Titanium alloy solid-state additive connection local vacuum seal welding processing method

Abstract

The invention discloses a titanium alloy solid-state additive connection local vacuum seal welding machining method, and relates to the technical field of metal forming. The sealing strip with the suction nozzle is welded to the blank bonding interface, local sealing of the bonding interface is achieved, and the vacuum degree requirement of the bonding interface can be met through the vacuum pump and the molecular pump. According to the method, a large vacuum chamber is not needed, the space and equipment requirements can be greatly reduced, the vacuumizing time can be greatly shortened, the production efficiency is remarkably improved, and the production cost can be greatly reduced. The method is suitable for vacuum seal welding treatment before solid-state additive connection of a plurality of titanium alloy blanks, and after seal welding treatment is completed, the procedures of vacuumizing, heating, solid-state additive and the like can be continuously carried out.

Description

Technical Field

[0001] The invention relates to the technical field of metal forming, and in particular to a titanium alloy solid-state additive connection local vacuum sealing welding processing method. Background Art

[0002] Large-sized billets are the basis for manufacturing large titanium alloy components. When a single billet is used to manufacture large titanium alloy components, the core of the large single weight and large-sized billet is prone to composition segregation, structural coarsening, and performance deterioration, resulting in the final performance of the component being difficult to meet service requirements. The solid-state additive strategy is used to prepare large-sized billets from two or more small-sized, homogenized substrates, and high-performance fusion between the interfaces of small-sized substrates is achieved through diffusion welding, which can effectively solve the above problems. However, after the small billets are stacked on each other, there are gaps between their interfaces. The oxygen contained in the gaps will cause oxidation at the billet interface during the hot working process, and the oxide film at the interface will easily cause interface cracking during the forging process. Therefore, before solid-state additive, the billets need to be stacked and placed in a vacuum chamber to the required vacuum degree, and then electron beam welding is used to complete the sealing and fixing of the interface; or, hydrogen treatment is performed to perform diffusion welding in a diffusion welding mold, and then hydrogen is removed.

[0003] Chinese patent document CN113020772B discloses a low-temperature rapid diffusion welding method for titanium alloys, which firstly treats the clean titanium alloy with hydrogen in a pure hydrogen atmosphere; then places the hydrogenated titanium alloy in an electrode of a certain shape, wherein the electrode is designed according to the shape and size of the diffusion welding mold, and the upper pressure head descends to contact the upper electrode, keeps the electrode sealed and evacuates the diffusion welding furnace; a large pulse current flows directly through the sheet to be welded through the upper / lower electrodes, and is heated to the diffusion welding temperature ultra-rapidly; a set diffusion welding pressure is applied to the sheet to be welded by the upper pressure head, and the pressure is released after being kept at this temperature for a period of time; the temperature of the connection sample is reduced to the dehydrogenation temperature by reducing the current, and the dehydrogenation is carried out by keeping the temperature at this temperature for a certain period of time, and then the current is turned off to cool to room temperature.

[0004] Chinese patent document CN 111421218 A The present invention relates to a low-temperature diffusion welding method for hydrogenated Ti2AlNb-based alloy and TC4 titanium alloy. The hydrogenated Ti2AlNb-based alloy and TC4 titanium alloy are placed in a sheath, the sheath is evacuated and kept sealed, the sealed sheath is placed between an upper pressure head and a lower pressure head of a hot pressing device, after the temperature is raised to a set diffusion welding temperature, a set diffusion welding pressure is applied to the sheath through the upper and lower pressure heads, the heat and pressure are maintained for a period of time, and the pressure is released, and the sheath is cooled with the furnace.

[0005] However, for large-sized billets, the implementation of the above solution requires a large vacuum chamber and automatic electron beam welding equipment, and the vacuuming time is long, resulting in low production efficiency and equipment. Therefore, developing a titanium alloy solid-state additive connection local vacuum sealing method can effectively solve the above problems, improve production efficiency and reduce production costs. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a method for locally vacuum sealing and welding titanium alloy solid-state additives, so that large-sized billets can be used to manufacture large titanium alloy components.

