Manufacturing process of In625 forge piece with high energy absorption characteristic

Abstract

The invention relates to the technical field of metal material processing, in particular to a manufacturing process of an In625 forge piece with a high energy absorption characteristic, which comprises the following steps: preparing the following components in percentage by weight: 20.0-23.0% of Cr, 8.0-10.0% of Mo and the like, and the balance of Ni, preparing a master alloy ingot by a VIM + ESR duplex process, homogenizing at 1180-1220 DEG C, performing multidirectional forging, and performing solid solution, supersonic particle bombardment, aging and cryogenic circulation treatment on the forge piece to obtain the In625 forge piece with the high energy absorption characteristic. And a 50-200nm nanoscale Laves phase reinforcement is formed, so that the energy absorption capability is improved. According to the method, through cooperative regulation and control of a multi-field coupling process and microelements, gradient nanocrystalline layers and high-density dislocation entanglement are formed on the In625 forge piece, and nano Laves phase strengthening bodies are evenly distributed; the corrosion resistance and fatigue resistance are remarkably improved, the process energy consumption is reduced, the material utilization rate is increased, and the extreme working condition requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of metal material processing, in particular to a manufacturing process of In625 forgings with high energy absorption characteristics. Background Art

[0002] As a typical representative of nickel-based high-temperature alloys, In625 alloy occupies an important position in the fields of aerospace, energy and chemical engineering, marine engineering, etc. due to its excellent corrosion resistance, high-temperature strength and weldability. For example, in aircraft engines, it is used to manufacture turbine components that withstand high stress and corrosive media; in deep-sea engineering, it is often used to prepare pressure-resistant and corrosion-resistant pipes and pressure vessels. However, with the increasingly harsh service conditions of equipment, such as the need for aviation structures to cope with sudden impact loads and the need for deep-sea equipment to withstand the dynamic effects of strong ocean currents, the problems of insufficient deformation resistance and energy absorption performance of traditional In625 forgings under high-energy impacts have gradually become prominent. When encountering sudden loads, traditional forgings are prone to concentrated plastic deformation due to insufficient energy absorption, resulting in a significant increase in the risk of structural failure, making it difficult to meet the stringent safety and reliability requirements of modern high-end equipment.

[0003] Traditional In625 forgings are typically produced using a process consisting of vacuum melting, conventional forging, and solution aging. Their microstructure is primarily composed of an austenite matrix and a small amount of carbides. This process has the following inherent drawbacks: Conventional processes make it difficult to introduce efficient strengthening phases into the alloy, and the resistance to dislocation movement is insufficient, resulting in limited plastic deformation capacity of forgings under dynamic loads. For example, the carbides formed in traditional processes are large in size and unevenly distributed, which cannot effectively hinder dislocation movement, resulting in a single energy absorption path for forgings when loaded at high strain rates. For trace elements such as Yb, Hf, and Re, traditional smelting processes make it difficult to achieve uniform dispersion in the melt, and segregation areas are easily formed, which in turn leads to regional differences in the mechanical properties of forgings, affecting the overall performance stability. Traditional forging relies solely on mechanical force to improve the organization, lacks synergy with the physical field, and is difficult to achieve fine control of grains and uniform distribution of strengthening phases, resulting in difficulty in achieving strength and toughness matching of forgings that exceeds traditional levels.

[0004] Modern industry places higher demands on the energy absorption performance of structural materials, especially under extreme working conditions, where materials must achieve efficient dissipation of impact energy through multiple mechanisms. Although concepts such as nano-strengthening and gradient structures have been introduced into metal material design, their application in In625 alloy still faces many challenges: Traditional aging processes make it difficult to precisely control the formation conditions of nanoscale Laves phases. Their size, distribution, and volume fraction are difficult to regulate stably, and localized aggregation can easily lead to stress concentration sources, which in turn degrades material properties. Conventional surface treatment processes (such as shot peening) can improve surface hardness, but they struggle to form a gradient structure from the surface to the substrate. Furthermore, micro-damage can easily be introduced to the surface during the treatment process, becoming the starting point for crack initiation. When combining physical fields such as electromagnetic fields and pulsed currents with traditional forging processes, the interaction mechanisms between various field parameters (such as electromagnetic field frequency and current intensity) and mechanical deformation are complex, and there is a lack of systematic process optimization methods, making it difficult to achieve the desired results in practical applications. Summary of the Invention

[0005] (1) Technical problems solved In view of the deficiencies of the prior art, the present invention provides a manufacturing process for In625 forgings with high energy absorption characteristics.

