A method for preparing a 316Ti alloy forged rod for a heat pipe micro-stack substrate and the prepared alloy forged rod

Abstract

The application belongs to the technical field of metal material processing, and particularly relates to a preparation method of a 316Ti alloy forged rod for a heat pipe micro stack base and the prepared alloy forged rod. The preparation method comprises the steps of smelting an ingot, peeling and heating, multi-pass upsetting and drawing treatment, homogenization treatment, elongation forming and solid solution treatment, etc. Before formal forging, the method further comprises a surface pretreatment step, which is a surface circumferential rolling step added to the heated alloy ingot to prevent surface cracks in the upsetting process from further expanding to the inside of the ingot. Through process improvement, the application not only reduces the homogenization time and improves the production efficiency, but also prepares a 316Ti alloy forged rod for a heat pipe micro stack base with large specifications and high performance. The alloy forged rod has good grain size and uniformity, and also has good and uniform mechanical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material processing, and in particular relates to a method for preparing a 316Ti alloy forging rod for a heat pipe micro-repile substrate and the prepared alloy forging rod. Background Art

[0002] Micro-reactors (MSMRs) are small nuclear reactors (SMRs) with an installed capacity of 1 to 20 MWe, also known as "nuclear batteries." Heat pipe-based micro-reactors (SMRs) use heat pipes to transfer heat generated in the reactor core directly to a secondary circuit system or thermoelectric converter. Compared to other large nuclear power reactors, heat pipe-based micro-reactors offer greater flexibility. Because heat pipes operate passively at relatively low pressures, removing heat directly from the reactor core, they eliminate the need for a primary cooling circuit and, consequently, mechanical pumps, valves, or large-diameter primary circuit piping. The simplified system equipment of heat pipe-based micro-reactors further reduces reactor costs. Their compact size makes them more suitable for remote locations, mining facilities, defense installations, and other applications, ensuring the viability of the electricity market. Their inherent passive safety features ensure an extremely low accident rate, and even in the event of an accident, they will not cause fuel damage. The potential losses associated with micro-reactors are significantly smaller than those of large reactors.

[0003] The reactor core of a heat pipe microreactor primarily utilizes alloy forging rods as its base material. These rods are large and long. In recent years, to meet the requirements for long fuel life, high burnup, and zero breakage in reactor fuel assemblies, higher performance requirements have been placed on these rods, such as high alloy purity, fine and uniform microstructure, and excellent mechanical properties. Therefore, researchers are working to improve their overall performance by modifying the alloy's elemental composition, ratios, and processing techniques. However, most current alloy forging rod production processes only address grain size control for small forgings or plates. For example, patent publication number CN 111745104 B, titled "A Forging Method for Improving the Grain Size of High-Nitrogen Stainless Steel," primarily utilizes a combination of top forging, pre-forging, and final forging to distribute deformation and thereby control the grain size of medical implant components. Patent publication number CN 108246944 B, titled "A Forging Method for Improving the Grain Size of 15-5PH Stainless Steel," primarily utilizes a forging blank process involving upsetting, bending, and solution-solution-and-precipitation-hardening heat treatment. By completing the bending process during the final forging heat and reducing the forging heating temperature, the process aims to control grain growth in small aviation forgings. Few studies have addressed the process-based control of grain size and microstructure uniformity in large-scale, high-performance alloy forging rods. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for preparing a 316Ti alloy forged rod for a heat pipe micro-repile substrate and the alloy forged rod obtained. Through process improvement, a large-scale and high-performance alloy forged rod is prepared. The alloy forged rod not only has good grain size and structural uniformity, but also has good and uniform mechanical properties.

[0005] The specific technical solutions are as follows:

[0006] A method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate comprises the following steps:

[0007] 1) Smelting ingot: 316Ti alloy is placed in a vacuum induction furnace for smelting to obtain electrode rods, and then the electrode rods are placed in a vacuum consumable furnace for consumable remelting to obtain alloy ingots;

[0008] 2) Peeling and heating: peel the entire surface of the alloy ingot, then heat the heating furnace to 600-1000°C and place the alloy ingot in it, then raise the furnace temperature to 1100-1200°C at a heating rate of 60-100°C / h, and keep it warm for 2-4h to obtain bar blank 1;

