A heat treatment method for a large titanium alloy ring belt rib cylindrical cylinder welding structural member

Abstract

The application provides a heat treatment method of a large titanium alloy belt-ribbed cylindrical shell welding structure, which comprises the following steps: S1, placing a support in an argon-filled box, and then placing a to-be-treated cylinder on the support; S2, simulating and analyzing a gas flow field in the argon-filled box to determine a gas rarefaction area in the argon-filled box; according to a simulation result, designing a distribution mode of a gas filling pipeline and a gas outlet pipeline for supplying gas to the gas rarefaction area; S3, arranging a temperature detection element on the cylinder for detecting a heat treatment temperature of the cylinder; S4, filling an oxygen absorption medium in the argon-filled box, and then sealing the argon-filled box; S5, introducing a protective gas and performing atmosphere heat treatment, and then cooling the cylinder; and S6, taking out the cylinder; the application can realize high-quality heat treatment of the cylinder in a common heat treatment furnace without contaminating the surface of the cylinder, and can be popularized to other products which have special requirements on the surface and need heat treatment.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy heat treatment technology, and more specifically, to a heat treatment method for a large titanium alloy cylindrical welded structural component with ring ribs. Background Technology

[0002] Titanium and titanium alloys not only possess high specific strength, significantly reducing the weight of structural components, but also boast numerous advantages such as high-temperature resistance, low-temperature resistance, corrosion resistance, weldability, and non-magnetic properties, earning them the title of "marine metal" and making them the preferred material for marine engineering equipment. Welding is a crucial manufacturing method in the process of transforming titanium alloys from materials into specific equipment, and welded titanium alloy structural components typically require post-weld heat treatment to eliminate residual stress generated during the welding process.

[0003] Because titanium and titanium alloys are highly reactive, to prevent contamination by carbon, oxygen, and hydrogen during heat treatment and subsequent degradation of their properties, a bluing phenomenon is not permitted on their surface. Generally, vacuum heat treatment or heat treatment in a conventional atmospheric furnace after applying an anti-oxidation coating is employed. The anti-oxidation coating must be removed by sandblasting or similar methods after heat treatment. For a large titanium alloy cylindrical welded structure with ring ribs, vacuum heat treatment is not feasible due to furnace size limitations. Furthermore, because the ring ribs involve intermittent welds, sandblasting is not permitted after heat treatment to avoid contamination of the weld gaps. Therefore, heat treatment in a conventional atmospheric furnace is also not possible. Thus, it is necessary to research a heat treatment method for large titanium alloy cylindrical structures with ring ribs to ensure post-weld quality.

[0004] Patent document CN112126872A proposes a non-vacuum annealing method for large titanium castings. This patent combines anti-oxidation coating treatment, argon protection treatment, and sandblasting treatment to achieve stress-relieving annealing of large titanium castings in a conventional atmospheric annealing furnace. However, this method still contaminates the workpiece surface and is not suitable for large titanium alloy cylindrical welded structural components with ring ribs. Summary of the Invention

[0005] In view of this, the present invention aims to propose a heat treatment method for large titanium alloy cylindrical welded structural components with ring ribs to solve the problems in the prior art where large titanium alloy cylindrical welded structural components with ring ribs cannot be vacuum heat treated due to equipment size limitations, conventional atmospheric heat treatment easily causes oxidation contamination of the workpiece surface, and cannot meet the heat treatment requirements of structural components with high surface quality.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] A heat treatment method for a large titanium alloy cylindrical welded structural component with ring ribs includes the following steps:

[0008] S1: Place the support in the argon-filled chamber, and then place the cylinder to be treated on the support;

[0009] S2: Simulate and analyze the gas flow field inside the argon filling box to determine the rarefied regions within the box; design the distribution of filling and exhaust pipelines based on the simulation results to supply gas to the rarefied regions.

[0010] S3: A temperature detection element is installed on the cylinder to detect the heat treatment temperature of the cylinder;

[0011] S4: Fill the argon-filling box with an oxygen-absorbing medium, and then seal the argon-filling box;

[0012] S5: Introduce protective gas and perform atmosphere heat treatment, then cool the cylinder;

[0013] S6: Remove the cylinder.