[0007] The present invention proposes a technical solution to solve the above technical problems: a titanium alloy solid-state additive connection local vacuum sealing welding processing method, comprising the following steps: S1. Prepare a seal, and set at least one vacuum nozzle on the seal; S2. After surface treatment of the end surfaces of the two blanks for solid additive connection, stacking and aligning them, and then welding and fixing them; S3. After the seal is wrapped around the outer edge of the connection of the end face of the billet, the two ends of the seal are butt-welded, and after the center line of the seal is aligned with the butt interface, the edges of the seal on both sides are respectively welded to the corresponding billet, thereby achieving sealing welding at the butt interface of the solid additive billet; S4. Use a vacuum pump to evacuate the inside of the sealed weld structure from the nozzle, maintain the vacuum for at least 1 hour, and then test the air tightness.

[0008] Preferably, in S1, the number of nozzles is set to 2 to 4 according to the diameter of the blank, and a hole is first opened on the seal before the nozzle is set. The diameter of the hole is smaller than the diameter of the nozzle, and the diameter of the hole is not less than 3 mm. The number of holes is the same as the number of nozzles, and the positions of the holes are distributed at equal intervals when the seal is installed on the outer edge of the blank, and the nozzle and the seal are welded using tungsten inert gas welding.

[0009] Preferably, the length of the seal is 1.03~1.05 times the circumference of the outer edge of the blank, the width of the seal is 50~80mm, the thickness of the seal is 1.5~3mm, the material of the seal is pure titanium or low-strength titanium alloy, the diameter of the nozzle is 5~10mm, the wall thickness of the nozzle is 1.5~3mm, and the length of the nozzle is 50~100mm.

[0010] Preferably, the seal is made of pure titanium, which is easy to bend due to its low room temperature tensile strength and easy to weld with titanium alloy. The low-strength titanium alloy refers to a titanium alloy with a room temperature tensile strength of less than 700 MPa. The low-strength titanium alloy used is mainly considered to be easy to bend. The higher the tensile strength, the thinner the seal must be, and the better the welding performance with the blank titanium alloy.

[0011] Preferably, in S2, the surface treatment is to perform fine milling, fine grinding, degreasing, pickling and cleaning on the end faces of the two billets used for solid additive connection; the roughness after fine milling is not less than Ra3.2; the roughness after fine grinding is not less than Ra1.6; a special metal cleaning agent for titanium alloy is used for degreasing; the pickling uses acid solution, which is a mixture of 5% hydrofluoric acid by mass and 30% nitric acid by mass, and after pickling, the acid solution is cleaned with deionized water and blown dry.

[0012] Preferably, in S2, tungsten inert gas welding is used to perform segmented welding on the outer edges of the butt interface of the two billets during welding and fixing, the total length of the welded portion is 40% to 60% of the circumference of the butt interface, and the number of welded portions is 4 to 8 segments.

[0013] Preferably, in S3, when the seal wraps around the connection of the end face of the blank, the seal is bent to fit the outer edge of the blank, and after wrapping around the outer edge of the blank, the seal is cut to remove excess length, and then both ends of the seal are butt-welded using tungsten inert gas welding.

[0014] Preferably, in S3, the two side edges of the seal are respectively welded to the corresponding blanks by tungsten inert gas arc welding, and the blank welds between the seal and the blank and the butt welds between the seal and the blank completely cover the edges of the seal, thereby achieving sealing of the blank butt interface.

[0015] Preferably, in S4, the vacuum degree of the vacuum pumping is less than 0.001Pa.

[0016] Preferably, the method further comprises step S5, wherein the sealing blank is heated and pressurized to fuse the butt joint interface.

[0017] Preferably, the step S5 is to perform hot forging at 850° C. to 1000° C., and the seal falls off during the hot forging.