[0009] 3) Multi-pass upsetting treatment: The bar blank 1 is subjected to multi-pass upsetting deformation treatment until the blank is forged into an ingot of required specifications, thereby obtaining the bar blank 2;

[0010] 4) Homogenization treatment: heat the bar blank 2 to 1200-1300°C and keep it at this temperature for 4-6 hours to perform homogenization treatment to obtain the bar blank 3;

[0011] 5) Drawing and forming: The bar blank 3 is cooled to 1100-1150℃ along with the furnace, kept at this temperature for 1-4 hours, and then taken out of the furnace for multi-fire drawing and then rounded and finished to the required size of the finished product to obtain the bar blank 4;

[0012] 6) Solution treatment: The bar blank 4 is subjected to solution heat treatment at a temperature of 980-1050° C. for 30-60 min, and then water-cooled to obtain a 316Ti alloy forged rod for a heat pipe micro-stack substrate.

[0013] As a preferred embodiment of the above technical solution, the specification of the electrode rod in step 1) is Φ425±10 mm; the specification of the alloy ingot is Φ490±10 mm.

[0014] In the above technical solution, step 1) adopts a vacuum induction furnace + vacuum consumable furnace dual smelting process to complete the preparation of the alloy ingot, which can effectively reduce the oxygen content and inclusion content in the ingot, thereby ensuring that the alloy has good alloy purity.

[0015] In step 2), the alloy ingot is first subjected to surface grinding or overall peeling treatment to remove oxide scale and surface defects on the surface of the ingot.

[0016] As a preferred embodiment of the above technical solution, step 3) further includes a surface pretreatment step before formal forging: the surface of the bar blank 1 is subjected to circumferential rolling, and the reduction amount is controlled to be 20-40 mm.

[0017] Compared with traditional forging operations, the present invention performs surface pretreatment on the heated alloy ingot and performs circumferential rolling on the heated bar blank before formal forging. This is to remove the loose oxide layer formed on the surface of the ingot after heating and prevent surface cracks from further extending into the interior of the ingot along the oxide layer during the subsequent roughening process.

[0018] As a preferred embodiment of the above technical solution, during the upsetting deformation treatment in step 3), the length of the blank after upsetting is 2 / 5 to 7 / 10 of the length of the original bar; when drawing after upsetting, a 30 to 50 mm reduction is first applied to the circumferential surface of the blank, and then a 80 to 120 mm reduction is applied, and the length-to-width ratio of the blank after drawing is 2.0 to 2.5.

[0019] As a preferred embodiment of the above technical solution, the starting forging temperature of each pass is ≥ 950°C, and the final forging temperature is ≥ 800°C. When the temperature is lower than 800°C, the microstructure of the bar billet will further coarsen, affecting the uniformity of the microstructure. Therefore, in the present invention, the final forging temperature is always controlled above 800°C.

[0020] In this technical solution, by controlling the length of the billet after upsetting to 2 / 5 to 7 / 10 of the original bar length, the purpose of upsetting is effectively achieved, the forging ratio is increased, and further grain and carbide fragmentation are achieved, achieving uniform distribution and reducing differences in microstructure and mechanical properties in the transverse and longitudinal directions of the forged bar. Too little upsetting deformation will fail to achieve the upsetting purpose, while too much deformation may lead to breakage. The length-to-width ratio of the billet after stretching is controlled to 2.0 to 2.5 to facilitate subsequent upsetting deformation and prevent the billet from bending during the secondary upsetting process.

[0021] In the above technical solution, the present invention adopts the applicant's self-made special tooling (patent number CN202122512473.8, a roughening plate device that is convenient for docking and positioning) when performing the upsetting treatment. It can further increase the force-bearing area of ​​the forging hammer, distribute the forging pressure to the surface of the special tooling, and then evenly act on the upsetting force-bearing surface of the blank through the special tooling, so that the upsetting deformation is more uniform, and the alloy blank is prevented from bending during the upsetting process; then, by reasonably controlling the forging and drawing deformation of the blank and timely removing the circumferential oxide scale of the blank after upsetting, multiple upsetting treatments are successfully achieved.

[0022] As a preferred embodiment of the above technical solution, in step 3), after each upsetting pass, the billet is further rolled in the circumferential direction with a reduction of 10-30 mm. This is to promptly remove the circumferential oxide scale of the billet after upsetting, prevent cracks from further extending along the oxide layer toward the core, and reduce the risk of cracking during the drawing process.