[0006] (2) Technical solution A process for manufacturing an In625 forging having high energy absorption characteristics comprises the following steps: S1: Ingredients and smelting: In percentage by weight, Cr 20.0-23.0%, Mo 8.0-10.0%, Nb+Ta 3.15-4.15%, Fe≤5.0%, Al 0.15-0.40%, Ti 0.15-0.40%, C≤0.10%, Mn≤0.50%, Si≤0.50%, P≤0.015%, S≤0.015%, 0.05-0.15% Yb, 0.02-0.08% Hf, 0.01-0.05% Re, and the balance Ni are prepared by vacuum induction melting and electroslag remelting dual process to prepare a master alloy ingot; wherein, during the smelting process, argon gas with a flow rate of 5-10 L / min is introduced for protection and an alternating electromagnetic field is applied; S2: Homogenization treatment: Heat the master alloy ingot to 1180-1220℃, keep it at this temperature for 10-15 hours, furnace cool it to 800℃ at a cooling rate of 50-100℃ / hour, and then air cool it; S3: Multi-field coupled forging: uses a multi-directional forging process with an initial forging temperature of 1100-1150°C and a final forging temperature ≥950°C. During the forging process, a hydrostatic pressure of 10-20 MPa is applied, and a pulse current is applied simultaneously. S4: Solution treatment: Heat the forging to 1080-1120℃, keep warm for 1-2 hours, and cool with water; S5: Aging treatment: Heat the solution treated forgings to 760-800°C, hold for 8-12 hours, furnace cool to 650°C at a cooling rate of 50-100°C / hour, hold for another 8 hours, and then air cool. The process forms a nano-scale Laves phase reinforcement after aging treatment, and the reaction is as follows: Preferably, the method further includes performing a surface gradient nano-processing after the solution treatment in step S4: using supersonic particle bombardment technology and nitrogen as a carrier gas, accelerating ceramic particles with a particle size of 50-100 μm to 300-500 m / s, bombarding the forging surface for 5-15 minutes, and forming a nanocrystalline layer with a thickness of 50-200 μm. The grain size of the nanocrystalline layer is gradiently distributed from the surface to the inside, with a surface grain size of 10-50 nm and a transition layer grain size of 50-200 nm.

[0007] Preferably, the process further includes a cryogenic cycle treatment after the aging treatment in step S5: placing the forging in liquid nitrogen at -196°C for 2-4 hours, then heating to room temperature at a heating rate of 5-10°C / min, and repeating the cryogenic treatment 2-3 times; after the cryogenic cycle treatment, a high-density dislocation tangle is formed inside the forging, with a dislocation density of 10¹ 4 -10¹ 5 m⁻².

[0008] Preferably, in step S1, 0.01-0.03% B and 0.02-0.06% Zr are also added during the batching process, and the added amounts of B and Zr satisfy the relationship: 0.5≤B / Zr≤1.5; the B and Zr form a composite boride ZrB2 during the smelting process, and the average particle size of the composite boride is 100-300 nm.

[0009] Preferably, in step S3, the pulse current voltage is 100-300V, the frequency is 10-50Hz, and the pulse width is 10-50ms; the size of the dynamically recrystallized grains is reduced by 30-40%, and an amorphous layer with a width of 5-10nm is formed at the grain boundaries.

[0010] Preferably, in the aging treatment of step S5, stacking fault tetrahedrons are formed in the crystal by controlling the cooling rate, and the density of the stacking fault tetrahedrons is 10¹ 6 -10¹ 7 m⁻³, with a size of 5-20nm.

[0011] Preferably, the density of the In625 forging prepared by the process is 8.44-8.48 g / cm³, the yield strength at room temperature is ≥550 MPa, the tensile strength is ≥750 MPa, the elongation is ≥35%, and the impact absorption energy is ≥120 J.

[0012] Preferably, the In625 forgings prepared by the process are subjected to a strain rate of 10³-10 4The dynamic yield strength under s⁻¹ is ≥900MPa and the energy absorption capacity is ≥350MJ / m³.

[0013] Preferably, the grain size of the In625 forgings prepared by the process is ASTM 6-9, and a continuous carbide network is distributed at the grain boundaries. 23 Type C6 has an average thickness of 50-150 nm, and nano-sized Yb2O3 particles with a particle size of 10-30 nm are evenly distributed in the carbide network.