[0018] Compared with the prior art, the beneficial effects achieved by the present invention are: The present invention achieves local sealing at the bonding interface by welding a seal with a nozzle at the bonding interface of the blanks, and the vacuum degree requirement of the bonding interface can be achieved by using a vacuum pump and a molecular pump. The method does not require a large vacuum chamber, which can greatly reduce the space and equipment requirements, and can also greatly reduce the time of vacuuming, significantly improve production efficiency, and can greatly reduce production costs. The method is suitable for vacuum sealing and welding treatment of multiple titanium alloy blanks before solid-state additive connection. After the sealing and welding treatment is completed, vacuuming, heating, solid-state additive and other processes can be continued; the present invention does not require professional diffusion welding molds and diffusion welding equipment, and the blanks sealed with seals can be heated first, and then directly forged. During forging, as the oxide scale falls off, the seal will automatically fall off. It is particularly suitable for large workpieces, and the workpiece size is not affected by equipment and environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the blank and the sealing strip after sealing and welding of the present invention.

[0020] Figure 2 2 is a schematic diagram of the structure of the seal and the nozzle of the present invention.

[0021] The above-mentioned reference numerals are as follows: 1. Blank; 2. Seal; 3. Nozzle; 4. Butt weld; 5. Blank weld. DETAILED DESCRIPTION

[0022] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention. Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. Example 1

[0023] The titanium alloy solid-state additive connection local vacuum sealing welding processing method of this embodiment includes the following steps: S1. Prepare a seal 2, and set at least one vacuum nozzle 3 on the seal 2. The number of the nozzles 3 is set to 2 according to the diameter of the blank 1. Before setting the nozzle 3, a hole is opened on the seal 2. The diameter of the hole is 4 mm. The number of holes is the same as the number of the nozzles 3. The positions of the holes are evenly spaced when the seal 2 is installed on the outer edge of the blank 1. The nozzles 3 and the seal 2 are welded by tungsten inert gas welding; the length of the seal 2 is 1.03 times the circumference of the outer edge of the blank 1, the width of the seal 2 is 50 mm, the thickness of the seal 2 is 1.5~3 mm, the material of the seal 2 is pure titanium, the diameter of the nozzle 3 is 5 mm, the wall thickness of the nozzle 3 is 1.5 mm, and the length of the nozzle 3 is 50 mm.

[0024] S2. After surface treatment of the end faces of the two blanks 1 for solid-state additive connection, they are stacked and aligned, and then welded and fixed. The surface treatment is to perform fine milling, fine grinding, degreasing, pickling and cleaning on the end faces of the two blanks 1 for solid-state additive connection; the roughness after fine milling is not less than Ra3.2; the roughness after fine grinding is not less than Ra1.6; a special metal cleaning agent for titanium alloy is used for degreasing; the pickling uses acid solution, which is a mixture of 5% hydrofluoric acid and 30% nitric acid by mass. After pickling, the acid solution is cleaned with deionized water and blown dry; when welding and fixing, tungsten inert gas arc welding is used to perform segmented welding on the outer edges of the butt interface of the two blanks 1, the total length of the welded part is 40% of the circumference of the butt interface, and the number of welded parts is 4 sections; S3. After the seal 2 is wrapped around the outer edge of the end face connection of the blank 1 for one week, the two ends of the seal 2 are butt-welded. After the center line of the seal 2 is aligned with the butt interface, the two side edges of the seal 2 are respectively welded to the corresponding blank 1, so as to achieve the sealing welding at the butt interface of the solid additive blank 1. When the seal 2 wraps around the end face connection of the blank 1, the seal 2 is bent to fit the outer edge shape of the blank 1. After wrapping around the outer edge of the blank 1 for one week, the seal 2 is cut off from the excess length, and the two ends of the seal 2 are butt-welded by tungsten inert gas arc welding; the two side edges of the seal 2 are respectively welded to the corresponding blank 1 by tungsten inert gas arc welding, and the blank weld 5 of the seal 2 and the blank 1 and the butt weld 4 of the seal 2 completely cover the edge of the seal 2, so as to achieve the sealing of the butt interface of the blank 1; S4. The sealing structure is evacuated from the nozzle 3 by a vacuum pump, and after maintaining it for at least 1 hour, the air tightness is tested, and the vacuum degree of the evacuation is less than 0.001Pa; S5. The sealed blank 1 is heated and pressurized to fuse the butt interface, and hot forging is performed at 850° C. The seal 2 falls off during hot forging. Example 2