[0014] In some embodiments, in S1, the argon filling box includes a bottom plate, side wall plates, and a cover plate, wherein the bottom plate and side wall plates are welded and fixed; the outer surface of the argon filling box is provided with a reinforcing structure, and the cover plate is provided with a lifting structure;

[0015] In S5, the cover plate and the side wall plate are connected together by a clamping structure to achieve the sealing of the argon filling box;

[0016] The front wall of the argon filling box is provided with an inflation port, and the inflation pipe is inserted into the inflation port. The cover plate is provided with an exhaust port, and the exhaust pipe is inserted into the exhaust port, with the exhaust port being close to the rear end of the cover plate.

[0017] In some embodiments, in S1, the specific steps include:

[0018] S11: Place the support on the base plate;

[0019] S12: Install the external inflation pipe of the cylinder;

[0020] S13: Evenly spread oxygen-absorbing medium on the base plate;

[0021] S14: Install the air filling pipeline inside the cylinder;

[0022] S15: Fill the cylinder with oxygen-absorbing medium;

[0023] S16: Place the cylinder to be processed onto the support.

[0024] In some embodiments, in S2, gas flow simulation is performed using fluid simulation software, and the initial volume fraction ratio of air to argon is 1:0.

[0025] The inlet boundary conditions are set as follows: argon gas integral number is 1, air volume fraction is 0, and gas flow rate is 25-30 L / min;

[0026] The exit boundary conditions are set as follows: the ambient pressure is one standard atmosphere, the argon gas integral is 0, and the air volume fraction is 1; the rarefied region is determined by simulating the gas flow trajectory.

[0027] In some embodiments, in S2, multiple sets of inflation pipelines are provided both inside and outside the cylinder. The inflation pipelines include a main inflation pipeline and a sub-inflation pipeline connected to the lower part of the main inflation pipeline. The sub-inflation pipelines are provided with multiple air outlets that are not evenly distributed, and the distance between the air outlets near the connection between the main inflation pipeline and the sub-inflation pipeline is greater than the distance between the air outlets away from the connection.

[0028] In some embodiments, the inflation pipeline is provided with air outlets on the left, lower, and right sides.

[0029] In some embodiments, a silencer is provided on the sub-inflation pipeline, and the silencer is located between adjacent annular ribs inside the cylinder.

[0030] In some embodiments, in S3, the temperature sensing element is a thermocouple, and thermocouples are respectively installed at the front, middle and rear parts of the cylinder, and the thermocouples are arranged on the lower side of the cylinder.

[0031] In some embodiments, the oxygen-absorbing medium is titanium shavings, which are acid-washed and dried at 150°C for 1 hour before use.

[0032] In some embodiments, in S5, the atmosphere heat treatment includes the following steps:

[0033] S51: Fill the argon-filling chamber with protective gas and detect the oxygen content at the outlet until the oxygen content at the outlet stabilizes and drops to the set threshold.

[0034] S52: Place the argon-filling box into the furnace, heat it to 550°C, and keep it at 550°C for 2 hours, during which time protective gas is continuously introduced into the argon-filling box;

[0035] S53: After stopping the heat preservation, continue to introduce protective gas until the temperature of the cylinder drops below 100℃.

[0036] Compared with existing technologies, the heat treatment method for large titanium alloy cylindrical welded structural components with ring ribs described in this invention has the following advantages:

[0037] 1) It can achieve high-quality heat treatment of the cylinder in a conventional heat treatment furnace without contaminating the cylinder surface, and can be extended to other products with special surface requirements and heat treatment requirements;

[0038] 2) Argon filling boxes, gas pipes, titanium shavings, etc. can all be reused, effectively saving the cost of atmosphere heat treatment. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the argon-filling box described in an embodiment of the present invention;

[0040] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of the argon-filled box;

[0041] Figure 3 This is a schematic diagram of the main inflation pipe and branch inflation pipe inside the cylinder according to an embodiment of the present invention;

[0042] Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure at point AA;

[0043] Figure 5 This is a schematic diagram of the flow trajectory of argon gas in the argon-filled box simulated by the software in an embodiment of the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Argon filling box; 11. Base plate; 12. Side wall plate; 13. Cover plate; 131. Lifting structure; 14. Reinforcing structure; 15. Clamping structure; 2. Support; 3. Gas filling pipeline; 31. Main gas filling pipeline; 32. Sub-gas filling pipeline; 321. Gas outlet; 322. Silencer; 100. Cylinder; 101. Ring rib. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the described embodiments are only some, not all, of the embodiments of this invention. The specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0047] Example 1