[0014] Preferably, the hardness of the In625 forging prepared by the process is HB 200-250, the elastic modulus is 205-215 GPa, the Poisson's ratio is 0.31-0.33, and the tensile strength retention rate at a high temperature of 300°C is ≥85%.

[0015] (3) Beneficial technical effects Compared with the existing technology, the beneficial effects of the present invention are: 1. By introducing specific proportions of elements such as Yb, Hf, and Re into the ingredients and precisely controlling the temperature and time during the aging treatment, a uniformly distributed nanoscale Laves phase is generated. These strengthening phases range in size from 50 to 200 nm and are dispersed throughout the grain boundaries and within the grains, effectively hindering dislocation motion and significantly enhancing the alloy's work hardening ability. The pulsed current applied during the forging process works synergistically with the hydrostatic pressure to significantly promote dynamic recrystallization, enabling precise control of grain size while forming a nanoscale amorphous layer at the grain boundaries.

[0016] 2. The continuously distributed carbide network and dispersed nano-sized Yb2O3 particles at the grain boundaries effectively pin the grain boundaries and hinder grain growth, enabling the forgings to withstand higher stress levels under static loading while maintaining good plastic deformation capacity. This significantly enhances the forgings' deformation resistance under dynamic loads, more effectively converting impact energy into plastic deformation energy, meeting the requirements for safe service under extreme operating conditions.

[0017] 3. The alternating electromagnetic field applied during the vacuum induction melting process enhances the stirring effect of the melt, ensuring the uniform distribution of trace elements such as Yb and Hf, and avoiding the common problem of component segregation in traditional processes. The synergistic effect of the pulsed current and hydrostatic pressure in the forging process not only reduces the difficulty of forging and the number of processing times, but also achieves directional control of the microstructure through the coupling of physical fields and mechanical forces, thereby improving process efficiency and material performance stability. At high temperatures, the stable presence of the strengthening phase ensures strength retention, while the gradient structure design effectively suppresses the intrusion path of the corrosive medium. These characteristics give it significant advantages in extreme working conditions such as high-temperature aerospace components and deep-sea corrosion environments, greatly expanding the application scenarios of In625 alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a manufacturing process flow chart of an In625 forging with high energy absorption characteristics proposed by the present invention; Figure 2 1. is a comparison chart of room temperature yield strength and dynamic energy absorption of the embodiment and the comparative example; Figure 3 1. It is a bar chart comparing the high temperature strength retention and impact absorption energy of the embodiment and the comparative example; Figure 4 It is a radar comparison chart made after unifying the core performance data of the embodiment and the comparative example. DETAILED DESCRIPTION