[0025] The titanium alloy solid-state additive connection local vacuum sealing welding processing method of this embodiment includes the following steps: S1. Prepare a seal 2, and set at least one vacuum nozzle 3 on the seal 2. The number of the nozzles 3 is set to 3 according to the diameter of the blank 1. Before setting the nozzle 3, a hole is first opened on the seal 2, and the diameter of the hole is 4 mm. The number of holes is the same as the number of the nozzles 3. The positions of the holes are evenly spaced when the seal 2 is installed on the outer edge of the blank 1. The nozzles 3 and the seal 2 are welded by tungsten inert gas welding; the length of the seal 2 is 1.04 times the circumference of the outer edge of the blank 1, the width of the seal 2 is 75 mm, the thickness of the seal 2 is 2.5 mm, the material of the seal 2 is pure titanium, the diameter of the nozzle 3 is 8 mm, the wall thickness of the nozzle 3 is 2.5 mm, and the length of the nozzle 3 is 75 mm.

[0026] S2. After surface treatment of the end faces of the two blanks 1 for solid-state additive connection, they are stacked and aligned, and then welded and fixed. The surface treatment is to perform fine milling, fine grinding, degreasing, pickling and cleaning on the end faces of the two blanks 1 for solid-state additive connection; the roughness after fine milling is not less than Ra3.2; the roughness after fine grinding is not less than Ra1.6; a special metal cleaning agent for titanium alloy is used for degreasing; the pickling uses acid solution, which is a mixture of 5% hydrofluoric acid and 30% nitric acid by mass. After pickling, the acid solution is cleaned and blown dry with deionized water; when welding and fixing, tungsten inert gas arc welding is used to perform segmented welding on the outer edges of the butt interface of the two blanks 1, the total length of the welded part is 50% of the circumference of the butt interface, and the number of welded parts is 6 sections; S3. After the seal 2 is wrapped around the outer edge of the end face connection of the blank 1 for one week, the two ends of the seal 2 are butt-welded. After the center line of the seal 2 is aligned with the butt interface, the two side edges of the seal 2 are respectively welded to the corresponding blank 1, so as to achieve the sealing welding at the butt interface of the solid additive blank 1. When the seal 2 wraps around the end face connection of the blank 1, the seal 2 is bent to fit the outer edge shape of the blank 1. After wrapping around the outer edge of the blank 1 for one week, the seal 2 is cut off from the excess length, and the two ends of the seal 2 are butt-welded by tungsten inert gas arc welding; the two side edges of the seal 2 are respectively welded to the corresponding blank 1 by tungsten inert gas arc welding, and the blank weld 5 of the seal 2 and the blank 1 and the butt weld 4 of the seal 2 completely cover the edge of the seal 2, so as to achieve the sealing of the butt interface of the blank 1; S4. The sealing structure is evacuated from the nozzle 3 by a vacuum pump, and after maintaining it for at least 1 hour, the air tightness is tested, and the vacuum degree of the evacuation is less than 0.001Pa; S5. The sealed blank 1 is heated and pressurized to fuse the butt interface, and hot forging is performed at 950° C. The seal 2 falls off during hot forging. Example 3