[0048] like Figure 1-5 As shown in the figure, this embodiment provides a heat treatment method for a large titanium alloy cylindrical welded structural component with ring ribs, including the following steps:

[0049] S1: Place the support 2 inside the argon-filled box 1, and then place the cylinder 100 to be treated on the support 2;

[0050] S2: Simulate and analyze the gas flow field inside the argon filling box 1 to determine the gas-scarce regions inside the argon filling box 1; design the distribution of the filling pipeline 3 and the outlet pipeline based on the simulation results to supply gas to the gas-scarce regions.

[0051] S3: A temperature detection element is installed on the cylinder 100 to detect the heat treatment temperature of the cylinder 100;

[0052] S4: Fill the argon filling box 1 with oxygen-absorbing medium, and then seal the argon filling box 1.

[0053] S5: Introduce protective gas and perform atmosphere heat treatment, then cool the cylinder 100.

[0054] S6: Remove 100 units of the cylinder.

[0055] Specifically, this invention places the cylinder 100 to be treated in an argon-filled box 1 for atmosphere heat treatment, which can achieve high-quality heat treatment of the cylinder in a conventional heat treatment furnace without contaminating the surface of the cylinder. This not only effectively solves the bottleneck problem of heat treatment for this type of structural product, but can also be extended to other products with special surface requirements and heat treatment requirements. In addition, the argon-filled box, gas pipe, titanium shavings, etc. can all be reused, which effectively saves the cost of atmosphere heat treatment.

[0056] By simulating and analyzing the gas flow field inside the argon filling chamber 1 and designing the distribution of the filling pipeline 3 and the outlet pipeline accordingly, it is possible to supplement gas supply to areas with scarce gas in a targeted manner, eliminate the dead zones in gas flow caused by the special structure inside the cylinder 100, ensure that the protective gas is evenly distributed inside the chamber 1, eliminate local oxygen residue, thereby avoiding the blueing phenomenon on the surface of the cylinder 100 due to oxidation during heat treatment, and ensuring the surface quality of the product.

[0057] By filling the argon-filled box 1 with an oxygen-absorbing medium, the residual oxygen in the box can be further adsorbed, forming multiple layers of protection and effectively preventing the titanium alloy from being contaminated by elements such as carbon, oxygen, and hydrogen at high temperatures, thus reducing its mechanical properties and corrosion resistance.

[0058] By setting temperature detection elements to detect the actual temperature of the cylinder 100 in real time, inaccurate temperature control caused by temperature differences between the heat treatment furnace and the argon-filled box 1 is avoided, ensuring that stress-relieving annealing is carried out at the accurate process temperature, ensuring the full release of welding residual stress, and improving the dimensional stability and service reliability of the cylinder 100.

[0059] In detail, within the cylinder 100, the area between adjacent annular ribs 101 is a gas-scarce region; in S6, after the cylinder 100 has undergone heat treatment, its surface is observed, and a uniform silver-white or light yellow surface color indicates it is qualified.

[0060] Preferably, the outer dimensions of the cylinder 100 are Φ2000mm×4000mm, and the cylinder 100 is provided with 20 T-shaped ring ribs 101. The material grade of the cylinder 100 is TC4.

[0061] The thickness of support 2 in the front-to-back direction is 500mm, and the width in the left-to-right direction is 1600mm.

[0062] In some embodiments, in S1, the argon filling box 1 includes a bottom plate 11, a side wall plate 12, and a cover plate 13, wherein the bottom plate 11 and the side wall plate 12 are welded and fixed; the outer surface of the argon filling box 1 is provided with a reinforcing structure 14, and the cover plate 13 is provided with a hoisting structure 131;

[0063] In S5, the cover plate 13 and the side wall plate 12 are connected together by the clamping structure 15 to achieve the sealing of the argon filling box 1;

[0064] The front wall panel 12 of the argon filling box 1 is provided with an inflation port, the inflation pipe 3 is inserted into the inflation port, the cover plate 13 is provided with an exhaust port, the exhaust pipe is inserted into the exhaust port, and the exhaust port is close to the rear end of the cover plate 13.

