiece is also uniform. At the same time, by adjusting the nozzle flow rate and nozzle diameter, increase the water spraying pressure on the inner surface of the component to ensure that the water pressure can completely destroy the steam film formed on the inner surface; after quenching, quickly place the blank in liquid nitrogen for cooling for 1 - 1.5 h and then warm it back to room temperature; finally, perform low-temperature tempering treatment, with the tempering temperature being 230 - 360 °C and the tempering time being 2 - 4 h.

5. The preparation method according to claim 1, characterized in that, The total length of the deep blind hole component is 785 mm, the outer diameter is 152 mm, the total length of the inner hole is 600 mm, the length of the straight section is 530 mm, and the inner diameter is 91 mm.

6. The preparation method according to claim 1, wherein, During the radial precision forging deformation treatment, 4 - 6 hammers evenly distributed in the circumferential direction of the forward and backward extrusion pre-pressing workpiece are used to quickly and synchronously forge the workpiece, and the number of hammer forging times is 240 - 480 times / min.

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