[0027] The titanium alloy solid-state additive connection local vacuum sealing welding processing method of this embodiment includes the following steps: S1. Prepare a seal 2, and set at least one vacuum nozzle 3 on the seal 2. The number of the nozzles 3 is set to 4 according to the diameter of the blank 1. Before setting the nozzle 3, a hole is first opened on the seal 2. The diameter of the hole is smaller than the diameter of the nozzle 3, and the diameter of the hole is not less than 3mm. The number of holes is the same as the number of the nozzles 3. The positions of the holes are evenly spaced when the seal 2 is installed on the outer edge of the blank 1. The nozzle 3 and the seal 2 are welded by tungsten inert gas welding; the length of the seal 2 is 1.05 times the circumference of the outer edge of the blank 1, the width of the seal 2 is 80mm, the thickness of the seal 2 is 3mm, the material of the seal 2 is pure titanium or low-strength titanium alloy, the diameter of the nozzle 3 is 10mm, the wall thickness of the nozzle 3 is 3mm, and the length of the nozzle 3 is 100mm.

[0028] S2. After surface treatment of the end faces of the two blanks 1 for solid-state additive connection, they are stacked and aligned, and then welded and fixed. The surface treatment is to perform fine milling, fine grinding, degreasing, pickling and cleaning on the end faces of the two blanks 1 for solid-state additive connection; the roughness after fine milling is not less than Ra3.2; the roughness after fine grinding is not less than Ra1.6; a special metal cleaning agent for titanium alloy is used for degreasing; the pickling uses acid solution, which is a mixture of 5% hydrofluoric acid and 30% nitric acid by mass. After pickling, the acid solution is cleaned with deionized water and blown dry; when welding and fixing, tungsten inert gas arc welding is used to perform segmented welding on the outer edges of the butt interface of the two blanks 1, the total length of the welded part is 60% of the circumference of the butt interface, and the number of welded parts is 8 sections; S3. After the seal 2 is wrapped around the outer edge of the end face connection of the blank 1 for one week, the two ends of the seal 2 are butt-welded. After the center line of the seal 2 is aligned with the butt interface, the two side edges of the seal 2 are respectively welded to the corresponding blank 1, so as to achieve the sealing welding at the butt interface of the solid additive blank 1. When the seal 2 wraps around the end face connection of the blank 1, the seal 2 is bent to fit the outer edge shape of the blank 1. After wrapping around the outer edge of the blank 1 for one week, the seal 2 is cut off from the excess length, and the two ends of the seal 2 are butt-welded by tungsten inert gas arc welding; the two side edges of the seal 2 are respectively welded to the corresponding blank 1 by tungsten inert gas arc welding, and the blank weld 5 of the seal 2 and the blank 1 and the butt weld 4 of the seal 2 completely cover the edge of the seal 2, so as to achieve the sealing of the butt interface of the blank 1; S4. The sealing structure is evacuated from the nozzle 3 by a vacuum pump, and after maintaining it for at least 1 hour, the air tightness is tested, and the vacuum degree of the evacuation is less than 0.001Pa; S5. The sealed blank 1 is heated and pressurized to fuse the butt interface, and hot forging is performed at 1000° C. The seal 2 falls off during hot forging.

[0029] The titanium alloy solid-state additive connection local vacuum sealing welding processing method of the present invention can be made of titanium alloys with a titanium content greater than 85% and good welding performance. The blanks of Examples 1 to 3 are made of titanium alloys with a grade of Ti80.

[0030] Obviously, the above embodiments are merely examples for clearly illustrating the embodiments of the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. However, these obvious changes or modifications derived from the spirit of the present invention are still within the scope of protection of the present invention.

Claims

1. A titanium alloy solid-state additive connection local vacuum sealing welding processing method, characterized in that: The following steps are involved: S1. preparing a seal (2), and providing at least one vacuum nozzle (3) on the seal (2); S2. After surface treatment of the end surfaces of the two blanks (1) for solid additive connection, stacking and aligning, and then welding and fixing; S3. After the seal (2) is wrapped around the outer edge of the end surface connection of the blank (1), the two ends of the seal (2) are butt-welded, and after the center line of the seal (2) is aligned with the butt interface, the two side edges of the seal (2) are respectively welded to the corresponding blank (1), thereby achieving sealing welding at the butt interface of the solid additive blank (1); S4. Use a vacuum pump to evacuate the inside of the sealed weld structure from the suction nozzle (3), maintain the vacuum for at least 1 hour, and then test the air tightness.