[0065] Specifically, the argon filling box 1 adopts a split structure of bottom plate 11, side wall plate 12 and cover plate 13. The bottom plate 11 and side wall plate 12 are welded and fixed to form the main body of the box. The cover plate 13 is detachably set above the side wall plate 12, which facilitates the hoisting and removal of large cylinders 100 into the box and improves the efficiency of heat treatment operations.

[0066] By incorporating a reinforcing structure 14 on the outer surface of the argon filling chamber 1, the structural strength and rigidity of the argon filling chamber 1 under high-temperature heat treatment conditions are significantly enhanced. This prevents sealing failure or chamber damage caused by thermal deformation of the large chamber during heating and cooling, thereby improving its reliability and service life. A lifting structure 131 is provided on the cover plate 13, which facilitates the opening and closing of the cover plate 13 and reduces the difficulty of operation. The clamping structure 15 securely connects the cover plate 13 to the side wall plate 12, ensuring the airtightness of the argon filling chamber 1 throughout the heat treatment process and preventing external air from seeping in and causing oxidation of the surface of the cylinder 100. The gas inlet is located on the front side wall panel 12, and the gas outlet is located near the rear end of the cover plate 13. This allows the protective gas to enter from the bottom front end of the box 1, flow axially along the cylinder 100 to the rear end, and exit from the top, forming a directional airflow channel from bottom to top and from front to back. This helps to gradually "lift" the denser argon gas from the bottom up and drive away the air, while avoiding airflow short circuits. This ensures that the gas in all areas of the box 1, especially inside the cylinder 100 and between the ring ribs 101, is fully replaced, improving gas replacement efficiency and protection effect.

[0067] Preferably, the dimensions of the argon filling box 1 are 2500mm×4500mm×2500mm, and the bottom plate 11, side wall plate 12 and cover plate 13 are all stainless steel plates with a thickness of 6mm.

[0068] Preferably, in S1, the support 2 is placed on the bottom plate 11 of the argon-filled box 1, and the support 2 is spot-welded to the bottom plate 11.

[0069] Preferably, the reinforcing structure 14 is a carbon steel rectangular tube, which is welded to the surface of the argon-filling box 1. The carbon steel rectangular tube has dimensions of 200mm × 100mm × 10mm.

[0070] Preferably, the inflation pipe 3 and the air outlet pipe are divided into multiple sections, which are connected by threaded unions.

[0071] In detail, the side wall panel 12 includes a front side wall panel 12, a rear side wall panel 12, a left side wall panel 12, and a right side wall panel 12.

[0072] Understandably, when dealing with one type of cylinder 100, the support 2 is spot-welded to the base plate 11 during the first installation of the support 2; if another type of cylinder 100 needs to be dealt with, the corresponding support 2 needs to be replaced; this design facilitates the handling of different types of cylinder 100.

[0073] In some embodiments, in S1, the specific steps include:

[0074] S11: Place the support 2 on the base plate 11;

[0075] S12: Install external air inflation pipe 3 for cylinder 100;

[0076] S13: Evenly spread oxygen-absorbing medium on the base plate 11;

[0077] S14: Install the internal air filling pipeline 3 of the cylinder 100;

[0078] S15: Fill the cylinder 100 with oxygen-absorbing medium;

[0079] S16: Place the cylinder 100 to be processed onto the support 2.

[0080] Specifically, before placing the cylinder 100, the external air-filling pipe 3 of the cylinder 100 is installed first, which avoids the problem of not being able to install the pipe due to space constraints after the cylinder 100 is in place, and improves the convenience of operation. After evenly spreading the oxygen-absorbing medium on the bottom plate 11, the internal air-filling pipe 3 of the cylinder 100 is installed and filled with oxygen-absorbing medium, so that the oxygen-absorbing medium can cover the bottom of the box 1, the inside of the cylinder 100 and the subsequent gap areas, forming an all-round residual oxygen adsorption. Even in the local dead zone where the airflow is difficult to reach, the oxygen-absorbing medium can play a chemical adsorption role, thereby protecting the surface of the cylinder 100 from oxidation to the greatest extent.

[0081] In some embodiments, in S2, gas flow simulation is performed using fluid simulation software, and the initial volume fraction ratio of air to argon is 1:0.