[0023] As a preferred embodiment of the above technical solution, step 5) is specifically as follows: the bar blank 3 is cooled to 1100~1150℃ in the furnace, kept warm for 1~4 hours, and then taken out of the furnace for multi-fire drawing treatment, the bar blank 3 is drawn from 370*370mm to 275*275mm, and then rounded to Φ265mm, and then finished to the required finished product size of Φ245mm, to obtain the bar blank 4.

[0024] As a preferred embodiment of the above technical solution, in step 5), the furnace temperature for the intermediate re-melting process is set to 1050-1120°C for 1-2 hours. As the billet continues to deform, the forging temperature is appropriately lowered to prevent further grain growth during the recovery process during thermal deformation.

[0025] In the technical solution of the present invention, instead of the conventional homogenization treatment before forging, the alloy billet is homogenized after upsetting deformation, which can further improve the alloy structure and reduce segregation. Upsetting deformation breaks up the alloy grains, facilitating nucleation and recrystallization, increasing dislocation density and promoting diffusion. Compared with homogenization before forging, this reduces homogenization time and improves production efficiency.

[0026] Another object of the present invention is to provide an alloy forging rod.

[0027] A 316Ti alloy forging rod for a heat pipe micro-repile substrate is prepared by any of the above methods.

[0028] In summary, the present invention has the following beneficial effects:

[0029] 1. Compared with traditional forging operations, this method adds circumferential surface pretreatment to the heated alloy ingot before formal forging. With the help of specialized tooling, the forging roughing and drawing deformation of the billet are rationally controlled, successfully achieving multi-pass upsetting and drawing deformation. This multi-pass forging and drawing process increases the billet's forging ratio, further breaks up grains and carbides, and achieves uniform distribution, thereby reducing differences in the transverse and longitudinal microstructure and mechanical properties of the forged bars.

[0030] 2. Homogenizing the alloy billet after upsetting can further improve the unevenness of the alloy composition and the segregation of inclusions, reduce segregation, and improve the alloy structure and properties. Compared with homogenizing before forging, it reduces homogenization time and improves efficiency.

[0031] 3. By controlling the forging temperature of each pass, the final forging temperature, the solid solution temperature of the bar billet and the cooling, it is ensured that the structure of the bar billet will not be further coarsened and the mechanical properties of the finished bar billet are excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a microstructure photograph of a sample taken from the head of a 316Ti alloy forged rod used for the heat pipe micro-stack substrate prepared in Example 1.

[0033] Figure 2 This is a microstructure photograph of a sample taken from the tail of a 316Ti alloy forged rod used for the heat pipe micro-stack substrate prepared in Example 1. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described below with reference to specific embodiments. However, the specific details of the embodiments are only for the purpose of illustrating the present invention and do not represent all the technical methods under the concept of the present invention. Therefore, they should not be understood as limiting the overall technical solution of the present invention.

[0035] Example 1

[0036] A method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate comprises the following steps:

[0037] 1) Place 316Ti alloy into a vacuum induction furnace for smelting to obtain a Φ425mm electrode rod, and then place the electrode rod into a vacuum consumable furnace for consumable remelting to obtain a Φ490mm alloy ingot;

[0038] 2) Peeling the entire surface of the alloy ingot, then heating the furnace to 800°C and placing the alloy ingot, then raising the furnace temperature to 1150°C at a heating rate of 80°C / h and keeping the temperature for 3 hours to obtain a bar blank 1;

[0039] 3) Roll the surface of the bar blank 1 in the circumferential direction, and control the reduction amount to 30 mm to obtain the bar blank 2;

[0040] 4) The bar blank 2 is subjected to two upset and two drawing processes. The first upset is performed to 2 / 3 of the original bar length. When drawing, a 40mm reduction is first used, and then a 100mm reduction is used. After the first drawing, the length-to-width ratio of the billet is 2.2; the second upset is performed to 2 / 3 of the original bar length. When drawing, a 40mm reduction is first used, and then a 120mm reduction is used. After the second drawing, the length-to-width ratio of the billet is 2.5, thereby obtaining the bar blank 3. After each upset, the billet is subjected to circumferential surface rolling with a 20mm reduction. The start forging temperature of each pass is ≥950°C, and the final forging temperature is ≥800°C.