[0019] according to Figures 1 to 4 , the specific implementation of the present invention is as follows: 1. Example 1: Preparation of In625 forgings by standard process 1. Ingredients and smelting Accurately weigh the raw materials according to weight percentage: Main alloying elements: Cr 21.5%, Mo 9.0%, Nb+Ta 3.65%, Fe 3.0%, Al 0.25%, Ti 0.25%; trace elements: Yb 0.10%, Hf 0.05%, Re 0.03%; Impurity control: C≤0.08%, Mn≤0.40%, Si≤0.40%, P≤0.012%, S≤0.010%, the balance is Ni; Adopt VIM+ESR dual melting process: VIM stage: The raw materials are loaded into a magnesium oxide crucible, vacuumed to 5 Pa, and heated to 1580°C at a rate of 5°C / min. During the refining stage, 8L / min of high-purity argon (purity ≥99.999%) is introduced, and an 80Hz, 750A alternating electromagnetic field is applied. The electromagnetic stirring power density is 25kW / m³, and the melt surface fluctuation height is controlled at 30-50mm. Spectral analysis is performed every 5 minutes during the melting process to ensure that the composition deviation is ≤±1.2%. After melting, the master alloy ingot is cast at a cooling rate of 10°C / s to form a φ300mm×1000mm master alloy ingot. ESR stage: Using a CaF2 (60%)-Al2O3 (25%)-CaO (15%) slag system with a slag weight of 150kg; remelting current 5000A, voltage 45V, melting rate 8kg / min; crystallizer cooling water flow rate 120m³ / h, water temperature controlled at 25±5℃; obtained φ350mm×1200mm electrode ingots, which were tested by ultrasonic flaw detection and showed no internal defects; 2. Homogenization Heating was performed in a box-type resistance furnace with a heating rate of 100°C / h and a temperature accuracy of ±5°C. The temperature was maintained at 1200°C for 12 hours, and the temperature distribution in the furnace was recorded every hour (temperature difference ≤±3°C). The sample was cooled to 800°C (cooling rate 75°C / h) and then air-cooled. Metallographic examination was performed after treatment: the dendrite segregation index was ≤1.05, and 50-100 nm of M precipitated in the crystals was observed. 23 C6 carbide, hardness HB185; 3. Multi-field coupling forging Multidirectional forging is performed on a 4,000-ton high-speed forging press equipped with a hydrostatic loading system and pulse current device: First fire: Initial temperature 1130°C, hold for 2 hours to ensure temperature uniformity; 60mm reduction (25% deformation), 0.5s⁻¹ deformation rate; simultaneous application of 15MPa argon hydrostatic pressure (pressure fluctuation ≤±0.5MPa); 200V, 30Hz pulse current (pulse width 20ms), current density 10A / mm² Second to fourth fires: heat to 1130℃ each time, keep warm for 1 hour; deformation of each fire is 25%, total forging ratio is 5; final forging temperature is controlled above 980℃ (infrared temperature monitoring) Microstructure evolution: Dynamically recrystallized grain size 20-30 μm; 8 nm thick amorphous layer formed at grain boundaries; dislocation density increased from the initial 2 × 10¹³m⁻² to 2 × 10¹ 4 m⁻²; 4. Solution treatment A vacuum heat treatment furnace with a vacuum degree of 10⁻³Pa was used; the temperature was raised to 1100°C at a rate of 15°C / min and kept at that temperature for 1.5 hours; water-cooled quenching was performed at a water temperature of 25°C and a cooling rate of ≥100°C / s; the microstructure after treatment was single austenite, with a grain size of ASTM grade 6 and a hardness of HB205. 5. Surface nano-treatment Supersonic particle bombardment equipment was used: the working gas was nitrogen at a pressure of 1.5 MPa and a purity of ≥99.99%. The ceramic particles were Al2O3 with an average particle size of 80 μm and a hardness of HV 2000. The particle acceleration speed was 400 m / s. The distance between the spray gun and the workpiece was 100 mm, and the scanning speed was 50 mm / min. The bombardment time was 10 minutes, and the coverage was 300%. A 120 μm gradient nanocrystalline layer was formed. The surface grain size was 30 nm, and the transition layer was 150 nm. The surface hardness was HB 220, and the residual compressive stress was -320 MPa. 6. Timeliness processing Use a box-type resistance furnace with a heating rate of 50℃ / h; keep at 780℃ for 10 hours, with a temperature uniformity of ±3℃ in the furnace; cool to 650℃ at 75℃ / h, keep at this temperature for another 8 hours, and then air cool Precipitation phase characteristics: Laves phase (Ni3(Mo, Nb, Yb)2) average particle size 120nm; volume fraction 3.5%; uniformly distributed at grain boundaries and within grains, with a spacing of 80-150nm 7. Deep cold cycle treatment A liquid nitrogen deep freezer was used with a temperature control accuracy of ±2°C. The temperature was kept at -196°C for 3 hours, and the timing began after the temperature stabilized. The temperature was raised to room temperature at 7°C / min. The cycle was repeated twice, with a 30-minute interval between each cycle. After treatment, the dislocation density was increased to 8×10¹ 4 m⁻².

[0020] 2. Example 2: High Yb Content Strengthening Process 1. Ingredients and smelting Accurately weigh the raw materials according to weight percentage: main alloying elements: Cr 21.5%, Mo 9.0%, Nb+Ta 3.65%, Fe3.0%, Al 0.25%, Ti 0.25%; trace elements: Yb 0.15%, Hf 0.08%, Re 0.03%; Impurity control: C≤0.07%, Mn≤0.35%, Si≤0.30%, P≤0.010%, S≤0.008%, the balance is Ni; Adopt VIM+ESR dual melting process: VIM stage: The raw materials are loaded into a magnesium oxide crucible, vacuumed to 4 Pa, and heated to 1590°C at a rate of 5°C / min. During the refining stage, high-purity argon (purity ≥99.999%) is introduced at 9 L / min, and a 90 Hz, 800 A alternating electromagnetic field is applied. The electromagnetic stirring power density is 30 kW / m³, and the melt surface fluctuation height is controlled at 35-55 mm. Spectral analysis is performed every 4 minutes during the melting process to ensure that the composition deviation is ≤±1.0%. After melting, the master alloy ingot is cast at a cooling rate of 12°C / s to form a φ300 mm×1000 mm master alloy ingot. ESR stage: A CaF2 (55%)-Al2O3 (30%)-CaO (15%) slag system was used, with a slag weight of 160kg; the remelting current was 5200A, the voltage was 46V, and the melting rate was 7.5kg / min; the crystallizer cooling water flow rate was 130m³ / h, and the water temperature was controlled at 24±4℃; the resulting electrode ingots were φ350mm×1200mm, and no internal defects were found after ultrasonic testing.