[0082] The inlet boundary conditions are set as follows: argon gas integral number is 1, air volume fraction is 0, and gas flow rate is 25-30 L / min;

[0083] The exit boundary conditions are set as follows: the ambient pressure is one standard atmosphere, the argon gas integral is 0, and the air volume fraction is 1; the rarefied region is determined by simulating the gas flow trajectory.

[0084] Specifically, by using fluid simulation software to numerically simulate the gas flow field inside the argon-filled chamber 1, the distribution pattern of gas flow inside chamber 1 can be determined in advance before actual heat treatment, significantly reducing the research and development cycle and experimental costs; the initial conditions are set with an air to argon gas integral ratio of... The simulation simulated the initial state of chamber 1 when it was fully filled with air at the beginning of inflation. This conforms to the most unfavorable initial conditions in actual working conditions, making the simulation results more reliable and valuable for reference. The inlet boundary conditions were set with an argon gas integral of 1, an air volume fraction of 0, and a gas flow rate of 25-30 L / min. The outlet boundary conditions were set to an ambient pressure of one standard atmosphere. This accurately simulated the physical process of argon gas entering chamber 1 from the inflation port and pushing and driving the air out of the outlet during actual inflation. The simulation results can intuitively show the flow trajectory and concentration distribution of argon gas, thereby accurately locating the gas-scarce areas caused by the shape of the cylinder 100 (such as the gap area between adjacent ring ribs 101), providing a basis for the targeted layout of the subsequent inflation pipeline 3. By reasonably setting the boundary conditions, the location of the airflow dead zone can be accurately simulated, ensuring that the subsequent gas replenishment structures such as the inflation pipeline 32 and the silencer 322 are arranged near the gas-scarce areas. This ensures that the protective gas accurately covers all weak areas, eliminating the hidden danger of local oxygen residue from the source.

[0085] Preferably, the fluid simulation software is FlowSimulation.

[0086] In some embodiments, in S2, multiple sets of inflation pipes 3 are provided both inside and outside the cylinder 100. Each inflation pipe 3 includes a main inflation pipe 31. The lower part of the main inflation pipe 31 is connected to a sub-inflation pipe 32. The sub-inflation pipe 32 is provided with multiple air outlets 321 that are not evenly distributed. The distance between the air outlets 321 near the connection between the main inflation pipe 31 and the sub-inflation pipe 32 is greater than the distance between the air outlets 321 away from the connection.

[0087] Specifically, multiple sets of inflation pipes 3 are installed both inside and outside the cylinder to ensure that both the inner and outer sides of the cylinder receive sufficient protective gas. In particular, the welded area of ​​the annular ribs 101 on the inner wall of the cylinder 100 is a critical area where stress is concentrated and oxidation is likely to occur. It receives special protection through the dedicated gas supply from the internal inflation pipes 3. The "main trunk-branch" pipeline layout design of the main inflation pipe 31 and the branch inflation pipes 32 allows the protective gas to be distributed from the main inflation pipe 31 to each branch inflation pipe 32, and then evenly sprayed out through multiple air outlets 321 on the branch inflation pipes 32, achieving large-area and uniform coverage of the protective gas. The branch inflation pipes 32 have unequally spaced air outlets 321, with the spacing of the air outlets 321 near the connection between the main inflation pipe 31 and the branch inflation pipes 32 being larger than that of the air outlets further away from the connection. The 321-hole spacing is designed so that the air pressure and flow rate are high near the connection point, ensuring sufficient air output even with a larger spacing between the vent holes 321. As the air pressure gradually decreases further away from the connection point, the density of vent holes 321 per unit length is increased by reducing the spacing between the vent holes 321, which can compensate for the decrease in air output caused by the drop in air pressure. This ensures uniform air output along the entire length of the sub-filling pipeline 32, avoiding insufficient protective gas coverage due to local insufficient air output. This unequal spacing of the vent holes 321 design makes the gas distribution in the entire cylinder 100 tend to be consistent along the axial direction (front and back direction), further ensuring that the gas-scarce areas (especially the narrow gaps between adjacent ring ribs 101) can receive a uniform and sufficient supply of protective gas, significantly improving the quality consistency and stability of atmosphere heat treatment.