[0041] 5) Heating the bar blank 3 to 1250° C. and keeping the temperature for 5 hours to perform homogenization treatment to obtain the bar blank 4;

[0042] 6) Cool the bar blank 4 to 1150°C in the furnace, keep it at this temperature for 2 hours, then take it out of the furnace and perform two-pass drawing treatments to draw the bar blank 4 from 370*370mm to 275*275mm, then round it to Φ265mm, and then finish it to the required finished product size of Φ245mm, thus obtaining the bar blank 5;

[0043] 7) The bar blank 5 is subjected to solution heat treatment at a temperature of 1050° C. for 60 min, and then water-cooled to obtain a 316Ti alloy forged rod for a heat pipe micro-stack substrate.

[0044] The head and tail of the 316Ti alloy forged rod for the heat pipe micro-stack substrate prepared in this embodiment were sampled, and then the grain size was tested according to GB / T 6394-2017. Figure 1 and 2 shown.

[0045] Example 2

[0046] A method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate comprises the following steps:

[0047] 1) Place 316Ti alloy into a vacuum induction furnace for smelting to obtain a Φ425mm electrode rod, and then place the electrode rod into a vacuum consumable furnace for consumable remelting to obtain a Φ490mm alloy ingot;

[0048] 2) Peeling the entire surface of the alloy ingot, then heating the furnace to 800°C and placing the alloy ingot, then raising the furnace temperature to 1150°C at a heating rate of 80°C / h and keeping the temperature for 3 hours to obtain a bar blank 1;

[0049] 3) The bar blank 1 is subjected to two upset and two drawing processes. In the first upset, it is upset to 2 / 3 of the original bar length. When drawing, a 40mm reduction is first used, and then a 100mm reduction is used. After the first drawing, the length-to-width ratio of the billet is 2.2; in the second upset, it is upset to 2 / 3 of the original bar length. When drawing, a 40mm reduction is first used, and then a 120mm reduction is used. After the second drawing, the length-to-width ratio of the billet is 2.5, thereby obtaining the bar blank 2; wherein, the start forging temperature of each pass is ≥950°C, and the final forging temperature is ≥800°C.

[0050] 4) Heating the bar blank 2 to 1250°C and keeping the temperature for 5 hours to perform homogenization treatment to obtain the bar blank 3;

[0051] 5) Cool the bar blank 3 to 1150°C in the furnace, keep it warm for 2 hours, and then take it out of the furnace for two-pass drawing treatment. The bar blank 3 is drawn from 370*370mm to 275*275mm, then rounded to Φ265mm, and then finished to the required finished product size of Φ245mm, thereby obtaining the bar blank 4;

[0052] 6) The bar blank 4 is subjected to solution heat treatment at a temperature of 1050° C. for 60 min, and then water-cooled to obtain a 316Ti alloy forged rod for a heat pipe micro-stack substrate.

[0053] Example 3

[0054] A method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate comprises the following steps:

[0055] 1) Place 316Ti alloy into a vacuum induction furnace for smelting to obtain a Φ425mm electrode rod, and then place the electrode rod into a vacuum consumable furnace for consumable remelting to obtain a Φ500mm alloy ingot;

[0056] 2) Peeling the entire surface of the alloy ingot, then heating the heating furnace to 1000°C and placing the alloy ingot, then raising the furnace temperature to 1200°C at a heating rate of 100°C / h and keeping the temperature for 2h to obtain a bar blank 1;

[0057] 3) Roll the surface of the bar blank 1 in the circumferential direction, and control the reduction amount to 40 mm to obtain the bar blank 2;

[0058] 4) The bar blank 2 is subjected to two upset and two drawing processes. The first upset is performed to 2 / 5 of the original bar length. When drawing, a 30mm reduction is first used, and then a 120mm reduction is used. After the first drawing, the length-to-width ratio of the billet is 2.5; the second upset is performed to 7 / 10 of the original bar length. When drawing, a 50mm reduction is first used, and then an 80mm reduction is used. After the second drawing, the length-to-width ratio of the billet is 2.0, thereby obtaining the bar blank 3. After each upset, the billet is subjected to circumferential surface rolling with a 30mm reduction. The start forging temperature of each pass is ≥950°C, and the final forging temperature is ≥800°C.