[0021] 2. Homogenization A vacuum heat treatment furnace was used with a heating rate of 110°C / h and a temperature accuracy of ±4°C. The temperature was maintained at 1210°C for 13 hours, and the temperature distribution in the furnace was recorded every hour (temperature difference ≤±2.5°C). The furnace was cooled to 810°C (cooling rate 80°C / h) and then air-cooled. Metallographic examination after treatment showed that the dendrite segregation index was ≤1.03, and the precipitation of M in the crystal was 45-95nm. 23 C6 carbide, hardness HB188.

[0022] 3. Multi-field coupling forging Multidirectional forging is performed on a 4,000-ton high-speed forging press equipped with a hydrostatic loading system and pulse current device: First fire: Initial temperature 1135°C, hold for 2.2 hours to ensure temperature uniformity; 62mm reduction (25.8% deformation), 0.55s⁻¹ deformation rate; simultaneous application of 20MPa argon hydrostatic pressure (pressure fluctuation ≤±0.4MPa); 250V, 40Hz pulse current (pulse width 15ms), current density 11A / mm²; Second to fourth fires: each time heating to 1135℃, holding temperature for 1.2 hours; each fire deformation amount is 25.8%, total forging ratio is 5.16; final forging temperature is controlled above 950℃ (infrared temperature monitoring); Microstructure evolution: Dynamically recrystallized grain size 15-25μm (EBSD detection); 9nm thick amorphous layer formed at the grain boundary (TEM observation); dislocation density increased from the initial 2.5×10¹³m⁻² to 2.8×10¹ 4 m⁻².

[0023] 4. Solution treatment Use vacuum heat treatment furnace, vacuum degree 8×10⁻ 4 Pa; heating to 1105°C at 16°C / min and holding for 1.6 hours; water quenching (water temperature 24°C, cooling rate ≥110°C / s); the microstructure after treatment is single austenite, grain size ASTM grade 7, and hardness HB 208.

[0024] 5. Surface nano-treatment Using supersonic particle bombardment (SFPB) equipment: Working gas: nitrogen (pressure 1.6MPa, purity ≥99.995%); Ceramic particles: Al2O3 (average particle size 85μm, hardness HV 2100); Process parameters: particle acceleration speed 410m / s (calibrated by laser velocimeter); distance between spray gun and workpiece 105mm, scanning speed 52mm / min; bombardment time 11 minutes, coverage 320%; Treatment effect: formation of a 125μm gradient nanocrystalline layer (TEM detection); surface grain size 28nm, transition layer 145nm; surface hardness HB 225, residual compressive stress -330MPa.

[0025] 6. Timeliness processing A box-type resistance furnace was used with a heating rate of 55°C / h; the temperature was kept at 760°C for 12 hours, with a temperature uniformity of ±2.5°C in the furnace; the temperature was cooled to 640°C at a rate of 80°C / h, and then kept at this temperature for another 9 hours before air cooling. Precipitated phase characteristics: Laves phase (Ni3(Mo,Nb,Yb)2) average particle size 80nm; volume fraction 4.2% (Image-ProPlus quantitative analysis); uniformly distributed at grain boundaries and within grains, with a spacing of 70-130nm; 20nm Yb2O3 particles precipitated at grain boundaries (confirmed by STEM-EDS).

[0026] 7. Deep cold cycle treatment A liquid nitrogen cryogenic chamber was used with a temperature control accuracy of ±1.8°C. The temperature was maintained at -197°C for 3.2 hours, and the timing began after the temperature stabilized. The temperature was raised to room temperature at 7.5°C / min (using a programmable temperature control system). The cycle was repeated twice, with an interval of 35 minutes between each cycle. After treatment, the dislocation density was increased to 9×10¹ 4 m⁻².