[0088] In some embodiments, the sub-inflation pipeline 32 is provided with air outlets 321 on the left, lower, and right sides.

[0089] Specifically, this multi-directional gas outlet design allows the protective gas to simultaneously cover multiple spatial areas of the cylinder 100, reducing the number of gas filling pipes 3 and simplifying the complexity of the pipeline system. It also improves the utilization efficiency of the protective gas and the uniformity of space filling. Especially for the gas-sparse areas between the ring ribs 101, where the space is narrow and the airflow resistance is high, multi-directional gas injection can cross-replenish the gas in the sparse areas from different angles, effectively eliminating the airflow obstruction and flow dead zones that are difficult to avoid with single-direction gas supply. This further ensures that the critical parts are always in a pure argon protective atmosphere during the heat treatment process.

[0090] Preferably, the cylinder 100 is provided with three sets of air-filling pipes 3 arranged evenly in the left-right direction, both inside and outside.

[0091] Preferably, the specifications of the inflation pipe 3 and the air outlet pipe are as follows: The specifications of the vent 321 are as follows: .

[0092] In some embodiments, a silencer 322 is provided on the sub-inflation pipeline 32, and the silencer 322 is located between adjacent annular ribs 101 inside the cylinder 100.

[0093] Specifically, by installing a silencer 322 on the gas filling pipeline 32, the airflow noise generated when high-pressure gas is ejected from the outlet 321 can be effectively reduced, improving the working environment for operators. This is especially significant in large argon filling boxes 1 where multiple gas filling pipelines 3 supply gas simultaneously at high flow rates. More importantly, the silencer 322 itself has a porous structure, which can buffer and even out the high-speed airflow ejected from the outlet 321, allowing the gas to diffuse into the surrounding space more evenly and gently. This avoids localized gas turbulence and cold zones caused by the high-speed airflow directly impacting the surface of the cylinder 100. This improves the uniformity and stability of the protective gas distribution. By placing the silencer 322 between adjacent annular ribs 101 inside the cylinder 100, i.e., the rarefied region determined by gas simulation, the protective gas diffused from the silencer 322 can be released directly inside this region, minimizing the path of the protective gas to the rarefied region. This overcomes the problem that external gas supply is difficult to effectively enter the gap due to the blocking effect of the annular ribs 101, ensuring that this key welded part is always covered with sufficient protective gas during the heat treatment process, and effectively guaranteeing the heat treatment quality of the welded connection area between the annular ribs 101 and the cylinder 100.

[0094] In detail, the air filling pipes 32 inside the cylinder 100 are arranged close to the inner ring ribs 101 of the cylinder 100.

[0095] Preferably, the muffler 322 is provided with multiple air outlets. This design can increase the uniformity of air output, ensure that the gas in the area between adjacent ring ribs 101 is replenished in place, and avoid contamination of this critical position during heat treatment.

[0096] In some embodiments, in S3, the temperature sensing element is a thermocouple, and thermocouples are respectively provided at the front, middle and rear parts of the cylinder 100, and the thermocouples are arranged on the lower side of the cylinder 100.

[0097] Specifically, thermocouples have the advantages of fast response speed, high measurement accuracy, and good high temperature resistance, making them suitable for long-term, continuous, real-time temperature monitoring during the heat treatment of large titanium alloy structural components. By installing thermocouples at the front, middle, and rear of the cylinder 100, the temperature distribution along the axial direction of the cylinder 100 can be comprehensively reflected, avoiding localized temperature deviations caused by uneven temperature fields within the heat treatment furnace. Through comprehensive judgment of the temperatures at the front, middle, and rear, the overall temperature state of the cylinder 100 can be accurately grasped, ensuring that the entire cylinder 100 is within the set heat treatment temperature range. Placing the thermocouples on the lower side of the cylinder 100 fully utilizes the gap between the cylinder 100 and the side wall plate 12 of the argon filling box 1 for installation, simplifying the installation process and improving operational efficiency.

[0098] In some embodiments, the oxygen-absorbing medium is titanium shavings, which are acid-washed and dried at 150°C for 1 hour before use.