[0059] 5) Heating the bar blank 3 to 1200° C. and holding the temperature for 6 h to perform homogenization treatment to obtain the bar blank 4;

[0060] 6) Cool the bar blank 4 to 1100°C in the furnace, keep it at this temperature for 3 hours, and then take it out of the furnace for two-pass drawing treatment. The bar blank 4 is drawn from 370*370mm to 275*275mm, then rounded to Φ265mm, and then finished to the required finished product size of Φ245mm, thereby obtaining the bar blank 5;

[0061] 7) The bar blank 5 is subjected to solution heat treatment at a temperature of 980° C. for 60 min, and then water-cooled to obtain a 316Ti alloy forged rod for a heat pipe micro-stack substrate.

[0062] Example 4

[0063] A method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate comprises the following steps:

[0064] 1) Place 316Ti alloy into a vacuum induction furnace for smelting to obtain a Φ425mm electrode rod, and then place the electrode rod into a vacuum consumable furnace for consumable remelting to obtain a Φ490mm alloy ingot;

[0065] 2) Peeling the entire surface of the alloy ingot, then heating the furnace to 600°C and placing the alloy ingot in it, then raising the furnace temperature to 1100°C at a heating rate of 60°C / h and keeping the temperature for 4 hours to obtain a bar blank 1;

[0066] 3) Roll the surface of the bar blank 1 in the circumferential direction, and control the reduction amount to 20 mm to obtain the bar blank 2;

[0067] 4) The bar blank 2 is subjected to two upset and two drawing processes. The first upset is performed to 7 / 10 of the original bar length. When drawing, a 50mm reduction is first used, and then an 80mm reduction is used. After the first drawing, the length-to-width ratio of the blank is 2.0; the second upset is performed to 2 / 5 of the original bar length. When drawing, a 40mm reduction is first used, and then a 120mm reduction is used. After the second drawing, the length-to-width ratio of the blank is 2.4, and a bar blank 3 of 370*370mm is obtained. Among them, after each upset, the blank is subjected to circumferential surface rolling with a 10mm reduction. The start forging temperature of each pass is ≥950℃, and the final forging temperature is ≥800℃.

[0068] 5) Heating the bar blank 3 to 1300° C. and holding the temperature for 4 h to perform homogenization treatment to obtain the bar blank 4;

[0069] 6) Cool the bar blank 4 to 1150°C in the furnace, keep it at this temperature for 2 hours, then take it out of the furnace and perform two-pass drawing treatments to draw the bar blank 4 from 370*370mm to 275*275mm, then round it to Φ265mm, and then finish it to the required finished product size of Φ245mm, thus obtaining the bar blank 5;

[0070] 7) The bar blank 5 is subjected to solution heat treatment at a temperature of 1050° C. for 30 min, and then water-cooled to obtain a 316Ti alloy forged rod for a heat pipe micro-stack substrate.

[0071] Comparative Example

[0072] A method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate comprises the following steps:

[0073] 1) Place 316Ti alloy into a vacuum induction furnace for smelting to obtain a Φ425mm electrode rod, and then place the electrode rod into a vacuum consumable furnace for consumable remelting to obtain a Φ490mm alloy ingot;

[0074] 2) Peeling the entire surface of the alloy ingot, then heating the furnace to 800°C and placing the alloy ingot, then raising the furnace temperature to 1250°C at a heating rate of 80°C / h and keeping the temperature for 12 hours to obtain a bar blank 1;

[0075] 3) The bar blank 1 is subjected to two upset and two drawing processes. In the first upset, it is upset to 2 / 3 of the original bar length. When drawing, a 40mm reduction is first used, and then a 100mm reduction is used. After the first drawing, the length-to-width ratio of the billet is 2.2; in the second upset, it is upset to 2 / 3 of the original bar length. When drawing, a 40mm reduction is first used, and then a 120mm reduction is used. After the second drawing, the length-to-width ratio of the billet is 2.5, thereby obtaining the bar blank 2; wherein, the start forging temperature of each pass is ≥950°C, and the final forging temperature is ≥800°C.