[0027] 3. Example 3: Gradient Nano-Structure Deep Strengthening Process 1. Ingredients and smelting Accurately weigh the raw materials according to weight percentage: Main alloying elements: Cr 21.5%, Mo 9.0%, Nb+Ta 3.65%, Fe 3.0%, Al 0.25%, Ti 0.25%; Trace elements: Yb 0.10%, Hf 0.05%, Re 0.03%; Impurity control: C≤0.075%, Mn≤0.38%, Si≤0.32%, P≤0.011%, S≤0.009%, the balance is Ni; Adopt VIM+ESR dual melting process: VIM stage: The raw materials are loaded into a magnesium oxide crucible, vacuumed to 5 Pa, and heated to 1585°C at a rate of 5.5°C / min. During the refining stage, 8.5L / min of high-purity argon (purity ≥99.999%) is introduced, and an 85Hz, 780A alternating electromagnetic field is applied. The electromagnetic stirring power density is 27kW / m³, and the melt surface fluctuation height is controlled at 32-52mm. Spectral analysis is performed every 4.5 minutes during the melting process to ensure that the composition deviation is ≤±1.1%. After melting, the master alloy ingot is cast at a cooling rate of 11°C / s to form a φ300mm×1000mm master alloy ingot. ESR stage: A CaF2 (58%)-Al2O3 (27%)-CaO (15%) slag system was used, with a slag weight of 155kg; the remelting current was 5100A, the voltage was 45.5V, and the melting rate was 7.8kg / min; the crystallizer cooling water flow rate was 125m³ / h, and the water temperature was controlled at 25±5℃; the resulting electrode ingots were φ350mm×1200mm, and no internal defects were found after ultrasonic testing.

[0028] 2. Homogenization Heating was performed in a box-type resistance furnace with a heating rate of 105°C / h and a temperature accuracy of ±4.5°C. The temperature was maintained at 1205°C for 12.5 hours, and the temperature distribution in the furnace was recorded every hour (temperature difference ≤±2.8°C). The furnace was cooled to 805°C (cooling rate 78°C / h) and then air-cooled. Metallographic examination after treatment showed that the dendrite segregation index was ≤1.04, and the precipitation of M in the crystals was 48-98nm. 23 C6 carbide, hardness HB 186.

[0029] 3. Multi-field coupling forging Multidirectional forging is performed on a 4,000-ton high-speed forging press equipped with a hydrostatic loading system and pulse current device: First fire: Initial temperature 1132°C, hold for 2.1 hours to ensure temperature uniformity; 59mm reduction (24.6% deformation), 0.52s⁻¹ deformation rate; simultaneous application of 15MPa argon hydrostatic pressure (pressure fluctuation ≤±0.45MPa); 200V, 32Hz pulse current (pulse width 18ms), current density 10.5A / mm²; Second to fourth fires: each time heating to 1132℃, holding temperature for 1.1 hours; each fire deformation amount is 24.6%, total forging ratio is 4.92; final forging temperature is controlled above 985℃ (infrared temperature monitoring); Microstructure evolution: Dynamically recrystallized grain size 18-28μm (EBSD detection); 7.5nm thick amorphous layer formed at the grain boundary (TEM observation); dislocation density increased from the initial 2.2×10¹³m⁻² to 2.5×10¹ 4 m⁻².

[0030] 4. Solution treatment Use vacuum heat treatment furnace, vacuum degree 9×10⁻ 4 Pa; heating to 1103°C at 15.5°C / min and holding for 1.55 hours; water quenching (water temperature 24.5°C, cooling rate ≥105°C / s); the microstructure after treatment is single austenite, grain size ASTM 6.5, hardness HB 206.

[0031] 5. Surface nano-treatment Using supersonic particle bombardment (SFPB) equipment: Working gas: nitrogen (pressure 2.0MPa, purity ≥99.999%); Ceramic particles: SiC (average particle size 50 μm, hardness HV 2800); Process parameters: particle acceleration speed 500m / s (calibrated by laser velocimeter); distance between spray gun and workpiece 80mm, scanning speed 45mm / min; bombardment time 15 minutes, coverage 400%; Treatment effect: formation of a 200μm gradient nanocrystalline layer (TEM detection); surface grain size 10nm, transition layer 50-150nm; surface hardness HB 240, residual compressive stress -380MPa.