2. A titanium alloy solid-state additive connection local vacuum sealing method according to claim 1, characterized in that: In the S1, the number of the suction nozzles (3) is set to 2 to 4 according to the diameter of the blank (1). Before setting the suction nozzles (3), a hole is first opened on the seal (2). The diameter of the hole is smaller than the diameter of the suction nozzle (3) and the diameter of the hole is not less than 3 mm. The number of holes is the same as the number of the suction nozzles (3). The positions of the holes are distributed at equal intervals when the seal (2) is installed on the outer edge of the blank (1). The suction nozzle (3) and the seal (2) are welded using tungsten inert gas arc welding.

3. A titanium alloy solid-state additive connection local vacuum sealing method according to claim 1, characterized in that: The length of the seal (2) is 1.03 to 1.05 times the circumference of the outer edge of the blank (1), the width of the seal (2) is 50 to 80 mm, the thickness of the seal (2) is 1.5 to 3 mm, the material of the seal (2) is pure titanium or a low-strength titanium alloy, the diameter of the nozzle (3) is 5 to 10 mm, the wall thickness of the nozzle (3) is 1.5 to 3 mm, and the length of the nozzle (3) is 50 to 100 mm.

4. A titanium alloy solid-state additive connection local vacuum sealing method according to claim 1, characterized in that: In S2, the surface treatment is to perform fine milling, fine grinding, degreasing, pickling and cleaning on the end faces of the two blanks (1) for solid additive connection; the roughness after fine milling is not less than Ra3.2; the roughness after fine grinding is not less than Ra1.6; a special metal cleaning agent for titanium alloy is used for degreasing; the pickling uses acid solution, which is a mixture of 5% by mass hydrofluoric acid and 30% by mass nitric acid, and after pickling, the acid solution is cleaned with deionized water and blown dry.

5. A titanium alloy solid-state additive connection local vacuum sealing method according to claim 1, characterized in that: In S2, tungsten inert gas arc welding is used to weld the outer edges of the butt interface of the two blanks (1) in sections during welding and fixing, the total length of the welded portion is 40% to 60% of the circumference of the butt interface, and the number of welded portions is 4 to 8 sections.

6. A titanium alloy solid-state additive connection local vacuum sealing method according to claim 1, characterized in that: In the above-mentioned S3, when the seal (2) surrounds the connection of the end face of the blank (1), the seal (2) is bent to fit the outer edge shape of the blank (1), and after surrounding the outer edge of the blank (1) for one circle, the seal (2) is cut to remove the excess length, and then the two ends of the seal (2) are butt-welded using tungsten inert gas arc welding.

7. A titanium alloy solid-state additive connection local vacuum sealing method according to claim 1, characterized in that: In S3, the two side edges of the seal (2) are respectively welded to the corresponding blank (1) by using tungsten inert gas arc welding, and the blank weld (5) between the seal (2) and the blank (1) and the butt weld (4) of the seal (2) completely cover the edge of the seal (2), thereby achieving sealing of the butt interface of the blank (1).

8. A titanium alloy solid-state additive connection local vacuum sealing method according to any one of claims 1 to 7, characterized in that: In the above S4, the vacuum degree of the evacuation is less than 0.001Pa.

9. A titanium alloy solid-state additive connection local vacuum sealing method according to any one of claims 1 to 7, characterized in that: The method further comprises step S5, wherein the sealed blank (1) is heated and pressurized to fuse the butt joint interface.

10. A titanium alloy solid-state additive connection local vacuum sealing method according to claim 9, characterized in that: The step S5 is to perform hot forging at 850° C. to 1000° C., and the seal (2) falls off during the hot forging.

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