[0076] 4) Cool the bar blank 2 to 1150°C in the furnace, keep it warm for 2 hours, and then take it out of the furnace for two-pass drawing treatment. The bar blank 2 is drawn from 370*370mm to 275*275mm, then rounded to Φ265mm, and then finished to the required finished product size of Φ245mm to obtain bar blank 3;

[0077] 5) The bar blank 3 is subjected to solution heat treatment at a temperature of 1050° C. for 60 min, and then water-cooled to obtain a 316Ti alloy forged rod for a heat pipe micro-stack substrate.

[0078] The heat pipe micro-stack substrates prepared in the above examples and comparative examples were sampled from the head and tail of the 316Ti alloy forging rods, and then stretched at room temperature according to GB / T 6394-2021. The results are shown in the following table.

[0079] Table 1 Room temperature mechanical properties test results of forged rod head and tail

[0080]

[0081] It can be seen from the above results that the 316Ti alloy forging rod for the heat pipe micro-stack substrate prepared by the present invention has good mechanical properties, and the performance results at the head and tail are comparable, indicating that the mechanical properties of the alloy forging rod are uniform.

Claims

1. A method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate, comprising the following steps: 1) Smelting ingot: 316Ti alloy is placed in a vacuum induction furnace for smelting to obtain electrode rods, and then the electrode rods are placed in a vacuum consumable furnace for consumable remelting to obtain alloy ingots; 2) Peeling and heating: peel the entire surface of the alloy ingot, then heat the heating furnace to 600-1000°C and place the alloy ingot in it, then raise the furnace temperature to 1100-1200°C at a heating rate of 60-100°C / h, and keep it warm for 2-4h to obtain bar blank 1; 3) Multi-pass upsetting treatment: The bar blank 1 is subjected to multi-pass upsetting deformation treatment until the blank is forged into an ingot of required specifications, thereby obtaining the bar blank 2; 4) Homogenization treatment: heat the bar blank 2 to 1200-1300°C and keep it at this temperature for 4-6 hours to perform homogenization treatment to obtain the bar blank 3; 5) Drawing and forming: The bar blank 3 is cooled to 1100-1150℃ along with the furnace, kept at this temperature for 1-4 hours, and then taken out of the furnace for multi-fire drawing and then rounded and finished to the required size of the finished product to obtain the bar blank 4; 6) Solution treatment: The bar blank 4 is subjected to solution heat treatment at a temperature of 980-1050° C. for 30-60 min, and then water-cooled to obtain a 316Ti alloy forged rod for the heat pipe micro-stack substrate; Step 3) Before the formal forging, a surface pretreatment step is also included: the surface of the bar blank 1 is circumferentially rolled, and the reduction is controlled to be 20-40 mm; In step 3), during the upsetting deformation process, the length of the blank after upsetting is 2 / 5 to 7 / 10 of the length of the original bar. When stretching after upsetting, a 30 to 50 mm reduction is first applied to the circumferential surface of the blank, and then a 80 to 120 mm reduction is applied. The length-to-width ratio of the blank after stretching is 2.0 to 2.

5.

2. The method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate according to claim 1, characterized in that: In step 1), the specification of the electrode rod is Φ425±10 mm; the specification of the alloy ingot is Φ490±10 mm.

3. The method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate according to claim 1, characterized in that: In step 3), the starting forging temperature of each pass is ≥950°C, and the final forging temperature is ≥800°C.

4. The method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate according to claim 1, characterized in that: In step 3), after each upsetting pass, the blank is further subjected to circumferential surface rolling with a reduction of 10 to 30 mm.

5. The method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate according to claim 1, characterized in that: Step 5) is as follows: the bar blank 3 is cooled to 1100-1150°C in the furnace, kept at this temperature for 1-4 hours, and then taken out of the furnace for multi-fire drawing treatment. The bar blank 3 is drawn from 370*370mm to 275*275mm, then rounded to Φ265mm, and then finished to the required finished product size of Φ245mm, thereby obtaining the bar blank 4.

6. The method for preparing a 316Ti alloy forged rod for a heat pipe micro-reactor substrate according to claim 1, characterized in that: In step 5), the furnace temperature of the intermediate re-melting process is set to 1050-1120°C and kept at this temperature for 1-2 hours.

7. A 316Ti alloy forging rod for a heat pipe micro-reactor substrate, prepared by the method according to any one of claims 1 to 6.

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