[0032] 6. Timeliness processing A box-type resistance furnace was used with a heating rate of 60°C / h; the temperature was kept at 800°C for 8 hours, with a temperature uniformity of ±2°C in the furnace; the temperature was cooled to 630°C at a rate of 85°C / h, and then kept at this temperature for another 7 hours before air cooling. Precipitated phase characteristics: Laves phase (Ni3(Mo,Nb,Yb)2) average particle size 200nm; volume fraction 2.8% (Image-ProPlus quantitative analysis); uniformly distributed at grain boundaries and within grains, with a spacing of 150-250nm.

[0033] 7. Deep cold cycle treatment A liquid nitrogen cryogenic chamber was used with a temperature control accuracy of ±1.5°C. The temperature was maintained at -198°C for 4 hours, and the timer began after the temperature stabilized. The temperature was raised to room temperature at 5°C / min (using a programmable temperature control system). The cycle was repeated 3 times, with a 40-minute interval between each cycle. After treatment, the dislocation density was increased to 1×10¹ 5 m⁻².

[0034] 4. Comparative example: In625 forgings were prepared by traditional process.

[0035] 1. Ingredients Accurately weigh the raw materials according to weight percentage: Main alloying elements: Cr 22%, Mo 9%, Nb+Ta 3.5%; Impurity control: C≤0.10%, Mn≤0.50%, Si≤0.50%, P≤0.015%, S≤0.015% Does not contain trace elements such as Yb, Hf, Re, etc. 2. Melting Using a single VIM process: The raw materials were placed in a magnesium oxide crucible, evacuated to 100 Pa, and heated to 1550°C at a rate of 8°C / min. During the refining phase, argon gas (purity ≥ 99.99%) was introduced at 6 L / min without electromagnetic field assistance. The refining time was 30 minutes, and spectral analysis was performed every 10 minutes. After smelting, the alloy was cast at a cooling rate of 8°C / s to form a φ320 mm × 1100 mm master alloy ingot. Inclusion rating: A2.0-B1.5 (GB / T 10561-2005).

[0036] 3. Forging Conventional multi-directional forging was performed on a 3,000-ton high-speed forging press: initial temperature 1,100°C, hold temperature 3 hours; completed in 5 passes, with a deformation of 20% per pass and a total forging ratio of 6; final forging temperature 900°C; air cooling after forging, grain size 50-80μm, ASTM grade 3.

[0037] 4. Heat treatment Solution treatment: Use a box-type resistance furnace, raise the temperature to 1050℃ at 100℃ / h; keep at this temperature for 2 hours, then take the furnace out and air cool; Aging treatment: heating to 700℃ at 80℃ / h, keeping at this temperature for 16 hours; then air-cooling to precipitate coarse Laves phase (particle size > 500nm).

[0038] The core performance comparison of the embodiment and the comparative example is shown in the following table: Table 1 The embodiments of the present invention significantly outperform conventional processes in terms of room-temperature strength, dynamic energy absorption, and high-temperature performance. Specifically, the dynamic energy absorption capacity of Example 3 reaches 370 MJ / m³, a 68.2% increase over the control example, and the high-temperature strength retention rate exceeds 85%, demonstrating the synergistic advantages of multi-field coupling and gradient structures.

[0039] The microstructure parameters of the embodiment and the comparative example are compared in the following table: Table 2 The Example uses electromagnetic field stirring and pulsed current processes to refine grains by over 50%, increase dislocation density by 2-3 orders of magnitude, and achieve a nanocrystalline layer thickness of 200μm (Example 3). However, due to the lack of physical field control, the comparative example exhibits coarse grains and excessive precipitate size, resulting in significantly insufficient strengthening.