[0099] Specifically, titanium has a very high chemical affinity for oxygen. Under high temperature conditions, titanium shavings can react with the residual oxygen in the argon-filled chamber 1 to generate titanium oxide, thereby fixing the oxygen in the gas phase in the form of solid oxide, achieving the effect of chemical deoxygenation. This chemical oxygen absorption method can make up for the insufficiency of physical gas replacement in reducing the oxygen concentration to an extremely low level. Together with the physical expulsion of argon, it forms a synergistic protection mechanism to reduce the oxygen partial pressure in chamber 1 to the lowest level.

[0100] The titanium shavings and the cylinder 100 to be treated are both made of titanium alloy. Even if the titanium shavings come into partial contact with the surface of the cylinder 100 at high temperatures, they will not cause contamination of the cylinder 100 with foreign elements due to material incompatibility, thus ensuring the purity and consistency of the product material. The titanium shavings are pickled before use, which can effectively remove the original oxide layer and impurities such as oil stains from the surface of the titanium shavings, thereby ensuring that they have a strong oxygen absorption capacity. The heat treatment and drying at 150°C for 1 hour can further remove the residual moisture and volatile substances after pickling, avoid the generation of water vapor due to moisture evaporation during the heat treatment process, and prevent the titanium alloy from being damaged by hydrogen embrittlement at high temperatures. This ensures the oxygen absorption effect while also ensuring that the surface quality and mechanical properties of the cylinder 100 are not affected.

[0101] It is understandable that if the oxygen in the argon filling box 1 is not completely purged, it will preferentially react with the titanium shavings to avoid contamination of the cylinder 100.

[0102] In some embodiments, in S5, the atmosphere heat treatment includes the following steps:

[0103] S51: Fill the argon filling box 1 with protective gas and detect the oxygen content at the outlet until the oxygen content at the outlet stabilizes and drops to the set threshold.

[0104] S52: Place the argon-filling box 1 into the furnace, heat it to 550°C, and keep it at 550°C for 2 hours, during which time protective gas is continuously filled into the argon-filling box 1;

[0105] S53: After stopping the heat preservation, continue to introduce protective gas until the temperature of the cylinder drops below 100℃.

[0106] Specifically, before heating, S51 first fills the argon-filled chamber 1 with protective gas and detects the oxygen content at the gas outlet until it stabilizes and drops to the set threshold. This ensures that most of the air in chamber 1 has been replaced and discharged by protective gas before the formal heating, thus avoiding the surface quality deterioration that may be caused by accelerated oxidation reaction due to increased temperature during the heating process. This ensures the purity of the atmosphere during the heat treatment process from the source.

[0107] The S52 was held at 550℃ for 2 hours. This temperature parameter was determined based on the welding residual stress relief temperature window of titanium alloy TC4. It can effectively eliminate the residual stress generated during the welding process, and will not cause significant coarsening or phase transformation of the titanium alloy structure due to excessive temperature. The 2-hour holding time ensures that the stress is fully released while taking into account production efficiency. During the heating and holding process, protective gas is continuously introduced and the oxygen content is dynamically monitored to ensure that the interior of the chamber 1 is kept in a low-oxygen environment throughout the entire holding process.

[0108] After S53 stops heat preservation, protective gas continues to be introduced until the temperature of cylinder 100 drops below 100℃, ensuring that the surface of cylinder 100 remains in a protected state throughout the cooling process. Gas supply is stopped only when the temperature drops to a lower range, ultimately resulting in a qualified product with a uniform silver-white or light yellow surface color.

[0109] Specifically, in S51, the flow rate of the protective gas is 30 L / min; in S52, the flow rate of the protective gas is 25 L / min.

[0110] In some embodiments, the protective gas is argon with a purity of not less than 99.99%.

[0111] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A heat treatment method for a large titanium alloy cylindrical welded structural component with ring ribs, characterized in that, Includes the following steps: S1: Place the support (2) inside the argon-filled box (1), and then place the cylinder to be treated (100) on the support (2); S2: Simulate and analyze the gas flow field in the argon filling box (1) to determine the gas-scarce region in the argon filling box (1); design the distribution of the gas filling pipeline (3) and the gas outlet pipeline according to the simulation results to supply gas to the gas-scarce region; S3: A temperature detection element is installed on the cylinder (100) to detect the heat treatment temperature of the cylinder (100); S4: Fill the argon filling box (1) with oxygen-absorbing medium, and then seal the argon filling box (1); S5: Introduce protective gas and perform atmosphere heat treatment, then cool the cylinder (100); S6: Remove the cylinder (100).