[0040] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A process for manufacturing In625 forgings with high energy absorption characteristics, characterized in that: The following steps are involved: S1: Ingredients and smelting: In percentage by weight, Cr 20.0-23.0%, Mo 8.0-10.0%, Nb+Ta 3.15-4.15%, Fe≤5.0%, Al 0.15-0.40%, Ti 0.15-0.40%, C≤0.10%, Mn≤0.50%, Si≤0.50%, P≤0.015%, S≤0.015%, 0.05-0.15% Yb, 0.02-0.08% Hf, 0.01-0.05% Re, and the balance Ni are prepared by vacuum induction melting and electroslag remelting dual process to prepare a master alloy ingot; wherein, during the smelting process, argon gas with a flow rate of 5-10 L / min is introduced for protection and an alternating electromagnetic field is applied; S2: Homogenization treatment: Heat the master alloy ingot to 1180-1220℃, keep it at this temperature for 10-15 hours, furnace cool it to 800℃ at a cooling rate of 50-100℃ / hour, and then air cool it; S3: Multi-field coupled forging: uses a multi-directional forging process with an initial forging temperature of 1100-1150°C and a final forging temperature ≥950°C. During the forging process, a hydrostatic pressure of 10-20 MPa is applied, and a pulsed current is applied simultaneously. S4: Solution treatment: Heat the forging to 1080-1120℃, keep warm for 1-2 hours, and cool with water; S5: Aging treatment: Heat the solution treated forgings to 760-800°C, hold for 8-12 hours, furnace cool to 650°C at a cooling rate of 50-100°C / hour, hold for another 8 hours, and then air cool. The process forms a nano-scale Laves phase reinforcement after aging treatment, and the reaction is as follows: 。 2. The manufacturing process of In625 forgings with high energy absorption characteristics according to claim 1, characterized in that: The method further includes a surface gradient nano-processing after the solution treatment in step S4: using supersonic particle bombardment technology, with nitrogen as the carrier gas, ceramic particles with a particle size of 50-100 μm are accelerated to 300-500 m / s, bombarding the forging surface for 5-15 minutes to form a nanocrystalline layer with a thickness of 50-200 μm. The grain size of the nanocrystalline layer is gradiently distributed from the surface to the inside, with a surface grain size of 10-50 nm and a transition layer grain size of 50-200 nm.

3. The manufacturing process of In625 forgings with high energy absorption characteristics according to claim 1, characterized in that: The method further includes a cryogenic cycle treatment after the aging treatment in step S5: placing the forging in liquid nitrogen at -196°C for 2-4 hours, then heating to room temperature at a heating rate of 5-10°C / min, and repeating the cryogenic treatment 2-3 times; after the cryogenic cycle treatment, a high-density dislocation tangle is formed inside the forging, with a dislocation density of 10 4 -10¹ 5 m⁻².

4. The manufacturing process of In625 forgings with high energy absorption characteristics according to claim 1, characterized in that: In step S1, 0.01-0.03% B and 0.02-0.06% Zr are also added during the batching process, and the added amounts of B and Zr satisfy the relationship: 0.5≤B / Zr≤1.5; the B and Zr form a composite boride ZrB2 during the smelting process, and the average particle size of the composite boride is 100-300 nm.

5. The manufacturing process of In625 forgings with high energy absorption characteristics according to claim 1, characterized in that: In step S3, the pulse current voltage is 100-300V, the frequency is 10-50Hz, and the pulse width is 10-50ms; the size of the dynamically recrystallized grains is reduced by 30-40%, and an amorphous layer with a width of 5-10nm is formed at the grain boundary.

6. The manufacturing process of In625 forgings with high energy absorption characteristics according to claim 1, characterized in that: In the aging treatment step S5, stacking fault tetrahedrons are formed in the crystal by controlling the cooling rate, and the density of the stacking fault tetrahedrons is 10¹ 6 -10¹ 7 m⁻³, with a size of 5-20nm.

7. The manufacturing process of In625 forgings with high energy absorption characteristics according to claim 1, characterized in that: The In625 forgings prepared by the process have a density of 8.44-8.48 g / cm³, a yield strength of ≥550 MPa at room temperature, a tensile strength of ≥750 MPa, an elongation of ≥35%, and an impact absorption energy of ≥120 J.

8. The manufacturing process of In625 forgings with high energy absorption characteristics according to claim 1, characterized in that: The In625 forgings prepared by the process are subjected to a strain rate of 10³-10 4 The dynamic yield strength under s⁻¹ is ≥900MPa and the energy absorption capacity is ≥350MJ / m³.

9. The manufacturing process of In625 forgings with high energy absorption characteristics according to claim 1, characterized in that: The grain size of the In625 forgings prepared by the process is ASTM 6-9, and a continuous carbide network is distributed at the grain boundaries. 23 Type C6 has an average thickness of 50-150 nm, and nano-sized Yb2O3 particles with a particle size of 10-30 nm are evenly distributed in the carbide network.

10. The manufacturing process of In625 forgings with high energy absorption characteristics according to claim 1, characterized in that: The In625 forgings prepared by the process have a hardness of HB 200-250, an elastic modulus of 205-215 GPa, a Poisson's ratio of 0.31-0.33, and a tensile strength retention rate of ≥85% at a high temperature of 300°C.

Images