2. The heat treatment method for the large titanium alloy cylindrical welded structural component with ring ribs according to claim 1, characterized in that, In S1, the argon filling box (1) includes a bottom plate (11), a side wall plate (12), and a cover plate (13). The bottom plate (11) and the side wall plate (12) are welded and fixed. The outer surface of the argon filling box (1) is provided with a reinforcing structure (14), and the cover plate (13) is provided with a hoisting structure (131). In S5, the cover plate (13) and the side wall plate (12) are connected together by a clamping structure (15) to achieve the sealing of the argon filling box (1). The front side wall panel (12) of the argon filling box (1) is provided with an air filling port, the air filling pipe (3) is inserted into the air filling port, the cover plate (13) is provided with an air outlet, the air outlet pipe is inserted into the air outlet, and the air outlet is close to the rear end of the cover plate (13).

3. The heat treatment method for the large titanium alloy cylindrical welded structural component with ring ribs according to claim 2, characterized in that, In S1, the specific steps include: S11: Place the support (2) on the base plate (11); S12: Install the external air inflator (3) of the cylinder (100); S13: Spread oxygen-absorbing medium evenly on the base plate (11); S14: Install the air filling pipeline (3) inside the cylinder (100); S15: Fill the cylinder (100) with oxygen-absorbing medium; S16: Place the cylinder (100) to be processed onto the support (2).

4. The heat treatment method for the large titanium alloy cylindrical welded structural component with ring ribs according to claim 1, characterized in that, In S2, gas flow simulation software is used to simulate the gas flow. Under the initial conditions, the volume fraction ratio of air to argon is: ; The inlet boundary conditions are set as follows: argon gas integral number is 1, air volume fraction is 0, and gas flow rate is 25-30 L / min; The exit boundary conditions are set as follows: the ambient pressure is one standard atmosphere, the argon gas integral is 0, and the air volume fraction is 1; the rarefied region is determined by simulating the gas flow trajectory.

5. The heat treatment method for the large titanium alloy cylindrical welded structural component with ring ribs according to claim 2, characterized in that, In S2, multiple sets of inflation pipes (3) are provided inside and outside the cylinder (100). The inflation pipes (3) include a main inflation pipe (31). The lower part of the main inflation pipe (31) is connected to a sub-inflation pipe (32). The sub-inflation pipe (32) is provided with multiple air outlets (321) that are not evenly distributed. The distance between the air outlets (321) near the connection between the main inflation pipe (31) and the sub-inflation pipe (32) is greater than the distance between the air outlets (321) far from the connection.

6. The heat treatment method for the large titanium alloy cylindrical welded structural component with ring ribs according to claim 5, characterized in that, The sub-inflation pipeline (32) is provided with air outlets (321) on the left, lower and right sides.

7. The heat treatment method for the large titanium alloy cylindrical welded structural component with ring ribs according to claim 6, characterized in that, A silencer (322) is provided on the sub-inflation pipeline (32), and the silencer (322) is located between adjacent annular ribs (101) inside the cylinder (100).

8. The heat treatment method for the large titanium alloy cylindrical welded structural component with ring ribs according to claim 1, characterized in that, In S3, the temperature detection element is a thermocouple. Thermocouples are respectively installed at the front, middle and rear of the cylinder (100), and the thermocouples are arranged on the lower side of the cylinder (100).

9. The heat treatment method for a large titanium alloy cylindrical welded structural component with ring ribs according to claim 1, characterized in that, The oxygen-absorbing medium is titanium shavings, which need to be acid-washed and dried at 150°C for 1 hour before use.

10. The heat treatment method for a large titanium alloy cylindrical welded structural component with ring ribs according to claim 1, characterized in that, In S5, the atmosphere heat treatment includes the following steps: S51: Fill the argon filling box (1) with protective gas and detect the oxygen content at the outlet until the oxygen content at the outlet is stable and drops to the set threshold. S52: Place the argon filling box (1) into the furnace, heat it to 550°C, and keep it at 550°C for 2 hours. During this period, continuously fill the argon filling box (1) with protective gas. S53: After stopping the heat preservation, continue to introduce protective gas until the temperature of the cylinder (100) drops below 100℃.

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